[Ffmpeg-cvslog] Re: r5468 - trunk/libavformat/mov.c

Michael Niedermayer michaelni
Tue Jun 13 02:01:13 CEST 2006


On Mon, Jun 12, 2006 at 07:55:47PM +0200, Baptiste Coudurier wrote:
> >> Now, situation is:
> >> - either remove streams like I did.
> >> - present them to libavformat, assigning CODEC_ID_DATA or CODEC_ID_NONE.
> >>
> >> Do you prefer the latter ?
> > 
> > yes
> All right then. What would be the best way ? Adding CODEC_ID_DATA, or
> using CODEC_ID_NONE ? Somewhat I feel using CODEC_ID_NONE will cause
> problems.

id say use CODEC_ID_NONE, we can always add CODEC_ID_DATA later if
any complex problems appear due to it

> > it would also be nice if we could remux (-*codec copy) these streams
> I totally agree and will do that. Im thinking about adding -newdata to
> ffmpeg commandline options, though I feel like stream mappings between
> formats will be a big mess. Allowing only stream copy for now, and
> between same/compatible formats, maybe it's time for FORMAT_ID_MOV ?
> > [...]
> While we are at it, I also have 2 problems concerning demuxing/muxing
> mov/mp4:
> - to properly seek into a non-interleaved mov/mp4 I need to know the
> exact timestamp in AV_TIME_BASE unit and not stream time unit, since I
> need to seek by time and not by chunk offset. I can still rescale to get
> the correct timestamps but It is not really accurate/correct.

i dont fully understand the problem, please elaborate

> - to stream copy audio tracks I need to know codec->frame_size to set
> 'stts' correctly. I can either assign it in the demuxer, from the
> original 'stts' atom, but it sometimes contains more than one value, or
> assume it according to codec used, AAC uses 1024, AMR 160, PCM 1.
> What do you think ?

i think that the timebase (or samplerate or samplerate/frame_size if known)
and AVPacket.dts should be used this reminds me that the mov muxer doesnt 
work with non constant fps videos ...


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is

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