[FFmpeg-devel] [PATCH]Do not use mjpeg frame-threads with cbr and threads=auto

Reimar Döffinger Reimar.Doeffinger at gmx.de
Thu Dec 19 11:57:28 CET 2013

Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
>Reimar Döffinger <Reimar.Doeffinger <at> gmx.de> writes:
>> Carl Eugen Hoyos <cehoyos <at> ag.or.at> wrote:
>> >Michael Niedermayer <michaelni <at> gmx.at> writes:
>> >
>> >> > +       && !(avctx->flags & CODEC_FLAG_QSCALE))
>> >> > +        avctx->thread_type &= ~FF_THREAD_FRAME;
>> >> 
>> >> i would reduce the number of threads to 1 with slice 
>> >> threads you generate jpegs with resync markers, i have no
>> >> idea how widely binary decoders support such mjpegs
>> >
>> >I tried to find a decoder that doesn't support slice-encoded 
>> >(m)jpeg but couldn't find one. Where you thinking about a 
>> >particular decoder?
>> I doubt he was, but I would imagine digital cameras 
>As in:
>Produce a mjpeg file with FFmpeg and copy it to your 
>digital camera to watch it on the camera screen?
>Or do I misunderstand?

Yes. Though some actually could both record and play MJPEG movies, which might be more interesting.
Also since those need to be decoded fast.

>> and old mobile phones might be typical ones to miss
>> support since they wouldn't normally across such files.
>I will try to test with older phones.

Note that I don't know how relevant it really is, so unless you're curious anyway don't spend much time on it.

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