if (s->qscale <= 0)
return AVERROR_INVALIDDATA;
+ if (s->pict_type != AV_PICTURE_TYPE_I && show_bits(&s->gb, 1)) {
+ GetBitContext gb = s->gb;
+ int skip_type = get_bits(&gb, 2);
+ int run = skip_type == SKIP_TYPE_COL ? s->mb_width : s->mb_height;
+
+ while (run > 0) {
+ int block = FFMIN(run, 25);
+ if (get_bits(&gb, block) + 1 != 1<<block)
+ break;
+ run -= block;
+ }
+ if (!run)
+ return FRAME_SKIPPED;
+ }
+
return 0;
}
}
s->dc_table_index = get_bits1(&s->gb);
+
+ // at minimum one bit per macroblock is required at least in a valid frame,
+ // we discard frames much smaller than this. Frames smaller than 1/8 of the
+ // smallest "black/skip" frame generally contain not much recoverable content
+ // while at the same time they have the highest computational requirements
+ // per byte
+ if (get_bits_left(&s->gb) * 8LL < (s->width+15)/16 * ((s->height+15)/16))
+ return AVERROR_INVALIDDATA;
}
s->inter_intra_pred = 0;
s->no_rounding = 1;