[FFmpeg-devel] [PATCH]Support muxing more qcelp samples in mov

Carl Eugen Hoyos cehoyos at ag.or.at
Tue Jul 9 10:55:23 CEST 2013


Michael Niedermayer <michaelni <at> gmx.at> writes:

> > > are "official" qcelp in mov files also stored in 
> > > this inefficient way ?
> > 
> > All files in our collection have constant packet size.
> 
> The way i understand the patch is that it increases 
> the size of all packets to 35 bytes

That is what the patch does.

> (which can waste alot of space if many are
> smaller)

(waste compared to what? ffmpeg currently silently 
muxes unplayable files.)

> What i meant was, do we have samples that also 
> bloat packet up in such way?

No.
(Actually I am not sure but it is ok imo to 
assume that we don't have such a sample.)

> and do we have samples that have smaller packets ?

Yes (but one of them does not play with QT - it 
does after remuxing with my patch - I still don't 
understand why another one works).

> Which would imply that theres a more efficient 
> way to mux them

Of course.
Using an encoder with a specified bitrate allows the 
muxer to mux with the exact specified bitrate.
Since ffmpeg does not scan the whole (qcp) file 
before remuxing, it cannot know the optimal muxing 
rate.

Or do I miss something?

Carl Eugen



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