On Tue, Dec 09, 2014 at 10:21:01AM +0100, Erik Johansson wrote: > On Thu, Dec 4, 2014 at 5:27 PM, Michael Niedermayer <michae...@gmx.at> wrote: > > > > On Thu, Dec 04, 2014 at 01:11:08PM +0100, Erik Johansson wrote: > > > Hi, > > > > > > Setting setting sample_aspect_ratio in AVContext does not produce the > > > expected aspect index value in the MPEG2 sequence header. > > > > > > Problem seems to be around line 263 in mpeg12enc.c. Setting the > > > sample_aspect_ratio to 16/9 leads the current error minimization > > > routine to determine that > > > > > > error -= (1LL<<32)*(221/100)*(1080/1920) > > > > > > is smaller than > > > > > > error -= (1LL<<32)*(16/9)*(1080/1920) > > > > > > thus picking aspect index value 4 rather than 3. > > > > > > Proposed fix in attached patch. > > > > how can this bug be reproduced ? > > > > The problem was detected by a client using 'Baton', file based QC > software from Interra Systems. > > In summary, we create the MPEG2 essence as follows: > > m_avcodec = avcodec_find_encoder(CODEC_ID_MPEG2VIDEO) > m_avcontext = avcodec_alloc_context3(m_avcodec)
> m_avcontext->sample_aspect_ratio = (AVRational){16,9}
This is incorrect you mixup sample and display aspect
> m_avcontext->width = 1920
> m_avcontext->width = 1080
there is probably a typo in there
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
It is what and why we do it that matters, not just one of them.
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