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

[Bob Maple]

On 10/18/2012 4:45 AM, Tim Nicholson wrote:

>> Files generated by ffmpeg
>> wind up about 25% odd-length and thus cause subsequent un-alignment.

> Is this for video only or both?

Both.  Video-only is unaligned too.

> ISTR you previously thought it was an issue with the A/V interleave, are
> you now saying that is not the case?

I think it could be a bit of both;  The much smaller packets and 
interleaving of the ffmpeg-generated ones was just one thing I noticed, 
and Thomas caught the unalignment.

Even though the machine should be well fast enough anyway (I'm not 
pegging any cores on playback either) it's hard to speak about the code 
in Quicktime its self and how poorly it might be written... but with the 
smaller more interleaved packets combined with the odd-sized reads, I 
could see how it could be causing these weird issues.


On 10/18/2012 5:15 AM, Thomas Worth wrote:

 > Off the top of my head, I don't think the chunks are aligned even when
 > it's just picture. It could be that QuickTime Player doesn't have a
 > problem when it's video only. But, throw unaligned audio into the mix
 > and yep, you've got trouble.

Exactly.

 > I believe this is also the issue that triggers the Media Performance
 > Warning in Final Cut Pro. It only happens when it's video and audio
 > together. Video by itself seems to work fine.

Good bet there too, I'm sure you're right.


-- 

|  Bob Maple
|
|  When love is gone, there's always justice.  And when justice is gone,
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|  Hi, Mom!   -Laurie Anderson