[Ffmpeg-devel] Interleaving audio and video

Michael Niedermayer michaelni
Sun Feb 4 10:32:12 CET 2007


On Sat, Feb 03, 2007 at 10:12:17PM -0800, Roman Shaposhnik wrote:
> > > That should be also perfect for other formats, there is no framer for
> > > pcm atm, what do you suggests ?
> > > 
> > > Add option to ffmpeg.c ? Set enc->frame_size to 1920 or so, though that
> > > will perturb mov muxer for example which expect frame_size to 1 for pcm.
> > 
> > if mxf/gxf are the only containers havig such odd limitations then the code
> > to deal with it should be in them (its already there i assume and so its
> > the least work and seems simplest)
>   DV is even worse. Its actually funny that these muxers seem to be the
> only serious  users of Fifos because they have to keep [re]packetizing
> at muxer level which leads to code duplication.

well, you can suggest a change (=send patch) which simplifies the code and
removes the code duplication

> > also keep in mind that in reality audio and video come from different
> > hardware and their sampling intervals are not synchronized so the idea
> > of X audio samples per video sample is broken by design, its not a
> > problem in reality as audio can be resampled video frames can be droped
> > or duplicated but if your goal is good quality then such a limitation is
> > unaccpetable, iam really curious why formats like that are being designed
> > while much simpler, more advanced and less retarded formats already 
> > exist
>   DV is more flexible in that regard. In non-locked mode the clocks are
> allowed to drift a bit. But I'm not surprised that GXF/MXF have the
> same kind of requirements as far as audio goes as DV does. After all
> the 3 of them are supposed to be easy for heavy editing. And once
> you start edit and splice -- I think locked audio with a fixed # of
> audio frames per fixed # of video frames actually makes sense.
> Wouldn't you agree ?

as ive said, if you care about quality such things are not possible
unless you have the sampling times synchronized at hw level

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No human being will ever know the Truth, for even if they happen to say it
by chance, they would not even known they had done so. -- Xenophanes
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