[FFmpeg-user] ProRes Quicktimes with audio not playing back reliably

[Thomas Worth]

On Sat, Oct 27, 2012 at 10:18 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Fri, Oct 26, 2012 at 07:30:10PM -0700, Thomas Worth wrote:
>> On Fri, Oct 26, 2012 at 7:20 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
>> >> While all of the packets in this remux are even-sized, the entire
>> >> thing is out of alignment file position wise, apparently due to
>> >> something in the header winding up odd sized.. but no matter, it
>> >> seems to play.  The primary difference is that the muxing rate is
>> >> much longer than what ffmpeg generates.  For instance, ffmpeg makes:
>> >>
>> >> VaaVaaVaVaaVaVaaVaVaaVaaVaVaaVaVaaVaVaaVaaVaVaaVaVaaVaVaaVaVaaVaaVaVaaVaVaaVaVaaVaaVaVaaVaVaaVaVaaVaVaaVaaVaVaaVaVaaVaVaaVaaVaVaaVaVaaVaVaaVaaVaVaaVaVaaVaVaaVaVaaVaaVaVaaVa
>> >>
>> >> etc. while the Quicktime Pro remux (and other "real" ProRes files)
>> >> look more like:
>> >>
>> >> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaVVVVVVVVVVVVVVVaaaaaaaaaaaaaaaaaaaaaaaaVVVVVVVVVVVVVVVaaaaaaaaaaaaaaaaaaaaaaaaVVVVVVVVVVVVVVVaaaaaaaaaaaaaaaaaaaaaaaaVVVVVVVVVVVVVVV
>> >>
>> >> At this point I'm feeling confident that it's a general performance
>> >> issue with the very tight mux ffmpeg is doing, AND almost certainly
>> >> exacerbated by the odd frame lengths in most situations which helps
>> >> explain why the behavior is so erratic.
>> >>
>> >> So my next question, is there any way to tell ffmpeg to mux/re-mux
>> >> with larger runs, to see if this greatly improves the reliability of
>> >> playback, or is this hard-coded into the muxer (in which case, is
>> >
>> > see -chunk_duration and -chunk_size
>>
>> Michael, could these options be used in lieu of the asetnsamples
>> filter? In other words, could the same mux behavior be achieved only
>> by using the -chunk_duration and -chunk_size options?
>
> no, why do you ask? is one working and the other not ?

Bob was using the asetnsamples filter to force the muxer to write the
audio in larger chunks than normal. Could he have used -chunk_duration
with a value of say, 1000000 to group the muxing of audio/video into 1
second chunks?