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) > Just replace the assert with a error return, that should cover everything. > > - Hendrik > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Its not that you shouldnt use gotos but rather that you should write readable code and code with gotos often but not always is less readable
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