On Wed, Sep 30, 2015 at 2:51 PM, Michael Niedermayer <michae...@gmx.at> wrote: > On Wed, Sep 30, 2015 at 02:39:21PM +0200, Hendrik Leppkes wrote: >> On Wed, Sep 30, 2015 at 2:33 PM, Michael Niedermayer <michae...@gmx.at> >> wrote: >> > On Wed, Sep 30, 2015 at 02:29:43PM +0200, Hendrik Leppkes wrote: >> >> On Wed, Sep 30, 2015 at 2:10 PM, Michael Niedermayer <michae...@gmx.at> >> >> wrote: >> >> > On Wed, Sep 30, 2015 at 12:42:59PM +0200, Hendrik Leppkes wrote: >> >> >> The chroma format can be still unset in postinit when a badly cut >> >> >> stream >> >> >> starts with a slice instead of a sequence header. This is a common >> >> >> occurance when feeding avcodec from a Live TV stream. >> >> >> --- >> >> >> libavcodec/mpeg12dec.c | 1 - >> >> >> 1 file changed, 1 deletion(-) >> >> >> >> >> >> diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c >> >> >> index 5d916d1..b3c2c45 100644 >> >> >> --- a/libavcodec/mpeg12dec.c >> >> >> +++ b/libavcodec/mpeg12dec.c >> >> >> @@ -1389,7 +1389,6 @@ static int mpeg_decode_postinit(AVCodecContext >> >> >> *avctx) >> >> >> case 1: avctx->chroma_sample_location = >> >> >> AVCHROMA_LOC_LEFT; break; >> >> >> case 2: >> >> >> case 3: avctx->chroma_sample_location = >> >> >> AVCHROMA_LOC_TOPLEFT; break; >> >> >> - default: av_assert0(0); >> >> >> } >> >> >> } // MPEG-2 >> >> > >> >> > This assert double checks that the context init which uses >> >> > width/height/chroma format is done after the chroma format and w/h has >> >> > been read from the headers >> >> > if this is reached without the headers being read then the code is >> >> > buggy and removing the assert will not fix that bug >> >> > >> >> > also if there is no sequence header how is width/height set ? >> >> > theres a check for width/height before mpeg_decode_postinit is called >> >> > >> >> >> >> The dimensions are set by the caller in the avctx before opening the >> >> codec, which apparently inits the mpeg context as well. >> >> >> >> Feel free to fix it differently, error out or something, but I can >> >> trip an assert with input data, which should never happen. >> > >> > how can this be reproduced ? >> > >> >> I can only trigger it with API usage, not through the CLI tools, so I >> cannot produce a test case. > > is this with a unmodified up to date ffmpeg ? > i fixed this assert failing a while ago > (b54e03c9dc2a05324c08b503bfe7535c49c0f281) > >
Its up to date, but slightly modified - but nothing pertinent to the mpeg2 decoder as far as I know. I'll just add this to the list of modifications then. I can clearly trigger this assert in a release build (which is hilarious on its own, asserts are a debugging tool), which crashes the application, so thats no good. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
