ffmpeg/libavcodec/h264_parse.c

/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "get_bits.h"
#include "golomb.h"
#include "h264.h"
#include "h264_parse.h"

int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
                              const int *ref_count, int slice_type_nos,
                              H264PredWeightTable *pwt)
{
    int list, i;
    int luma_def, chroma_def;

    pwt->use_weight             = 0;
    pwt->use_weight_chroma      = 0;
    pwt->luma_log2_weight_denom = get_ue_golomb(gb);
    if (sps->chroma_format_idc)
        pwt->chroma_log2_weight_denom = get_ue_golomb(gb);

    if (pwt->luma_log2_weight_denom > 7U) {
        av_log(NULL, AV_LOG_ERROR, "luma_log2_weight_denom %d is out of range\n", pwt->luma_log2_weight_denom);
        pwt->luma_log2_weight_denom = 0;
    }
    if (pwt->chroma_log2_weight_denom > 7U) {
        av_log(NULL, AV_LOG_ERROR, "chroma_log2_weight_denom %d is out of range\n", pwt->chroma_log2_weight_denom);
        pwt->chroma_log2_weight_denom = 0;
    }

    luma_def   = 1 << pwt->luma_log2_weight_denom;
    chroma_def = 1 << pwt->chroma_log2_weight_denom;

    for (list = 0; list < 2; list++) {
        pwt->luma_weight_flag[list]   = 0;
        pwt->chroma_weight_flag[list] = 0;
        for (i = 0; i < ref_count[list]; i++) {
            int luma_weight_flag, chroma_weight_flag;

            luma_weight_flag = get_bits1(gb);
            if (luma_weight_flag) {
                pwt->luma_weight[i][list][0] = get_se_golomb(gb);
                pwt->luma_weight[i][list][1] = get_se_golomb(gb);
                if (pwt->luma_weight[i][list][0] != luma_def ||
                    pwt->luma_weight[i][list][1] != 0) {
                    pwt->use_weight             = 1;
                    pwt->luma_weight_flag[list] = 1;
                }
            } else {
                pwt->luma_weight[i][list][0] = luma_def;
                pwt->luma_weight[i][list][1] = 0;
            }

            if (sps->chroma_format_idc) {
                chroma_weight_flag = get_bits1(gb);
                if (chroma_weight_flag) {
                    int j;
                    for (j = 0; j < 2; j++) {
                        pwt->chroma_weight[i][list][j][0] = get_se_golomb(gb);
                        pwt->chroma_weight[i][list][j][1] = get_se_golomb(gb);
                        if (pwt->chroma_weight[i][list][j][0] != chroma_def ||
                            pwt->chroma_weight[i][list][j][1] != 0) {
                            pwt->use_weight_chroma        = 1;
                            pwt->chroma_weight_flag[list] = 1;
                        }
                    }
                } else {
                    int j;
                    for (j = 0; j < 2; j++) {
                        pwt->chroma_weight[i][list][j][0] = chroma_def;
                        pwt->chroma_weight[i][list][j][1] = 0;
                    }
                }
            }
        }
        if (slice_type_nos != AV_PICTURE_TYPE_B)
            break;
    }
    pwt->use_weight = pwt->use_weight || pwt->use_weight_chroma;
    return 0;
}