FFmpeg/libavcodec/h264_parse.h

/*
 * 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 decoder/parser shared code
 */

#ifndef AVCODEC_H264_PARSE_H
#define AVCODEC_H264_PARSE_H

#include "config.h"

#include <stdint.h>

#include "libavutil/attributes.h"

#include "get_bits.h"
#include "h264_ps.h"

#define MB_TYPE_REF0       MB_TYPE_CODEC_SPECIFIC
#define MB_TYPE_8x8DCT     0x01000000

// This table must be here because scan8[constant] must be known at compile time
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
};

/**
 * 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;

typedef struct H264PredWeightTable {
    int use_weight;
    int use_weight_chroma;
    int luma_log2_weight_denom;
    int chroma_log2_weight_denom;
    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
    // The following 2 can be changed to int8_t but that causes a 10 CPU cycles speed loss
    int luma_weight[48][2][2];
    int chroma_weight[48][2][2][2];
    int implicit_weight[48][48][2];
} H264PredWeightTable;

typedef struct H264POCContext {
    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
} H264POCContext;

int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
                              const int *ref_count, int slice_type_nos,
                              H264PredWeightTable *pwt,
                              int picture_structure, void *logctx);

/**
 * 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(int8_t *pred_mode_cache, void *logctx,
                                     int top_samples_available, int left_samples_available);

/**
 * 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(void *logctx, int top_samples_available,
                                  int left_samples_available,
                                  int mode, int is_chroma);

int ff_h264_parse_ref_count(int *plist_count, int ref_count[2],
                            GetBitContext *gb, const PPS *pps,
                            int slice_type_nos, int picture_structure, void *logctx);

int ff_h264_init_poc(int pic_field_poc[2], int *pic_poc,
                     const SPS *sps, H264POCContext *poc,
                     int picture_structure, int nal_ref_idc);

int ff_h264_decode_extradata(const uint8_t *data, int size, H264ParamSets *ps,
                             int *is_avc, int *nal_length_size,
                             int err_recognition, void *logctx);

static av_always_inline uint32_t pack16to32(unsigned a, unsigned b)
{
#if HAVE_BIGENDIAN
    return (b & 0xFFFF) + (a << 16);
#else
    return (a & 0xFFFF) + (b << 16);
#endif
}

#endif /* AVCODEC_H264_PARSE_H */