/*
  * Copyright (C) 2007 Marco Gerards <marco@gnu.org>
  * Copyright (C) 2009 David Conrad

  * Copyright (C) 2011 Jordi Ortiz

  *
  * 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
  */
 
 /**

  * @file

  * Dirac Decoder

  * @author Marco Gerards <marco@gnu.org>, David Conrad, Jordi Ortiz <nenjordi@gmail.com>

  */
 
 #include "avcodec.h"
 #include "dsputil.h"
 #include "get_bits.h"
 #include "bytestream.h"

 #include "internal.h"

 #include "golomb.h"
 #include "dirac_arith.h"
 #include "mpeg12data.h"
 #include "dwt.h"
 #include "dirac.h"
 #include "diracdsp.h"
 
 /**
  * The spec limits the number of wavelet decompositions to 4 for both
  * level 1 (VC-2) and 128 (long-gop default).
  * 5 decompositions is the maximum before >16-bit buffers are needed.
  * Schroedinger allows this for DD 9,7 and 13,7 wavelets only, limiting
  * the others to 4 decompositions (or 3 for the fidelity filter).
  *
  * We use this instead of MAX_DECOMPOSITIONS to save some memory.
  */
 #define MAX_DWT_LEVELS 5
 
 /**
  * The spec limits this to 3 for frame coding, but in practice can be as high as 6
  */
 #define MAX_REFERENCE_FRAMES 8

 #define MAX_DELAY 5         /* limit for main profile for frame coding (TODO: field coding) */

 #define MAX_FRAMES (MAX_REFERENCE_FRAMES + MAX_DELAY + 1)

 #define MAX_QUANT 68        /* max quant for VC-2 */
 #define MAX_BLOCKSIZE 32    /* maximum xblen/yblen we support */

 
 /**
  * DiracBlock->ref flags, if set then the block does MC from the given ref
  */
 #define DIRAC_REF_MASK_REF1   1
 #define DIRAC_REF_MASK_REF2   2
 #define DIRAC_REF_MASK_GLOBAL 4
 
 /**
  * Value of Picture.reference when Picture is not a reference picture, but
  * is held for delayed output.
  */
 #define DELAYED_PIC_REF 4
 

 #define ff_emulated_edge_mc ff_emulated_edge_mc_8 /* Fix: change the calls to this function regarding bit depth */

 #define CALC_PADDING(size, depth)                       \
     (((size + (1 << depth) - 1) >> depth) << depth)

 
 #define DIVRNDUP(a, b) (((a) + (b) - 1) / (b))
 
 typedef struct {

     AVFrame avframe;

     int interpolated[3];    /* 1 if hpel[] is valid */

     uint8_t *hpel[3][4];
     uint8_t *hpel_base[3][4];

 } DiracFrame;
 
 typedef struct {
     union {
         int16_t mv[2][2];
         int16_t dc[3];

     } u; /* anonymous unions aren't in C99 :( */

     uint8_t ref;
 } DiracBlock;
 
 typedef struct SubBand {
     int level;
     int orientation;
     int stride;
     int width;
     int height;
     int quant;
     IDWTELEM *ibuf;
     struct SubBand *parent;
 

     /* for low delay */

     unsigned length;
     const uint8_t *coeff_data;
 } SubBand;
 
 typedef struct Plane {
     int width;
     int height;
     int stride;
 
     int idwt_width;
     int idwt_height;
     int idwt_stride;
     IDWTELEM *idwt_buf;
     IDWTELEM *idwt_buf_base;
     IDWTELEM *idwt_tmp;
 

     /* block length */

     uint8_t xblen;
     uint8_t yblen;

     /* block separation (block n+1 starts after this many pixels in block n) */

     uint8_t xbsep;
     uint8_t ybsep;

     /* amount of overspill on each edge (half of the overlap between blocks) */

     uint8_t xoffset;
     uint8_t yoffset;
 
     SubBand band[MAX_DWT_LEVELS][4];
 } Plane;
 
 typedef struct DiracContext {
     AVCodecContext *avctx;
     DSPContext dsp;
     DiracDSPContext diracdsp;
     GetBitContext gb;
     dirac_source_params source;
     int seen_sequence_header;

     int frame_number;           /* number of the next frame to display       */

     Plane plane[3];
     int chroma_x_shift;
     int chroma_y_shift;
 

     int zero_res;               /* zero residue flag                         */
     int is_arith;               /* whether coeffs use arith or golomb coding */
     int low_delay;              /* use the low delay syntax                  */
     int globalmc_flag;          /* use global motion compensation            */
     int num_refs;               /* number of reference pictures              */

     /* wavelet decoding */
     unsigned wavelet_depth;     /* depth of the IDWT                         */

     unsigned wavelet_idx;
 
     /**
      * schroedinger older than 1.0.8 doesn't store
      * quant delta if only one codebook exists in a band
      */
     unsigned old_delta_quant;
     unsigned codeblock_mode;
 
     struct {
         unsigned width;
         unsigned height;
     } codeblock[MAX_DWT_LEVELS+1];
 
     struct {

         unsigned num_x;         /* number of horizontal slices               */
         unsigned num_y;         /* number of vertical slices                 */
         AVRational bytes;       /* average bytes per slice                   */
         uint8_t quant[MAX_DWT_LEVELS][4]; /* [DIRAC_STD] E.1 */

     } lowdelay;
 
     struct {

         int pan_tilt[2];        /* pan/tilt vector                           */
         int zrs[2][2];          /* zoom/rotate/shear matrix                  */
         int perspective[2];     /* perspective vector                        */

         unsigned zrs_exp;
         unsigned perspective_exp;
     } globalmc[2];
 

     /* motion compensation */
     uint8_t mv_precision;       /* [DIRAC_STD] REFS_WT_PRECISION             */
     int16_t weight[2];          /* [DIRAC_STD] REF1_WT and REF2_WT           */
     unsigned weight_log2denom;  /* [DIRAC_STD] REFS_WT_PRECISION             */

     int blwidth;                /* number of blocks (horizontally)           */
     int blheight;               /* number of blocks (vertically)             */
     int sbwidth;                /* number of superblocks (horizontally)      */
     int sbheight;               /* number of superblocks (vertically)        */

 
     uint8_t *sbsplit;
     DiracBlock *blmotion;
 
     uint8_t *edge_emu_buffer[4];
     uint8_t *edge_emu_buffer_base;
 

     uint16_t *mctmp;            /* buffer holding the MC data multipled by OBMC weights */

     uint8_t *mcscratch;

     int buffer_stride;

 
     DECLARE_ALIGNED(16, uint8_t, obmc_weight)[3][MAX_BLOCKSIZE*MAX_BLOCKSIZE];
 
     void (*put_pixels_tab[4])(uint8_t *dst, const uint8_t *src[5], int stride, int h);
     void (*avg_pixels_tab[4])(uint8_t *dst, const uint8_t *src[5], int stride, int h);
     void (*add_obmc)(uint16_t *dst, const uint8_t *src, int stride, const uint8_t *obmc_weight, int yblen);
     dirac_weight_func weight_func;
     dirac_biweight_func biweight_func;
 
     DiracFrame *current_picture;
     DiracFrame *ref_pics[2];
 
     DiracFrame *ref_frames[MAX_REFERENCE_FRAMES+1];
     DiracFrame *delay_frames[MAX_DELAY+1];
     DiracFrame all_frames[MAX_FRAMES];
 } DiracContext;
 

 /**
  * Dirac Specification ->
  * Parse code values. 9.6.1 Table 9.1
  */

 enum dirac_parse_code {
     pc_seq_header         = 0x00,
     pc_eos                = 0x10,
     pc_aux_data           = 0x20,
     pc_padding            = 0x30,
 };
 
 enum dirac_subband {
     subband_ll = 0,
     subband_hl = 1,
     subband_lh = 2,
     subband_hh = 3
 };
 
 static const uint8_t default_qmat[][4][4] = {
     { { 5,  3,  3,  0}, { 0,  4,  4,  1}, { 0,  5,  5,  2}, { 0,  6,  6,  3} },
     { { 4,  2,  2,  0}, { 0,  4,  4,  2}, { 0,  5,  5,  3}, { 0,  7,  7,  5} },
     { { 5,  3,  3,  0}, { 0,  4,  4,  1}, { 0,  5,  5,  2}, { 0,  6,  6,  3} },
     { { 8,  4,  4,  0}, { 0,  4,  4,  0}, { 0,  4,  4,  0}, { 0,  4,  4,  0} },
     { { 8,  4,  4,  0}, { 0,  4,  4,  0}, { 0,  4,  4,  0}, { 0,  4,  4,  0} },
     { { 0,  4,  4,  8}, { 0,  8,  8, 12}, { 0, 13, 13, 17}, { 0, 17, 17, 21} },
     { { 3,  1,  1,  0}, { 0,  4,  4,  2}, { 0,  6,  6,  5}, { 0,  9,  9,  7} },
 };
 
 static const int qscale_tab[MAX_QUANT+1] = {

     4,     5,     6,     7,     8,    10,    11,    13,
     16,    19,    23,    27,    32,    38,    45,    54,
     64,    76,    91,   108,   128,   152,   181,   215,
     256,   304,   362,   431,   512,   609,   724,   861,
     1024,  1218,  1448,  1722,  2048,  2435,  2896,  3444,
     4096,  4871,  5793,  6889,  8192,  9742, 11585, 13777,

     16384, 19484, 23170, 27554, 32768, 38968, 46341, 55109,
     65536, 77936
 };
 
 static const int qoffset_intra_tab[MAX_QUANT+1] = {

     1,     2,     3,     4,     4,     5,     6,     7,
     8,    10,    12,    14,    16,    19,    23,    27,
     32,    38,    46,    54,    64,    76,    91,   108,
     128,   152,   181,   216,   256,   305,   362,   431,
     512,   609,   724,   861,  1024,  1218,  1448,  1722,
     2048,  2436,  2897,  3445,  4096,  4871,  5793,  6889,
     8192,  9742, 11585, 13777, 16384, 19484, 23171, 27555,

     32768, 38968
 };
 
 static const int qoffset_inter_tab[MAX_QUANT+1] = {

     1,     2,     2,     3,     3,     4,     4,     5,
     6,     7,     9,    10,    12,    14,    17,    20,
     24,    29,    34,    41,    48,    57,    68,    81,
     96,   114,   136,   162,   192,   228,   272,   323,
     384,   457,   543,   646,   768,   913,  1086,  1292,
     1536,  1827,  2172,  2583,  3072,  3653,  4344,  5166,
     6144,  7307,  8689, 10333, 12288, 14613, 17378, 20666,

     24576, 29226
 };
 

 /* magic number division by 3 from schroedinger */

 static inline int divide3(int x)
 {
     return ((x+1)*21845 + 10922) >> 16;
 }
 
 static DiracFrame *remove_frame(DiracFrame *framelist[], int picnum)
 {
     DiracFrame *remove_pic = NULL;
     int i, remove_idx = -1;
 
     for (i = 0; framelist[i]; i++)
         if (framelist[i]->avframe.display_picture_number == picnum) {
             remove_pic = framelist[i];
             remove_idx = i;
         }
 
     if (remove_pic)
         for (i = remove_idx; framelist[i]; i++)
             framelist[i] = framelist[i+1];
 
     return remove_pic;
 }
 
 static int add_frame(DiracFrame *framelist[], int maxframes, DiracFrame *frame)
 {
     int i;
     for (i = 0; i < maxframes; i++)
         if (!framelist[i]) {
             framelist[i] = frame;
             return 0;
         }
     return -1;
 }
 
 static int alloc_sequence_buffers(DiracContext *s)
 {
     int sbwidth  = DIVRNDUP(s->source.width,  4);
     int sbheight = DIVRNDUP(s->source.height, 4);
     int i, w, h, top_padding;
 

     /* todo: think more about this / use or set Plane here */

     for (i = 0; i < 3; i++) {
         int max_xblen = MAX_BLOCKSIZE >> (i ? s->chroma_x_shift : 0);
         int max_yblen = MAX_BLOCKSIZE >> (i ? s->chroma_y_shift : 0);
         w = s->source.width  >> (i ? s->chroma_x_shift : 0);
         h = s->source.height >> (i ? s->chroma_y_shift : 0);
 

         /* we allocate the max we support here since num decompositions can
          * change from frame to frame. Stride is aligned to 16 for SIMD, and
          * 1<<MAX_DWT_LEVELS top padding to avoid if(y>0) in arith decoding
          * MAX_BLOCKSIZE padding for MC: blocks can spill up to half of that
          * on each side */

         top_padding = FFMAX(1<<MAX_DWT_LEVELS, max_yblen/2);

         w = FFALIGN(CALC_PADDING(w, MAX_DWT_LEVELS), 8); /* FIXME: Should this be 16 for SSE??? */

         h = top_padding + CALC_PADDING(h, MAX_DWT_LEVELS) + max_yblen/2;
 
         s->plane[i].idwt_buf_base = av_mallocz((w+max_xblen)*h * sizeof(IDWTELEM));
         s->plane[i].idwt_tmp      = av_malloc((w+16) * sizeof(IDWTELEM));
         s->plane[i].idwt_buf      = s->plane[i].idwt_buf_base + top_padding*w;
         if (!s->plane[i].idwt_buf_base || !s->plane[i].idwt_tmp)
             return AVERROR(ENOMEM);
     }
 

     /* fixme: allocate using real stride here */

     s->sbsplit  = av_malloc_array(sbwidth, sbheight);
     s->blmotion = av_malloc_array(sbwidth, sbheight * 16 * sizeof(*s->blmotion));
 
     if (!s->sbsplit || !s->blmotion)
         return AVERROR(ENOMEM);
     return 0;
 }
 
 static int alloc_buffers(DiracContext *s, int stride)
 {
     int w = s->source.width;
     int h = s->source.height;
 
     av_assert0(stride >= w);
     stride += 64;
 
     if (s->buffer_stride >= stride)
         return 0;
     s->buffer_stride = 0;
 
     av_freep(&s->edge_emu_buffer_base);
     memset(s->edge_emu_buffer, 0, sizeof(s->edge_emu_buffer));
     av_freep(&s->mctmp);
     av_freep(&s->mcscratch);

     s->edge_emu_buffer_base = av_malloc_array(stride, MAX_BLOCKSIZE);

     s->mctmp     = av_malloc_array((stride+MAX_BLOCKSIZE), (h+MAX_BLOCKSIZE) * sizeof(*s->mctmp));
     s->mcscratch = av_malloc_array(stride, MAX_BLOCKSIZE);
 
     if (!s->edge_emu_buffer_base || !s->mctmp || !s->mcscratch)

         return AVERROR(ENOMEM);

 
     s->buffer_stride = stride;

     return 0;
 }
 
 static void free_sequence_buffers(DiracContext *s)
 {
     int i, j, k;
 
     for (i = 0; i < MAX_FRAMES; i++) {
         if (s->all_frames[i].avframe.data[0]) {
             s->avctx->release_buffer(s->avctx, &s->all_frames[i].avframe);
             memset(s->all_frames[i].interpolated, 0, sizeof(s->all_frames[i].interpolated));
         }
 
         for (j = 0; j < 3; j++)
             for (k = 1; k < 4; k++)
                 av_freep(&s->all_frames[i].hpel_base[j][k]);
     }
 
     memset(s->ref_frames, 0, sizeof(s->ref_frames));
     memset(s->delay_frames, 0, sizeof(s->delay_frames));
 
     for (i = 0; i < 3; i++) {
         av_freep(&s->plane[i].idwt_buf_base);
         av_freep(&s->plane[i].idwt_tmp);
     }
 

     s->buffer_stride = 0;

     av_freep(&s->sbsplit);
     av_freep(&s->blmotion);
     av_freep(&s->edge_emu_buffer_base);
 
     av_freep(&s->mctmp);
     av_freep(&s->mcscratch);
 }
 
 static av_cold int dirac_decode_init(AVCodecContext *avctx)
 {
     DiracContext *s = avctx->priv_data;
     s->avctx = avctx;
     s->frame_number = -1;
 
     if (avctx->flags&CODEC_FLAG_EMU_EDGE) {
         av_log(avctx, AV_LOG_ERROR, "Edge emulation not supported!\n");
         return AVERROR_PATCHWELCOME;
     }
 

     ff_dsputil_init(&s->dsp, avctx);

     ff_diracdsp_init(&s->diracdsp);
 
     return 0;
 }
 
 static void dirac_decode_flush(AVCodecContext *avctx)
 {
     DiracContext *s = avctx->priv_data;
     free_sequence_buffers(s);
     s->seen_sequence_header = 0;
     s->frame_number = -1;
 }
 
 static av_cold int dirac_decode_end(AVCodecContext *avctx)
 {
     dirac_decode_flush(avctx);
     return 0;
 }
 
 #define SIGN_CTX(x) (CTX_SIGN_ZERO + ((x) > 0) - ((x) < 0))
 
 static inline void coeff_unpack_arith(DiracArith *c, int qfactor, int qoffset,
                                       SubBand *b, IDWTELEM *buf, int x, int y)
 {
     int coeff, sign;
     int sign_pred = 0;
     int pred_ctx = CTX_ZPZN_F1;
 

     /* Check if the parent subband has a 0 in the corresponding position */

     if (b->parent)
         pred_ctx += !!b->parent->ibuf[b->parent->stride * (y>>1) + (x>>1)] << 1;
 
     if (b->orientation == subband_hl)
         sign_pred = buf[-b->stride];
 

     /* Determine if the pixel has only zeros in its neighbourhood */

     if (x) {
         pred_ctx += !(buf[-1] | buf[-b->stride] | buf[-1-b->stride]);
         if (b->orientation == subband_lh)
             sign_pred = buf[-1];
     } else {
         pred_ctx += !buf[-b->stride];
     }
 
     coeff = dirac_get_arith_uint(c, pred_ctx, CTX_COEFF_DATA);
     if (coeff) {

         coeff = (coeff * qfactor + qoffset + 2) >> 2;
         sign  = dirac_get_arith_bit(c, SIGN_CTX(sign_pred));

         coeff = (coeff ^ -sign) + sign;
     }
     *buf = coeff;
 }
 
 static inline int coeff_unpack_golomb(GetBitContext *gb, int qfactor, int qoffset)
 {
     int sign, coeff;
 
     coeff = svq3_get_ue_golomb(gb);
     if (coeff) {

         coeff = (coeff * qfactor + qoffset + 2) >> 2;
         sign  = get_bits1(gb);

         coeff = (coeff ^ -sign) + sign;
     }
     return coeff;
 }
 
 /**
  * Decode the coeffs in the rectangle defined by left, right, top, bottom
  * [DIRAC_STD] 13.4.3.2 Codeblock unpacking loop. codeblock()
  */
 static inline void codeblock(DiracContext *s, SubBand *b,
                              GetBitContext *gb, DiracArith *c,
                              int left, int right, int top, int bottom,
                              int blockcnt_one, int is_arith)
 {
     int x, y, zero_block;
     int qoffset, qfactor;
     IDWTELEM *buf;
 

     /* check for any coded coefficients in this codeblock */

     if (!blockcnt_one) {
         if (is_arith)
             zero_block = dirac_get_arith_bit(c, CTX_ZERO_BLOCK);
         else
             zero_block = get_bits1(gb);
 
         if (zero_block)
             return;
     }
 
     if (s->codeblock_mode && !(s->old_delta_quant && blockcnt_one)) {

         int quant = b->quant;

         if (is_arith)

             quant += dirac_get_arith_int(c, CTX_DELTA_Q_F, CTX_DELTA_Q_DATA);

         else

             quant += dirac_get_se_golomb(gb);
         if (quant < 0) {
             av_log(s->avctx, AV_LOG_ERROR, "Invalid quant\n");
             return;
         }
         b->quant = quant;

     }
 
     b->quant = FFMIN(b->quant, MAX_QUANT);
 
     qfactor = qscale_tab[b->quant];

     /* TODO: context pointer? */

     if (!s->num_refs)
         qoffset = qoffset_intra_tab[b->quant];
     else
         qoffset = qoffset_inter_tab[b->quant];
 

     buf = b->ibuf + top * b->stride;

     for (y = top; y < bottom; y++) {
         for (x = left; x < right; x++) {

             /* [DIRAC_STD] 13.4.4 Subband coefficients. coeff_unpack() */

             if (is_arith)
                 coeff_unpack_arith(c, qfactor, qoffset, b, buf+x, x, y);
             else
                 buf[x] = coeff_unpack_golomb(gb, qfactor, qoffset);
         }
         buf += b->stride;
     }
 }
 

 /**
  * Dirac Specification ->
  * 13.3 intra_dc_prediction(band)
  */

 static inline void intra_dc_prediction(SubBand *b)
 {
     IDWTELEM *buf = b->ibuf;
     int x, y;
 
     for (x = 1; x < b->width; x++)
         buf[x] += buf[x-1];
     buf += b->stride;
 
     for (y = 1; y < b->height; y++) {
         buf[0] += buf[-b->stride];
 
         for (x = 1; x < b->width; x++) {
             int pred = buf[x - 1] + buf[x - b->stride] + buf[x - b->stride-1];

             buf[x]  += divide3(pred);

         }
         buf += b->stride;
     }
 }
 

 /**
  * Dirac Specification ->
  * 13.4.2 Non-skipped subbands.  subband_coeffs()
  */

 static av_always_inline void decode_subband_internal(DiracContext *s, SubBand *b, int is_arith)

 {
     int cb_x, cb_y, left, right, top, bottom;
     DiracArith c;
     GetBitContext gb;
     int cb_width  = s->codeblock[b->level + (b->orientation != subband_ll)].width;
     int cb_height = s->codeblock[b->level + (b->orientation != subband_ll)].height;
     int blockcnt_one = (cb_width + cb_height) == 2;
 
     if (!b->length)
         return;
 
     init_get_bits(&gb, b->coeff_data, b->length*8);
 
     if (is_arith)
         ff_dirac_init_arith_decoder(&c, &gb, b->length);
 
     top = 0;
     for (cb_y = 0; cb_y < cb_height; cb_y++) {
         bottom = (b->height * (cb_y+1)) / cb_height;
         left = 0;
         for (cb_x = 0; cb_x < cb_width; cb_x++) {
             right = (b->width * (cb_x+1)) / cb_width;
             codeblock(s, b, &gb, &c, left, right, top, bottom, blockcnt_one, is_arith);
             left = right;
         }
         top = bottom;
     }
 
     if (b->orientation == subband_ll && s->num_refs == 0)
         intra_dc_prediction(b);
 }
 
 static int decode_subband_arith(AVCodecContext *avctx, void *b)
 {
     DiracContext *s = avctx->priv_data;
     decode_subband_internal(s, b, 1);
     return 0;
 }
 
 static int decode_subband_golomb(AVCodecContext *avctx, void *arg)
 {
     DiracContext *s = avctx->priv_data;

     SubBand **b     = arg;

     decode_subband_internal(s, *b, 0);
     return 0;
 }
 

 /**
  * Dirac Specification ->
  * [DIRAC_STD] 13.4.1 core_transform_data()
  */

 static void decode_component(DiracContext *s, int comp)
 {
     AVCodecContext *avctx = s->avctx;
     SubBand *bands[3*MAX_DWT_LEVELS+1];
     enum dirac_subband orientation;
     int level, num_bands = 0;
 

     /* Unpack all subbands at all levels. */

     for (level = 0; level < s->wavelet_depth; level++) {
         for (orientation = !!level; orientation < 4; orientation++) {
             SubBand *b = &s->plane[comp].band[level][orientation];
             bands[num_bands++] = b;
 
             align_get_bits(&s->gb);

             /* [DIRAC_STD] 13.4.2 subband() */

             b->length = svq3_get_ue_golomb(&s->gb);
             if (b->length) {
                 b->quant = svq3_get_ue_golomb(&s->gb);
                 align_get_bits(&s->gb);
                 b->coeff_data = s->gb.buffer + get_bits_count(&s->gb)/8;

                 b->length = FFMIN(b->length, FFMAX(get_bits_left(&s->gb)/8, 0));

                 skip_bits_long(&s->gb, b->length*8);
             }
         }

         /* arithmetic coding has inter-level dependencies, so we can only execute one level at a time */

         if (s->is_arith)
             avctx->execute(avctx, decode_subband_arith, &s->plane[comp].band[level][!!level],
                            NULL, 4-!!level, sizeof(SubBand));
     }

     /* golomb coding has no inter-level dependencies, so we can execute all subbands in parallel */

     if (!s->is_arith)
         avctx->execute(avctx, decode_subband_golomb, bands, NULL, num_bands, sizeof(SubBand*));
 }
 

 /* [DIRAC_STD] 13.5.5.2 Luma slice subband data. luma_slice_band(level,orient,sx,sy) --> if b2 == NULL */
 /* [DIRAC_STD] 13.5.5.3 Chroma slice subband data. chroma_slice_band(level,orient,sx,sy) --> if b2 != NULL */

 static void lowdelay_subband(DiracContext *s, GetBitContext *gb, int quant,
                              int slice_x, int slice_y, int bits_end,
                              SubBand *b1, SubBand *b2)
 {

     int left   = b1->width  * slice_x    / s->lowdelay.num_x;
     int right  = b1->width  *(slice_x+1) / s->lowdelay.num_x;
     int top    = b1->height * slice_y    / s->lowdelay.num_y;
     int bottom = b1->height *(slice_y+1) / s->lowdelay.num_y;

 
     int qfactor = qscale_tab[FFMIN(quant, MAX_QUANT)];
     int qoffset = qoffset_intra_tab[FFMIN(quant, MAX_QUANT)];
 

     IDWTELEM *buf1 =      b1->ibuf + top * b1->stride;
     IDWTELEM *buf2 = b2 ? b2->ibuf + top * b2->stride : NULL;

     int x, y;

     /* we have to constantly check for overread since the spec explictly
        requires this, with the meaning that all remaining coeffs are set to 0 */

     if (get_bits_count(gb) >= bits_end)
         return;
 
     for (y = top; y < bottom; y++) {
         for (x = left; x < right; x++) {
             buf1[x] = coeff_unpack_golomb(gb, qfactor, qoffset);
             if (get_bits_count(gb) >= bits_end)
                 return;
             if (buf2) {
                 buf2[x] = coeff_unpack_golomb(gb, qfactor, qoffset);
                 if (get_bits_count(gb) >= bits_end)
                     return;
             }
         }
         buf1 += b1->stride;
         if (buf2)
             buf2 += b2->stride;
     }
 }
 
 struct lowdelay_slice {
     GetBitContext gb;
     int slice_x;
     int slice_y;
     int bytes;
 };
 
 

 /**
  * Dirac Specification ->
  * 13.5.2 Slices. slice(sx,sy)
  */

 static int decode_lowdelay_slice(AVCodecContext *avctx, void *arg)
 {
     DiracContext *s = avctx->priv_data;
     struct lowdelay_slice *slice = arg;
     GetBitContext *gb = &slice->gb;
     enum dirac_subband orientation;
     int level, quant, chroma_bits, chroma_end;
 

     int quant_base  = get_bits(gb, 7); /*[DIRAC_STD] qindex */

     int length_bits = av_log2(8 * slice->bytes)+1;

     int luma_bits   = get_bits_long(gb, length_bits);
     int luma_end    = get_bits_count(gb) + FFMIN(luma_bits, get_bits_left(gb));
 

     /* [DIRAC_STD] 13.5.5.2 luma_slice_band */

     for (level = 0; level < s->wavelet_depth; level++)
         for (orientation = !!level; orientation < 4; orientation++) {
             quant = FFMAX(quant_base - s->lowdelay.quant[level][orientation], 0);
             lowdelay_subband(s, gb, quant, slice->slice_x, slice->slice_y, luma_end,
                              &s->plane[0].band[level][orientation], NULL);
         }
 

     /* consume any unused bits from luma */

     skip_bits_long(gb, get_bits_count(gb) - luma_end);
 
     chroma_bits = 8*slice->bytes - 7 - length_bits - luma_bits;

     chroma_end  = get_bits_count(gb) + FFMIN(chroma_bits, get_bits_left(gb));

     /* [DIRAC_STD] 13.5.5.3 chroma_slice_band */

     for (level = 0; level < s->wavelet_depth; level++)
         for (orientation = !!level; orientation < 4; orientation++) {
             quant = FFMAX(quant_base - s->lowdelay.quant[level][orientation], 0);
             lowdelay_subband(s, gb, quant, slice->slice_x, slice->slice_y, chroma_end,
                              &s->plane[1].band[level][orientation],
                              &s->plane[2].band[level][orientation]);
         }
 
     return 0;
 }
 

 /**
  * Dirac Specification ->
  * 13.5.1 low_delay_transform_data()
  */

 static void decode_lowdelay(DiracContext *s)
 {
     AVCodecContext *avctx = s->avctx;
     int slice_x, slice_y, bytes, bufsize;
     const uint8_t *buf;
     struct lowdelay_slice *slices;
     int slice_num = 0;
 
     slices = av_mallocz(s->lowdelay.num_x * s->lowdelay.num_y * sizeof(struct lowdelay_slice));
 
     align_get_bits(&s->gb);

     /*[DIRAC_STD] 13.5.2 Slices. slice(sx,sy) */

     buf = s->gb.buffer + get_bits_count(&s->gb)/8;
     bufsize = get_bits_left(&s->gb);
 

     for (slice_y = 0; bufsize > 0 && slice_y < s->lowdelay.num_y; slice_y++)
         for (slice_x = 0; bufsize > 0 && slice_x < s->lowdelay.num_x; slice_x++) {

             bytes = (slice_num+1) * s->lowdelay.bytes.num / s->lowdelay.bytes.den

                 - slice_num    * s->lowdelay.bytes.num / s->lowdelay.bytes.den;

 
             slices[slice_num].bytes   = bytes;
             slices[slice_num].slice_x = slice_x;
             slices[slice_num].slice_y = slice_y;
             init_get_bits(&slices[slice_num].gb, buf, bufsize);
             slice_num++;
 
             buf     += bytes;
             bufsize -= bytes*8;
         }
 
     avctx->execute(avctx, decode_lowdelay_slice, slices, NULL, slice_num,

                    sizeof(struct lowdelay_slice)); /* [DIRAC_STD] 13.5.2 Slices */
     intra_dc_prediction(&s->plane[0].band[0][0]);  /* [DIRAC_STD] 13.3 intra_dc_prediction() */
     intra_dc_prediction(&s->plane[1].band[0][0]);  /* [DIRAC_STD] 13.3 intra_dc_prediction() */
     intra_dc_prediction(&s->plane[2].band[0][0]);  /* [DIRAC_STD] 13.3 intra_dc_prediction() */

     av_free(slices);
 }
 
 static void init_planes(DiracContext *s)
 {
     int i, w, h, level, orientation;
 
     for (i = 0; i < 3; i++) {
         Plane *p = &s->plane[i];
 

         p->width       = s->source.width  >> (i ? s->chroma_x_shift : 0);
         p->height      = s->source.height >> (i ? s->chroma_y_shift : 0);

         p->idwt_width  = w = CALC_PADDING(p->width , s->wavelet_depth);
         p->idwt_height = h = CALC_PADDING(p->height, s->wavelet_depth);
         p->idwt_stride = FFALIGN(p->idwt_width, 8);
 
         for (level = s->wavelet_depth-1; level >= 0; level--) {
             w = w>>1;
             h = h>>1;
             for (orientation = !!level; orientation < 4; orientation++) {
                 SubBand *b = &p->band[level][orientation];
 
                 b->ibuf   = p->idwt_buf;
                 b->level  = level;
                 b->stride = p->idwt_stride << (s->wavelet_depth - level);
                 b->width  = w;
                 b->height = h;
                 b->orientation = orientation;
 
                 if (orientation & 1)
                     b->ibuf += w;
                 if (orientation > 1)
                     b->ibuf += b->stride>>1;
 
                 if (level)
                     b->parent = &p->band[level-1][orientation];
             }
         }
 
         if (i > 0) {
             p->xblen = s->plane[0].xblen >> s->chroma_x_shift;
             p->yblen = s->plane[0].yblen >> s->chroma_y_shift;
             p->xbsep = s->plane[0].xbsep >> s->chroma_x_shift;
             p->ybsep = s->plane[0].ybsep >> s->chroma_y_shift;
         }
 
         p->xoffset = (p->xblen - p->xbsep)/2;
         p->yoffset = (p->yblen - p->ybsep)/2;
     }
 }
 
 /**
  * Unpack the motion compensation parameters

  * Dirac Specification ->
  * 11.2 Picture prediction data. picture_prediction()

  */
 static int dirac_unpack_prediction_parameters(DiracContext *s)
 {
     static const uint8_t default_blen[] = { 4, 12, 16, 24 };
     static const uint8_t default_bsep[] = { 4,  8, 12, 16 };
 
     GetBitContext *gb = &s->gb;
     unsigned idx, ref;
 
     align_get_bits(gb);

     /* [DIRAC_STD] 11.2.2 Block parameters. block_parameters() */
     /* Luma and Chroma are equal. 11.2.3 */
     idx = svq3_get_ue_golomb(gb); /* [DIRAC_STD] index */

     if (idx > 4) {

         av_log(s->avctx, AV_LOG_ERROR, "Block prediction index too high\n");

         return -1;

     }

 
     if (idx == 0) {
         s->plane[0].xblen = svq3_get_ue_golomb(gb);
         s->plane[0].yblen = svq3_get_ue_golomb(gb);
         s->plane[0].xbsep = svq3_get_ue_golomb(gb);
         s->plane[0].ybsep = svq3_get_ue_golomb(gb);
     } else {

         /*[DIRAC_STD] preset_block_params(index). Table 11.1 */

         s->plane[0].xblen = default_blen[idx-1];
         s->plane[0].yblen = default_blen[idx-1];
         s->plane[0].xbsep = default_bsep[idx-1];
         s->plane[0].ybsep = default_bsep[idx-1];
     }

     /*[DIRAC_STD] 11.2.4 motion_data_dimensions()
       Calculated in function dirac_unpack_block_motion_data */

     if (!s->plane[0].xbsep || !s->plane[0].ybsep || s->plane[0].xbsep < s->plane[0].xblen/2 || s->plane[0].ybsep < s->plane[0].yblen/2) {

         av_log(s->avctx, AV_LOG_ERROR, "Block separation too small\n");
         return -1;
     }
     if (s->plane[0].xbsep > s->plane[0].xblen || s->plane[0].ybsep > s->plane[0].yblen) {

         av_log(s->avctx, AV_LOG_ERROR, "Block separation greater than size\n");

         return -1;
     }
     if (FFMAX(s->plane[0].xblen, s->plane[0].yblen) > MAX_BLOCKSIZE) {
         av_log(s->avctx, AV_LOG_ERROR, "Unsupported large block size\n");
         return -1;
     }
 

     /*[DIRAC_STD] 11.2.5 Motion vector precision. motion_vector_precision()
       Read motion vector precision */

     s->mv_precision = svq3_get_ue_golomb(gb);
     if (s->mv_precision > 3) {
         av_log(s->avctx, AV_LOG_ERROR, "MV precision finer than eighth-pel\n");
         return -1;
     }
 

     /*[DIRAC_STD] 11.2.6 Global motion. global_motion()
       Read the global motion compensation parameters */

     s->globalmc_flag = get_bits1(gb);
     if (s->globalmc_flag) {
         memset(s->globalmc, 0, sizeof(s->globalmc));

         /* [DIRAC_STD] pan_tilt(gparams) */

         for (ref = 0; ref < s->num_refs; ref++) {
             if (get_bits1(gb)) {
                 s->globalmc[ref].pan_tilt[0] = dirac_get_se_golomb(gb);
                 s->globalmc[ref].pan_tilt[1] = dirac_get_se_golomb(gb);
             }

             /* [DIRAC_STD] zoom_rotate_shear(gparams)
                zoom/rotation/shear parameters */

             if (get_bits1(gb)) {

                 s->globalmc[ref].zrs_exp   = svq3_get_ue_golomb(gb);

                 s->globalmc[ref].zrs[0][0] = dirac_get_se_golomb(gb);
                 s->globalmc[ref].zrs[0][1] = dirac_get_se_golomb(gb);
                 s->globalmc[ref].zrs[1][0] = dirac_get_se_golomb(gb);
                 s->globalmc[ref].zrs[1][1] = dirac_get_se_golomb(gb);
             } else {
                 s->globalmc[ref].zrs[0][0] = 1;
                 s->globalmc[ref].zrs[1][1] = 1;
             }

             /* [DIRAC_STD] perspective(gparams) */

             if (get_bits1(gb)) {
                 s->globalmc[ref].perspective_exp = svq3_get_ue_golomb(gb);

                 s->globalmc[ref].perspective[0]  = dirac_get_se_golomb(gb);
                 s->globalmc[ref].perspective[1]  = dirac_get_se_golomb(gb);

             }
         }
     }
 

     /*[DIRAC_STD] 11.2.7 Picture prediction mode. prediction_mode()
       Picture prediction mode, not currently used. */

     if (svq3_get_ue_golomb(gb)) {
         av_log(s->avctx, AV_LOG_ERROR, "Unknown picture prediction mode\n");
         return -1;
     }
 

     /* [DIRAC_STD] 11.2.8 Reference picture weight. reference_picture_weights()
        just data read, weight calculation will be done later on. */

     s->weight_log2denom = 1;
     s->weight[0]        = 1;
     s->weight[1]        = 1;
 
     if (get_bits1(gb)) {
         s->weight_log2denom = svq3_get_ue_golomb(gb);
         s->weight[0] = dirac_get_se_golomb(gb);
         if (s->num_refs == 2)
             s->weight[1] = dirac_get_se_golomb(gb);
     }
     return 0;
 }
 

 /**
  * Dirac Specification ->
  * 11.3 Wavelet transform data. wavelet_transform()
  */

 static int dirac_unpack_idwt_params(DiracContext *s)
 {
     GetBitContext *gb = &s->gb;
     int i, level;

     unsigned tmp;
 
 #define CHECKEDREAD(dst, cond, errmsg) \
     tmp = svq3_get_ue_golomb(gb); \
     if (cond) { \
         av_log(s->avctx, AV_LOG_ERROR, errmsg); \
         return -1; \
     }\
     dst = tmp;

 
     align_get_bits(gb);
 
     s->zero_res = s->num_refs ? get_bits1(gb) : 0;
     if (s->zero_res)
         return 0;
 

     /*[DIRAC_STD] 11.3.1 Transform parameters. transform_parameters() */

     CHECKEDREAD(s->wavelet_idx, tmp > 6, "wavelet_idx is too big\n")

     CHECKEDREAD(s->wavelet_depth, tmp > MAX_DWT_LEVELS || tmp < 1, "invalid number of DWT decompositions\n")

 
     if (!s->low_delay) {

         /* Codeblock parameters (core syntax only) */

         if (get_bits1(gb)) {
             for (i = 0; i <= s->wavelet_depth; i++) {

                 CHECKEDREAD(s->codeblock[i].width , tmp < 1, "codeblock width invalid\n")
                 CHECKEDREAD(s->codeblock[i].height, tmp < 1, "codeblock height invalid\n")

             }
 

             CHECKEDREAD(s->codeblock_mode, tmp > 1, "unknown codeblock mode\n")

         } else
             for (i = 0; i <= s->wavelet_depth; i++)
                 s->codeblock[i].width = s->codeblock[i].height = 1;
     } else {

         /* Slice parameters + quantization matrix*/
         /*[DIRAC_STD] 11.3.4 Slice coding Parameters (low delay syntax only). slice_parameters() */

         s->lowdelay.num_x     = svq3_get_ue_golomb(gb);
         s->lowdelay.num_y     = svq3_get_ue_golomb(gb);
         s->lowdelay.bytes.num = svq3_get_ue_golomb(gb);
         s->lowdelay.bytes.den = svq3_get_ue_golomb(gb);
 

         if (s->lowdelay.bytes.den <= 0) {
             av_log(s->avctx,AV_LOG_ERROR,"Invalid lowdelay.bytes.den\n");
             return AVERROR_INVALIDDATA;
         }
 

         /* [DIRAC_STD] 11.3.5 Quantisation matrices (low-delay syntax). quant_matrix() */

         if (get_bits1(gb)) {

             av_log(s->avctx,AV_LOG_DEBUG,"Low Delay: Has Custom Quantization Matrix!\n");
             /* custom quantization matrix */

             s->lowdelay.quant[0][0] = svq3_get_ue_golomb(gb);
             for (level = 0; level < s->wavelet_depth; level++) {
                 s->lowdelay.quant[level][1] = svq3_get_ue_golomb(gb);
                 s->lowdelay.quant[level][2] = svq3_get_ue_golomb(gb);
                 s->lowdelay.quant[level][3] = svq3_get_ue_golomb(gb);
             }
         } else {

             if (s->wavelet_depth > 4) {
                 av_log(s->avctx,AV_LOG_ERROR,"Mandatory custom low delay matrix missing for depth %d\n", s->wavelet_depth);
                 return AVERROR_INVALIDDATA;
             }

             /* default quantization matrix */

             for (level = 0; level < s->wavelet_depth; level++)
                 for (i = 0; i < 4; i++) {
                     s->lowdelay.quant[level][i] = default_qmat[s->wavelet_idx][level][i];

                     /* haar with no shift differs for different depths */

                     if (s->wavelet_idx == 3)
                         s->lowdelay.quant[level][i] += 4*(s->wavelet_depth-1 - level);
                 }
         }
     }
     return 0;
 }
 
 static inline int pred_sbsplit(uint8_t *sbsplit, int stride, int x, int y)
 {
     static const uint8_t avgsplit[7] = { 0, 0, 1, 1, 1, 2, 2 };
 
     if (!(x|y))
         return 0;
     else if (!y)
         return sbsplit[-1];
     else if (!x)
         return sbsplit[-stride];
 
     return avgsplit[sbsplit[-1] + sbsplit[-stride] + sbsplit[-stride-1]];
 }
 
 static inline int pred_block_mode(DiracBlock *block, int stride, int x, int y, int refmask)
 {
     int pred;
 
     if (!(x|y))
         return 0;
     else if (!y)
         return block[-1].ref & refmask;
     else if (!x)
         return block[-stride].ref & refmask;
 

     /* return the majority */

     pred = (block[-1].ref & refmask) + (block[-stride].ref & refmask) + (block[-stride-1].ref & refmask);
     return (pred >> 1) & refmask;
 }
 
 static inline void pred_block_dc(DiracBlock *block, int stride, int x, int y)
 {
     int i, n = 0;
 
     memset(block->u.dc, 0, sizeof(block->u.dc));
 
     if (x && !(block[-1].ref & 3)) {
         for (i = 0; i < 3; i++)
             block->u.dc[i] += block[-1].u.dc[i];
         n++;
     }
 
     if (y && !(block[-stride].ref & 3)) {
         for (i = 0; i < 3; i++)
             block->u.dc[i] += block[-stride].u.dc[i];
         n++;
     }
 
     if (x && y && !(block[-1-stride].ref & 3)) {
         for (i = 0; i < 3; i++)
             block->u.dc[i] += block[-1-stride].u.dc[i];
         n++;
     }
 
     if (n == 2) {
         for (i = 0; i < 3; i++)
             block->u.dc[i] = (block->u.dc[i]+1)>>1;
     } else if (n == 3) {
         for (i = 0; i < 3; i++)
             block->u.dc[i] = divide3(block->u.dc[i]);
     }
 }
 
 static inline void pred_mv(DiracBlock *block, int stride, int x, int y, int ref)
 {
     int16_t *pred[3];
     int refmask = ref+1;

     int mask = refmask | DIRAC_REF_MASK_GLOBAL; /*  exclude gmc blocks */

     int n = 0;
 
     if (x && (block[-1].ref & mask) == refmask)
         pred[n++] = block[-1].u.mv[ref];
 
     if (y && (block[-stride].ref & mask) == refmask)
         pred[n++] = block[-stride].u.mv[ref];
 
     if (x && y && (block[-stride-1].ref & mask) == refmask)
         pred[n++] = block[-stride-1].u.mv[ref];
 
     switch (n) {
     case 0:
         block->u.mv[ref][0] = 0;
         block->u.mv[ref][1] = 0;
         break;
     case 1:
         block->u.mv[ref][0] = pred[0][0];
         block->u.mv[ref][1] = pred[0][1];
         break;
     case 2:
         block->u.mv[ref][0] = (pred[0][0] + pred[1][0] + 1) >> 1;
         block->u.mv[ref][1] = (pred[0][1] + pred[1][1] + 1) >> 1;
         break;
     case 3:
         block->u.mv[ref][0] = mid_pred(pred[0][0], pred[1][0], pred[2][0]);
         block->u.mv[ref][1] = mid_pred(pred[0][1], pred[1][1], pred[2][1]);
         break;
     }
 }
 
 static void global_mv(DiracContext *s, DiracBlock *block, int x, int y, int ref)
 {

     int ez      = s->globalmc[ref].zrs_exp;
     int ep      = s->globalmc[ref].perspective_exp;

     int (*A)[2] = s->globalmc[ref].zrs;

     int *b      = s->globalmc[ref].pan_tilt;
     int *c      = s->globalmc[ref].perspective;

     int m       = (1<<ep) - (c[0]*x + c[1]*y);
     int mx      = m * ((A[0][0] * x + A[0][1]*y) + (1<<ez) * b[0]);
     int my      = m * ((A[1][0] * x + A[1][1]*y) + (1<<ez) * b[1]);

 
     block->u.mv[ref][0] = (mx + (1<<(ez+ep))) >> (ez+ep);
     block->u.mv[ref][1] = (my + (1<<(ez+ep))) >> (ez+ep);
 }
 
 static void decode_block_params(DiracContext *s, DiracArith arith[8], DiracBlock *block,
                                 int stride, int x, int y)
 {
     int i;
 

     block->ref  = pred_block_mode(block, stride, x, y, DIRAC_REF_MASK_REF1);

     block->ref ^= dirac_get_arith_bit(arith, CTX_PMODE_REF1);
 
     if (s->num_refs == 2) {
         block->ref |= pred_block_mode(block, stride, x, y, DIRAC_REF_MASK_REF2);
         block->ref ^= dirac_get_arith_bit(arith, CTX_PMODE_REF2) << 1;
     }
 
     if (!block->ref) {
         pred_block_dc(block, stride, x, y);
         for (i = 0; i < 3; i++)
             block->u.dc[i] += dirac_get_arith_int(arith+1+i, CTX_DC_F1, CTX_DC_DATA);
         return;
     }
 
     if (s->globalmc_flag) {
         block->ref |= pred_block_mode(block, stride, x, y, DIRAC_REF_MASK_GLOBAL);
         block->ref ^= dirac_get_arith_bit(arith, CTX_GLOBAL_BLOCK) << 2;
     }
 
     for (i = 0; i < s->num_refs; i++)
         if (block->ref & (i+1)) {
             if (block->ref & DIRAC_REF_MASK_GLOBAL) {
                 global_mv(s, block, x, y, i);
             } else {
                 pred_mv(block, stride, x, y, i);

                 block->u.mv[i][0] += dirac_get_arith_int(arith + 4 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
                 block->u.mv[i][1] += dirac_get_arith_int(arith + 5 + 2 * i, CTX_MV_F1, CTX_MV_DATA);

             }
         }
 }
 
 /**
  * Copies the current block to the other blocks covered by the current superblock split mode
  */
 static void propagate_block_data(DiracBlock *block, int stride, int size)
 {
     int x, y;
     DiracBlock *dst = block;
 
     for (x = 1; x < size; x++)
         dst[x] = *block;
 
     for (y = 1; y < size; y++) {
         dst += stride;
         for (x = 0; x < size; x++)
             dst[x] = *block;
     }
 }
 

 /**
  * Dirac Specification ->
  * 12. Block motion data syntax
  */

 static int dirac_unpack_block_motion_data(DiracContext *s)

 {
     GetBitContext *gb = &s->gb;
     uint8_t *sbsplit = s->sbsplit;
     int i, x, y, q, p;
     DiracArith arith[8];
 
     align_get_bits(gb);
 

     /* [DIRAC_STD] 11.2.4 and 12.2.1 Number of blocks and superblocks */

     s->sbwidth  = DIVRNDUP(s->source.width,  4*s->plane[0].xbsep);
     s->sbheight = DIVRNDUP(s->source.height, 4*s->plane[0].ybsep);

     s->blwidth  = 4 * s->sbwidth;
     s->blheight = 4 * s->sbheight;

     /* [DIRAC_STD] 12.3.1 Superblock splitting modes. superblock_split_modes()
        decode superblock split modes */
     ff_dirac_init_arith_decoder(arith, gb, svq3_get_ue_golomb(gb));     /* svq3_get_ue_golomb(gb) is the length */

     for (y = 0; y < s->sbheight; y++) {
         for (x = 0; x < s->sbwidth; x++) {

             unsigned int split  = dirac_get_arith_uint(arith, CTX_SB_F1, CTX_SB_DATA);
             if (split > 2)
                 return -1;

             sbsplit[x] = (split + pred_sbsplit(sbsplit+x, s->sbwidth, x, y)) % 3;
         }
         sbsplit += s->sbwidth;
     }
 

     /* setup arith decoding */

     ff_dirac_init_arith_decoder(arith, gb, svq3_get_ue_golomb(gb));
     for (i = 0; i < s->num_refs; i++) {

         ff_dirac_init_arith_decoder(arith + 4 + 2 * i, gb, svq3_get_ue_golomb(gb));
         ff_dirac_init_arith_decoder(arith + 5 + 2 * i, gb, svq3_get_ue_golomb(gb));

     }
     for (i = 0; i < 3; i++)
         ff_dirac_init_arith_decoder(arith+1+i, gb, svq3_get_ue_golomb(gb));
 
     for (y = 0; y < s->sbheight; y++)
         for (x = 0; x < s->sbwidth; x++) {

             int blkcnt = 1 << s->sbsplit[y * s->sbwidth + x];
             int step   = 4 >> s->sbsplit[y * s->sbwidth + x];

 
             for (q = 0; q < blkcnt; q++)
                 for (p = 0; p < blkcnt; p++) {

                     int bx = 4 * x + p*step;
                     int by = 4 * y + q*step;

                     DiracBlock *block = &s->blmotion[by*s->blwidth + bx];
                     decode_block_params(s, arith, block, s->blwidth, bx, by);
                     propagate_block_data(block, s->blwidth, step);
                 }
         }

 
     return 0;

 }
 
 static int weight(int i, int blen, int offset)
 {

 #define ROLLOFF(i) offset == 1 ? ((i) ? 5 : 3) :        \

     (1 + (6*(i) + offset - 1) / (2*offset - 1))
 
     if (i < 2*offset)
         return ROLLOFF(i);
     else if (i > blen-1 - 2*offset)
         return ROLLOFF(blen-1 - i);
     return 8;
 }
 
 static void init_obmc_weight_row(Plane *p, uint8_t *obmc_weight, int stride,
                                  int left, int right, int wy)
 {
     int x;
     for (x = 0; left && x < p->xblen >> 1; x++)
         obmc_weight[x] = wy*8;
     for (; x < p->xblen >> right; x++)
         obmc_weight[x] = wy*weight(x, p->xblen, p->xoffset);
     for (; x < p->xblen; x++)
         obmc_weight[x] = wy*8;
     for (; x < stride; x++)
         obmc_weight[x] = 0;
 }
 
 static void init_obmc_weight(Plane *p, uint8_t *obmc_weight, int stride,
                              int left, int right, int top, int bottom)
 {
     int y;
     for (y = 0; top && y < p->yblen >> 1; y++) {
         init_obmc_weight_row(p, obmc_weight, stride, left, right, 8);
         obmc_weight += stride;
     }
     for (; y < p->yblen >> bottom; y++) {
         int wy = weight(y, p->yblen, p->yoffset);
         init_obmc_weight_row(p, obmc_weight, stride, left, right, wy);
         obmc_weight += stride;
     }
     for (; y < p->yblen; y++) {
         init_obmc_weight_row(p, obmc_weight, stride, left, right, 8);
         obmc_weight += stride;
     }
 }
 
 static void init_obmc_weights(DiracContext *s, Plane *p, int by)
 {
     int top = !by;
     int bottom = by == s->blheight-1;
 

     /* don't bother re-initing for rows 2 to blheight-2, the weights don't change */

     if (top || bottom || by == 1) {
         init_obmc_weight(p, s->obmc_weight[0], MAX_BLOCKSIZE, 1, 0, top, bottom);
         init_obmc_weight(p, s->obmc_weight[1], MAX_BLOCKSIZE, 0, 0, top, bottom);
         init_obmc_weight(p, s->obmc_weight[2], MAX_BLOCKSIZE, 0, 1, top, bottom);
     }
 }
 
 static const uint8_t epel_weights[4][4][4] = {
     {{ 16,  0,  0,  0 },
      { 12,  4,  0,  0 },
      {  8,  8,  0,  0 },
      {  4, 12,  0,  0 }},
     {{ 12,  0,  4,  0 },
      {  9,  3,  3,  1 },
      {  6,  6,  2,  2 },
      {  3,  9,  1,  3 }},
     {{  8,  0,  8,  0 },
      {  6,  2,  6,  2 },
      {  4,  4,  4,  4 },
      {  2,  6,  2,  6 }},
     {{  4,  0, 12,  0 },
      {  3,  1,  9,  3 },
      {  2,  2,  6,  6 },
      {  1,  3,  3,  9 }}
 };
 
 /**
  * For block x,y, determine which of the hpel planes to do bilinear
  * interpolation from and set src[] to the location in each hpel plane
  * to MC from.
  *
  * @return the index of the put_dirac_pixels_tab function to use
  *  0 for 1 plane (fpel,hpel), 1 for 2 planes (qpel), 2 for 4 planes (qpel), and 3 for epel
  */
 static int mc_subpel(DiracContext *s, DiracBlock *block, const uint8_t *src[5],
                      int x, int y, int ref, int plane)
 {
     Plane *p = &s->plane[plane];
     uint8_t **ref_hpel = s->ref_pics[ref]->hpel[plane];
     int motion_x = block->u.mv[ref][0];
     int motion_y = block->u.mv[ref][1];
     int mx, my, i, epel, nplanes = 0;
 
     if (plane) {
         motion_x >>= s->chroma_x_shift;
         motion_y >>= s->chroma_y_shift;
     }
 

     mx         = motion_x & ~(-1U << s->mv_precision);
     my         = motion_y & ~(-1U << s->mv_precision);

     motion_x >>= s->mv_precision;
     motion_y >>= s->mv_precision;

     /* normalize subpel coordinates to epel */
     /* TODO: template this function? */

     mx      <<= 3 - s->mv_precision;
     my      <<= 3 - s->mv_precision;

 
     x += motion_x;
     y += motion_y;
     epel = (mx|my)&1;
 

     /* hpel position */

     if (!((mx|my)&3)) {
         nplanes = 1;
         src[0] = ref_hpel[(my>>1)+(mx>>2)] + y*p->stride + x;
     } else {

         /* qpel or epel */

         nplanes = 4;
         for (i = 0; i < 4; i++)
             src[i] = ref_hpel[i] + y*p->stride + x;
 

         /* if we're interpolating in the right/bottom halves, adjust the planes as needed
            we increment x/y because the edge changes for half of the pixels */

         if (mx > 4) {
             src[0] += 1;
             src[2] += 1;
             x++;
         }
         if (my > 4) {
             src[0] += p->stride;
             src[1] += p->stride;
             y++;
         }
 

         /* hpel planes are:
            [0]: F  [1]: H
            [2]: V  [3]: C */

         if (!epel) {

             /* check if we really only need 2 planes since either mx or my is
                a hpel position. (epel weights of 0 handle this there) */

             if (!(mx&3)) {

                 /* mx == 0: average [0] and [2]
                    mx == 4: average [1] and [3] */

                 src[!mx] = src[2 + !!mx];
                 nplanes = 2;
             } else if (!(my&3)) {
                 src[0] = src[(my>>1)  ];
                 src[1] = src[(my>>1)+1];
                 nplanes = 2;
             }
         } else {

             /* adjust the ordering if needed so the weights work */

             if (mx > 4) {
                 FFSWAP(const uint8_t *, src[0], src[1]);
                 FFSWAP(const uint8_t *, src[2], src[3]);
             }
             if (my > 4) {
                 FFSWAP(const uint8_t *, src[0], src[2]);
                 FFSWAP(const uint8_t *, src[1], src[3]);
             }
             src[4] = epel_weights[my&3][mx&3];
         }
     }
 

     /* fixme: v/h _edge_pos */

     if (x + p->xblen > p->width +EDGE_WIDTH/2 ||
         y + p->yblen > p->height+EDGE_WIDTH/2 ||
         x < 0 || y < 0) {

         for (i = 0; i < nplanes; i++) {
             ff_emulated_edge_mc(s->edge_emu_buffer[i], src[i], p->stride,
                                 p->xblen, p->yblen, x, y,
                                 p->width+EDGE_WIDTH/2, p->height+EDGE_WIDTH/2);
             src[i] = s->edge_emu_buffer[i];
         }
     }
     return (nplanes>>1) + epel;
 }
 
 static void add_dc(uint16_t *dst, int dc, int stride,
                    uint8_t *obmc_weight, int xblen, int yblen)
 {
     int x, y;
     dc += 128;
 
     for (y = 0; y < yblen; y++) {
         for (x = 0; x < xblen; x += 2) {
             dst[x  ] += dc * obmc_weight[x  ];
             dst[x+1] += dc * obmc_weight[x+1];
         }

         dst          += stride;
         obmc_weight  += MAX_BLOCKSIZE;

     }
 }
 
 static void block_mc(DiracContext *s, DiracBlock *block,
                      uint16_t *mctmp, uint8_t *obmc_weight,
                      int plane, int dstx, int dsty)
 {
     Plane *p = &s->plane[plane];
     const uint8_t *src[5];
     int idx;
 
     switch (block->ref&3) {

     case 0: /* DC */

         add_dc(mctmp, block->u.dc[plane], p->stride, obmc_weight, p->xblen, p->yblen);
         return;
     case 1:
     case 2:
         idx = mc_subpel(s, block, src, dstx, dsty, (block->ref&3)-1, plane);
         s->put_pixels_tab[idx](s->mcscratch, src, p->stride, p->yblen);
         if (s->weight_func)
             s->weight_func(s->mcscratch, p->stride, s->weight_log2denom,
                            s->weight[0] + s->weight[1], p->yblen);
         break;
     case 3:
         idx = mc_subpel(s, block, src, dstx, dsty, 0, plane);
         s->put_pixels_tab[idx](s->mcscratch, src, p->stride, p->yblen);
         idx = mc_subpel(s, block, src, dstx, dsty, 1, plane);
         if (s->biweight_func) {

             /* fixme: +32 is a quick hack */

             s->put_pixels_tab[idx](s->mcscratch + 32, src, p->stride, p->yblen);
             s->biweight_func(s->mcscratch, s->mcscratch+32, p->stride, s->weight_log2denom,
                              s->weight[0], s->weight[1], p->yblen);
         } else
             s->avg_pixels_tab[idx](s->mcscratch, src, p->stride, p->yblen);
         break;
     }
     s->add_obmc(mctmp, s->mcscratch, p->stride, obmc_weight, p->yblen);
 }
 
 static void mc_row(DiracContext *s, DiracBlock *block, uint16_t *mctmp, int plane, int dsty)
 {
     Plane *p = &s->plane[plane];
     int x, dstx = p->xbsep - p->xoffset;
 
     block_mc(s, block, mctmp, s->obmc_weight[0], plane, -p->xoffset, dsty);
     mctmp += p->xbsep;
 
     for (x = 1; x < s->blwidth-1; x++) {
         block_mc(s, block+x, mctmp, s->obmc_weight[1], plane, dstx, dsty);
         dstx  += p->xbsep;
         mctmp += p->xbsep;
     }
     block_mc(s, block+x, mctmp, s->obmc_weight[2], plane, dstx, dsty);
 }
 
 static void select_dsp_funcs(DiracContext *s, int width, int height, int xblen, int yblen)
 {
     int idx = 0;
     if (xblen > 8)
         idx = 1;
     if (xblen > 16)
         idx = 2;
 
     memcpy(s->put_pixels_tab, s->diracdsp.put_dirac_pixels_tab[idx], sizeof(s->put_pixels_tab));
     memcpy(s->avg_pixels_tab, s->diracdsp.avg_dirac_pixels_tab[idx], sizeof(s->avg_pixels_tab));
     s->add_obmc = s->diracdsp.add_dirac_obmc[idx];
     if (s->weight_log2denom > 1 || s->weight[0] != 1 || s->weight[1] != 1) {
         s->weight_func   = s->diracdsp.weight_dirac_pixels_tab[idx];
         s->biweight_func = s->diracdsp.biweight_dirac_pixels_tab[idx];
     } else {
         s->weight_func   = NULL;
         s->biweight_func = NULL;
     }
 }
 
 static void interpolate_refplane(DiracContext *s, DiracFrame *ref, int plane, int width, int height)
 {

     /* chroma allocates an edge of 8 when subsampled
        which for 4:2:2 means an h edge of 16 and v edge of 8
        just use 8 for everything for the moment */

     int i, edge = EDGE_WIDTH/2;
 
     ref->hpel[plane][0] = ref->avframe.data[plane];

     s->dsp.draw_edges(ref->hpel[plane][0], ref->avframe.linesize[plane], width, height, edge, edge, EDGE_TOP | EDGE_BOTTOM); /* EDGE_TOP | EDGE_BOTTOM values just copied to make it build, this needs to be ensured */

     /* no need for hpel if we only have fpel vectors */

     if (!s->mv_precision)
         return;
 
     for (i = 1; i < 4; i++) {
         if (!ref->hpel_base[plane][i])
             ref->hpel_base[plane][i] = av_malloc((height+2*edge) * ref->avframe.linesize[plane] + 32);

         /* we need to be 16-byte aligned even for chroma */

         ref->hpel[plane][i] = ref->hpel_base[plane][i] + edge*ref->avframe.linesize[plane] + 16;
     }
 
     if (!ref->interpolated[plane]) {
         s->diracdsp.dirac_hpel_filter(ref->hpel[plane][1], ref->hpel[plane][2],
                                       ref->hpel[plane][3], ref->hpel[plane][0],
                                       ref->avframe.linesize[plane], width, height);
         s->dsp.draw_edges(ref->hpel[plane][1], ref->avframe.linesize[plane], width, height, edge, edge, EDGE_TOP | EDGE_BOTTOM);

         s->dsp.draw_edges(ref->hpel[plane][2], ref->avframe.linesize[plane], width, height, edge, edge, EDGE_TOP | EDGE_BOTTOM);

         s->dsp.draw_edges(ref->hpel[plane][3], ref->avframe.linesize[plane], width, height, edge, edge, EDGE_TOP | EDGE_BOTTOM);
     }
     ref->interpolated[plane] = 1;
 }
 

 /**
  * Dirac Specification ->
  * 13.0 Transform data syntax. transform_data()
  */

 static int dirac_decode_frame_internal(DiracContext *s)
 {

     DWTContext d;
     int y, i, comp, dsty;
 
     if (s->low_delay) {
         /* [DIRAC_STD] 13.5.1 low_delay_transform_data() */
         for (comp = 0; comp < 3; comp++) {
             Plane *p = &s->plane[comp];
             memset(p->idwt_buf, 0, p->idwt_stride * p->idwt_height * sizeof(IDWTELEM));
         }
         if (!s->zero_res)
             decode_lowdelay(s);
     }

 
     for (comp = 0; comp < 3; comp++) {

         Plane *p       = &s->plane[comp];

         uint8_t *frame = s->current_picture->avframe.data[comp];
 
         /* FIXME: small resolutions */
         for (i = 0; i < 4; i++)
             s->edge_emu_buffer[i] = s->edge_emu_buffer_base + i*FFALIGN(p->width, 16);

         if (!s->zero_res && !s->low_delay)
         {
             memset(p->idwt_buf, 0, p->idwt_stride * p->idwt_height * sizeof(IDWTELEM));
             decode_component(s, comp); /* [DIRAC_STD] 13.4.1 core_transform_data() */
         }
         if (ff_spatial_idwt_init2(&d, p->idwt_buf, p->idwt_width, p->idwt_height, p->idwt_stride,
                                   s->wavelet_idx+2, s->wavelet_depth, p->idwt_tmp))
             return -1;

         if (!s->num_refs) { /* intra */
             for (y = 0; y < p->height; y += 16) {
                 ff_spatial_idwt_slice2(&d, y+16); /* decode */
                 s->diracdsp.put_signed_rect_clamped(frame + y*p->stride, p->stride,
                                                     p->idwt_buf + y*p->idwt_stride, p->idwt_stride, p->width, 16);
             }
         } else { /* inter */
             int rowheight = p->ybsep*p->stride;

             select_dsp_funcs(s, p->width, p->height, p->xblen, p->yblen);

             for (i = 0; i < s->num_refs; i++)
                 interpolate_refplane(s, s->ref_pics[i], comp, p->width, p->height);

             memset(s->mctmp, 0, 4*p->yoffset*p->stride);

             dsty = -p->yoffset;
             for (y = 0; y < s->blheight; y++) {

                 int h     = 0,
                     start = FFMAX(dsty, 0);
                 uint16_t *mctmp    = s->mctmp + y*rowheight;

                 DiracBlock *blocks = s->blmotion + y*s->blwidth;

                 init_obmc_weights(s, p, y);

                 if (y == s->blheight-1 || start+p->ybsep > p->height)
                     h = p->height - start;
                 else
                     h = p->ybsep - (start - dsty);
                 if (h < 0)
                     break;

                 memset(mctmp+2*p->yoffset*p->stride, 0, 2*rowheight);
                 mc_row(s, blocks, mctmp, comp, dsty);

                 mctmp += (start - dsty)*p->stride + p->xoffset;
                 ff_spatial_idwt_slice2(&d, start + h); /* decode */
                 s->diracdsp.add_rect_clamped(frame + start*p->stride, mctmp, p->stride,
                                              p->idwt_buf + start*p->idwt_stride, p->idwt_stride, p->width, h);
 
                 dsty += p->ybsep;
             }
         }

     }
 
 

     return 0;

 }
 

 /**
  * Dirac Specification ->
  * 11.1.1 Picture Header. picture_header()
  */

 static int dirac_decode_picture_header(DiracContext *s)
 {
     int retire, picnum;
     int i, j, refnum, refdist;
     GetBitContext *gb = &s->gb;
 

     /* [DIRAC_STD] 11.1.1 Picture Header. picture_header() PICTURE_NUM */

     picnum = s->current_picture->avframe.display_picture_number = get_bits_long(gb, 32);
 
 
     av_log(s->avctx,AV_LOG_DEBUG,"PICTURE_NUM: %d\n",picnum);
 

     /* if this is the first keyframe after a sequence header, start our
        reordering from here */

     if (s->frame_number < 0)
         s->frame_number = picnum;
 
     s->ref_pics[0] = s->ref_pics[1] = NULL;
     for (i = 0; i < s->num_refs; i++) {
         refnum = picnum + dirac_get_se_golomb(gb);
         refdist = INT_MAX;
 

         /* find the closest reference to the one we want */
         /* Jordi: this is needed if the referenced picture hasn't yet arrived */

         for (j = 0; j < MAX_REFERENCE_FRAMES && refdist; j++)
             if (s->ref_frames[j]
                 && FFABS(s->ref_frames[j]->avframe.display_picture_number - refnum) < refdist) {
                 s->ref_pics[i] = s->ref_frames[j];
                 refdist = FFABS(s->ref_frames[j]->avframe.display_picture_number - refnum);
             }
 
         if (!s->ref_pics[i] || refdist)
             av_log(s->avctx, AV_LOG_DEBUG, "Reference not found\n");
 

         /* if there were no references at all, allocate one */

         if (!s->ref_pics[i])
             for (j = 0; j < MAX_FRAMES; j++)
                 if (!s->all_frames[j].avframe.data[0]) {
                     s->ref_pics[i] = &s->all_frames[j];

                     ff_get_buffer(s->avctx, &s->ref_pics[i]->avframe);

                     break;

                 }
     }
 

     /* retire the reference frames that are not used anymore */

     if (s->current_picture->avframe.reference) {
         retire = picnum + dirac_get_se_golomb(gb);
         if (retire != picnum) {
             DiracFrame *retire_pic = remove_frame(s->ref_frames, retire);
 
             if (retire_pic)
                 retire_pic->avframe.reference &= DELAYED_PIC_REF;
             else
                 av_log(s->avctx, AV_LOG_DEBUG, "Frame to retire not found\n");
         }
 

         /* if reference array is full, remove the oldest as per the spec */

         while (add_frame(s->ref_frames, MAX_REFERENCE_FRAMES, s->current_picture)) {
             av_log(s->avctx, AV_LOG_ERROR, "Reference frame overflow\n");
             remove_frame(s->ref_frames, s->ref_frames[0]->avframe.display_picture_number)->avframe.reference &= DELAYED_PIC_REF;
         }
     }
 
     if (s->num_refs) {

         if (dirac_unpack_prediction_parameters(s))  /* [DIRAC_STD] 11.2 Picture Prediction Data. picture_prediction() */

             return -1;

         if (dirac_unpack_block_motion_data(s))      /* [DIRAC_STD] 12. Block motion data syntax                       */
             return -1;

     }

     if (dirac_unpack_idwt_params(s))                /* [DIRAC_STD] 11.3 Wavelet transform data                        */

         return -1;
 

     init_planes(s);

     return 0;
 }
 

 static int get_delayed_pic(DiracContext *s, AVFrame *picture, int *got_frame)

 {
     DiracFrame *out = s->delay_frames[0];

     int i, out_idx  = 0;

     /* find frame with lowest picture number */

     for (i = 1; s->delay_frames[i]; i++)
         if (s->delay_frames[i]->avframe.display_picture_number < out->avframe.display_picture_number) {

             out     = s->delay_frames[i];

             out_idx = i;
         }
 
     for (i = out_idx; s->delay_frames[i]; i++)
         s->delay_frames[i] = s->delay_frames[i+1];
 
     if (out) {
         out->avframe.reference ^= DELAYED_PIC_REF;

         *got_frame = 1;

         *(AVFrame *)picture = out->avframe;

     }
 
     return 0;
 }
 

 /**
  * Dirac Specification ->
  * 9.6 Parse Info Header Syntax. parse_info()
  * 4 byte start code + byte parse code + 4 byte size + 4 byte previous size
  */

 #define DATA_UNIT_HEADER_SIZE 13
 

 /* [DIRAC_STD] dirac_decode_data_unit makes reference to the while defined in 9.3
    inside the function parse_sequence() */

 static int dirac_decode_data_unit(AVCodecContext *avctx, const uint8_t *buf, int size)
 {

     DiracContext *s   = avctx->priv_data;
     DiracFrame *pic   = NULL;

     int i, parse_code = buf[4];

     unsigned tmp;

 
     if (size < DATA_UNIT_HEADER_SIZE)
         return -1;
 
     init_get_bits(&s->gb, &buf[13], 8*(size - DATA_UNIT_HEADER_SIZE));
 
     if (parse_code == pc_seq_header) {
         if (s->seen_sequence_header)
             return 0;
 

         /* [DIRAC_STD] 10. Sequence header */

         if (avpriv_dirac_parse_sequence_header(avctx, &s->gb, &s->source))
             return -1;
 
         avcodec_get_chroma_sub_sample(avctx->pix_fmt, &s->chroma_x_shift, &s->chroma_y_shift);
 
         if (alloc_sequence_buffers(s))
             return -1;
 
         s->seen_sequence_header = 1;

     } else if (parse_code == pc_eos) { /* [DIRAC_STD] End of Sequence */

         free_sequence_buffers(s);
         s->seen_sequence_header = 0;
     } else if (parse_code == pc_aux_data) {

         if (buf[13] == 1) {     /* encoder implementation/version */

             int ver[3];

             /* versions older than 1.0.8 don't store quant delta for
                subbands with only one codeblock */

             if (sscanf(buf+14, "Schroedinger %d.%d.%d", ver, ver+1, ver+2) == 3)
                 if (ver[0] == 1 && ver[1] == 0 && ver[2] <= 7)
                     s->old_delta_quant = 1;
         }

     } else if (parse_code & 0x8) {  /* picture data unit */

         if (!s->seen_sequence_header) {
             av_log(avctx, AV_LOG_DEBUG, "Dropping frame without sequence header\n");
             return -1;
         }
 

         /* find an unused frame */

         for (i = 0; i < MAX_FRAMES; i++)
             if (s->all_frames[i].avframe.data[0] == NULL)
                 pic = &s->all_frames[i];
         if (!pic) {
             av_log(avctx, AV_LOG_ERROR, "framelist full\n");
             return -1;
         }
 
         avcodec_get_frame_defaults(&pic->avframe);
 

         /* [DIRAC_STD] Defined in 9.6.1 ... */

         tmp            =  parse_code & 0x03;                   /* [DIRAC_STD] num_refs()      */
         if (tmp > 2) {
             av_log(avctx, AV_LOG_ERROR, "num_refs of 3\n");
             return -1;
         }
         s->num_refs    = tmp;

         s->is_arith    = (parse_code & 0x48) == 0x08;          /* [DIRAC_STD] using_ac()      */
         s->low_delay   = (parse_code & 0x88) == 0x88;          /* [DIRAC_STD] is_low_delay()  */
         pic->avframe.reference = (parse_code & 0x0C) == 0x0C;  /* [DIRAC_STD]  is_reference() */
         pic->avframe.key_frame = s->num_refs == 0;             /* [DIRAC_STD] is_intra()      */
         pic->avframe.pict_type = s->num_refs + 1;              /* Definition of AVPictureType in avutil.h */

         if (ff_get_buffer(avctx, &pic->avframe) < 0) {

             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
             return -1;
         }
         s->current_picture = pic;
         s->plane[0].stride = pic->avframe.linesize[0];
         s->plane[1].stride = pic->avframe.linesize[1];
         s->plane[2].stride = pic->avframe.linesize[2];
 

         if (alloc_buffers(s, FFMAX3(FFABS(s->plane[0].stride), FFABS(s->plane[1].stride), FFABS(s->plane[2].stride))) < 0)
             return AVERROR(ENOMEM);
 

         /* [DIRAC_STD] 11.1 Picture parse. picture_parse() */

         if (dirac_decode_picture_header(s))
             return -1;
 

         /* [DIRAC_STD] 13.0 Transform data syntax. transform_data() */

         if (dirac_decode_frame_internal(s))
             return -1;
     }
     return 0;
 }
 

 static int dirac_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *pkt)

 {

     DiracContext *s     = avctx->priv_data;

     DiracFrame *picture = data;

     uint8_t *buf        = pkt->data;
     int buf_size        = pkt->size;

     int i, data_unit_size, buf_idx = 0;
 

     /* release unused frames */

     for (i = 0; i < MAX_FRAMES; i++)
         if (s->all_frames[i].avframe.data[0] && !s->all_frames[i].avframe.reference) {
             avctx->release_buffer(avctx, &s->all_frames[i].avframe);
             memset(s->all_frames[i].interpolated, 0, sizeof(s->all_frames[i].interpolated));
         }
 
     s->current_picture = NULL;

     *got_frame = 0;

     /* end of stream, so flush delayed pics */

     if (buf_size == 0)

         return get_delayed_pic(s, (AVFrame *)data, got_frame);

 
     for (;;) {

         /*[DIRAC_STD] Here starts the code from parse_info() defined in 9.6
           [DIRAC_STD] PARSE_INFO_PREFIX = "BBCD" as defined in ISO/IEC 646
           BBCD start code search */

         for (; buf_idx + DATA_UNIT_HEADER_SIZE < buf_size; buf_idx++) {
             if (buf[buf_idx  ] == 'B' && buf[buf_idx+1] == 'B' &&
                 buf[buf_idx+2] == 'C' && buf[buf_idx+3] == 'D')
                 break;
         }

         /* BBCD found or end of data */

         if (buf_idx + DATA_UNIT_HEADER_SIZE >= buf_size)
             break;
 
         data_unit_size = AV_RB32(buf+buf_idx+5);

         if (buf_idx + data_unit_size > buf_size || !data_unit_size) {
             if(buf_idx + data_unit_size > buf_size)

             av_log(s->avctx, AV_LOG_ERROR,

                    "Data unit with size %d is larger than input buffer, discarding\n",
                    data_unit_size);

             buf_idx += 4;
             continue;
         }

         /* [DIRAC_STD] dirac_decode_data_unit makes reference to the while defined in 9.3 inside the function parse_sequence() */

         if (dirac_decode_data_unit(avctx, buf+buf_idx, data_unit_size))

         {

             av_log(s->avctx, AV_LOG_ERROR,"Error in dirac_decode_data_unit\n");

             return -1;

         }

         buf_idx += data_unit_size;
     }
 
     if (!s->current_picture)

         return buf_size;

 
     if (s->current_picture->avframe.display_picture_number > s->frame_number) {
         DiracFrame *delayed_frame = remove_frame(s->delay_frames, s->frame_number);
 
         s->current_picture->avframe.reference |= DELAYED_PIC_REF;
 
         if (add_frame(s->delay_frames, MAX_DELAY, s->current_picture)) {
             int min_num = s->delay_frames[0]->avframe.display_picture_number;

             /* Too many delayed frames, so we display the frame with the lowest pts */

             av_log(avctx, AV_LOG_ERROR, "Delay frame overflow\n");
             delayed_frame = s->delay_frames[0];
 
             for (i = 1; s->delay_frames[i]; i++)
                 if (s->delay_frames[i]->avframe.display_picture_number < min_num)
                     min_num = s->delay_frames[i]->avframe.display_picture_number;
 
             delayed_frame = remove_frame(s->delay_frames, min_num);
             add_frame(s->delay_frames, MAX_DELAY, s->current_picture);
         }
 
         if (delayed_frame) {
             delayed_frame->avframe.reference ^= DELAYED_PIC_REF;

             *(AVFrame*)data = delayed_frame->avframe;

             *got_frame = 1;

         }
     } else if (s->current_picture->avframe.display_picture_number == s->frame_number) {

         /* The right frame at the right time :-) */
         *(AVFrame*)data = s->current_picture->avframe;

         *got_frame = 1;

     }
 

     if (*got_frame)

         s->frame_number = picture->avframe.display_picture_number + 1;
 
     return buf_idx;
 }
 
 AVCodec ff_dirac_decoder = {

     .name           = "dirac",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_DIRAC,

     .priv_data_size = sizeof(DiracContext),
     .init           = dirac_decode_init,
     .close          = dirac_decode_end,
     .decode         = dirac_decode_frame,
     .capabilities   = CODEC_CAP_DELAY,
     .flush          = dirac_decode_flush,
     .long_name      = NULL_IF_CONFIG_SMALL("BBC Dirac VC-2"),

 };