On Wed, Sep 30, 2015 at 4:35 PM, Paul B Mahol <one...@gmail.com> wrote: > On 9/30/15, Hendrik Leppkes <h.lepp...@gmail.com> wrote: >> 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. > > WTF, can you just give sample/link something?
Like I said earlier in the thread, it happens with API usage in a Live TV scenario. I cannot produce a sample of that. - Hendrik _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel