/*
  * DCA compatible decoder
  * Copyright (C) 2004 Gildas Bazin
  * Copyright (C) 2004 Benjamin Zores
  * Copyright (C) 2006 Benjamin Larsson
  * Copyright (C) 2007 Konstantin Shishkov
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <math.h>
 #include <stddef.h>
 #include <stdio.h>
 

 #include "libavutil/channel_layout.h"

 #include "libavutil/common.h"

 #include "libavutil/float_dsp.h"

 #include "libavutil/internal.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/mathematics.h"

 #include "libavutil/opt.h"

 #include "libavutil/samplefmt.h"

 #include "avcodec.h"

 #include "fft.h"

 #include "get_bits.h"

 #include "dcadata.h"
 #include "dcahuff.h"

 #include "dca.h"

 #include "mathops.h"

 #include "synth_filter.h"

 #include "dcadsp.h"

 #include "fmtconvert.h"

 #include "internal.h"

 #if ARCH_ARM
 #   include "arm/dca.h"
 #endif
 

 //#define TRACE
 

 #define DCA_PRIM_CHANNELS_MAX  (7)
 #define DCA_ABITS_MAX         (32)      /* Should be 28 */
 #define DCA_SUBSUBFRAMES_MAX   (4)
 #define DCA_SUBFRAMES_MAX     (16)
 #define DCA_BLOCKS_MAX        (16)
 #define DCA_LFE_MAX            (3)

 #define DCA_CHSETS_MAX         (4)
 #define DCA_CHSET_CHANS_MAX    (8)

 
 enum DCAMode {
     DCA_MONO = 0,
     DCA_CHANNEL,
     DCA_STEREO,
     DCA_STEREO_SUMDIFF,
     DCA_STEREO_TOTAL,
     DCA_3F,
     DCA_2F1R,
     DCA_3F1R,
     DCA_2F2R,
     DCA_3F2R,
     DCA_4F2R
 };
 

 /* these are unconfirmed but should be mostly correct */
 enum DCAExSSSpeakerMask {
     DCA_EXSS_FRONT_CENTER          = 0x0001,
     DCA_EXSS_FRONT_LEFT_RIGHT      = 0x0002,
     DCA_EXSS_SIDE_REAR_LEFT_RIGHT  = 0x0004,
     DCA_EXSS_LFE                   = 0x0008,
     DCA_EXSS_REAR_CENTER           = 0x0010,
     DCA_EXSS_FRONT_HIGH_LEFT_RIGHT = 0x0020,
     DCA_EXSS_REAR_LEFT_RIGHT       = 0x0040,
     DCA_EXSS_FRONT_HIGH_CENTER     = 0x0080,
     DCA_EXSS_OVERHEAD              = 0x0100,
     DCA_EXSS_CENTER_LEFT_RIGHT     = 0x0200,
     DCA_EXSS_WIDE_LEFT_RIGHT       = 0x0400,
     DCA_EXSS_SIDE_LEFT_RIGHT       = 0x0800,
     DCA_EXSS_LFE2                  = 0x1000,
     DCA_EXSS_SIDE_HIGH_LEFT_RIGHT  = 0x2000,
     DCA_EXSS_REAR_HIGH_CENTER      = 0x4000,
     DCA_EXSS_REAR_HIGH_LEFT_RIGHT  = 0x8000,
 };
 

 enum DCAXxchSpeakerMask {
     DCA_XXCH_FRONT_CENTER          = 0x0000001,
     DCA_XXCH_FRONT_LEFT            = 0x0000002,
     DCA_XXCH_FRONT_RIGHT           = 0x0000004,
     DCA_XXCH_SIDE_REAR_LEFT        = 0x0000008,
     DCA_XXCH_SIDE_REAR_RIGHT       = 0x0000010,
     DCA_XXCH_LFE1                  = 0x0000020,
     DCA_XXCH_REAR_CENTER           = 0x0000040,
     DCA_XXCH_SURROUND_REAR_LEFT    = 0x0000080,
     DCA_XXCH_SURROUND_REAR_RIGHT   = 0x0000100,
     DCA_XXCH_SIDE_SURROUND_LEFT    = 0x0000200,
     DCA_XXCH_SIDE_SURROUND_RIGHT   = 0x0000400,
     DCA_XXCH_FRONT_CENTER_LEFT     = 0x0000800,
     DCA_XXCH_FRONT_CENTER_RIGHT    = 0x0001000,
     DCA_XXCH_FRONT_HIGH_LEFT       = 0x0002000,
     DCA_XXCH_FRONT_HIGH_CENTER     = 0x0004000,
     DCA_XXCH_FRONT_HIGH_RIGHT      = 0x0008000,
     DCA_XXCH_LFE2                  = 0x0010000,
     DCA_XXCH_SIDE_FRONT_LEFT       = 0x0020000,
     DCA_XXCH_SIDE_FRONT_RIGHT      = 0x0040000,
     DCA_XXCH_OVERHEAD              = 0x0080000,
     DCA_XXCH_SIDE_HIGH_LEFT        = 0x0100000,
     DCA_XXCH_SIDE_HIGH_RIGHT       = 0x0200000,
     DCA_XXCH_REAR_HIGH_CENTER      = 0x0400000,
     DCA_XXCH_REAR_HIGH_LEFT        = 0x0800000,
     DCA_XXCH_REAR_HIGH_RIGHT       = 0x1000000,
     DCA_XXCH_REAR_LOW_CENTER       = 0x2000000,
     DCA_XXCH_REAR_LOW_LEFT         = 0x4000000,
     DCA_XXCH_REAR_LOW_RIGHT        = 0x8000000,
 };
 
 static const uint32_t map_xxch_to_native[28] = {
     AV_CH_FRONT_CENTER,
     AV_CH_FRONT_LEFT,
     AV_CH_FRONT_RIGHT,
     AV_CH_SIDE_LEFT,
     AV_CH_SIDE_RIGHT,
     AV_CH_LOW_FREQUENCY,
     AV_CH_BACK_CENTER,
     AV_CH_BACK_LEFT,
     AV_CH_BACK_RIGHT,
     AV_CH_SIDE_LEFT,           /* side surround left -- dup sur side L */
     AV_CH_SIDE_RIGHT,          /* side surround right -- dup sur side R */
     AV_CH_FRONT_LEFT_OF_CENTER,
     AV_CH_FRONT_RIGHT_OF_CENTER,
     AV_CH_TOP_FRONT_LEFT,
     AV_CH_TOP_FRONT_CENTER,
     AV_CH_TOP_FRONT_RIGHT,
     AV_CH_LOW_FREQUENCY,        /* lfe2 -- duplicate lfe1 position */
     AV_CH_FRONT_LEFT_OF_CENTER, /* side front left -- dup front cntr L */
     AV_CH_FRONT_RIGHT_OF_CENTER,/* side front right -- dup front cntr R */
     AV_CH_TOP_CENTER,           /* overhead */
     AV_CH_TOP_FRONT_LEFT,       /* side high left -- dup */
     AV_CH_TOP_FRONT_RIGHT,      /* side high right -- dup */
     AV_CH_TOP_BACK_CENTER,
     AV_CH_TOP_BACK_LEFT,
     AV_CH_TOP_BACK_RIGHT,
     AV_CH_BACK_CENTER,          /* rear low center -- dup */
     AV_CH_BACK_LEFT,            /* rear low left -- dup */
     AV_CH_BACK_RIGHT            /* read low right -- dup  */
 };
 

 enum DCAExtensionMask {
     DCA_EXT_CORE       = 0x001, ///< core in core substream
     DCA_EXT_XXCH       = 0x002, ///< XXCh channels extension in core substream
     DCA_EXT_X96        = 0x004, ///< 96/24 extension in core substream
     DCA_EXT_XCH        = 0x008, ///< XCh channel extension in core substream
     DCA_EXT_EXSS_CORE  = 0x010, ///< core in ExSS (extension substream)
     DCA_EXT_EXSS_XBR   = 0x020, ///< extended bitrate extension in ExSS
     DCA_EXT_EXSS_XXCH  = 0x040, ///< XXCh channels extension in ExSS
     DCA_EXT_EXSS_X96   = 0x080, ///< 96/24 extension in ExSS
     DCA_EXT_EXSS_LBR   = 0x100, ///< low bitrate component in ExSS
     DCA_EXT_EXSS_XLL   = 0x200, ///< lossless extension in ExSS
 };
 

 /* -1 are reserved or unknown */
 static const int dca_ext_audio_descr_mask[] = {
     DCA_EXT_XCH,
     -1,
     DCA_EXT_X96,
     DCA_EXT_XCH | DCA_EXT_X96,
     -1,
     -1,
     DCA_EXT_XXCH,
     -1,
 };
 
 /* extensions that reside in core substream */
 #define DCA_CORE_EXTS (DCA_EXT_XCH | DCA_EXT_XXCH | DCA_EXT_X96)
 

 /* Tables for mapping dts channel configurations to libavcodec multichannel api.
  * Some compromises have been made for special configurations. Most configurations
  * are never used so complete accuracy is not needed.
  *
  * L = left, R = right, C = center, S = surround, F = front, R = rear, T = total, OV = overhead.

  * S  -> side, when both rear and back are configured move one of them to the side channel

  * OV -> center back

  * All 2 channel configurations -> AV_CH_LAYOUT_STEREO

  */

 static const uint64_t dca_core_channel_layout[] = {

     AV_CH_FRONT_CENTER,                                                     ///< 1, A
     AV_CH_LAYOUT_STEREO,                                                    ///< 2, A + B (dual mono)
     AV_CH_LAYOUT_STEREO,                                                    ///< 2, L + R (stereo)
     AV_CH_LAYOUT_STEREO,                                                    ///< 2, (L + R) + (L - R) (sum-difference)
     AV_CH_LAYOUT_STEREO,                                                    ///< 2, LT + RT (left and right total)
     AV_CH_LAYOUT_STEREO | AV_CH_FRONT_CENTER,                               ///< 3, C + L + R
     AV_CH_LAYOUT_STEREO | AV_CH_BACK_CENTER,                                ///< 3, L + R + S
     AV_CH_LAYOUT_STEREO | AV_CH_FRONT_CENTER | AV_CH_BACK_CENTER,           ///< 4, C + L + R + S
     AV_CH_LAYOUT_STEREO | AV_CH_SIDE_LEFT | AV_CH_SIDE_RIGHT,               ///< 4, L + R + SL + SR
 
     AV_CH_LAYOUT_STEREO | AV_CH_FRONT_CENTER | AV_CH_SIDE_LEFT |
     AV_CH_SIDE_RIGHT,                                                       ///< 5, C + L + R + SL + SR
 
     AV_CH_LAYOUT_STEREO | AV_CH_SIDE_LEFT | AV_CH_SIDE_RIGHT |
     AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_FRONT_RIGHT_OF_CENTER,               ///< 6, CL + CR + L + R + SL + SR
 
     AV_CH_LAYOUT_STEREO | AV_CH_BACK_LEFT | AV_CH_BACK_RIGHT |
     AV_CH_FRONT_CENTER  | AV_CH_BACK_CENTER,                                ///< 6, C + L + R + LR + RR + OV
 
     AV_CH_FRONT_CENTER | AV_CH_FRONT_RIGHT_OF_CENTER |
     AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_BACK_CENTER   |
     AV_CH_BACK_LEFT | AV_CH_BACK_RIGHT,                                     ///< 6, CF + CR + LF + RF + LR + RR
 
     AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_FRONT_CENTER   |
     AV_CH_FRONT_RIGHT_OF_CENTER | AV_CH_LAYOUT_STEREO |
     AV_CH_SIDE_LEFT | AV_CH_SIDE_RIGHT,                                     ///< 7, CL + C + CR + L + R + SL + SR
 
     AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_FRONT_RIGHT_OF_CENTER |
     AV_CH_LAYOUT_STEREO | AV_CH_SIDE_LEFT | AV_CH_SIDE_RIGHT |
     AV_CH_BACK_LEFT | AV_CH_BACK_RIGHT,                                     ///< 8, CL + CR + L + R + SL1 + SL2 + SR1 + SR2
 
     AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_FRONT_CENTER   |
     AV_CH_FRONT_RIGHT_OF_CENTER | AV_CH_LAYOUT_STEREO |
     AV_CH_SIDE_LEFT | AV_CH_BACK_CENTER | AV_CH_SIDE_RIGHT,                 ///< 8, CL + C + CR + L + R + SL + S + SR

 };
 

 static const int8_t dca_lfe_index[] = {

     1, 2, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 1, 3, 2, 3

 };
 

 static const int8_t dca_channel_reorder_lfe[][9] = {
     { 0, -1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 2,  0,  1, -1, -1, -1, -1, -1, -1},
     { 0,  1,  3, -1, -1, -1, -1, -1, -1},
     { 2,  0,  1,  4, -1, -1, -1, -1, -1},
     { 0,  1,  3,  4, -1, -1, -1, -1, -1},
     { 2,  0,  1,  4,  5, -1, -1, -1, -1},
     { 3,  4,  0,  1,  5,  6, -1, -1, -1},
     { 2,  0,  1,  4,  5,  6, -1, -1, -1},
     { 0,  6,  4,  5,  2,  3, -1, -1, -1},
     { 4,  2,  5,  0,  1,  6,  7, -1, -1},
     { 5,  6,  0,  1,  7,  3,  8,  4, -1},
     { 4,  2,  5,  0,  1,  6,  8,  7, -1},

 };
 

 static const int8_t dca_channel_reorder_lfe_xch[][9] = {
     { 0,  2, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1,  3, -1, -1, -1, -1, -1, -1},
     { 0,  1,  3, -1, -1, -1, -1, -1, -1},
     { 0,  1,  3, -1, -1, -1, -1, -1, -1},
     { 0,  1,  3, -1, -1, -1, -1, -1, -1},
     { 2,  0,  1,  4, -1, -1, -1, -1, -1},
     { 0,  1,  3,  4, -1, -1, -1, -1, -1},
     { 2,  0,  1,  4,  5, -1, -1, -1, -1},
     { 0,  1,  4,  5,  3, -1, -1, -1, -1},
     { 2,  0,  1,  5,  6,  4, -1, -1, -1},
     { 3,  4,  0,  1,  6,  7,  5, -1, -1},
     { 2,  0,  1,  4,  5,  6,  7, -1, -1},
     { 0,  6,  4,  5,  2,  3,  7, -1, -1},
     { 4,  2,  5,  0,  1,  7,  8,  6, -1},
     { 5,  6,  0,  1,  8,  3,  9,  4,  7},
     { 4,  2,  5,  0,  1,  6,  9,  8,  7},

 };
 

 static const int8_t dca_channel_reorder_nolfe[][9] = {
     { 0, -1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 2,  0,  1, -1, -1, -1, -1, -1, -1},
     { 0,  1,  2, -1, -1, -1, -1, -1, -1},
     { 2,  0,  1,  3, -1, -1, -1, -1, -1},
     { 0,  1,  2,  3, -1, -1, -1, -1, -1},
     { 2,  0,  1,  3,  4, -1, -1, -1, -1},
     { 2,  3,  0,  1,  4,  5, -1, -1, -1},
     { 2,  0,  1,  3,  4,  5, -1, -1, -1},
     { 0,  5,  3,  4,  1,  2, -1, -1, -1},
     { 3,  2,  4,  0,  1,  5,  6, -1, -1},
     { 4,  5,  0,  1,  6,  2,  7,  3, -1},
     { 3,  2,  4,  0,  1,  5,  7,  6, -1},
 };
 
 static const int8_t dca_channel_reorder_nolfe_xch[][9] = {
     { 0,  1, -1, -1, -1, -1, -1, -1, -1},
     { 0,  1,  2, -1, -1, -1, -1, -1, -1},
     { 0,  1,  2, -1, -1, -1, -1, -1, -1},
     { 0,  1,  2, -1, -1, -1, -1, -1, -1},
     { 0,  1,  2, -1, -1, -1, -1, -1, -1},
     { 2,  0,  1,  3, -1, -1, -1, -1, -1},
     { 0,  1,  2,  3, -1, -1, -1, -1, -1},
     { 2,  0,  1,  3,  4, -1, -1, -1, -1},
     { 0,  1,  3,  4,  2, -1, -1, -1, -1},
     { 2,  0,  1,  4,  5,  3, -1, -1, -1},
     { 2,  3,  0,  1,  5,  6,  4, -1, -1},
     { 2,  0,  1,  3,  4,  5,  6, -1, -1},
     { 0,  5,  3,  4,  1,  2,  6, -1, -1},
     { 3,  2,  4,  0,  1,  6,  7,  5, -1},
     { 4,  5,  0,  1,  7,  2,  8,  3,  6},
     { 3,  2,  4,  0,  1,  5,  8,  7,  6},
 };

 #define DCA_DOLBY                  101           /* FIXME */

 #define DCA_CHANNEL_BITS             6
 #define DCA_CHANNEL_MASK          0x3F

 #define DCA_LFE                   0x80

 #define HEADER_SIZE                 14

 #define DCA_MAX_FRAME_SIZE       16384
 #define DCA_MAX_EXSS_HEADER_SIZE  4096

 #define DCA_BUFFER_PADDING_SIZE   1024

 #define DCA_NSYNCAUX        0x9A1105A0
 

 /** Bit allocation */
 typedef struct {
     int offset;                 ///< code values offset
     int maxbits[8];             ///< max bits in VLC
     int wrap;                   ///< wrap for get_vlc2()
     VLC vlc[8];                 ///< actual codes
 } BitAlloc;
 
 static BitAlloc dca_bitalloc_index;    ///< indexes for samples VLC select
 static BitAlloc dca_tmode;             ///< transition mode VLCs
 static BitAlloc dca_scalefactor;       ///< scalefactor VLCs
 static BitAlloc dca_smpl_bitalloc[11]; ///< samples VLCs
 

 static av_always_inline int get_bitalloc(GetBitContext *gb, BitAlloc *ba,
                                          int idx)

 {

     return get_vlc2(gb, ba->vlc[idx].table, ba->vlc[idx].bits, ba->wrap) +
            ba->offset;

 }
 
 typedef struct {

     const AVClass *class;       ///< class for AVOptions

     AVCodecContext *avctx;
     /* Frame header */
     int frame_type;             ///< type of the current frame
     int samples_deficit;        ///< deficit sample count
     int crc_present;            ///< crc is present in the bitstream
     int sample_blocks;          ///< number of PCM sample blocks
     int frame_size;             ///< primary frame byte size
     int amode;                  ///< audio channels arrangement
     int sample_rate;            ///< audio sampling rate
     int bit_rate;               ///< transmission bit rate

     int bit_rate_index;         ///< transmission bit rate index

 
     int dynrange;               ///< embedded dynamic range flag
     int timestamp;              ///< embedded time stamp flag
     int aux_data;               ///< auxiliary data flag
     int hdcd;                   ///< source material is mastered in HDCD
     int ext_descr;              ///< extension audio descriptor flag
     int ext_coding;             ///< extended coding flag
     int aspf;                   ///< audio sync word insertion flag
     int lfe;                    ///< low frequency effects flag
     int predictor_history;      ///< predictor history flag
     int header_crc;             ///< header crc check bytes
     int multirate_inter;        ///< multirate interpolator switch
     int version;                ///< encoder software revision
     int copy_history;           ///< copy history
     int source_pcm_res;         ///< source pcm resolution
     int front_sum;              ///< front sum/difference flag
     int surround_sum;           ///< surround sum/difference flag
     int dialog_norm;            ///< dialog normalisation parameter
 
     /* Primary audio coding header */
     int subframes;              ///< number of subframes

     int total_channels;         ///< number of channels including extensions

     int prim_channels;          ///< number of primary audio channels
     int subband_activity[DCA_PRIM_CHANNELS_MAX];    ///< subband activity count
     int vq_start_subband[DCA_PRIM_CHANNELS_MAX];    ///< high frequency vq start subband
     int joint_intensity[DCA_PRIM_CHANNELS_MAX];     ///< joint intensity coding index
     int transient_huffman[DCA_PRIM_CHANNELS_MAX];   ///< transient mode code book
     int scalefactor_huffman[DCA_PRIM_CHANNELS_MAX]; ///< scale factor code book
     int bitalloc_huffman[DCA_PRIM_CHANNELS_MAX];    ///< bit allocation quantizer select
     int quant_index_huffman[DCA_PRIM_CHANNELS_MAX][DCA_ABITS_MAX]; ///< quantization index codebook select
     float scalefactor_adj[DCA_PRIM_CHANNELS_MAX][DCA_ABITS_MAX];   ///< scale factor adjustment
 
     /* Primary audio coding side information */

     int subsubframes[DCA_SUBFRAMES_MAX];                         ///< number of subsubframes
     int partial_samples[DCA_SUBFRAMES_MAX];                      ///< partial subsubframe samples count

     int prediction_mode[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS];    ///< prediction mode (ADPCM used or not)
     int prediction_vq[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS];      ///< prediction VQ coefs
     int bitalloc[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS];           ///< bit allocation index
     int transition_mode[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS];    ///< transition mode (transients)

     int32_t scale_factor[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS][2];///< scale factors (2 if transient)

     int joint_huff[DCA_PRIM_CHANNELS_MAX];                       ///< joint subband scale factors codebook
     int joint_scale_factor[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS]; ///< joint subband scale factors

     float downmix_coef[DCA_PRIM_CHANNELS_MAX + 1][2];            ///< stereo downmix coefficients

     int dynrange_coef;                                           ///< dynamic range coefficient
 

     /* Core substream's embedded downmix coefficients (cf. ETSI TS 102 114 V1.4.1)
      * Input:  primary audio channels (incl. LFE if present)
      * Output: downmix audio channels (up to 4, no LFE) */
     uint8_t  core_downmix;                                       ///< embedded downmix coefficients available
     uint8_t  core_downmix_amode;                                 ///< audio channel arrangement of embedded downmix
     uint16_t core_downmix_codes[DCA_PRIM_CHANNELS_MAX + 1][4];   ///< embedded downmix coefficients (9-bit codes)
 

     int32_t  high_freq_vq[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS];  ///< VQ encoded high frequency subbands

     float lfe_data[2 * DCA_LFE_MAX * (DCA_BLOCKS_MAX + 4)];      ///< Low frequency effect data

     int lfe_scale_factor;
 
     /* Subband samples history (for ADPCM) */

     DECLARE_ALIGNED(16, float, subband_samples_hist)[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS][4];

     DECLARE_ALIGNED(32, float, subband_fir_hist)[DCA_PRIM_CHANNELS_MAX][512];
     DECLARE_ALIGNED(32, float, subband_fir_noidea)[DCA_PRIM_CHANNELS_MAX][32];

     int hist_index[DCA_PRIM_CHANNELS_MAX];

     DECLARE_ALIGNED(32, float, raXin)[32];

 
     int output;                 ///< type of output
 

     DECLARE_ALIGNED(32, float, subband_samples)[DCA_BLOCKS_MAX][DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS][8];

     float *samples_chanptr[DCA_PRIM_CHANNELS_MAX + 1];

     float *extra_channels[DCA_PRIM_CHANNELS_MAX + 1];
     uint8_t *extra_channels_buffer;
     unsigned int extra_channels_buffer_size;

     uint8_t dca_buffer[DCA_MAX_FRAME_SIZE + DCA_MAX_EXSS_HEADER_SIZE + DCA_BUFFER_PADDING_SIZE];

     int dca_buffer_size;        ///< how much data is in the dca_buffer
 

     const int8_t *channel_order_tab;  ///< channel reordering table, lfe and non lfe

     GetBitContext gb;
     /* Current position in DCA frame */
     int current_subframe;
     int current_subsubframe;
 

     int core_ext_mask;          ///< present extensions in the core substream
 

     /* XCh extension information */

     int xch_present;            ///< XCh extension present and valid

     int xch_base_channel;       ///< index of first (only) channel containing XCH data

     int xch_disable;            ///< whether the XCh extension should be decoded or not

     /* XXCH extension information */
     int xxch_chset;
     int xxch_nbits_spk_mask;
     uint32_t xxch_core_spkmask;
     uint32_t xxch_spk_masks[4]; /* speaker masks, last element is core mask */
     int xxch_chset_nch[4];
     float xxch_dmix_sf[DCA_CHSETS_MAX];
 
     uint32_t xxch_dmix_embedded;  /* lower layer has mix pre-embedded, per chset */
     float xxch_dmix_coeff[DCA_PRIM_CHANNELS_MAX][32]; /* worst case sizing */
 
     int8_t xxch_order_tab[32];
     int8_t lfe_index;
 

     /* ExSS header parser */
     int static_fields;          ///< static fields present
     int mix_metadata;           ///< mixing metadata present
     int num_mix_configs;        ///< number of mix out configurations
     int mix_config_num_ch[4];   ///< number of channels in each mix out configuration
 
     int profile;
 

     int debug_flag;             ///< used for suppressing repeated error messages output

     AVFloatDSPContext fdsp;

     FFTContext imdct;

     SynthFilterContext synth;

     DCADSPContext dcadsp;

     FmtConvertContext fmt_conv;

 } DCAContext;
 

 static float dca_dmix_code(unsigned code);
 

 static const uint16_t dca_vlc_offs[] = {
         0,   512,   640,   768,  1282,  1794,  2436,  3080,  3770,  4454,  5364,
      5372,  5380,  5388,  5392,  5396,  5412,  5420,  5428,  5460,  5492,  5508,
      5572,  5604,  5668,  5796,  5860,  5892,  6412,  6668,  6796,  7308,  7564,
      7820,  8076,  8620,  9132,  9388,  9910, 10166, 10680, 11196, 11726, 12240,
     12752, 13298, 13810, 14326, 14840, 15500, 16022, 16540, 17158, 17678, 18264,
     18796, 19352, 19926, 20468, 21472, 22398, 23014, 23622,
 };
 

 static av_cold void dca_init_vlcs(void)

 {

     static int vlcs_initialized = 0;

     int i, j, c = 14;
     static VLC_TYPE dca_table[23622][2];

     if (vlcs_initialized)

         return;
 
     dca_bitalloc_index.offset = 1;

     dca_bitalloc_index.wrap = 2;

     for (i = 0; i < 5; i++) {
         dca_bitalloc_index.vlc[i].table = &dca_table[dca_vlc_offs[i]];
         dca_bitalloc_index.vlc[i].table_allocated = dca_vlc_offs[i + 1] - dca_vlc_offs[i];

         init_vlc(&dca_bitalloc_index.vlc[i], bitalloc_12_vlc_bits[i], 12,
                  bitalloc_12_bits[i], 1, 1,

                  bitalloc_12_codes[i], 2, 2, INIT_VLC_USE_NEW_STATIC);
     }

     dca_scalefactor.offset = -64;
     dca_scalefactor.wrap = 2;

     for (i = 0; i < 5; i++) {
         dca_scalefactor.vlc[i].table = &dca_table[dca_vlc_offs[i + 5]];
         dca_scalefactor.vlc[i].table_allocated = dca_vlc_offs[i + 6] - dca_vlc_offs[i + 5];

         init_vlc(&dca_scalefactor.vlc[i], SCALES_VLC_BITS, 129,
                  scales_bits[i], 1, 1,

                  scales_codes[i], 2, 2, INIT_VLC_USE_NEW_STATIC);
     }

     dca_tmode.offset = 0;
     dca_tmode.wrap = 1;

     for (i = 0; i < 4; i++) {
         dca_tmode.vlc[i].table = &dca_table[dca_vlc_offs[i + 10]];
         dca_tmode.vlc[i].table_allocated = dca_vlc_offs[i + 11] - dca_vlc_offs[i + 10];

         init_vlc(&dca_tmode.vlc[i], tmode_vlc_bits[i], 4,
                  tmode_bits[i], 1, 1,

                  tmode_codes[i], 2, 2, INIT_VLC_USE_NEW_STATIC);
     }

     for (i = 0; i < 10; i++)

         for (j = 0; j < 7; j++) {
             if (!bitalloc_codes[i][j])
                 break;
             dca_smpl_bitalloc[i + 1].offset                 = bitalloc_offsets[i];
             dca_smpl_bitalloc[i + 1].wrap                   = 1 + (j > 4);
             dca_smpl_bitalloc[i + 1].vlc[j].table           = &dca_table[dca_vlc_offs[c]];
             dca_smpl_bitalloc[i + 1].vlc[j].table_allocated = dca_vlc_offs[c + 1] - dca_vlc_offs[c];
 
             init_vlc(&dca_smpl_bitalloc[i + 1].vlc[j], bitalloc_maxbits[i][j],

                      bitalloc_sizes[i],
                      bitalloc_bits[i][j], 1, 1,

                      bitalloc_codes[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
             c++;

         }

     vlcs_initialized = 1;

 }
 
 static inline void get_array(GetBitContext *gb, int *dst, int len, int bits)
 {

     while (len--)

         *dst++ = get_bits(gb, bits);
 }
 

 static inline int dca_xxch2index(DCAContext *s, int xxch_ch)
 {
     int i, base, mask;
 
     /* locate channel set containing the channel */
     for (i = -1, base = 0, mask = (s->xxch_core_spkmask & ~DCA_XXCH_LFE1);
          i <= s->xxch_chset && !(mask & xxch_ch); mask = s->xxch_spk_masks[++i])
         base += av_popcount(mask);
 
     return base + av_popcount(mask & (xxch_ch - 1));
 }
 
 static int dca_parse_audio_coding_header(DCAContext *s, int base_channel,
                                          int xxch)

 {
     int i, j;
     static const float adj_table[4] = { 1.0, 1.1250, 1.2500, 1.4375 };
     static const int bitlen[11] = { 0, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3 };

     static const int thr[11]    = { 0, 1, 3, 3, 3, 3, 7, 7, 7, 7, 7 };

     int hdr_pos = 0, hdr_size = 0;

     float scale_factor;

     int this_chans, acc_mask;
     int embedded_downmix;
     int nchans, mask[8];
     int coeff, ichan;
 
     /* xxch has arbitrary sized audio coding headers */
     if (xxch) {
         hdr_pos  = get_bits_count(&s->gb);
         hdr_size = get_bits(&s->gb, 7) + 1;
     }

     nchans = get_bits(&s->gb, 3) + 1;
     s->total_channels = nchans + base_channel;

     s->prim_channels  = s->total_channels;

     /* obtain speaker layout mask & downmix coefficients for XXCH */
     if (xxch) {
         acc_mask = s->xxch_core_spkmask;
 
         this_chans = get_bits(&s->gb, s->xxch_nbits_spk_mask - 6) << 6;
         s->xxch_spk_masks[s->xxch_chset] = this_chans;
         s->xxch_chset_nch[s->xxch_chset] = nchans;
 
         for (i = 0; i <= s->xxch_chset; i++)
             acc_mask |= s->xxch_spk_masks[i];
 
         /* check for downmixing information */
         if (get_bits1(&s->gb)) {
             embedded_downmix = get_bits1(&s->gb);

             coeff            = get_bits(&s->gb, 6);

 
             if (coeff<1 || coeff>61) {
                 av_log(s->avctx, AV_LOG_ERROR, "6bit coeff %d is out of range\n", coeff);
                 return AVERROR_INVALIDDATA;
             }
 

             scale_factor     = -1.0f / dca_dmix_code((coeff<<2)-3);

 
             s->xxch_dmix_sf[s->xxch_chset] = scale_factor;
 
             for (i = base_channel; i < s->prim_channels; i++) {
                 mask[i] = get_bits(&s->gb, s->xxch_nbits_spk_mask);
             }
 
             for (j = base_channel; j < s->prim_channels; j++) {
                 memset(s->xxch_dmix_coeff[j], 0, sizeof(s->xxch_dmix_coeff[0]));
                 s->xxch_dmix_embedded |= (embedded_downmix << j);
                 for (i = 0; i < s->xxch_nbits_spk_mask; i++) {
                     if (mask[j] & (1 << i)) {
                         if ((1 << i) == DCA_XXCH_LFE1) {
                             av_log(s->avctx, AV_LOG_WARNING,
                                    "DCA-XXCH: dmix to LFE1 not supported.\n");
                             continue;
                         }
 
                         coeff = get_bits(&s->gb, 7);
                         ichan = dca_xxch2index(s, 1 << i);

                         if ((coeff&63)<1 || (coeff&63)>61) {
                             av_log(s->avctx, AV_LOG_ERROR, "7bit coeff %d is out of range\n", coeff);
                             return AVERROR_INVALIDDATA;
                         }

                         s->xxch_dmix_coeff[j][ichan] = dca_dmix_code((coeff<<2)-3);

                     }
                 }
             }
         }
     }
 

     if (s->prim_channels > DCA_PRIM_CHANNELS_MAX)

         s->prim_channels = DCA_PRIM_CHANNELS_MAX;

     for (i = base_channel; i < s->prim_channels; i++) {

         s->subband_activity[i] = get_bits(&s->gb, 5) + 2;
         if (s->subband_activity[i] > DCA_SUBBANDS)
             s->subband_activity[i] = DCA_SUBBANDS;
     }

     for (i = base_channel; i < s->prim_channels; i++) {

         s->vq_start_subband[i] = get_bits(&s->gb, 5) + 1;
         if (s->vq_start_subband[i] > DCA_SUBBANDS)
             s->vq_start_subband[i] = DCA_SUBBANDS;
     }

     get_array(&s->gb, s->joint_intensity + base_channel,     s->prim_channels - base_channel, 3);
     get_array(&s->gb, s->transient_huffman + base_channel,   s->prim_channels - base_channel, 2);
     get_array(&s->gb, s->scalefactor_huffman + base_channel, s->prim_channels - base_channel, 3);
     get_array(&s->gb, s->bitalloc_huffman + base_channel,    s->prim_channels - base_channel, 3);

 
     /* Get codebooks quantization indexes */

     if (!base_channel)
         memset(s->quant_index_huffman, 0, sizeof(s->quant_index_huffman));

     for (j = 1; j < 11; j++)

         for (i = base_channel; i < s->prim_channels; i++)

             s->quant_index_huffman[i][j] = get_bits(&s->gb, bitlen[j]);
 
     /* Get scale factor adjustment */
     for (j = 0; j < 11; j++)

         for (i = base_channel; i < s->prim_channels; i++)

             s->scalefactor_adj[i][j] = 1;
 
     for (j = 1; j < 11; j++)

         for (i = base_channel; i < s->prim_channels; i++)

             if (s->quant_index_huffman[i][j] < thr[j])
                 s->scalefactor_adj[i][j] = adj_table[get_bits(&s->gb, 2)];
 

     if (!xxch) {
         if (s->crc_present) {
             /* Audio header CRC check */
             get_bits(&s->gb, 16);
         }
     } else {
         /* Skip to the end of the header, also ignore CRC if present  */
         i = get_bits_count(&s->gb);
         if (hdr_pos + 8 * hdr_size > i)
             skip_bits_long(&s->gb, hdr_pos + 8 * hdr_size - i);

     }
 

     s->current_subframe    = 0;

     s->current_subsubframe = 0;
 
 #ifdef TRACE
     av_log(s->avctx, AV_LOG_DEBUG, "subframes: %i\n", s->subframes);
     av_log(s->avctx, AV_LOG_DEBUG, "prim channels: %i\n", s->prim_channels);

     for (i = base_channel; i < s->prim_channels; i++) {
         av_log(s->avctx, AV_LOG_DEBUG, "subband activity: %i\n",
                s->subband_activity[i]);
         av_log(s->avctx, AV_LOG_DEBUG, "vq start subband: %i\n",
                s->vq_start_subband[i]);
         av_log(s->avctx, AV_LOG_DEBUG, "joint intensity: %i\n",
                s->joint_intensity[i]);
         av_log(s->avctx, AV_LOG_DEBUG, "transient mode codebook: %i\n",
                s->transient_huffman[i]);
         av_log(s->avctx, AV_LOG_DEBUG, "scale factor codebook: %i\n",
                s->scalefactor_huffman[i]);
         av_log(s->avctx, AV_LOG_DEBUG, "bit allocation quantizer: %i\n",
                s->bitalloc_huffman[i]);

         av_log(s->avctx, AV_LOG_DEBUG, "quant index huff:");
         for (j = 0; j < 11; j++)

             av_log(s->avctx, AV_LOG_DEBUG, " %i", s->quant_index_huffman[i][j]);

         av_log(s->avctx, AV_LOG_DEBUG, "\n");
         av_log(s->avctx, AV_LOG_DEBUG, "scalefac adj:");
         for (j = 0; j < 11; j++)
             av_log(s->avctx, AV_LOG_DEBUG, " %1.3f", s->scalefactor_adj[i][j]);
         av_log(s->avctx, AV_LOG_DEBUG, "\n");
     }
 #endif
 

     return 0;

 }
 

 static int dca_parse_frame_header(DCAContext *s)

 {

     init_get_bits(&s->gb, s->dca_buffer, s->dca_buffer_size * 8);
 
     /* Sync code */

     skip_bits_long(&s->gb, 32);

 
     /* Frame header */
     s->frame_type        = get_bits(&s->gb, 1);
     s->samples_deficit   = get_bits(&s->gb, 5) + 1;
     s->crc_present       = get_bits(&s->gb, 1);
     s->sample_blocks     = get_bits(&s->gb, 7) + 1;
     s->frame_size        = get_bits(&s->gb, 14) + 1;
     if (s->frame_size < 95)

         return AVERROR_INVALIDDATA;

     s->amode             = get_bits(&s->gb, 6);

     s->sample_rate       = avpriv_dca_sample_rates[get_bits(&s->gb, 4)];

     if (!s->sample_rate)

         return AVERROR_INVALIDDATA;

     s->bit_rate_index    = get_bits(&s->gb, 5);

     s->bit_rate          = dca_bit_rates[s->bit_rate_index];

     if (!s->bit_rate)

         return AVERROR_INVALIDDATA;

     skip_bits1(&s->gb); // always 0 (reserved, cf. ETSI TS 102 114 V1.4.1)

     s->dynrange          = get_bits(&s->gb, 1);
     s->timestamp         = get_bits(&s->gb, 1);
     s->aux_data          = get_bits(&s->gb, 1);
     s->hdcd              = get_bits(&s->gb, 1);
     s->ext_descr         = get_bits(&s->gb, 3);
     s->ext_coding        = get_bits(&s->gb, 1);
     s->aspf              = get_bits(&s->gb, 1);
     s->lfe               = get_bits(&s->gb, 2);
     s->predictor_history = get_bits(&s->gb, 1);
 

     if (s->lfe > 2) {

         s->lfe = 0;

         av_log(s->avctx, AV_LOG_ERROR, "Invalid LFE value: %d\n", s->lfe);
         return AVERROR_INVALIDDATA;

     }
 

     /* TODO: check CRC */
     if (s->crc_present)
         s->header_crc    = get_bits(&s->gb, 16);
 
     s->multirate_inter   = get_bits(&s->gb, 1);
     s->version           = get_bits(&s->gb, 4);
     s->copy_history      = get_bits(&s->gb, 2);
     s->source_pcm_res    = get_bits(&s->gb, 3);
     s->front_sum         = get_bits(&s->gb, 1);
     s->surround_sum      = get_bits(&s->gb, 1);
     s->dialog_norm       = get_bits(&s->gb, 4);
 
     /* FIXME: channels mixing levels */

     s->output = s->amode;

     if (s->lfe)
         s->output |= DCA_LFE;

 
 #ifdef TRACE
     av_log(s->avctx, AV_LOG_DEBUG, "frame type: %i\n", s->frame_type);
     av_log(s->avctx, AV_LOG_DEBUG, "samples deficit: %i\n", s->samples_deficit);
     av_log(s->avctx, AV_LOG_DEBUG, "crc present: %i\n", s->crc_present);
     av_log(s->avctx, AV_LOG_DEBUG, "sample blocks: %i (%i samples)\n",
            s->sample_blocks, s->sample_blocks * 32);
     av_log(s->avctx, AV_LOG_DEBUG, "frame size: %i bytes\n", s->frame_size);
     av_log(s->avctx, AV_LOG_DEBUG, "amode: %i (%i channels)\n",
            s->amode, dca_channels[s->amode]);

     av_log(s->avctx, AV_LOG_DEBUG, "sample rate: %i Hz\n",
            s->sample_rate);
     av_log(s->avctx, AV_LOG_DEBUG, "bit rate: %i bits/s\n",
            s->bit_rate);

     av_log(s->avctx, AV_LOG_DEBUG, "dynrange: %i\n", s->dynrange);
     av_log(s->avctx, AV_LOG_DEBUG, "timestamp: %i\n", s->timestamp);
     av_log(s->avctx, AV_LOG_DEBUG, "aux_data: %i\n", s->aux_data);
     av_log(s->avctx, AV_LOG_DEBUG, "hdcd: %i\n", s->hdcd);
     av_log(s->avctx, AV_LOG_DEBUG, "ext descr: %i\n", s->ext_descr);
     av_log(s->avctx, AV_LOG_DEBUG, "ext coding: %i\n", s->ext_coding);
     av_log(s->avctx, AV_LOG_DEBUG, "aspf: %i\n", s->aspf);
     av_log(s->avctx, AV_LOG_DEBUG, "lfe: %i\n", s->lfe);
     av_log(s->avctx, AV_LOG_DEBUG, "predictor history: %i\n",
            s->predictor_history);
     av_log(s->avctx, AV_LOG_DEBUG, "header crc: %i\n", s->header_crc);
     av_log(s->avctx, AV_LOG_DEBUG, "multirate inter: %i\n",
            s->multirate_inter);
     av_log(s->avctx, AV_LOG_DEBUG, "version number: %i\n", s->version);
     av_log(s->avctx, AV_LOG_DEBUG, "copy history: %i\n", s->copy_history);
     av_log(s->avctx, AV_LOG_DEBUG,
            "source pcm resolution: %i (%i bits/sample)\n",
            s->source_pcm_res, dca_bits_per_sample[s->source_pcm_res]);
     av_log(s->avctx, AV_LOG_DEBUG, "front sum: %i\n", s->front_sum);
     av_log(s->avctx, AV_LOG_DEBUG, "surround sum: %i\n", s->surround_sum);
     av_log(s->avctx, AV_LOG_DEBUG, "dialog norm: %i\n", s->dialog_norm);
     av_log(s->avctx, AV_LOG_DEBUG, "\n");
 #endif
 
     /* Primary audio coding header */
     s->subframes         = get_bits(&s->gb, 4) + 1;
 

     return dca_parse_audio_coding_header(s, 0, 0);

 }
 
 

 static inline int get_scale(GetBitContext *gb, int level, int value, int log2range)

 {

     if (level < 5) {
         /* huffman encoded */
         value += get_bitalloc(gb, &dca_scalefactor, level);

         value = av_clip(value, 0, (1 << log2range) - 1);

     } else if (level < 8) {
         if (level + 1 > log2range) {
             skip_bits(gb, level + 1 - log2range);
             value = get_bits(gb, log2range);
         } else {
             value = get_bits(gb, level + 1);
         }
     }

     return value;

 }
 

 static int dca_subframe_header(DCAContext *s, int base_channel, int block_index)

 {
     /* Primary audio coding side information */
     int j, k;
 

     if (get_bits_left(&s->gb) < 0)

         return AVERROR_INVALIDDATA;

     if (!base_channel) {

         s->subsubframes[s->current_subframe]    = get_bits(&s->gb, 2) + 1;

         s->partial_samples[s->current_subframe] = get_bits(&s->gb, 3);
     }
 
     for (j = base_channel; j < s->prim_channels; j++) {

         for (k = 0; k < s->subband_activity[j]; k++)
             s->prediction_mode[j][k] = get_bits(&s->gb, 1);
     }
 
     /* Get prediction codebook */

     for (j = base_channel; j < s->prim_channels; j++) {

         for (k = 0; k < s->subband_activity[j]; k++) {
             if (s->prediction_mode[j][k] > 0) {
                 /* (Prediction coefficient VQ address) */
                 s->prediction_vq[j][k] = get_bits(&s->gb, 12);
             }
         }
     }
 
     /* Bit allocation index */

     for (j = base_channel; j < s->prim_channels; j++) {

         for (k = 0; k < s->vq_start_subband[j]; k++) {
             if (s->bitalloc_huffman[j] == 6)
                 s->bitalloc[j][k] = get_bits(&s->gb, 5);
             else if (s->bitalloc_huffman[j] == 5)
                 s->bitalloc[j][k] = get_bits(&s->gb, 4);

             else if (s->bitalloc_huffman[j] == 7) {
                 av_log(s->avctx, AV_LOG_ERROR,
                        "Invalid bit allocation index\n");

                 return AVERROR_INVALIDDATA;

             } else {

                 s->bitalloc[j][k] =

                     get_bitalloc(&s->gb, &dca_bitalloc_index, s->bitalloc_huffman[j]);

             }
 
             if (s->bitalloc[j][k] > 26) {

                 av_dlog(s->avctx, "bitalloc index [%i][%i] too big (%i)\n",
                         j, k, s->bitalloc[j][k]);

                 return AVERROR_INVALIDDATA;

             }
         }
     }
 
     /* Transition mode */

     for (j = base_channel; j < s->prim_channels; j++) {

         for (k = 0; k < s->subband_activity[j]; k++) {
             s->transition_mode[j][k] = 0;

             if (s->subsubframes[s->current_subframe] > 1 &&

                 k < s->vq_start_subband[j] && s->bitalloc[j][k] > 0) {
                 s->transition_mode[j][k] =
                     get_bitalloc(&s->gb, &dca_tmode, s->transient_huffman[j]);
             }
         }
     }
 

     if (get_bits_left(&s->gb) < 0)

         return AVERROR_INVALIDDATA;

     for (j = base_channel; j < s->prim_channels; j++) {

         const uint32_t *scale_table;

         int scale_sum, log_size;

         memset(s->scale_factor[j], 0,
                s->subband_activity[j] * sizeof(s->scale_factor[0][0][0]) * 2);

         if (s->scalefactor_huffman[j] == 6) {

             scale_table = scale_factor_quant7;

             log_size = 7;
         } else {

             scale_table = scale_factor_quant6;

             log_size = 6;
         }

 
         /* When huffman coded, only the difference is encoded */
         scale_sum = 0;
 
         for (k = 0; k < s->subband_activity[j]; k++) {
             if (k >= s->vq_start_subband[j] || s->bitalloc[j][k] > 0) {

                 scale_sum = get_scale(&s->gb, s->scalefactor_huffman[j], scale_sum, log_size);

                 s->scale_factor[j][k][0] = scale_table[scale_sum];
             }
 
             if (k < s->vq_start_subband[j] && s->transition_mode[j][k]) {
                 /* Get second scale factor */

                 scale_sum = get_scale(&s->gb, s->scalefactor_huffman[j], scale_sum, log_size);

                 s->scale_factor[j][k][1] = scale_table[scale_sum];
             }
         }
     }
 
     /* Joint subband scale factor codebook select */

     for (j = base_channel; j < s->prim_channels; j++) {

         /* Transmitted only if joint subband coding enabled */
         if (s->joint_intensity[j] > 0)
             s->joint_huff[j] = get_bits(&s->gb, 3);
     }
 

     if (get_bits_left(&s->gb) < 0)

         return AVERROR_INVALIDDATA;

     /* Scale factors for joint subband coding */

     for (j = base_channel; j < s->prim_channels; j++) {

         int source_channel;
 
         /* Transmitted only if joint subband coding enabled */
         if (s->joint_intensity[j] > 0) {
             int scale = 0;
             source_channel = s->joint_intensity[j] - 1;
 
             /* When huffman coded, only the difference is encoded
              * (is this valid as well for joint scales ???) */
 
             for (k = s->subband_activity[j]; k < s->subband_activity[source_channel]; k++) {

                 scale = get_scale(&s->gb, s->joint_huff[j], 64 /* bias */, 7);

                 s->joint_scale_factor[j][k] = scale;    /*joint_scale_table[scale]; */
             }
 

             if (!(s->debug_flag & 0x02)) {

                 av_log(s->avctx, AV_LOG_DEBUG,
                        "Joint stereo coding not supported\n");
                 s->debug_flag |= 0x02;
             }
         }
     }
 
     /* Dynamic range coefficient */

     if (!base_channel && s->dynrange)

         s->dynrange_coef = get_bits(&s->gb, 8);
 
     /* Side information CRC check word */
     if (s->crc_present) {
         get_bits(&s->gb, 16);
     }
 
     /*
      * Primary audio data arrays
      */
 
     /* VQ encoded high frequency subbands */

     for (j = base_channel; j < s->prim_channels; j++)

         for (k = s->vq_start_subband[j]; k < s->subband_activity[j]; k++)
             /* 1 vector -> 32 samples */
             s->high_freq_vq[j][k] = get_bits(&s->gb, 10);
 
     /* Low frequency effect data */

     if (!base_channel && s->lfe) {

         int quant7;

         /* LFE samples */

         int lfe_samples = 2 * s->lfe * (4 + block_index);

         int lfe_end_sample = 2 * s->lfe * (4 + block_index + s->subsubframes[s->current_subframe]);

         float lfe_scale;
 

         for (j = lfe_samples; j < lfe_end_sample; j++) {

             /* Signed 8 bits int */
             s->lfe_data[j] = get_sbits(&s->gb, 8);
         }
 
         /* Scale factor index */

         quant7 = get_bits(&s->gb, 8);
         if (quant7 > 127) {

             avpriv_request_sample(s->avctx, "LFEScaleIndex larger than 127");

             return AVERROR_INVALIDDATA;
         }
         s->lfe_scale_factor = scale_factor_quant7[quant7];

 
         /* Quantization step size * scale factor */
         lfe_scale = 0.035 * s->lfe_scale_factor;
 

         for (j = lfe_samples; j < lfe_end_sample; j++)

             s->lfe_data[j] *= lfe_scale;
     }
 
 #ifdef TRACE

     av_log(s->avctx, AV_LOG_DEBUG, "subsubframes: %i\n",
            s->subsubframes[s->current_subframe]);

     av_log(s->avctx, AV_LOG_DEBUG, "partial samples: %i\n",

            s->partial_samples[s->current_subframe]);

     for (j = base_channel; j < s->prim_channels; j++) {

         av_log(s->avctx, AV_LOG_DEBUG, "prediction mode:");
         for (k = 0; k < s->subband_activity[j]; k++)
             av_log(s->avctx, AV_LOG_DEBUG, " %i", s->prediction_mode[j][k]);
         av_log(s->avctx, AV_LOG_DEBUG, "\n");
     }

     for (j = base_channel; j < s->prim_channels; j++) {

         for (k = 0; k < s->subband_activity[j]; k++)

             av_log(s->avctx, AV_LOG_DEBUG,
                    "prediction coefs: %f, %f, %f, %f\n",
                    (float) adpcm_vb[s->prediction_vq[j][k]][0] / 8192,
                    (float) adpcm_vb[s->prediction_vq[j][k]][1] / 8192,
                    (float) adpcm_vb[s->prediction_vq[j][k]][2] / 8192,
                    (float) adpcm_vb[s->prediction_vq[j][k]][3] / 8192);

     }

     for (j = base_channel; j < s->prim_channels; j++) {

         av_log(s->avctx, AV_LOG_DEBUG, "bitalloc index: ");
         for (k = 0; k < s->vq_start_subband[j]; k++)
             av_log(s->avctx, AV_LOG_DEBUG, "%2.2i ", s->bitalloc[j][k]);
         av_log(s->avctx, AV_LOG_DEBUG, "\n");
     }

     for (j = base_channel; j < s->prim_channels; j++) {

         av_log(s->avctx, AV_LOG_DEBUG, "Transition mode:");
         for (k = 0; k < s->subband_activity[j]; k++)
             av_log(s->avctx, AV_LOG_DEBUG, " %i", s->transition_mode[j][k]);
         av_log(s->avctx, AV_LOG_DEBUG, "\n");
     }

     for (j = base_channel; j < s->prim_channels; j++) {

         av_log(s->avctx, AV_LOG_DEBUG, "Scale factor:");
         for (k = 0; k < s->subband_activity[j]; k++) {
             if (k >= s->vq_start_subband[j] || s->bitalloc[j][k] > 0)
                 av_log(s->avctx, AV_LOG_DEBUG, " %i", s->scale_factor[j][k][0]);
             if (k < s->vq_start_subband[j] && s->transition_mode[j][k])
                 av_log(s->avctx, AV_LOG_DEBUG, " %i(t)", s->scale_factor[j][k][1]);
         }
         av_log(s->avctx, AV_LOG_DEBUG, "\n");
     }

     for (j = base_channel; j < s->prim_channels; j++) {

         if (s->joint_intensity[j] > 0) {

             int source_channel = s->joint_intensity[j] - 1;

             av_log(s->avctx, AV_LOG_DEBUG, "Joint scale factor index:\n");
             for (k = s->subband_activity[j]; k < s->subband_activity[source_channel]; k++)
                 av_log(s->avctx, AV_LOG_DEBUG, " %i", s->joint_scale_factor[j][k]);
             av_log(s->avctx, AV_LOG_DEBUG, "\n");
         }
     }

     for (j = base_channel; j < s->prim_channels; j++)

         for (k = s->vq_start_subband[j]; k < s->subband_activity[j]; k++)
             av_log(s->avctx, AV_LOG_DEBUG, "VQ index: %i\n", s->high_freq_vq[j][k]);

     if (!base_channel && s->lfe) {

         int lfe_samples = 2 * s->lfe * (4 + block_index);
         int lfe_end_sample = 2 * s->lfe * (4 + block_index + s->subsubframes[s->current_subframe]);
 

         av_log(s->avctx, AV_LOG_DEBUG, "LFE samples:\n");

         for (j = lfe_samples; j < lfe_end_sample; j++)

             av_log(s->avctx, AV_LOG_DEBUG, " %f", s->lfe_data[j]);
         av_log(s->avctx, AV_LOG_DEBUG, "\n");
     }
 #endif
 
     return 0;
 }
 

 static void qmf_32_subbands(DCAContext *s, int chans,

                             float samples_in[32][8], float *samples_out,

                             float scale)

 {

     const float *prCoeff;

     int sb_act = s->subband_activity[chans];

     scale *= sqrt(1 / 8.0);

 
     /* Select filter */
     if (!s->multirate_inter)    /* Non-perfect reconstruction */

         prCoeff = fir_32bands_nonperfect;

     else                        /* Perfect reconstruction */

         prCoeff = fir_32bands_perfect;

     s->dcadsp.qmf_32_subbands(samples_in, sb_act, &s->synth, &s->imdct,
                               s->subband_fir_hist[chans],
                               &s->hist_index[chans],
                               s->subband_fir_noidea[chans], prCoeff,
                               samples_out, s->raXin, scale);

 }
 

 static void lfe_interpolation_fir(DCAContext *s, int decimation_select,

                                   int num_deci_sample, float *samples_in,

                                   float *samples_out)

 {
     /* samples_in: An array holding decimated samples.
      *   Samples in current subframe starts from samples_in[0],
      *   while samples_in[-1], samples_in[-2], ..., stores samples
      *   from last subframe as history.
      *
      * samples_out: An array holding interpolated samples
      */
 

     int idx;

     const float *prCoeff;
     int deciindex;
 
     /* Select decimation filter */
     if (decimation_select == 1) {

         idx = 1;

         prCoeff = lfe_fir_128;
     } else {

         idx = 0;

         prCoeff = lfe_fir_64;
     }
     /* Interpolation */
     for (deciindex = 0; deciindex < num_deci_sample; deciindex++) {

         s->dcadsp.lfe_fir[idx](samples_out, samples_in, prCoeff);

         samples_in++;

         samples_out += 2 * 32 * (1 + idx);

     }
 }
 
 /* downmixing routines */

 #define MIX_REAR1(samples, s1, rs, coef)            \
     samples[0][i] += samples[s1][i] * coef[rs][0];  \
     samples[1][i] += samples[s1][i] * coef[rs][1];

 #define MIX_REAR2(samples, s1, s2, rs, coef)                                          \
     samples[0][i] += samples[s1][i] * coef[rs][0] + samples[s2][i] * coef[rs + 1][0]; \
     samples[1][i] += samples[s1][i] * coef[rs][1] + samples[s2][i] * coef[rs + 1][1];

 
 #define MIX_FRONT3(samples, coef)                                      \

     t = samples[c][i];                                                 \
     u = samples[l][i];                                                 \
     v = samples[r][i];                                                 \
     samples[0][i] = t * coef[0][0] + u * coef[1][0] + v * coef[2][0];  \
     samples[1][i] = t * coef[0][1] + u * coef[1][1] + v * coef[2][1];

 #define DOWNMIX_TO_STEREO(op1, op2)             \
     for (i = 0; i < 256; i++) {                 \
         op1                                     \
         op2                                     \

     }
 

 static void dca_downmix(float **samples, int srcfmt, int lfe_present,
                         float coef[DCA_PRIM_CHANNELS_MAX + 1][2],

                         const int8_t *channel_mapping)

 {

     int c, l, r, sl, sr, s;

     int i;

     float t, u, v;

 
     switch (srcfmt) {
     case DCA_MONO:
     case DCA_4F2R:

         av_log(NULL, AV_LOG_ERROR, "Not implemented!\n");

         break;

     case DCA_CHANNEL:

     case DCA_STEREO:

     case DCA_STEREO_TOTAL:
     case DCA_STEREO_SUMDIFF:

         break;
     case DCA_3F:

         c = channel_mapping[0];
         l = channel_mapping[1];
         r = channel_mapping[2];

         DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef), );

         break;
     case DCA_2F1R:

         s = channel_mapping[2];
         DOWNMIX_TO_STEREO(MIX_REAR1(samples, s, 2, coef), );

         break;
     case DCA_3F1R:

         c = channel_mapping[0];
         l = channel_mapping[1];
         r = channel_mapping[2];
         s = channel_mapping[3];

         DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),

                           MIX_REAR1(samples, s, 3, coef));

         break;
     case DCA_2F2R:

         sl = channel_mapping[2];
         sr = channel_mapping[3];
         DOWNMIX_TO_STEREO(MIX_REAR2(samples, sl, sr, 2, coef), );

         break;
     case DCA_3F2R:

         c  = channel_mapping[0];
         l  = channel_mapping[1];
         r  = channel_mapping[2];
         sl = channel_mapping[3];
         sr = channel_mapping[4];

         DOWNMIX_TO_STEREO(MIX_FRONT3(samples, coef),

                           MIX_REAR2(samples, sl, sr, 3, coef));

         break;
     }

     if (lfe_present) {
         int lf_buf = dca_lfe_index[srcfmt];
         int lf_idx = dca_channels [srcfmt];
         for (i = 0; i < 256; i++) {
             samples[0][i] += samples[lf_buf][i] * coef[lf_idx][0];
             samples[1][i] += samples[lf_buf][i] * coef[lf_idx][1];
         }
     }

 }
 
 

 #ifndef decode_blockcodes

 /* Very compact version of the block code decoder that does not use table
  * look-up but is slightly slower */

 static int decode_blockcode(int code, int levels, int32_t *values)

 {
     int i;
     int offset = (levels - 1) >> 1;
 
     for (i = 0; i < 4; i++) {

         int div = FASTDIV(code, levels);

         values[i] = code - offset - div * levels;

         code = div;

     }
 

     return code;
 }
 

 static int decode_blockcodes(int code1, int code2, int levels, int32_t *values)

 {
     return decode_blockcode(code1, levels, values) |
            decode_blockcode(code2, levels, values + 4);

 }

 #endif

 static const uint8_t abits_sizes[7]  = { 7, 10, 12, 13, 15, 17, 19 };
 static const uint8_t abits_levels[7] = { 3,  5,  7,  9, 13, 17, 25 };

 static int dca_subsubframe(DCAContext *s, int base_channel, int block_index)

 {
     int k, l;
     int subsubframe = s->current_subsubframe;
 

     const float *quant_step_table;

 
     /* FIXME */

     float (*subband_samples)[DCA_SUBBANDS][8] = s->subband_samples[block_index];

     LOCAL_ALIGNED_16(int32_t, block, [8 * DCA_SUBBANDS]);

 
     /*
      * Audio data
      */
 
     /* Select quantization step size table */

     if (s->bit_rate_index == 0x1f)

         quant_step_table = lossless_quant_d;

     else

         quant_step_table = lossy_quant_d;

     for (k = base_channel; k < s->prim_channels; k++) {

         float rscale[DCA_SUBBANDS];
 

         if (get_bits_left(&s->gb) < 0)

             return AVERROR_INVALIDDATA;

         for (l = 0; l < s->vq_start_subband[k]; l++) {
             int m;
 
             /* Select the mid-tread linear quantizer */
             int abits = s->bitalloc[k][l];
 
             float quant_step_size = quant_step_table[abits];
 
             /*
              * Determine quantization index code book and its type
              */
 
             /* Select quantization index code book */
             int sel = s->quant_index_huffman[k][abits];
 
             /*
              * Extract bits from the bit stream
              */

             if (!abits) {

                 rscale[l] = 0;
                 memset(block + 8 * l, 0, 8 * sizeof(block[0]));

             } else {
                 /* Deal with transients */
                 int sfi = s->transition_mode[k][l] && subsubframe >= s->transition_mode[k][l];

                 rscale[l] = quant_step_size * s->scale_factor[k][l][sfi] *

                                s->scalefactor_adj[k][sel];

                 if (abits >= 11 || !dca_smpl_bitalloc[abits].vlc[sel].table) {
                     if (abits <= 7) {

                         /* Block code */

                         int block_code1, block_code2, size, levels, err;

                         size   = abits_sizes[abits - 1];
                         levels = abits_levels[abits - 1];

 
                         block_code1 = get_bits(&s->gb, size);
                         block_code2 = get_bits(&s->gb, size);

                         err = decode_blockcodes(block_code1, block_code2,

                                                 levels, block + 8 * l);

                         if (err) {
                             av_log(s->avctx, AV_LOG_ERROR,
                                    "ERROR: block code look-up failed\n");
                             return AVERROR_INVALIDDATA;
                         }

                     } else {

                         /* no coding */
                         for (m = 0; m < 8; m++)

                             block[8 * l + m] = get_sbits(&s->gb, abits - 3);

                     }

                 } else {

                     /* Huffman coded */

                     for (m = 0; m < 8; m++)

                         block[8 * l + m] = get_bitalloc(&s->gb,

                                                 &dca_smpl_bitalloc[abits], sel);

                 }
 

             }

         }
 
         s->fmt_conv.int32_to_float_fmul_array8(&s->fmt_conv, subband_samples[k][0],
                                                block, rscale, 8 * s->vq_start_subband[k]);

         for (l = 0; l < s->vq_start_subband[k]; l++) {
             int m;

             /*
              * Inverse ADPCM if in prediction mode
              */
             if (s->prediction_mode[k][l]) {
                 int n;

                 if (s->predictor_history)
                     subband_samples[k][l][0] += (adpcm_vb[s->prediction_vq[k][l]][0] *
                                                  s->subband_samples_hist[k][l][3] +
                                                  adpcm_vb[s->prediction_vq[k][l]][1] *
                                                  s->subband_samples_hist[k][l][2] +
                                                  adpcm_vb[s->prediction_vq[k][l]][2] *
                                                  s->subband_samples_hist[k][l][1] +
                                                  adpcm_vb[s->prediction_vq[k][l]][3] *
                                                  s->subband_samples_hist[k][l][0]) *
                                                 (1.0f / 8192);
                 for (m = 1; m < 8; m++) {
                     float sum = adpcm_vb[s->prediction_vq[k][l]][0] *
                                 subband_samples[k][l][m - 1];
                     for (n = 2; n <= 4; n++)

                         if (m >= n)

                             sum += adpcm_vb[s->prediction_vq[k][l]][n - 1] *
                                    subband_samples[k][l][m - n];

                         else if (s->predictor_history)

                             sum += adpcm_vb[s->prediction_vq[k][l]][n - 1] *
                                    s->subband_samples_hist[k][l][m - n + 4];

                     subband_samples[k][l][m] += sum * (1.0f / 8192);

                 }
             }
         }
 
         /*
          * Decode VQ encoded high frequencies
          */

         if (s->subband_activity[k] > s->vq_start_subband[k]) {

             if (!(s->debug_flag & 0x01)) {

                 av_log(s->avctx, AV_LOG_DEBUG,
                        "Stream with high frequencies VQ coding\n");

                 s->debug_flag |= 0x01;
             }

             s->dcadsp.decode_hf(subband_samples[k], s->high_freq_vq[k],
                                 high_freq_vq, subsubframe * 8,
                                 s->scale_factor[k], s->vq_start_subband[k],
                                 s->subband_activity[k]);

         }
     }
 
     /* Check for DSYNC after subsubframe */

     if (s->aspf || subsubframe == s->subsubframes[s->current_subframe] - 1) {

         if (0xFFFF == get_bits(&s->gb, 16)) {   /* 0xFFFF */
 #ifdef TRACE
             av_log(s->avctx, AV_LOG_DEBUG, "Got subframe DSYNC\n");
 #endif
         } else {
             av_log(s->avctx, AV_LOG_ERROR, "Didn't get subframe DSYNC\n");

             return AVERROR_INVALIDDATA;

         }
     }
 
     /* Backup predictor history for adpcm */

     for (k = base_channel; k < s->prim_channels; k++)

         for (l = 0; l < s->vq_start_subband[k]; l++)

             AV_COPY128(s->subband_samples_hist[k][l], &subband_samples[k][l][4]);

     return 0;
 }
 

 static int dca_filter_channels(DCAContext *s, int block_index)

 {
     float (*subband_samples)[DCA_SUBBANDS][8] = s->subband_samples[block_index];
     int k;
 

     /* 32 subbands QMF */
     for (k = 0; k < s->prim_channels; k++) {

 /*        static float pcm_to_double[8] = { 32768.0, 32768.0, 524288.0, 524288.0,
                                             0, 8388608.0, 8388608.0 };*/

         if (s->channel_order_tab[k] >= 0)
             qmf_32_subbands(s, k, subband_samples[k],
                             s->samples_chanptr[s->channel_order_tab[k]],
                             M_SQRT1_2 / 32768.0 /* pcm_to_double[s->source_pcm_res] */);

     }
 
     /* Generate LFE samples for this subsubframe FIXME!!! */

     if (s->lfe) {

         lfe_interpolation_fir(s, s->lfe, 2 * s->lfe,

                               s->lfe_data + 2 * s->lfe * (block_index + 4),

                               s->samples_chanptr[s->lfe_index]);

         /* Outputs 20bits pcm samples */
     }
 

     /* Downmixing to Stereo */
     if (s->prim_channels + !!s->lfe > 2 &&
         s->avctx->request_channel_layout == AV_CH_LAYOUT_STEREO) {
         dca_downmix(s->samples_chanptr, s->amode, !!s->lfe, s->downmix_coef,
                     s->channel_order_tab);
     }
 

     return 0;
 }
 
 

 static int dca_subframe_footer(DCAContext *s, int base_channel)

 {

     int in, out, aux_data_count, aux_data_end, reserved;

     uint32_t nsyncaux;

 
     /*
      * Unpack optional information
      */
 

     /* presumably optional information only appears in the core? */
     if (!base_channel) {

         if (s->timestamp)

             skip_bits_long(&s->gb, 32);

         if (s->aux_data) {

             aux_data_count = get_bits(&s->gb, 6);

             // align (32-bit)
             skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
 
             aux_data_end = 8 * aux_data_count + get_bits_count(&s->gb);
 

             if ((nsyncaux = get_bits_long(&s->gb, 32)) != DCA_NSYNCAUX) {
                 av_log(s->avctx, AV_LOG_ERROR, "nSYNCAUX mismatch %#"PRIx32"\n",
                        nsyncaux);

                 return AVERROR_INVALIDDATA;

             }

 
             if (get_bits1(&s->gb)) { // bAUXTimeStampFlag
                 avpriv_request_sample(s->avctx,
                                       "Auxiliary Decode Time Stamp Flag");
                 // align (4-bit)
                 skip_bits(&s->gb, (-get_bits_count(&s->gb)) & 4);
                 // 44 bits: nMSByte (8), nMarker (4), nLSByte (28), nMarker (4)
                 skip_bits_long(&s->gb, 44);
             }
 
             if ((s->core_downmix = get_bits1(&s->gb))) {

                 int am = get_bits(&s->gb, 3);
                 switch (am) {

                 case 0:
                     s->core_downmix_amode = DCA_MONO;
                     break;
                 case 1:
                     s->core_downmix_amode = DCA_STEREO;
                     break;
                 case 2:
                     s->core_downmix_amode = DCA_STEREO_TOTAL;
                     break;
                 case 3:
                     s->core_downmix_amode = DCA_3F;
                     break;
                 case 4:
                     s->core_downmix_amode = DCA_2F1R;
                     break;
                 case 5:
                     s->core_downmix_amode = DCA_2F2R;
                     break;
                 case 6:
                     s->core_downmix_amode = DCA_3F1R;
                     break;
                 default:

                     av_log(s->avctx, AV_LOG_ERROR,
                            "Invalid mode %d for embedded downmix coefficients\n",
                            am);

                     return AVERROR_INVALIDDATA;
                 }
                 for (out = 0; out < dca_channels[s->core_downmix_amode]; out++) {
                     for (in = 0; in < s->prim_channels + !!s->lfe; in++) {
                         uint16_t tmp = get_bits(&s->gb, 9);

                         if ((tmp & 0xFF) > 241) {
                             av_log(s->avctx, AV_LOG_ERROR,
                                    "Invalid downmix coefficient code %"PRIu16"\n",
                                    tmp);

                             return AVERROR_INVALIDDATA;

                         }

                         s->core_downmix_codes[in][out] = tmp;
                     }
                 }
             }
 
             align_get_bits(&s->gb); // byte align
             skip_bits(&s->gb, 16);  // nAUXCRC16
 
             // additional data (reserved, cf. ETSI TS 102 114 V1.4.1)

             if ((reserved = (aux_data_end - get_bits_count(&s->gb))) < 0) {

                  av_log(s->avctx, AV_LOG_ERROR,
                         "Overread auxiliary data by %d bits\n", -reserved);

                 return AVERROR_INVALIDDATA;

             } else if (reserved) {

                 avpriv_request_sample(s->avctx,
                                       "Core auxiliary data reserved content");
                 skip_bits_long(&s->gb, reserved);
             }
         }

         if (s->crc_present && s->dynrange)

             get_bits(&s->gb, 16);

     }

 
     return 0;
 }
 
 /**
  * Decode a dca frame block
  *
  * @param s     pointer to the DCAContext
  */
 

 static int dca_decode_block(DCAContext *s, int base_channel, int block_index)

 {

     int ret;

 
     /* Sanity check */
     if (s->current_subframe >= s->subframes) {
         av_log(s->avctx, AV_LOG_DEBUG, "check failed: %i>%i",
                s->current_subframe, s->subframes);

         return AVERROR_INVALIDDATA;

     }
 
     if (!s->current_subsubframe) {
 #ifdef TRACE
         av_log(s->avctx, AV_LOG_DEBUG, "DSYNC dca_subframe_header\n");
 #endif
         /* Read subframe header */

         if ((ret = dca_subframe_header(s, base_channel, block_index)))
             return ret;

     }
 
     /* Read subsubframe */
 #ifdef TRACE
     av_log(s->avctx, AV_LOG_DEBUG, "DSYNC dca_subsubframe\n");
 #endif

     if ((ret = dca_subsubframe(s, base_channel, block_index)))
         return ret;

 
     /* Update state */
     s->current_subsubframe++;

     if (s->current_subsubframe >= s->subsubframes[s->current_subframe]) {

         s->current_subsubframe = 0;
         s->current_subframe++;
     }
     if (s->current_subframe >= s->subframes) {
 #ifdef TRACE
         av_log(s->avctx, AV_LOG_DEBUG, "DSYNC dca_subframe_footer\n");
 #endif
         /* Read subframe footer */

         if ((ret = dca_subframe_footer(s, base_channel)))
             return ret;

     }
 
     return 0;
 }
 
 /**

  * Return the number of channels in an ExSS speaker mask (HD)
  */
 static int dca_exss_mask2count(int mask)
 {
     /* count bits that mean speaker pairs twice */

     return av_popcount(mask) +
            av_popcount(mask & (DCA_EXSS_CENTER_LEFT_RIGHT      |
                                DCA_EXSS_FRONT_LEFT_RIGHT       |
                                DCA_EXSS_FRONT_HIGH_LEFT_RIGHT  |
                                DCA_EXSS_WIDE_LEFT_RIGHT        |
                                DCA_EXSS_SIDE_LEFT_RIGHT        |
                                DCA_EXSS_SIDE_HIGH_LEFT_RIGHT   |
                                DCA_EXSS_SIDE_REAR_LEFT_RIGHT   |
                                DCA_EXSS_REAR_LEFT_RIGHT        |
                                DCA_EXSS_REAR_HIGH_LEFT_RIGHT));

 }
 
 /**
  * Skip mixing coefficients of a single mix out configuration (HD)
  */
 static void dca_exss_skip_mix_coeffs(GetBitContext *gb, int channels, int out_ch)
 {

     int i;
 
     for (i = 0; i < channels; i++) {

         int mix_map_mask = get_bits(gb, out_ch);
         int num_coeffs = av_popcount(mix_map_mask);
         skip_bits_long(gb, num_coeffs * 6);
     }
 }
 
 /**
  * Parse extension substream asset header (HD)
  */
 static int dca_exss_parse_asset_header(DCAContext *s)
 {
     int header_pos = get_bits_count(&s->gb);
     int header_size;

     int channels = 0;

     int embedded_stereo = 0;

     int embedded_6ch    = 0;

     int drc_code_present;

     int av_uninit(extensions_mask);

     int i, j;
 
     if (get_bits_left(&s->gb) < 16)
         return -1;
 
     /* We will parse just enough to get to the extensions bitmask with which
      * we can set the profile value. */
 
     header_size = get_bits(&s->gb, 9) + 1;
     skip_bits(&s->gb, 3); // asset index
 
     if (s->static_fields) {
         if (get_bits1(&s->gb))
             skip_bits(&s->gb, 4); // asset type descriptor
         if (get_bits1(&s->gb))
             skip_bits_long(&s->gb, 24); // language descriptor
 
         if (get_bits1(&s->gb)) {
             /* How can one fit 1024 bytes of text here if the maximum value
              * for the asset header size field above was 512 bytes? */
             int text_length = get_bits(&s->gb, 10) + 1;
             if (get_bits_left(&s->gb) < text_length * 8)
                 return -1;
             skip_bits_long(&s->gb, text_length * 8); // info text
         }
 
         skip_bits(&s->gb, 5); // bit resolution - 1
         skip_bits(&s->gb, 4); // max sample rate code
         channels = get_bits(&s->gb, 8) + 1;
 
         if (get_bits1(&s->gb)) { // 1-to-1 channels to speakers
             int spkr_remap_sets;
             int spkr_mask_size = 16;
             int num_spkrs[7];
 
             if (channels > 2)
                 embedded_stereo = get_bits1(&s->gb);
             if (channels > 6)
                 embedded_6ch = get_bits1(&s->gb);
 
             if (get_bits1(&s->gb)) {
                 spkr_mask_size = (get_bits(&s->gb, 2) + 1) << 2;
                 skip_bits(&s->gb, spkr_mask_size); // spkr activity mask
             }
 
             spkr_remap_sets = get_bits(&s->gb, 3);
 
             for (i = 0; i < spkr_remap_sets; i++) {
                 /* std layout mask for each remap set */
                 num_spkrs[i] = dca_exss_mask2count(get_bits(&s->gb, spkr_mask_size));
             }
 
             for (i = 0; i < spkr_remap_sets; i++) {
                 int num_dec_ch_remaps = get_bits(&s->gb, 5) + 1;
                 if (get_bits_left(&s->gb) < 0)
                     return -1;
 
                 for (j = 0; j < num_spkrs[i]; j++) {
                     int remap_dec_ch_mask = get_bits_long(&s->gb, num_dec_ch_remaps);
                     int num_dec_ch = av_popcount(remap_dec_ch_mask);
                     skip_bits_long(&s->gb, num_dec_ch * 5); // remap codes
                 }
             }
 
         } else {
             skip_bits(&s->gb, 3); // representation type
         }
     }
 
     drc_code_present = get_bits1(&s->gb);
     if (drc_code_present)
         get_bits(&s->gb, 8); // drc code
 
     if (get_bits1(&s->gb))
         skip_bits(&s->gb, 5); // dialog normalization code
 
     if (drc_code_present && embedded_stereo)
         get_bits(&s->gb, 8); // drc stereo code
 
     if (s->mix_metadata && get_bits1(&s->gb)) {
         skip_bits(&s->gb, 1); // external mix
         skip_bits(&s->gb, 6); // post mix gain code
 
         if (get_bits(&s->gb, 2) != 3) // mixer drc code
             skip_bits(&s->gb, 3); // drc limit
         else
             skip_bits(&s->gb, 8); // custom drc code
 
         if (get_bits1(&s->gb)) // channel specific scaling
             for (i = 0; i < s->num_mix_configs; i++)
                 skip_bits_long(&s->gb, s->mix_config_num_ch[i] * 6); // scale codes
         else
             skip_bits_long(&s->gb, s->num_mix_configs * 6); // scale codes
 
         for (i = 0; i < s->num_mix_configs; i++) {
             if (get_bits_left(&s->gb) < 0)
                 return -1;
             dca_exss_skip_mix_coeffs(&s->gb, channels, s->mix_config_num_ch[i]);
             if (embedded_6ch)
                 dca_exss_skip_mix_coeffs(&s->gb, 6, s->mix_config_num_ch[i]);
             if (embedded_stereo)
                 dca_exss_skip_mix_coeffs(&s->gb, 2, s->mix_config_num_ch[i]);
         }
     }
 
     switch (get_bits(&s->gb, 2)) {
     case 0: extensions_mask = get_bits(&s->gb, 12); break;
     case 1: extensions_mask = DCA_EXT_EXSS_XLL;     break;
     case 2: extensions_mask = DCA_EXT_EXSS_LBR;     break;
     case 3: extensions_mask = 0; /* aux coding */   break;
     }
 
     /* not parsed further, we were only interested in the extensions mask */
 
     if (get_bits_left(&s->gb) < 0)
         return -1;
 
     if (get_bits_count(&s->gb) - header_pos > header_size * 8) {
         av_log(s->avctx, AV_LOG_WARNING, "Asset header size mismatch.\n");
         return -1;
     }
     skip_bits_long(&s->gb, header_pos + header_size * 8 - get_bits_count(&s->gb));
 
     if (extensions_mask & DCA_EXT_EXSS_XLL)
         s->profile = FF_PROFILE_DTS_HD_MA;

     else if (extensions_mask & (DCA_EXT_EXSS_XBR | DCA_EXT_EXSS_X96 |
                                 DCA_EXT_EXSS_XXCH))

         s->profile = FF_PROFILE_DTS_HD_HRA;
 
     if (!(extensions_mask & DCA_EXT_CORE))
         av_log(s->avctx, AV_LOG_WARNING, "DTS core detection mismatch.\n");

     if ((extensions_mask & DCA_CORE_EXTS) != s->core_ext_mask)

         av_log(s->avctx, AV_LOG_WARNING,
                "DTS extensions detection mismatch (%d, %d)\n",

                extensions_mask & DCA_CORE_EXTS, s->core_ext_mask);

 
     return 0;
 }
 

 static int dca_xbr_parse_frame(DCAContext *s)
 {
     int scale_table_high[DCA_CHSET_CHANS_MAX][DCA_SUBBANDS][2];
     int active_bands[DCA_CHSETS_MAX][DCA_CHSET_CHANS_MAX];
     int abits_high[DCA_CHSET_CHANS_MAX][DCA_SUBBANDS];
     int anctemp[DCA_CHSET_CHANS_MAX];
     int chset_fsize[DCA_CHSETS_MAX];
     int n_xbr_ch[DCA_CHSETS_MAX];
     int hdr_size, num_chsets, xbr_tmode, hdr_pos;
     int i, j, k, l, chset, chan_base;
 
     av_log(s->avctx, AV_LOG_DEBUG, "DTS-XBR: decoding XBR extension\n");
 
     /* get bit position of sync header */
     hdr_pos = get_bits_count(&s->gb) - 32;
 
     hdr_size = get_bits(&s->gb, 6) + 1;
     num_chsets = get_bits(&s->gb, 2) + 1;
 
     for(i = 0; i < num_chsets; i++)
         chset_fsize[i] = get_bits(&s->gb, 14) + 1;
 
     xbr_tmode = get_bits1(&s->gb);
 
     for(i = 0; i < num_chsets; i++) {
         n_xbr_ch[i] = get_bits(&s->gb, 3) + 1;
         k = get_bits(&s->gb, 2) + 5;
         for(j = 0; j < n_xbr_ch[i]; j++)
             active_bands[i][j] = get_bits(&s->gb, k) + 1;
     }
 
     /* skip to the end of the header */
     i = get_bits_count(&s->gb);
     if(hdr_pos + hdr_size * 8 > i)
         skip_bits_long(&s->gb, hdr_pos + hdr_size * 8 - i);
 
     /* loop over the channel data sets */
     /* only decode as many channels as we've decoded base data for */
     for(chset = 0, chan_base = 0;
         chset < num_chsets && chan_base + n_xbr_ch[chset] <= s->prim_channels;
         chan_base += n_xbr_ch[chset++]) {
         int start_posn = get_bits_count(&s->gb);
         int subsubframe = 0;
         int subframe = 0;
 
         /* loop over subframes */
         for (k = 0; k < (s->sample_blocks / 8); k++) {
             /* parse header if we're on first subsubframe of a block */
             if(subsubframe == 0) {
                 /* Parse subframe header */
                 for(i = 0; i < n_xbr_ch[chset]; i++) {
                     anctemp[i] = get_bits(&s->gb, 2) + 2;
                 }
 
                 for(i = 0; i < n_xbr_ch[chset]; i++) {
                     get_array(&s->gb, abits_high[i], active_bands[chset][i], anctemp[i]);
                 }
 
                 for(i = 0; i < n_xbr_ch[chset]; i++) {
                     anctemp[i] = get_bits(&s->gb, 3);
                     if(anctemp[i] < 1) {
                         av_log(s->avctx, AV_LOG_ERROR, "DTS-XBR: SYNC ERROR\n");
                         return AVERROR_INVALIDDATA;
                     }
                 }
 
                 /* generate scale factors */
                 for(i = 0; i < n_xbr_ch[chset]; i++) {
                     const uint32_t *scale_table;
                     int nbits;
 
                     if (s->scalefactor_huffman[chan_base+i] == 6) {
                         scale_table = scale_factor_quant7;
                     } else {
                         scale_table = scale_factor_quant6;
                     }
 
                     nbits = anctemp[i];
 
                     for(j = 0; j < active_bands[chset][i]; j++) {
                         if(abits_high[i][j] > 0) {
                             scale_table_high[i][j][0] =
                                 scale_table[get_bits(&s->gb, nbits)];
 
                             if(xbr_tmode && s->transition_mode[i][j]) {
                                 scale_table_high[i][j][1] =
                                     scale_table[get_bits(&s->gb, nbits)];
                             }
                         }
                     }
                 }
             }
 
             /* decode audio array for this block */
             for(i = 0; i < n_xbr_ch[chset]; i++) {
                 for(j = 0; j < active_bands[chset][i]; j++) {
                     const int xbr_abits = abits_high[i][j];
                     const float quant_step_size = lossless_quant_d[xbr_abits];
                     const int sfi = xbr_tmode && s->transition_mode[i][j] && subsubframe >= s->transition_mode[i][j];
                     const float rscale = quant_step_size * scale_table_high[i][j][sfi];
                     float *subband_samples = s->subband_samples[k][chan_base+i][j];
                     int block[8];
 
                     if(xbr_abits <= 0)
                         continue;
 
                     if(xbr_abits > 7) {
                         get_array(&s->gb, block, 8, xbr_abits - 3);
                     } else {
                         int block_code1, block_code2, size, levels, err;
 
                         size   = abits_sizes[xbr_abits - 1];
                         levels = abits_levels[xbr_abits - 1];
 
                         block_code1 = get_bits(&s->gb, size);
                         block_code2 = get_bits(&s->gb, size);
                         err = decode_blockcodes(block_code1, block_code2,
                                                 levels, block);
                         if (err) {
                             av_log(s->avctx, AV_LOG_ERROR,
                                    "ERROR: DTS-XBR: block code look-up failed\n");
                             return AVERROR_INVALIDDATA;
                         }
                     }
 
                     /* scale & sum into subband */
                     for(l = 0; l < 8; l++)
                         subband_samples[l] += (float)block[l] * rscale;
                 }
             }
 
             /* check DSYNC marker */
             if(s->aspf || subsubframe == s->subsubframes[subframe] - 1) {
                 if(get_bits(&s->gb, 16) != 0xffff) {
                     av_log(s->avctx, AV_LOG_ERROR, "DTS-XBR: Didn't get subframe DSYNC\n");
                     return AVERROR_INVALIDDATA;
                 }
             }
 
             /* advance sub-sub-frame index */
             if(++subsubframe >= s->subsubframes[subframe]) {
                 subsubframe = 0;
                 subframe++;
             }
         }
 
         /* skip to next channel set */
         i = get_bits_count(&s->gb);
         if(start_posn + chset_fsize[chset] * 8 != i) {
             j = start_posn + chset_fsize[chset] * 8 - i;
             if(j < 0 || j >= 8)
                 av_log(s->avctx, AV_LOG_ERROR, "DTS-XBR: end of channel set,"
                        " skipping further than expected (%d bits)\n", j);
             skip_bits_long(&s->gb, j);
         }
     }
 
     return 0;
 }
 
 /* parse initial header for XXCH and dump details */
 static int dca_xxch_decode_frame(DCAContext *s)
 {

     int hdr_size, spkmsk_bits, num_chsets, core_spk, hdr_pos;

     int i, chset, base_channel, chstart, fsize[8];
 
     /* assume header word has already been parsed */
     hdr_pos     = get_bits_count(&s->gb) - 32;
     hdr_size    = get_bits(&s->gb, 6) + 1;

   /*chhdr_crc   =*/ skip_bits1(&s->gb);

     spkmsk_bits = get_bits(&s->gb, 5) + 1;
     num_chsets  = get_bits(&s->gb, 2) + 1;
 
     for (i = 0; i < num_chsets; i++)
         fsize[i] = get_bits(&s->gb, 14) + 1;
 
     core_spk               = get_bits(&s->gb, spkmsk_bits);
     s->xxch_core_spkmask   = core_spk;
     s->xxch_nbits_spk_mask = spkmsk_bits;
     s->xxch_dmix_embedded  = 0;
 
     /* skip to the end of the header */
     i = get_bits_count(&s->gb);
     if (hdr_pos + hdr_size * 8 > i)
         skip_bits_long(&s->gb, hdr_pos + hdr_size * 8 - i);
 
     for (chset = 0; chset < num_chsets; chset++) {
         chstart       = get_bits_count(&s->gb);
         base_channel  = s->prim_channels;
         s->xxch_chset = chset;
 
         /* XXCH and Core headers differ, see 6.4.2 "XXCH Channel Set Header" vs.
            5.3.2 "Primary Audio Coding Header", DTS Spec 1.3.1 */
         dca_parse_audio_coding_header(s, base_channel, 1);
 
         /* decode channel data */
         for (i = 0; i < (s->sample_blocks / 8); i++) {
             if (dca_decode_block(s, base_channel, i)) {
                 av_log(s->avctx, AV_LOG_ERROR,
                        "Error decoding DTS-XXCH extension\n");
                 continue;
             }
         }
 
         /* skip to end of this section */
         i = get_bits_count(&s->gb);
         if (chstart + fsize[chset] * 8 > i)
             skip_bits_long(&s->gb, chstart + fsize[chset] * 8 - i);
     }
     s->xxch_chset = num_chsets;
 
     return 0;
 }
 

 /**
  * Parse extension substream header (HD)
  */
 static void dca_exss_parse_header(DCAContext *s)
 {

     int asset_size[8];

     int ss_index;
     int blownup;
     int num_audiop = 1;
     int num_assets = 1;
     int active_ss_mask[8];
     int i, j;

     int start_posn;
     int hdrsize;
     uint32_t mkr;

 
     if (get_bits_left(&s->gb) < 52)
         return;
 

     start_posn = get_bits_count(&s->gb) - 32;
 

     skip_bits(&s->gb, 8); // user data
     ss_index = get_bits(&s->gb, 2);
 
     blownup = get_bits1(&s->gb);

     hdrsize = get_bits(&s->gb,  8 + 4 * blownup) + 1; // header_size

     skip_bits(&s->gb, 16 + 4 * blownup); // hd_size

 
     s->static_fields = get_bits1(&s->gb);
     if (s->static_fields) {
         skip_bits(&s->gb, 2); // reference clock code
         skip_bits(&s->gb, 3); // frame duration code
 
         if (get_bits1(&s->gb))
             skip_bits_long(&s->gb, 36); // timestamp
 
         /* a single stream can contain multiple audio assets that can be
          * combined to form multiple audio presentations */
 
         num_audiop = get_bits(&s->gb, 3) + 1;
         if (num_audiop > 1) {

             avpriv_request_sample(s->avctx,
                                   "Multiple DTS-HD audio presentations");

             /* ignore such streams for now */
             return;
         }
 
         num_assets = get_bits(&s->gb, 3) + 1;
         if (num_assets > 1) {

             avpriv_request_sample(s->avctx, "Multiple DTS-HD audio assets");

             /* ignore such streams for now */
             return;
         }
 
         for (i = 0; i < num_audiop; i++)
             active_ss_mask[i] = get_bits(&s->gb, ss_index + 1);
 
         for (i = 0; i < num_audiop; i++)
             for (j = 0; j <= ss_index; j++)
                 if (active_ss_mask[i] & (1 << j))
                     skip_bits(&s->gb, 8); // active asset mask
 
         s->mix_metadata = get_bits1(&s->gb);
         if (s->mix_metadata) {
             int mix_out_mask_size;
 
             skip_bits(&s->gb, 2); // adjustment level

             mix_out_mask_size  = (get_bits(&s->gb, 2) + 1) << 2;
             s->num_mix_configs =  get_bits(&s->gb, 2) + 1;

 
             for (i = 0; i < s->num_mix_configs; i++) {

                 int mix_out_mask        = get_bits(&s->gb, mix_out_mask_size);

                 s->mix_config_num_ch[i] = dca_exss_mask2count(mix_out_mask);
             }
         }
     }
 

     av_assert0(num_assets > 0); // silence a warning
 

     for (i = 0; i < num_assets; i++)

         asset_size[i] = get_bits_long(&s->gb, 16 + 4 * blownup);

 
     for (i = 0; i < num_assets; i++) {
         if (dca_exss_parse_asset_header(s))
             return;
     }
 
     /* not parsed further, we were only interested in the extensions mask
      * from the asset header */

 
         j = get_bits_count(&s->gb);
         if (start_posn + hdrsize * 8 > j)
             skip_bits_long(&s->gb, start_posn + hdrsize * 8 - j);
 
         for (i = 0; i < num_assets; i++) {
             start_posn = get_bits_count(&s->gb);
             mkr        = get_bits_long(&s->gb, 32);
 
             /* parse extensions that we know about */
             if (mkr == 0x655e315e) {
                 dca_xbr_parse_frame(s);
             } else if (mkr == 0x47004a03) {
                 dca_xxch_decode_frame(s);
                 s->core_ext_mask |= DCA_EXT_XXCH; /* xxx use for chan reordering */
             } else {
                 av_log(s->avctx, AV_LOG_DEBUG,
                        "DTS-ExSS: unknown marker = 0x%08x\n", mkr);
             }
 
             /* skip to end of block */
             j = get_bits_count(&s->gb);
             if (start_posn + asset_size[i] * 8 > j)
                 skip_bits_long(&s->gb, start_posn + asset_size[i] * 8 - j);
         }

 }
 

 static float dca_dmix_code(unsigned code)
 {
     int sign = (code >> 8) - 1;
     code &= 0xff;

     return ((dca_dmixtable[code] ^ sign) - sign) * (1.0 / (1 << 15));

 }
 

 /**

  * Main frame decoding function
  * FIXME add arguments
  */

 static int dca_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame_ptr, AVPacket *avpkt)

 {

     AVFrame *frame     = data;

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     int channel_mask;
     int channel_layout;

     int lfe_samples;

     int num_core_channels = 0;

     int i, ret;

     float **samples_flt;

     float *src_chan;
     float *dst_chan;

     DCAContext *s = avctx->priv_data;

     int core_ss_end;

     int channels, full_channels;

     float scale;
     int achan;
     int chset;
     int mask;
     int lavc;
     int posn;
     int j, k;
     int endch;

     s->xch_present = 0;

     s->dca_buffer_size = ff_dca_convert_bitstream(buf, buf_size, s->dca_buffer,
                                                   DCA_MAX_FRAME_SIZE + DCA_MAX_EXSS_HEADER_SIZE);

     if (s->dca_buffer_size == AVERROR_INVALIDDATA) {

         av_log(avctx, AV_LOG_ERROR, "Not a valid DCA frame\n");

         return AVERROR_INVALIDDATA;

     }
 

     if ((ret = dca_parse_frame_header(s)) < 0) {

         //seems like the frame is corrupt, try with the next one

         return ret;

     }
     //set AVCodec values with parsed data
     avctx->sample_rate = s->sample_rate;

     avctx->bit_rate    = s->bit_rate;

     s->profile = FF_PROFILE_DTS;
 

     for (i = 0; i < (s->sample_blocks / 8); i++) {

         if ((ret = dca_decode_block(s, 0, i))) {
             av_log(avctx, AV_LOG_ERROR, "error decoding block\n");
             return ret;
         }

     }
 
     /* record number of core channels incase less than max channels are requested */
     num_core_channels = s->prim_channels;
 

     if (s->prim_channels + !!s->lfe > 2 &&

         avctx->request_channel_layout == AV_CH_LAYOUT_STEREO) {

             /* Stereo downmix coefficients
              *
              * The decoder can only downmix to 2-channel, so we need to ensure
              * embedded downmix coefficients are actually targeting 2-channel.
              */
             if (s->core_downmix && (s->core_downmix_amode == DCA_STEREO ||
                                     s->core_downmix_amode == DCA_STEREO_TOTAL)) {

                 for (i = 0; i < num_core_channels + !!s->lfe; i++) {

                     /* Range checked earlier */
                     s->downmix_coef[i][0] = dca_dmix_code(s->core_downmix_codes[i][0]);
                     s->downmix_coef[i][1] = dca_dmix_code(s->core_downmix_codes[i][1]);

                 }

                 s->output = s->core_downmix_amode;

             } else {
                 int am = s->amode & DCA_CHANNEL_MASK;
                 if (am >= FF_ARRAY_ELEMS(dca_default_coeffs)) {
                     av_log(s->avctx, AV_LOG_ERROR,
                            "Invalid channel mode %d\n", am);
                     return AVERROR_INVALIDDATA;
                 }

                 if (num_core_channels + !!s->lfe >

                     FF_ARRAY_ELEMS(dca_default_coeffs[0])) {
                     avpriv_request_sample(s->avctx, "Downmixing %d channels",
                                           s->prim_channels + !!s->lfe);
                     return AVERROR_PATCHWELCOME;
                 }

                 for (i = 0; i < num_core_channels + !!s->lfe; i++) {

                     s->downmix_coef[i][0] = dca_default_coeffs[am][i][0];
                     s->downmix_coef[i][1] = dca_default_coeffs[am][i][1];
                 }

             }

             av_dlog(s->avctx, "Stereo downmix coeffs:\n");

             for (i = 0; i < num_core_channels + !!s->lfe; i++) {

                 av_dlog(s->avctx, "L, input channel %d = %f\n", i,
                         s->downmix_coef[i][0]);
                 av_dlog(s->avctx, "R, input channel %d = %f\n", i,
                         s->downmix_coef[i][1]);

             }

             av_dlog(s->avctx, "\n");

     }
 

     if (s->ext_coding)
         s->core_ext_mask = dca_ext_audio_descr_mask[s->ext_descr];
     else
         s->core_ext_mask = 0;

     core_ss_end = FFMIN(s->frame_size, s->dca_buffer_size) * 8;
 

     /* only scan for extensions if ext_descr was unknown or indicated a
      * supported XCh extension */

     if (s->core_ext_mask < 0 || s->core_ext_mask & (DCA_EXT_XCH | DCA_EXT_XXCH)) {

 
         /* if ext_descr was unknown, clear s->core_ext_mask so that the
          * extensions scan can fill it up */
         s->core_ext_mask = FFMAX(s->core_ext_mask, 0);
 
         /* extensions start at 32-bit boundaries into bitstream */
         skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
 

         while (core_ss_end - get_bits_count(&s->gb) >= 32) {
             uint32_t bits = get_bits_long(&s->gb, 32);

             switch (bits) {
             case 0x5a5a5a5a: {
                 int ext_amode, xch_fsize;

                 s->xch_base_channel = s->prim_channels;

                 /* validate sync word using XCHFSIZE field */
                 xch_fsize = show_bits(&s->gb, 10);
                 if ((s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + xch_fsize) &&
                     (s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + xch_fsize + 1))
                     continue;

                 /* skip length-to-end-of-frame field for the moment */
                 skip_bits(&s->gb, 10);

                 s->core_ext_mask |= DCA_EXT_XCH;

                 /* extension amode(number of channels in extension) should be 1 */
                 /* AFAIK XCh is not used for more channels */
                 if ((ext_amode = get_bits(&s->gb, 4)) != 1) {
                     av_log(avctx, AV_LOG_ERROR, "XCh extension amode %d not"
                            " supported!\n", ext_amode);

                     continue;
                 }

                 if (s->xch_base_channel < 2) {

                     avpriv_request_sample(avctx, "XCh with fewer than 2 base channels");

                     continue;
                 }
 

                 /* much like core primary audio coding header */

                 dca_parse_audio_coding_header(s, s->xch_base_channel, 0);

 
                 for (i = 0; i < (s->sample_blocks / 8); i++)
                     if ((ret = dca_decode_block(s, s->xch_base_channel, i))) {
                         av_log(avctx, AV_LOG_ERROR, "error decoding XCh extension\n");
                         continue;
                     }
 
                 s->xch_present = 1;
                 break;

             }

             case 0x47004a03:
                 /* XXCh: extended channels */
                 /* usually found either in core or HD part in DTS-HD HRA streams,
                  * but not in DTS-ES which contains XCh extensions instead */
                 s->core_ext_mask |= DCA_EXT_XXCH;

                 dca_xxch_decode_frame(s);

                 break;
 
             case 0x1d95f262: {
                 int fsize96 = show_bits(&s->gb, 12) + 1;
                 if (s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + fsize96)
                     continue;

                 av_log(avctx, AV_LOG_DEBUG, "X96 extension found at %d bits\n",
                        get_bits_count(&s->gb));
                 skip_bits(&s->gb, 12);
                 av_log(avctx, AV_LOG_DEBUG, "FSIZE96 = %d bytes\n", fsize96);
                 av_log(avctx, AV_LOG_DEBUG, "REVNO = %d\n", get_bits(&s->gb, 4));

                 s->core_ext_mask |= DCA_EXT_X96;
                 break;
             }
             }

             skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
         }

     } else {
         /* no supported extensions, skip the rest of the core substream */
         skip_bits_long(&s->gb, core_ss_end - get_bits_count(&s->gb));
     }
 
     if (s->core_ext_mask & DCA_EXT_X96)
         s->profile = FF_PROFILE_DTS_96_24;
     else if (s->core_ext_mask & (DCA_EXT_XCH | DCA_EXT_XXCH))
         s->profile = FF_PROFILE_DTS_ES;
 

     /* check for ExSS (HD part) */

     if (s->dca_buffer_size - s->frame_size > 32 &&
         get_bits_long(&s->gb, 32) == DCA_HD_MARKER)

         dca_exss_parse_header(s);
 
     avctx->profile = s->profile;
 

     full_channels = channels = s->prim_channels + !!s->lfe;

     /* If we have XXCH then the channel layout is managed differently */
     /* note that XLL will also have another way to do things */
     if (!(s->core_ext_mask & DCA_EXT_XXCH)
         || (s->core_ext_mask & DCA_EXT_XXCH && avctx->request_channels > 0
             && avctx->request_channels
             < num_core_channels + !!s->lfe + s->xxch_chset_nch[0]))
     { /* xxx should also do MA extensions */
         if (s->amode < 16) {
             avctx->channel_layout = dca_core_channel_layout[s->amode];

 
             if (s->prim_channels + !!s->lfe > 2 &&
                 avctx->request_channel_layout == AV_CH_LAYOUT_STEREO) {
                 /*
                  * Neither the core's auxiliary data nor our default tables contain
                  * downmix coefficients for the additional channel coded in the XCh
                  * extension, so when we're doing a Stereo downmix, don't decode it.
                  */
                 s->xch_disable = 1;
             }

 #if FF_API_REQUEST_CHANNELS
 FF_DISABLE_DEPRECATION_WARNINGS

             if (s->xch_present && !s->xch_disable &&
                 (!avctx->request_channels ||
                  avctx->request_channels > num_core_channels + !!s->lfe)) {

 FF_ENABLE_DEPRECATION_WARNINGS
 #else

             if (s->xch_present && !s->xch_disable) {

 #endif

                 avctx->channel_layout |= AV_CH_BACK_CENTER;
                 if (s->lfe) {
                     avctx->channel_layout |= AV_CH_LOW_FREQUENCY;
                     s->channel_order_tab = dca_channel_reorder_lfe_xch[s->amode];
                 } else {
                     s->channel_order_tab = dca_channel_reorder_nolfe_xch[s->amode];
                 }

                 if (s->channel_order_tab[s->xch_base_channel] < 0)
                     return AVERROR_INVALIDDATA;

             } else {

                 channels = num_core_channels + !!s->lfe;
                 s->xch_present = 0; /* disable further xch processing */
                 if (s->lfe) {
                     avctx->channel_layout |= AV_CH_LOW_FREQUENCY;
                     s->channel_order_tab = dca_channel_reorder_lfe[s->amode];
                 } else
                     s->channel_order_tab = dca_channel_reorder_nolfe[s->amode];

             }

 
             if (channels > !!s->lfe &&
                 s->channel_order_tab[channels - 1 - !!s->lfe] < 0)
                 return AVERROR_INVALIDDATA;
 

             if (av_get_channel_layout_nb_channels(avctx->channel_layout) != channels) {
                 av_log(avctx, AV_LOG_ERROR, "Number of channels %d mismatches layout %d\n", channels, av_get_channel_layout_nb_channels(avctx->channel_layout));
                 return AVERROR_INVALIDDATA;
             }
 

             if (num_core_channels + !!s->lfe > 2 &&

                 avctx->request_channel_layout == AV_CH_LAYOUT_STEREO) {

                 channels = 2;

                 s->output = s->prim_channels == 2 ? s->amode : DCA_STEREO;

                 avctx->channel_layout = AV_CH_LAYOUT_STEREO;
             }
             else if (avctx->request_channel_layout & AV_CH_LAYOUT_NATIVE) {
                 static const int8_t dca_channel_order_native[9] = { 0, 1, 2, 3, 4, 5, 6, 7, 8 };
                 s->channel_order_tab = dca_channel_order_native;
             }
             s->lfe_index = dca_lfe_index[s->amode];

         } else {

             av_log(avctx, AV_LOG_ERROR,
                    "Non standard configuration %d !\n", s->amode);
             return AVERROR_INVALIDDATA;
         }
 

         s->xxch_dmix_embedded = 0;

     } else {
         /* we only get here if an XXCH channel set can be added to the mix */
         channel_mask = s->xxch_core_spkmask;
 
         if (avctx->request_channels > 0
             && avctx->request_channels < s->prim_channels) {

             channels = num_core_channels + !!s->lfe;

             for (i = 0; i < s->xxch_chset && channels + s->xxch_chset_nch[i]
                                               <= avctx->request_channels; i++) {
                 channels += s->xxch_chset_nch[i];
                 channel_mask |= s->xxch_spk_masks[i];
             }
         } else {
             channels = s->prim_channels + !!s->lfe;
             for (i = 0; i < s->xxch_chset; i++) {
                 channel_mask |= s->xxch_spk_masks[i];
             }

         }

         /* Given the DTS spec'ed channel mask, generate an avcodec version */
         channel_layout = 0;
         for (i = 0; i < s->xxch_nbits_spk_mask; ++i) {
             if (channel_mask & (1 << i)) {
                 channel_layout |= map_xxch_to_native[i];
             }
         }

         /* make sure that we have managed to get equivalent dts/avcodec channel

          * masks in some sense -- unfortunately some channels could overlap */
         if (av_popcount(channel_mask) != av_popcount(channel_layout)) {
             av_log(avctx, AV_LOG_DEBUG,

                    "DTS-XXCH: Inconsistent avcodec/dts channel layouts\n");

             return AVERROR_INVALIDDATA;

         }
 

         avctx->channel_layout = channel_layout;
 
         if (!(avctx->request_channel_layout & AV_CH_LAYOUT_NATIVE)) {
             /* Estimate DTS --> avcodec ordering table */
             for (chset = -1, j = 0; chset < s->xxch_chset; ++chset) {
                 mask = chset >= 0 ? s->xxch_spk_masks[chset]
                                   : s->xxch_core_spkmask;
                 for (i = 0; i < s->xxch_nbits_spk_mask; i++) {
                     if (mask & ~(DCA_XXCH_LFE1 | DCA_XXCH_LFE2) & (1 << i)) {
                         lavc = map_xxch_to_native[i];
                         posn = av_popcount(channel_layout & (lavc - 1));
                         s->xxch_order_tab[j++] = posn;
                     }
                 }

             }

             s->lfe_index = av_popcount(channel_layout & (AV_CH_LOW_FREQUENCY-1));
         } else { /* native ordering */
             for (i = 0; i < channels; i++)
                 s->xxch_order_tab[i] = i;
 
             s->lfe_index = channels - 1;
         }
 
         s->channel_order_tab = s->xxch_order_tab;

     }

     if (avctx->channels != channels) {

         if (avctx->channels)
             av_log(avctx, AV_LOG_INFO, "Number of channels changed in DCA decoder (%d -> %d)\n", avctx->channels, channels);
         avctx->channels = channels;

     }

     /* get output buffer */

     frame->nb_samples = 256 * (s->sample_blocks / 8);

     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

         return ret;

     samples_flt = (float **)frame->extended_data;

     /* allocate buffer for extra channels if downmixing */
     if (avctx->channels < full_channels) {
         ret = av_samples_get_buffer_size(NULL, full_channels - channels,

                                          frame->nb_samples,

                                          avctx->sample_fmt, 0);
         if (ret < 0)
             return ret;
 
         av_fast_malloc(&s->extra_channels_buffer,
                        &s->extra_channels_buffer_size, ret);
         if (!s->extra_channels_buffer)
             return AVERROR(ENOMEM);
 
         ret = av_samples_fill_arrays((uint8_t **)s->extra_channels, NULL,
                                      s->extra_channels_buffer,
                                      full_channels - channels,

                                      frame->nb_samples, avctx->sample_fmt, 0);

         if (ret < 0)
             return ret;
     }
 

     /* filter to get final output */

     for (i = 0; i < (s->sample_blocks / 8); i++) {

         int ch;
 
         for (ch = 0; ch < channels; ch++)
             s->samples_chanptr[ch] = samples_flt[ch] + i * 256;

         for (; ch < full_channels; ch++)
             s->samples_chanptr[ch] = s->extra_channels[ch - channels] + i * 256;

         dca_filter_channels(s, i);

 
         /* If this was marked as a DTS-ES stream we need to subtract back- */
         /* channel from SL & SR to remove matrixed back-channel signal */

         if ((s->source_pcm_res & 1) && s->xch_present) {

             float *back_chan = s->samples_chanptr[s->channel_order_tab[s->xch_base_channel]];
             float *lt_chan   = s->samples_chanptr[s->channel_order_tab[s->xch_base_channel - 2]];
             float *rt_chan   = s->samples_chanptr[s->channel_order_tab[s->xch_base_channel - 1]];

             s->fdsp.vector_fmac_scalar(lt_chan, back_chan, -M_SQRT1_2, 256);
             s->fdsp.vector_fmac_scalar(rt_chan, back_chan, -M_SQRT1_2, 256);

         }

 
         /* If stream contains XXCH, we might need to undo an embedded downmix */
         if (s->xxch_dmix_embedded) {
             /* Loop over channel sets in turn */
             ch = num_core_channels;
             for (chset = 0; chset < s->xxch_chset; chset++) {
                 endch = ch + s->xxch_chset_nch[chset];
                 mask = s->xxch_dmix_embedded;
 
                 /* undo downmix */
                 for (j = ch; j < endch; j++) {
                     if (mask & (1 << j)) { /* this channel has been mixed-out */

                         src_chan = s->samples_chanptr[s->channel_order_tab[j]];

                         for (k = 0; k < endch; k++) {
                             achan = s->channel_order_tab[k];
                             scale = s->xxch_dmix_coeff[j][k];
                             if (scale != 0.0) {

                                 dst_chan = s->samples_chanptr[achan];

                                 s->fdsp.vector_fmac_scalar(dst_chan, src_chan,
                                                            -scale, 256);
                             }
                         }
                     }
                 }
 
                 /* if a downmix has been embedded then undo the pre-scaling */
                 if ((mask & (1 << ch)) && s->xxch_dmix_sf[chset] != 1.0f) {
                     scale = s->xxch_dmix_sf[chset];
 
                     for (j = 0; j < ch; j++) {

                         src_chan = s->samples_chanptr[s->channel_order_tab[j]];

                         for (k = 0; k < 256; k++)
                             src_chan[k] *= scale;
                     }
 
                     /* LFE channel is always part of core, scale if it exists */
                     if (s->lfe) {

                         src_chan = s->samples_chanptr[s->lfe_index];

                         for (k = 0; k < 256; k++)
                             src_chan[k] *= scale;
                     }
                 }
 
                 ch = endch;
             }
 
         }

     }
 

     /* update lfe history */
     lfe_samples = 2 * s->lfe * (s->sample_blocks / 8);

     for (i = 0; i < 2 * s->lfe * 4; i++)

         s->lfe_data[i] = s->lfe_data[i + lfe_samples];
 

     /* AVMatrixEncoding
      *
      * DCA_STEREO_TOTAL (Lt/Rt) is equivalent to Dolby Surround */
     ret = ff_side_data_update_matrix_encoding(frame,
                                               (s->output & ~DCA_LFE) == DCA_STEREO_TOTAL ?
                                               AV_MATRIX_ENCODING_DOLBY : AV_MATRIX_ENCODING_NONE);
     if (ret < 0)
         return ret;
 

     *got_frame_ptr = 1;

     return buf_size;
 }
 
 
 
 /**
  * DCA initialization
  *
  * @param avctx     pointer to the AVCodecContext
  */
 

 static av_cold int dca_decode_init(AVCodecContext *avctx)

 {
     DCAContext *s = avctx->priv_data;
 
     s->avctx = avctx;
     dca_init_vlcs();
 

     avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);

     ff_mdct_init(&s->imdct, 6, 1, 1.0);

     ff_synth_filter_init(&s->synth);

     ff_dcadsp_init(&s->dcadsp);

     ff_fmt_convert_init(&s->fmt_conv, avctx);

     avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;

     /* allow downmixing to stereo */

 #if FF_API_REQUEST_CHANNELS
 FF_DISABLE_DEPRECATION_WARNINGS
     if (avctx->request_channels == 2)
         avctx->request_channel_layout = AV_CH_LAYOUT_STEREO;
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif
     if (avctx->channels > 2 &&
         avctx->request_channel_layout == AV_CH_LAYOUT_STEREO)
         avctx->channels = 2;

     return 0;
 }
 

 static av_cold int dca_decode_end(AVCodecContext *avctx)

 {
     DCAContext *s = avctx->priv_data;
     ff_mdct_end(&s->imdct);

     av_freep(&s->extra_channels_buffer);

     return 0;
 }

 static const AVProfile profiles[] = {
     { FF_PROFILE_DTS,        "DTS"        },
     { FF_PROFILE_DTS_ES,     "DTS-ES"     },
     { FF_PROFILE_DTS_96_24,  "DTS 96/24"  },
     { FF_PROFILE_DTS_HD_HRA, "DTS-HD HRA" },
     { FF_PROFILE_DTS_HD_MA,  "DTS-HD MA"  },
     { FF_PROFILE_UNKNOWN },
 };
 

 static const AVOption options[] = {
     { "disable_xch", "disable decoding of the XCh extension", offsetof(DCAContext, xch_disable), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AV_OPT_FLAG_DECODING_PARAM|AV_OPT_FLAG_AUDIO_PARAM },
     { NULL },
 };
 
 static const AVClass dca_decoder_class = {
     .class_name = "DCA decoder",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,

     .category   = AV_CLASS_CATEGORY_DECODER,

 };
 

 AVCodec ff_dca_decoder = {

     .name            = "dca",

     .long_name       = NULL_IF_CONFIG_SMALL("DCA (DTS Coherent Acoustics)"),

     .type            = AVMEDIA_TYPE_AUDIO,

     .id              = AV_CODEC_ID_DTS,

     .priv_data_size  = sizeof(DCAContext),
     .init            = dca_decode_init,
     .decode          = dca_decode_frame,
     .close           = dca_decode_end,
     .capabilities    = CODEC_CAP_CHANNEL_CONF | CODEC_CAP_DR1,

     .sample_fmts     = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,

                                                        AV_SAMPLE_FMT_NONE },
     .profiles        = NULL_IF_CONFIG_SMALL(profiles),

     .priv_class      = &dca_decoder_class,

 };