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

[Bob Maple]

On 10/23/2012 4:43 AM, Tim Nicholson wrote:

> So remuxing a QT quicktime in ffmpeg stays good (assuming the answer to
> Carls question is yes, but remuxing an ffmpeg quicktime in QT doesn't
> completely fix the issue (well it didn't for me)

Well it was remuxing an FCP-original ProRes file in ffmpeg, but yes that 
seems to work OK.

> Shouldn't we be looking at the coder not the muxer?

I believe so - I assume that a single encoded frame has to be in one 
complete 'packet' as shown by ffprobe, in which case the encoded frame 
sizes are what can't be odd and it's not something that can be fixed 
with just muxing.

I'm still trying to decypher the source (all of the actual codec 
algorithm stuff is way over my head!) to see if I can even hack it to 
shove a pad byte in there (even if it means trashing the visual frames a 
bit) as a test.

Or maybe the easier thing to do is to come up with a single visual frame 
that compresses out to an even length and repeat it and see if that 
works.  It's just that the nature of the playback issue is so 
inconsistent, I have files ffmpeg encoded minutes long that play fine, 
whereas others fail within seconds.  It'd be more useful I think to at 
least hack the encoder and run a ton of test material through it to see.