X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fmsmpeg4dec.c;h=49df06a9d7eb54b7ad5ecbe05ab9021ebfff4608;hb=98f7e0081b998d0a31bda2a3214856435e321850;hp=457a37e745806926bd0da65ddc2680d744046cfa;hpb=f8377ffce35251bba043aeda5d81df0d411a0595;p=ffmpeg

diff --git a/libavcodec/msmpeg4dec.c b/libavcodec/msmpeg4dec.c
index 457a37e7458..49df06a9d7e 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){
@@ -880,7 +888,7 @@ AVCodec ff_msmpeg4v1_decoder = {
     .close          = ff_h263_decode_end,
     .decode         = ff_h263_decode_frame,
     .capabilities   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
-    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
+    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM | FF_CODEC_CAP_INIT_CLEANUP,
     .max_lowres     = 3,
     .pix_fmts       = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_YUV420P,
@@ -898,7 +906,7 @@ AVCodec ff_msmpeg4v2_decoder = {
     .close          = ff_h263_decode_end,
     .decode         = ff_h263_decode_frame,
     .capabilities   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
-    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
+    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM | FF_CODEC_CAP_INIT_CLEANUP,
     .max_lowres     = 3,
     .pix_fmts       = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_YUV420P,
@@ -916,7 +924,7 @@ AVCodec ff_msmpeg4v3_decoder = {
     .close          = ff_h263_decode_end,
     .decode         = ff_h263_decode_frame,
     .capabilities   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
-    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
+    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM | FF_CODEC_CAP_INIT_CLEANUP,
     .max_lowres     = 3,
     .pix_fmts       = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_YUV420P,
@@ -934,7 +942,7 @@ AVCodec ff_wmv1_decoder = {
     .close          = ff_h263_decode_end,
     .decode         = ff_h263_decode_frame,
     .capabilities   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
-    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
+    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM | FF_CODEC_CAP_INIT_CLEANUP,
     .max_lowres     = 3,
     .pix_fmts       = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_YUV420P,