diff --git a/libavcodec/msmpeg4dec.c b/libavcodec/msmpeg4dec.c index 457a37e745806926bd0da65ddc2680d744046cfa..16b67192b51ee77bde9589e75a5cb88b35ae37c4 100644 --- a/libavcodec/msmpeg4dec.c +++ b/libavcodec/msmpeg4dec.c @@ -412,6 +412,14 @@ int ff_msmpeg4_decode_picture_header(MpegEncContext * s) { int code; + // 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; + if(s->msmpeg4_version==1){ int start_code = get_bits_long(&s->gb, 32); if(start_code!=0x00000100){