[Ffmpeg-devel] [PATCH] mov dnxhd muxing

Michael Niedermayer michaelni
Thu Mar 22 17:46:50 CET 2007


Hi

On Thu, Mar 22, 2007 at 01:53:48PM +0100, Baptiste Coudurier wrote:
[...]
> >> Also, avid codecs need those specific mov atoms for some codecs ffmpeg
> >> already supports, what would be the good way to write them ?
> >>
> >> Example: you can mux dv into mov using "AVdv" tag, then avid codecs will
> >> decode stream perfectly if those atoms are present, though quicktime
> >> wont decode it by default.
> >>
> >> Quicktime has a native decoder for dv25 so use native one, but for dv50,
> >>   there is no decoder. We can use Final cut one, which use his own
> >> codec/own tag but only useable when fcp is installed, or Avid ones which
> >> are freely available.
> >>
> >> So what muxing by default, and how to switch ? codec_tag ("stsd" tag) is
> >> a solution, but people will have to know which tag to use.
> > 
> > i dont think codec_tag should be (mis)used for this, but rather a new muxer
> > similar to the one for psp should be added to movenc.c
> 
> Humm I would prefer not, and I would like to remove those fancy flavors
> of mp4 muxers, Im looking for a generic way to handle specific atoms
> required for ipod/psp. 3g2 muxer is code duplication and it only change
> brand of ftyp atom, psp only adds a few atoms, maybe a "target" or
> "flavor" field in AVFormatContext, then a table of flavors in muxers ?
> That should provide also some kind of "target" support, we could provide
> some AVOption tables to be used.

advantages: none i can see
disadvantages:
* one more field in AVCodecContext
* one more table in AVOutputFormat
* one more parameter _every_ application must deal with and no AVOption
  cannot magically make user apps select an entry from the table in
  the specific AVOutputFormat
* breaking API & ABI

considering the above comparision its not hard to decide which is better

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct awnser.
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