/*
  * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
  *
  * 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

  * H.264 / AVC / MPEG4 part10 codec.
  * @author Michael Niedermayer <michaelni@gmx.at>
  */
 

 #ifndef AVCODEC_H264_H
 #define AVCODEC_H264_H

 #include "libavutil/intreadwrite.h"

 #include "cabac.h"

 #include "error_resilience.h"

 #include "get_bits.h"

 #include "mpegvideo.h"

 #include "h264chroma.h"

 #include "h264dsp.h"

 #include "h264pred.h"

 #include "h264qpel.h"

 #include "rectangle.h"

 #define MAX_SPS_COUNT          32
 #define MAX_PPS_COUNT         256

 #define MAX_MMCO_COUNT         66

 #define MAX_DELAYED_PIC_COUNT  16

 #define MAX_MBPAIR_SIZE (256*1024) // a tighter bound could be calculated if someone cares about a few bytes
 

 /* Compiling in interlaced support reduces the speed
  * of progressive decoding by about 2%. */
 #define ALLOW_INTERLACE
 

 #define FMO 0
 

 /**
  * The maximum number of slices supported by the decoder.
  * must be a power of 2
  */
 #define MAX_SLICES 16
 

 #ifdef ALLOW_INTERLACE

 #define MB_MBAFF(h)    h->mb_mbaff

 #define MB_FIELD(h)    h->mb_field_decoding_flag

 #define FRAME_MBAFF(h) h->mb_aff_frame

 #define FIELD_PICTURE(h) (h->picture_structure != PICT_FRAME)

 #define LEFT_MBS 2

 #define LTOP     0
 #define LBOT     1
 #define LEFT(i)  (i)

 #else

 #define MB_MBAFF(h)      0

 #define MB_FIELD(h)      0

 #define FRAME_MBAFF(h)   0

 #define FIELD_PICTURE(h) 0

 #undef  IS_INTERLACED
 #define IS_INTERLACED(mb_type) 0

 #define LEFT_MBS 1

 #define LTOP     0
 #define LBOT     0
 #define LEFT(i)  0

 #endif

 #define FIELD_OR_MBAFF_PICTURE(h) (FRAME_MBAFF(h) || FIELD_PICTURE(h))

 #ifndef CABAC

 #define CABAC(h) h->pps.cabac

 #endif
 

 #define CHROMA(h)    (h->sps.chroma_format_idc)

 #define CHROMA422(h) (h->sps.chroma_format_idc == 2)

 #define CHROMA444(h) (h->sps.chroma_format_idc == 3)

 #define EXTENDED_SAR       255

 #define MB_TYPE_REF0       MB_TYPE_ACPRED // dirty but it fits in 16 bit

 #define MB_TYPE_8x8DCT     0x01000000
 #define IS_REF0(a)         ((a) & MB_TYPE_REF0)
 #define IS_8x8DCT(a)       ((a) & MB_TYPE_8x8DCT)
 

 #define QP_MAX_NUM (51 + 6*6)           // The maximum supported qp

 /* NAL unit types */
 enum {

     NAL_SLICE           = 1,
     NAL_DPA             = 2,
     NAL_DPB             = 3,
     NAL_DPC             = 4,
     NAL_IDR_SLICE       = 5,
     NAL_SEI             = 6,
     NAL_SPS             = 7,
     NAL_PPS             = 8,
     NAL_AUD             = 9,
     NAL_END_SEQUENCE    = 10,
     NAL_END_STREAM      = 11,
     NAL_FILLER_DATA     = 12,
     NAL_SPS_EXT         = 13,

     NAL_AUXILIARY_SLICE = 19,
     NAL_FF_IGNORE       = 0xff0f001,

 };
 

 /**

  * SEI message types
  */
 typedef enum {

     SEI_TYPE_BUFFERING_PERIOD       = 0,   ///< buffering period (H.264, D.1.1)

     SEI_TYPE_PIC_TIMING             = 1,   ///< picture timing

     SEI_TYPE_USER_DATA_ITU_T_T35    = 4,   ///< user data registered by ITU-T Recommendation T.35

     SEI_TYPE_USER_DATA_UNREGISTERED = 5,   ///< unregistered user data

     SEI_TYPE_RECOVERY_POINT         = 6,   ///< recovery point (frame # to decoder sync)
     SEI_TYPE_FRAME_PACKING          = 45,  ///< frame packing arrangement

 } SEI_Type;
 
 /**

  * pic_struct in picture timing SEI message
  */
 typedef enum {
     SEI_PIC_STRUCT_FRAME             = 0, ///<  0: %frame
     SEI_PIC_STRUCT_TOP_FIELD         = 1, ///<  1: top field
     SEI_PIC_STRUCT_BOTTOM_FIELD      = 2, ///<  2: bottom field
     SEI_PIC_STRUCT_TOP_BOTTOM        = 3, ///<  3: top field, bottom field, in that order
     SEI_PIC_STRUCT_BOTTOM_TOP        = 4, ///<  4: bottom field, top field, in that order
     SEI_PIC_STRUCT_TOP_BOTTOM_TOP    = 5, ///<  5: top field, bottom field, top field repeated, in that order
     SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM = 6, ///<  6: bottom field, top field, bottom field repeated, in that order
     SEI_PIC_STRUCT_FRAME_DOUBLING    = 7, ///<  7: %frame doubling
     SEI_PIC_STRUCT_FRAME_TRIPLING    = 8  ///<  8: %frame tripling
 } SEI_PicStructType;
 
 /**

  * frame_packing_arrangement types
  */
 typedef enum {
     SEI_FPA_TYPE_CHECKERBOARD        = 0,
     SEI_FPA_TYPE_INTERLEAVE_COLUMN   = 1,
     SEI_FPA_TYPE_INTERLEAVE_ROW      = 2,
     SEI_FPA_TYPE_SIDE_BY_SIDE        = 3,
     SEI_FPA_TYPE_TOP_BOTTOM          = 4,
     SEI_FPA_TYPE_INTERLEAVE_TEMPORAL = 5,
     SEI_FPA_TYPE_2D                  = 6,
 } SEI_FpaType;
 
 /**

  * Sequence parameter set
  */

 typedef struct SPS {

     unsigned int sps_id;

     int profile_idc;
     int level_idc;

     int chroma_format_idc;

     int transform_bypass;              ///< qpprime_y_zero_transform_bypass_flag
     int log2_max_frame_num;            ///< log2_max_frame_num_minus4 + 4
     int poc_type;                      ///< pic_order_cnt_type
     int log2_max_poc_lsb;              ///< log2_max_pic_order_cnt_lsb_minus4
     int delta_pic_order_always_zero_flag;
     int offset_for_non_ref_pic;
     int offset_for_top_to_bottom_field;
     int poc_cycle_length;              ///< num_ref_frames_in_pic_order_cnt_cycle
     int ref_frame_count;               ///< num_ref_frames
     int gaps_in_frame_num_allowed_flag;

     int mb_width;                      ///< pic_width_in_mbs_minus1 + 1
     int mb_height;                     ///< pic_height_in_map_units_minus1 + 1

     int frame_mbs_only_flag;

     int mb_aff;                        ///< mb_adaptive_frame_field_flag

     int direct_8x8_inference_flag;

     int crop;                          ///< frame_cropping_flag

 
     /* those 4 are already in luma samples */

     unsigned int crop_left;            ///< frame_cropping_rect_left_offset
     unsigned int crop_right;           ///< frame_cropping_rect_right_offset
     unsigned int crop_top;             ///< frame_cropping_rect_top_offset
     unsigned int crop_bottom;          ///< frame_cropping_rect_bottom_offset

     int vui_parameters_present_flag;
     AVRational sar;

     int video_signal_type_present_flag;
     int full_range;
     int colour_description_present_flag;
     enum AVColorPrimaries color_primaries;
     enum AVColorTransferCharacteristic color_trc;
     enum AVColorSpace colorspace;

     int timing_info_present_flag;
     uint32_t num_units_in_tick;
     uint32_t time_scale;
     int fixed_frame_rate_flag;

     short offset_for_ref_frame[256]; // FIXME dyn aloc?

     int bitstream_restriction_flag;
     int num_reorder_frames;
     int scaling_matrix_present;
     uint8_t scaling_matrix4[6][16];

     uint8_t scaling_matrix8[6][64];

     int nal_hrd_parameters_present_flag;
     int vcl_hrd_parameters_present_flag;
     int pic_struct_present_flag;
     int time_offset_length;

     int cpb_cnt;                          ///< See H.264 E.1.2
     int initial_cpb_removal_delay_length; ///< initial_cpb_removal_delay_length_minus1 + 1
     int cpb_removal_delay_length;         ///< cpb_removal_delay_length_minus1 + 1
     int dpb_output_delay_length;          ///< dpb_output_delay_length_minus1 + 1
     int bit_depth_luma;                   ///< bit_depth_luma_minus8 + 8
     int bit_depth_chroma;                 ///< bit_depth_chroma_minus8 + 8
     int residual_color_transform_flag;    ///< residual_colour_transform_flag
     int constraint_set_flags;             ///< constraint_set[0-3]_flag

     int new;                              ///< flag to keep track if the decoder context needs re-init due to changed SPS

 } SPS;

 
 /**
  * Picture parameter set
  */

 typedef struct PPS {

     unsigned int sps_id;
     int cabac;                  ///< entropy_coding_mode_flag
     int pic_order_present;      ///< pic_order_present_flag
     int slice_group_count;      ///< num_slice_groups_minus1 + 1
     int mb_slice_group_map_type;
     unsigned int ref_count[2];  ///< num_ref_idx_l0/1_active_minus1 + 1
     int weighted_pred;          ///< weighted_pred_flag
     int weighted_bipred_idc;
     int init_qp;                ///< pic_init_qp_minus26 + 26
     int init_qs;                ///< pic_init_qs_minus26 + 26

     int chroma_qp_index_offset[2];

     int deblocking_filter_parameters_present; ///< deblocking_filter_parameters_present_flag

     int constrained_intra_pred;     ///< constrained_intra_pred_flag
     int redundant_pic_cnt_present;  ///< redundant_pic_cnt_present_flag
     int transform_8x8_mode;         ///< transform_8x8_mode_flag

     uint8_t scaling_matrix4[6][16];

     uint8_t scaling_matrix8[6][64];

     uint8_t chroma_qp_table[2][QP_MAX_NUM+1];  ///< pre-scaled (with chroma_qp_index_offset) version of qp_table

     int chroma_qp_diff;

 } PPS;

 
 /**

  * Frame Packing Arrangement Type
  */
 typedef struct FPA {
     int         frame_packing_arrangement_id;
     int         frame_packing_arrangement_cancel_flag; ///< is previous arrangement canceled, -1 if never received
     SEI_FpaType frame_packing_arrangement_type;
     int         frame_packing_arrangement_repetition_period;
     int         content_interpretation_type;
     int         quincunx_sampling_flag;
 } FPA;
 
 /**

  * Memory management control operation opcode.
  */

 typedef enum MMCOOpcode {
     MMCO_END = 0,

     MMCO_SHORT2UNUSED,
     MMCO_LONG2UNUSED,
     MMCO_SHORT2LONG,
     MMCO_SET_MAX_LONG,
     MMCO_RESET,
     MMCO_LONG,
 } MMCOOpcode;
 
 /**
  * Memory management control operation.
  */

 typedef struct MMCO {

     MMCOOpcode opcode;

     int short_pic_num;  ///< pic_num without wrapping (pic_num & max_pic_num)
     int long_arg;       ///< index, pic_num, or num long refs depending on opcode

 } MMCO;
 
 /**
  * H264Context
  */

 typedef struct H264Context {

     AVCodecContext *avctx;
     VideoDSPContext vdsp;

     H264DSPContext h264dsp;

     H264ChromaContext h264chroma;

     H264QpelContext h264qpel;

     MotionEstContext me;
     ParseContext parse_context;
     GetBitContext gb;

     DSPContext       dsp;

     ERContext er;
 
     Picture *DPB;
     Picture *cur_pic_ptr;
     Picture cur_pic;
 

     int pixel_shift;    ///< 0 for 8-bit H264, 1 for high-bit-depth H264

     int chroma_qp[2];   // QPc

     int qp_thresh;      ///< QP threshold to skip loopfilter
 

     /* coded dimensions -- 16 * mb w/h */

     int width, height;

     ptrdiff_t linesize, uvlinesize;

     int chroma_x_shift, chroma_y_shift;
 
     int qscale;
     int droppable;
     int data_partitioning;
     int coded_picture_number;
     int low_delay;
 
     int context_initialized;
     int flags;
     int workaround_bugs;
 

     int prev_mb_skipped;
     int next_mb_skipped;
 

     // prediction stuff

     int chroma_pred_mode;
     int intra16x16_pred_mode;
 

     int topleft_mb_xy;

     int top_mb_xy;

     int topright_mb_xy;

     int left_mb_xy[LEFT_MBS];

     int topleft_type;

     int top_type;

     int topright_type;

     int left_type[LEFT_MBS];

     const uint8_t *left_block;

     int topleft_partition;
 

     int8_t intra4x4_pred_mode_cache[5 * 8];
     int8_t(*intra4x4_pred_mode);

     H264PredContext hpc;

     unsigned int topleft_samples_available;
     unsigned int top_samples_available;
     unsigned int topright_samples_available;
     unsigned int left_samples_available;

     uint8_t (*top_borders[2])[(16 * 3) * 2];

 
     /**
      * non zero coeff count cache.
      * is 64 if not available.
      */

     DECLARE_ALIGNED(8, uint8_t, non_zero_count_cache)[15 * 8];

     uint8_t (*non_zero_count)[48];

 
     /**
      * Motion vector cache.
      */

     DECLARE_ALIGNED(16, int16_t, mv_cache)[2][5 * 8][2];
     DECLARE_ALIGNED(8, int8_t, ref_cache)[2][5 * 8];
 #define LIST_NOT_USED -1 // FIXME rename?

 #define PART_NOT_AVAILABLE -2
 
     /**
      * number of neighbors (top and/or left) that used 8x8 dct
      */
     int neighbor_transform_size;
 
     /**
      * block_offset[ 0..23] for frame macroblocks
      * block_offset[24..47] for field macroblocks
      */

     int block_offset[2 * (16 * 3)];

     uint32_t *mb2b_xy;  // FIXME are these 4 a good idea?

     uint32_t *mb2br_xy;

     int b_stride;       // FIXME use s->b4_stride

     ptrdiff_t mb_linesize;  ///< may be equal to s->linesize or s->linesize * 2, for mbaff

     ptrdiff_t mb_uvlinesize;

     unsigned current_sps_id; ///< id of the current SPS

     SPS sps; ///< current sps

     PPS pps; ///< current pps

     int au_pps_id; ///< pps_id of current access unit
 

     uint32_t dequant4_buffer[6][QP_MAX_NUM + 1][16]; // FIXME should these be moved down?
     uint32_t dequant8_buffer[6][QP_MAX_NUM + 1][64];
     uint32_t(*dequant4_coeff[6])[16];
     uint32_t(*dequant8_coeff[6])[64];

 
     int slice_num;

     uint16_t *slice_table;      ///< slice_table_base + 2*mb_stride + 1

     int slice_type;

     int slice_type_nos;         ///< S free slice type (SI/SP are remapped to I/P)

     int slice_type_fixed;
 

     // interlacing specific flags

     int mb_aff_frame;
     int mb_field_decoding_flag;

     int mb_mbaff;               ///< mb_aff_frame && mb_field_decoding_flag

     int picture_structure;
     int first_field;

     DECLARE_ALIGNED(8, uint16_t, sub_mb_type)[4];

     // Weighted pred stuff

     int use_weight;
     int use_weight_chroma;
     int luma_log2_weight_denom;
     int chroma_log2_weight_denom;

     // The following 2 can be changed to int8_t but that causes 10cpu cycles speedloss

     int luma_weight[48][2][2];
     int chroma_weight[48][2][2][2];

     int implicit_weight[48][48][2];

 
     int direct_spatial_mv_pred;

     int col_parity;
     int col_fieldoff;

     int dist_scale_factor[32];

     int dist_scale_factor_field[2][32];

     int map_col_to_list0[2][16 + 32];
     int map_col_to_list0_field[2][2][16 + 32];

 
     /**
      * num_ref_idx_l0/1_active_minus1 + 1
      */

     unsigned int ref_count[2];          ///< counts frames or fields, depending on current mb mode

     unsigned int list_count;

     uint8_t *list_counts;               ///< Array of list_count per MB specifying the slice type
     Picture ref_list[2][48];            /**< 0..15: frame refs, 16..47: mbaff field refs.
                                          *   Reordered version of default_ref_list
                                          *   according to picture reordering in slice header */
     int ref2frm[MAX_SLICES][2][64];     ///< reference to frame number lists, used in the loop filter, the first 2 are for -2,-1

     // data partitioning

     GetBitContext intra_gb;
     GetBitContext inter_gb;
     GetBitContext *intra_gb_ptr;
     GetBitContext *inter_gb_ptr;
 

     const uint8_t *intra_pcm_ptr;

     DECLARE_ALIGNED(16, int16_t, mb)[16 * 48 * 2]; ///< as a dct coeffecient is int32_t in high depth, we need to reserve twice the space.
     DECLARE_ALIGNED(16, int16_t, mb_luma_dc)[3][16 * 2];
     int16_t mb_padding[256 * 2];        ///< as mb is addressed by scantable[i] and scantable is uint8_t we can either check that i is not too large or ensure that there is some unused stuff after mb

 
     /**
      * Cabac
      */
     CABACContext cabac;

     uint8_t cabac_state[1024];

     /* 0x100 -> non null luma_dc, 0x80/0x40 -> non null chroma_dc (cb/cr), 0x?0 -> chroma_cbp(0, 1, 2), 0x0? luma_cbp */
     uint16_t *cbp_table;

     int cbp;
     int top_cbp;
     int left_cbp;
     /* chroma_pred_mode for i4x4 or i16x16, else 0 */

     uint8_t *chroma_pred_mode_table;
     int last_qscale_diff;
     uint8_t (*mvd_table[2])[2];
     DECLARE_ALIGNED(16, uint8_t, mvd_cache)[2][5 * 8][2];
     uint8_t *direct_table;
     uint8_t direct_cache[5 * 8];

 
     uint8_t zigzag_scan[16];
     uint8_t zigzag_scan8x8[64];
     uint8_t zigzag_scan8x8_cavlc[64];
     uint8_t field_scan[16];
     uint8_t field_scan8x8[64];
     uint8_t field_scan8x8_cavlc[64];

     uint8_t zigzag_scan_q0[16];
     uint8_t zigzag_scan8x8_q0[64];
     uint8_t zigzag_scan8x8_cavlc_q0[64];
     uint8_t field_scan_q0[16];
     uint8_t field_scan8x8_q0[64];
     uint8_t field_scan8x8_cavlc_q0[64];

 
     int x264_build;

     int mb_x, mb_y;
     int resync_mb_x;
     int resync_mb_y;
     int mb_skip_run;
     int mb_height, mb_width;
     int mb_stride;
     int mb_num;

     int mb_xy;
 
     int is_complex;
 

     // deblock
     int deblocking_filter;          ///< disable_deblocking_filter_idc with 1 <-> 0

     int slice_alpha_c0_offset;
     int slice_beta_offset;
 

     // =============================================================
     // Things below are not used in the MB or more inner code

 
     int nal_ref_idc;
     int nal_unit_type;
     uint8_t *rbsp_buffer[2];
     unsigned int rbsp_buffer_size[2];
 
     /**
      * Used to parse AVC variant of h264
      */

     int is_avc;           ///< this flag is != 0 if codec is avc1
     int nal_length_size;  ///< Number of bytes used for nal length (1, 2 or 4)
     int got_first;        ///< this flag is != 0 if we've parsed a frame

     int bit_depth_luma;         ///< luma bit depth from sps to detect changes
     int chroma_format_idc;      ///< chroma format from sps to detect changes

     SPS *sps_buffers[MAX_SPS_COUNT];
     PPS *pps_buffers[MAX_PPS_COUNT];
 

     int dequant_coeff_pps;      ///< reinit tables when pps changes

 
     uint16_t *slice_table_base;
 

     // POC stuff

     int poc_lsb;
     int poc_msb;
     int delta_poc_bottom;
     int delta_poc[2];
     int frame_num;

     int prev_poc_msb;           ///< poc_msb of the last reference pic for POC type 0
     int prev_poc_lsb;           ///< poc_lsb of the last reference pic for POC type 0
     int frame_num_offset;       ///< for POC type 2
     int prev_frame_num_offset;  ///< for POC type 2
     int prev_frame_num;         ///< frame_num of the last pic for POC type 1/2

 
     /**

      * frame_num for frames or 2 * frame_num + 1 for field pics.

      */
     int curr_pic_num;
 
     /**

      * max_frame_num or 2 * max_frame_num for field pics.

      */
     int max_pic_num;
 
     int redundant_pic_count;
 

     Picture default_ref_list[2][32]; ///< base reference list for all slices of a coded picture

     Picture *short_ref[32];
     Picture *long_ref[32];

     Picture *delayed_pic[MAX_DELAYED_PIC_COUNT + 2]; // FIXME size?

     int last_pocs[MAX_DELAYED_PIC_COUNT];

     Picture *next_output_pic;

     int outputed_poc;

     int next_outputed_poc;

 
     /**
      * memory management control operations buffer.
      */
     MMCO mmco[MAX_MMCO_COUNT];
     int mmco_index;

     int mmco_reset;

     int long_ref_count;     ///< number of actual long term references
     int short_ref_count;    ///< number of actual short term references

     int cabac_init_idc;

     /**

      * @name Members for slice based multithreading

      * @{
      */
     struct H264Context *thread_context[MAX_THREADS];
 
     /**

      * current slice number, used to initialize slice_num of each thread/context

      */
     int current_slice;
 
     /**
      * Max number of threads / contexts.
      * This is equal to AVCodecContext.thread_count unless
      * multithreaded decoding is impossible, in which case it is
      * reduced to 1.
      */
     int max_contexts;
 

     int slice_context_count;
 

     /**
      *  1 if the single thread fallback warning has already been
      *  displayed, 0 otherwise.
      */
     int single_decode_warning;
 

     enum AVPictureType pict_type;
 

     int last_slice_type;

     unsigned int last_ref_count[2];

     /** @} */
 

     /**
      * pic_struct in picture timing SEI message
      */
     SEI_PicStructType sei_pic_struct;

     /**

      * Complement sei_pic_struct
      * SEI_PIC_STRUCT_TOP_BOTTOM and SEI_PIC_STRUCT_BOTTOM_TOP indicate interlaced frames.
      * However, soft telecined frames may have these values.
      * This is used in an attempt to flag soft telecine progressive.
      */
     int prev_interlaced_frame;
 
     /**

      * frame_packing_arrangment SEI message
      */
     int sei_frame_packing_present;
     int frame_packing_arrangement_type;
     int content_interpretation_type;
     int quincunx_subsampling;
 
     /**

      * Bit set of clock types for fields/frames in picture timing SEI message.
      * For each found ct_type, appropriate bit is set (e.g., bit 1 for
      * interlaced).
      */
     int sei_ct_type;
 
     /**

      * dpb_output_delay in picture timing SEI message, see H.264 C.2.2
      */
     int sei_dpb_output_delay;
 
     /**

      * cpb_removal_delay in picture timing SEI message, see H.264 C.1.2
      */
     int sei_cpb_removal_delay;
 
     /**

      * recovery_frame_cnt from SEI message
      *
      * Set to -1 if no recovery point SEI message found or to number of frames
      * before playback synchronizes. Frames having recovery point are key
      * frames.
      */
     int sei_recovery_frame_cnt;
 

     /**

      * Are the SEI recovery points looking valid.
      */
     int valid_recovery_point;
 
     FPA sei_fpa;
 

     /**
      * recovery_frame is the frame_num at which the next frame should
      * be fully constructed.
      *
      * Set to -1 when not expecting a recovery point.
      */
     int recovery_frame;

 /**
  * We have seen an IDR, so all the following frames in coded order are correctly
  * decodable.
  */
 #define FRAME_RECOVERED_IDR  (1 << 0)
 /**
  * Sufficient number of frames have been decoded since a SEI recovery point,
  * so all the following frames in presentation order are correct.
  */
 #define FRAME_RECOVERED_SEI  (1 << 1)

     int frame_recovered;    ///< Initial frame has been completely recovered

     int luma_weight_flag[2];    ///< 7.4.3.2 luma_weight_lX_flag
     int chroma_weight_flag[2];  ///< 7.4.3.2 chroma_weight_lX_flag

 
     // Timestamp stuff

     int sei_buffering_period_present;   ///< Buffering period SEI flag
     int initial_cpb_removal_delay[32];  ///< Initial timestamps for CPBs

 
     int cur_chroma_format_idc;

     uint8_t *bipred_scratchpad;

 
     int16_t slice_row[MAX_SLICES]; ///< to detect when MAX_SLICES is too low

     uint8_t parse_history[4];
     int parse_history_count;
     int parse_last_mb;

     uint8_t *edge_emu_buffer;
     int16_t *dc_val_base;

     AVBufferPool *qscale_table_pool;
     AVBufferPool *mb_type_pool;
     AVBufferPool *motion_val_pool;
     AVBufferPool *ref_index_pool;

 } H264Context;

 extern const uint8_t ff_h264_chroma_qp[7][QP_MAX_NUM + 1]; ///< One chroma qp table for each possible bit depth (8-14).

 extern const uint16_t ff_h264_mb_sizes[4];

 /**
  * Decode SEI
  */
 int ff_h264_decode_sei(H264Context *h);
 
 /**
  * Decode SPS
  */
 int ff_h264_decode_seq_parameter_set(H264Context *h);
 
 /**

  * compute profile from sps
  */
 int ff_h264_get_profile(SPS *sps);
 
 /**

  * Decode PPS
  */
 int ff_h264_decode_picture_parameter_set(H264Context *h, int bit_length);
 
 /**

  * Decode a network abstraction layer unit.

  * @param consumed is the number of bytes used as input
  * @param length is the length of the array

  * @param dst_length is the number of decoded bytes FIXME here
  *                   or a decode rbsp tailing?

  * @return decoded bytes, might be src+1 if no escapes

  */

 const uint8_t *ff_h264_decode_nal(H264Context *h, const uint8_t *src,
                                   int *dst_length, int *consumed, int length);

 
 /**

  * Free any data that may have been allocated in the H264 context
  * like SPS, PPS etc.

  */

 void ff_h264_free_context(H264Context *h);

 /**

  * Reconstruct bitstream slice_type.

  */

 int ff_h264_get_slice_type(const H264Context *h);

 /**

  * Allocate tables.

  * needs width/height
  */
 int ff_h264_alloc_tables(H264Context *h);
 
 /**

  * Fill the default_ref_list.

  */
 int ff_h264_fill_default_ref_list(H264Context *h);
 
 int ff_h264_decode_ref_pic_list_reordering(H264Context *h);
 void ff_h264_fill_mbaff_ref_list(H264Context *h);
 void ff_h264_remove_all_refs(H264Context *h);
 
 /**

  * Execute the reference picture marking (memory management control operations).

  */
 int ff_h264_execute_ref_pic_marking(H264Context *h, MMCO *mmco, int mmco_count);
 

 int ff_h264_decode_ref_pic_marking(H264Context *h, GetBitContext *gb,
                                    int first_slice);

 int ff_generate_sliding_window_mmcos(H264Context *h, int first_slice);

 /**

  * Check if the top & left blocks are available if needed & change the
  * dc mode so it only uses the available blocks.

  */

 int ff_h264_check_intra4x4_pred_mode(H264Context *h);
 
 /**

  * Check if the top & left blocks are available if needed & change the
  * dc mode so it only uses the available blocks.

  */

 int ff_h264_check_intra_pred_mode(H264Context *h, int mode, int is_chroma);

 
 void ff_h264_hl_decode_mb(H264Context *h);

 int ff_h264_decode_extradata(H264Context *h, const uint8_t *buf, int size);

 int ff_h264_decode_init(AVCodecContext *avctx);
 void ff_h264_decode_init_vlc(void);

 
 /**

  * Decode a macroblock

  * @return 0 if OK, ER_AC_ERROR / ER_DC_ERROR / ER_MV_ERROR on error

  */
 int ff_h264_decode_mb_cavlc(H264Context *h);

 /**

  * Decode a CABAC coded macroblock

  * @return 0 if OK, ER_AC_ERROR / ER_DC_ERROR / ER_MV_ERROR on error

  */
 int ff_h264_decode_mb_cabac(H264Context *h);
 
 void ff_h264_init_cabac_states(H264Context *h);
 

 void ff_h264_direct_dist_scale_factor(H264Context *const h);
 void ff_h264_direct_ref_list_init(H264Context *const h);
 void ff_h264_pred_direct_motion(H264Context *const h, int *mb_type);

 void ff_h264_filter_mb_fast(H264Context *h, int mb_x, int mb_y,
                             uint8_t *img_y, uint8_t *img_cb, uint8_t *img_cr,
                             unsigned int linesize, unsigned int uvlinesize);
 void ff_h264_filter_mb(H264Context *h, int mb_x, int mb_y,
                        uint8_t *img_y, uint8_t *img_cb, uint8_t *img_cr,
                        unsigned int linesize, unsigned int uvlinesize);

 /**
  * Reset SEI values at the beginning of the frame.
  *
  * @param h H.264 context.
  */
 void ff_h264_reset_sei(H264Context *h);
 

 /**
  * Get stereo_mode string from the h264 frame_packing_arrangement
  * @param h H.264 context.
  */
 const char* ff_h264_sei_stereo_mode(H264Context *h);
 

 /*

  * o-o o-o
  *  / / /
  * o-o o-o
  *  ,---'
  * o-o o-o
  *  / / /
  * o-o o-o
  */

 
 /* Scan8 organization:

  *    0 1 2 3 4 5 6 7
  * 0  DY    y y y y y
  * 1        y Y Y Y Y
  * 2        y Y Y Y Y
  * 3        y Y Y Y Y
  * 4        y Y Y Y Y
  * 5  DU    u u u u u
  * 6        u U U U U
  * 7        u U U U U
  * 8        u U U U U
  * 9        u U U U U
  * 10 DV    v v v v v
  * 11       v V V V V
  * 12       v V V V V
  * 13       v V V V V
  * 14       v V V V V

  * DY/DU/DV are for luma/chroma DC.
  */
 

 #define LUMA_DC_BLOCK_INDEX   48
 #define CHROMA_DC_BLOCK_INDEX 49
 

 // This table must be here because scan8[constant] must be known at compiletime
 static const uint8_t scan8[16 * 3 + 3] = {
     4 +  1 * 8, 5 +  1 * 8, 4 +  2 * 8, 5 +  2 * 8,
     6 +  1 * 8, 7 +  1 * 8, 6 +  2 * 8, 7 +  2 * 8,
     4 +  3 * 8, 5 +  3 * 8, 4 +  4 * 8, 5 +  4 * 8,
     6 +  3 * 8, 7 +  3 * 8, 6 +  4 * 8, 7 +  4 * 8,
     4 +  6 * 8, 5 +  6 * 8, 4 +  7 * 8, 5 +  7 * 8,
     6 +  6 * 8, 7 +  6 * 8, 6 +  7 * 8, 7 +  7 * 8,
     4 +  8 * 8, 5 +  8 * 8, 4 +  9 * 8, 5 +  9 * 8,
     6 +  8 * 8, 7 +  8 * 8, 6 +  9 * 8, 7 +  9 * 8,
     4 + 11 * 8, 5 + 11 * 8, 4 + 12 * 8, 5 + 12 * 8,
     6 + 11 * 8, 7 + 11 * 8, 6 + 12 * 8, 7 + 12 * 8,
     4 + 13 * 8, 5 + 13 * 8, 4 + 14 * 8, 5 + 14 * 8,
     6 + 13 * 8, 7 + 13 * 8, 6 + 14 * 8, 7 + 14 * 8,
     0 +  0 * 8, 0 +  5 * 8, 0 + 10 * 8

 };
 

 static av_always_inline uint32_t pack16to32(int a, int b)
 {

 #if HAVE_BIGENDIAN

     return (b & 0xFFFF) + (a << 16);

 #else

     return (a & 0xFFFF) + (b << 16);

 #endif
 }
 

 static av_always_inline uint16_t pack8to16(int a, int b)
 {

 #if HAVE_BIGENDIAN

     return (b & 0xFF) + (a << 8);

 #else

     return (a & 0xFF) + (b << 8);

 #endif
 }
 

 /**

  * Get the chroma qp.

  */

 static av_always_inline int get_chroma_qp(H264Context *h, int t, int qscale)
 {

     return h->pps.chroma_qp_table[t][qscale];
 }
 

 /**

  * Get the predicted intra4x4 prediction mode.

  */

 static av_always_inline int pred_intra_mode(H264Context *h, int n)
 {
     const int index8 = scan8[n];
     const int left   = h->intra4x4_pred_mode_cache[index8 - 1];
     const int top    = h->intra4x4_pred_mode_cache[index8 - 8];
     const int min    = FFMIN(left, top);

     tprintf(h->avctx, "mode:%d %d min:%d\n", left, top, min);

     if (min < 0)
         return DC_PRED;
     else
         return min;

 }
 

 static av_always_inline void write_back_intra_pred_mode(H264Context *h)
 {
     int8_t *i4x4       = h->intra4x4_pred_mode + h->mb2br_xy[h->mb_xy];
     int8_t *i4x4_cache = h->intra4x4_pred_mode_cache;

     AV_COPY32(i4x4, i4x4_cache + 4 + 8 * 4);
     i4x4[4] = i4x4_cache[7 + 8 * 3];
     i4x4[5] = i4x4_cache[7 + 8 * 2];
     i4x4[6] = i4x4_cache[7 + 8 * 1];

 }

 static av_always_inline void write_back_non_zero_count(H264Context *h)
 {
     const int mb_xy    = h->mb_xy;
     uint8_t *nnz       = h->non_zero_count[mb_xy];

     uint8_t *nnz_cache = h->non_zero_count_cache;
 

     AV_COPY32(&nnz[ 0], &nnz_cache[4 + 8 * 1]);
     AV_COPY32(&nnz[ 4], &nnz_cache[4 + 8 * 2]);
     AV_COPY32(&nnz[ 8], &nnz_cache[4 + 8 * 3]);
     AV_COPY32(&nnz[12], &nnz_cache[4 + 8 * 4]);
     AV_COPY32(&nnz[16], &nnz_cache[4 + 8 * 6]);
     AV_COPY32(&nnz[20], &nnz_cache[4 + 8 * 7]);
     AV_COPY32(&nnz[32], &nnz_cache[4 + 8 * 11]);
     AV_COPY32(&nnz[36], &nnz_cache[4 + 8 * 12]);
 

     if (!h->chroma_y_shift) {

         AV_COPY32(&nnz[24], &nnz_cache[4 + 8 * 8]);
         AV_COPY32(&nnz[28], &nnz_cache[4 + 8 * 9]);
         AV_COPY32(&nnz[40], &nnz_cache[4 + 8 * 13]);
         AV_COPY32(&nnz[44], &nnz_cache[4 + 8 * 14]);

     }

 }
 

 static av_always_inline void write_back_motion_list(H264Context *h,
                                                     int b_stride,
                                                     int b_xy, int b8_xy,
                                                     int mb_type, int list)

 {

     int16_t(*mv_dst)[2] = &h->cur_pic.motion_val[list][b_xy];

     int16_t(*mv_src)[2] = &h->mv_cache[list][scan8[0]];
     AV_COPY128(mv_dst + 0 * b_stride, mv_src + 8 * 0);
     AV_COPY128(mv_dst + 1 * b_stride, mv_src + 8 * 1);
     AV_COPY128(mv_dst + 2 * b_stride, mv_src + 8 * 2);
     AV_COPY128(mv_dst + 3 * b_stride, mv_src + 8 * 3);

     if (CABAC(h)) {

         uint8_t (*mvd_dst)[2] = &h->mvd_table[list][FMO ? 8 * h->mb_xy
                                                         : h->mb2br_xy[h->mb_xy]];
         uint8_t(*mvd_src)[2]  = &h->mvd_cache[list][scan8[0]];
         if (IS_SKIP(mb_type)) {

             AV_ZERO128(mvd_dst);

         } else {
             AV_COPY64(mvd_dst, mvd_src + 8 * 3);
             AV_COPY16(mvd_dst + 3 + 3, mvd_src + 3 + 8 * 0);
             AV_COPY16(mvd_dst + 3 + 2, mvd_src + 3 + 8 * 1);
             AV_COPY16(mvd_dst + 3 + 1, mvd_src + 3 + 8 * 2);

         }
     }
 
     {

         int8_t *ref_index = &h->cur_pic.ref_index[list][b8_xy];

         int8_t *ref_cache = h->ref_cache[list];

         ref_index[0 + 0 * 2] = ref_cache[scan8[0]];
         ref_index[1 + 0 * 2] = ref_cache[scan8[4]];
         ref_index[0 + 1 * 2] = ref_cache[scan8[8]];
         ref_index[1 + 1 * 2] = ref_cache[scan8[12]];

     }

 }
 

 static av_always_inline void write_back_motion(H264Context *h, int mb_type)
 {
     const int b_stride      = h->b_stride;

     const int b_xy  = 4 * h->mb_x + 4 * h->mb_y * h->b_stride; // try mb2b(8)_xy

     const int b8_xy = 4 * h->mb_xy;

     if (USES_LIST(mb_type, 0)) {

         write_back_motion_list(h, b_stride, b_xy, b8_xy, mb_type, 0);

     } else {

         fill_rectangle(&h->cur_pic.ref_index[0][b8_xy],

                        2, 2, 2, (uint8_t)LIST_NOT_USED, 1);

     }

     if (USES_LIST(mb_type, 1))

         write_back_motion_list(h, b_stride, b_xy, b8_xy, mb_type, 1);

     if (h->slice_type_nos == AV_PICTURE_TYPE_B && CABAC(h)) {

         if (IS_8X8(mb_type)) {
             uint8_t *direct_table = &h->direct_table[4 * h->mb_xy];
             direct_table[1] = h->sub_mb_type[1] >> 1;
             direct_table[2] = h->sub_mb_type[2] >> 1;
             direct_table[3] = h->sub_mb_type[3] >> 1;

         }
     }
 }
 

 static av_always_inline int get_dct8x8_allowed(H264Context *h)
 {
     if (h->sps.direct_8x8_inference_flag)
         return !(AV_RN64A(h->sub_mb_type) &
                  ((MB_TYPE_16x8 | MB_TYPE_8x16 | MB_TYPE_8x8) *
                   0x0001000100010001ULL));

     else

         return !(AV_RN64A(h->sub_mb_type) &
                  ((MB_TYPE_16x8 | MB_TYPE_8x16 | MB_TYPE_8x8 | MB_TYPE_DIRECT2) *
                   0x0001000100010001ULL));

 }
 

 void ff_h264_draw_horiz_band(H264Context *h, int y, int height);

 int ff_init_poc(H264Context *h, int pic_field_poc[2], int *pic_poc);

 int ff_pred_weight_table(H264Context *h);
 int ff_set_ref_count(H264Context *h);

 #endif /* AVCODEC_H264_H */