Function decode_slice

libavcodec/h264_slice.c:2565–2770

}

static int decode_slice(struct AVCodecContext *avctx, void *arg)
{
    H264SliceContext *sl = arg;
    const H264Context *h = sl->h264;
    int lf_x_start = sl->mb_x;
    int orig_deblock = sl->deblocking_filter;
    int ret;

    sl->linesize   = h->cur_pic_ptr->f->linesize[0];
    sl->uvlinesize = h->cur_pic_ptr->f->linesize[1];

    ret = alloc_scratch_buffers(sl, sl->linesize);
    if (ret < 0)
        return ret;

    sl->mb_skip_run = -1;

    av_assert0(h->block_offset[15] == (4 * ((scan8[15] - scan8[0]) & 7) << h->pixel_shift) + 4 * sl->linesize * ((scan8[15] - scan8[0]) >> 3));

    if (h->postpone_filter)
        sl->deblocking_filter = 0;

    sl->is_complex = FRAME_MBAFF(h) || h->picture_structure != PICT_FRAME ||
                     (CONFIG_GRAY && (h->flags & AV_CODEC_FLAG_GRAY));

    if (!(h->avctx->active_thread_type & FF_THREAD_SLICE) && h->picture_structure == PICT_FRAME && sl->er->error_status_table) {
        const int start_i  = av_clip(sl->resync_mb_x + sl->resync_mb_y * h->mb_width, 0, h->mb_num - 1);
        if (start_i) {
            int prev_status = sl->er->error_status_table[sl->er->mb_index2xy[start_i - 1]];
            prev_status &= ~ VP_START;
            if (prev_status != (ER_MV_END | ER_DC_END | ER_AC_END))
                sl->er->error_occurred = 1;
        }
    }

    if (h->ps.pps->cabac) {
        /* realign */
        align_get_bits(&sl->gb);

        /* init cabac */
        ret = ff_init_cabac_decoder(&sl->cabac,
                              sl->gb.buffer + get_bits_count(&sl->gb) / 8,
                              (get_bits_left(&sl->gb) + 7) / 8);
        if (ret < 0)
            return ret;

        ff_h264_init_cabac_states(h, sl);

        for (;;) {
            int ret, eos;
            if (sl->mb_x + sl->mb_y * h->mb_width >= sl->next_slice_idx) {
                av_log(h->avctx, AV_LOG_ERROR, "Slice overlaps with next at %d\n",
                       sl->next_slice_idx);
                er_add_slice(sl, sl->resync_mb_x, sl->resync_mb_y, sl->mb_x,
                             sl->mb_y, ER_MB_ERROR);
                return AVERROR_INVALIDDATA;
            }