static int decode_slice(MpegEncContext *s) { const int part_mask = s->partitioned_frame ? (ER_AC_END | ER_AC_ERROR) : 0x7F; const int mb_size = 16; int ret; s->last_resync_gb = s->gb; s->first_slice_line = 1; s->resync_mb_x = s->mb_x; s->resync_mb_y = s->mb_y; ff_set_qscale(s, s->qscale); if (s->avctx->hwaccel) { const uint8_t *start = s->gb.buffer + get_bits_count(&s->gb) / 8; const uint8_t *end = ff_h263_find_resync_marker(start + 1, s->gb.buffer_end); skip_bits_long(&s->gb, 8 * (end - start)); return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start); } if (s->partitioned_frame) { const int qscale = s->qscale; if (CONFIG_MPEG4_DECODER && s->codec_id == AV_CODEC_ID_MPEG4) if ((ret = ff_mpeg4_decode_partitions(s->avctx->priv_data)) < 0) return ret; /* restore variables which were modified */ s->first_slice_line = 1; s->mb_x = s->resync_mb_x; s->mb_y = s->resync_mb_y; ff_set_qscale(s, qscale); } for (; s->mb_y < s->mb_height; s->mb_y++) { /* per-row end of slice checks */ if (s->msmpeg4_version) { if (s->resync_mb_y + s->slice_height == s->mb_y) { ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x - 1, s->mb_y, ER_MB_END); return 0; } } if (s->msmpeg4_version == 1) { s->last_dc[0] = s->last_dc[1] = s->last_dc[2] = 128; } ff_init_block_index(s); for (; s->mb_x < s->mb_width; s->mb_x++) { int ret; ff_update_block_index(s); if (s->resync_mb_x == s->mb_x && s->resync_mb_y + 1 == s->mb_y) s->first_slice_line = 0; /* DCT & quantize */ s->mv_dir = MV_DIR_FORWARD; s->mv_type = MV_TYPE_16X16; ff_dlog(s, "%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24)); ret = s->decode_mb(s, s->block); if (s->pict_type != AV_PICTURE_TYPE_B) ff_h263_update_motion_val(s); if (ret < 0) { const int xy = s->mb_x + s->mb_y * s->mb_stride; if (ret == SLICE_END) { ff_mpv_decode_mb(s, s->block); if (s->loop_filter) ff_h263_loop_filter(s); ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END & part_mask); s->padding_bug_score--; if (++s->mb_x >= s->mb_width) { s->mb_x = 0; ff_mpeg_draw_horiz_band(s, s->mb_y * mb_size, mb_size); ff_mpv_report_decode_progress(s); s->mb_y++; } return 0; } else if (ret == SLICE_NOEND) { av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy); ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x + 1, s->mb_y, ER_MB_END & part_mask); return AVERROR_INVALIDDATA; } av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy); ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR & part_mask); return AVERROR_INVALIDDATA; } ff_mpv_decode_mb(s, s->block); if (s->loop_filter) ff_h263_loop_filter(s); } ff_mpeg_draw_horiz_band(s, s->mb_y * mb_size, mb_size); ff_mpv_report_decode_progress(s); s->mb_x = 0; } assert(s->mb_x == 0 && s->mb_y == s->mb_height); if (s->codec_id == AV_CODEC_ID_MPEG4 && (s->workaround_bugs & FF_BUG_AUTODETECT) && get_bits_left(&s->gb) >= 48 && show_bits(&s->gb, 24) == 0x4010 && !s->data_partitioning) s->padding_bug_score += 32; /* try to detect the padding bug */ if (s->codec_id == AV_CODEC_ID_MPEG4 && (s->workaround_bugs & FF_BUG_AUTODETECT) && get_bits_left(&s->gb) >= 0 && get_bits_left(&s->gb) < 48 && !s->data_partitioning) { const int bits_count = get_bits_count(&s->gb); const int bits_left = s->gb.size_in_bits - bits_count; if (bits_left == 0) { s->padding_bug_score += 16; } else if (bits_left != 1) { int v = show_bits(&s->gb, 8); v |= 0x7F >> (7 - (bits_count & 7)); if (v == 0x7F && bits_left <= 8) s->padding_bug_score--; else if (v == 0x7F && ((get_bits_count(&s->gb) + 8) & 8) && bits_left <= 16) s->padding_bug_score += 4; else s->padding_bug_score++; } } if (s->workaround_bugs & FF_BUG_AUTODETECT) { if (s->codec_id == AV_CODEC_ID_H263 || (s->padding_bug_score > -2 && !s->data_partitioning)) s->workaround_bugs |= FF_BUG_NO_PADDING; else s->workaround_bugs &= ~FF_BUG_NO_PADDING; } // handle formats which don't have unique end markers if (s->msmpeg4_version || (s->workaround_bugs & FF_BUG_NO_PADDING)) { // FIXME perhaps solve this more cleanly int left = get_bits_left(&s->gb); int max_extra = 7; /* no markers in M$ crap */ if (s->msmpeg4_version && s->pict_type == AV_PICTURE_TYPE_I) max_extra += 17; /* buggy padding but the frame should still end approximately at * the bitstream end */ if ((s->workaround_bugs & FF_BUG_NO_PADDING) && (s->avctx->err_recognition & AV_EF_BUFFER)) max_extra += 48; else if ((s->workaround_bugs & FF_BUG_NO_PADDING)) max_extra += 256 * 256 * 256 * 64; if (left > max_extra) av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24)); else if (left < 0) av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left); else ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x - 1, s->mb_y, ER_MB_END); return 0; } av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n", get_bits_left(&s->gb), show_bits(&s->gb, 24), s->padding_bug_score); ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END & part_mask); return AVERROR_INVALIDDATA; }