[Ffmpeg-devel] [PATCH] apple caff demuxer

Michael Niedermayer michaelni
Wed Apr 4 18:37:08 CEST 2007


On Wed, Apr 04, 2007 at 11:18:02AM -0400, Justin Ruggles wrote:
> >>>>[...]
> >>>>+
> >>>>+    av_set_pts_info(st, 64, 1, st->codec->sample_rate);
> >>>>+    st->start_time = 0;
> >>>>+    st->duration = st->nb_frames;
> >>>
> >>>wrong, duration is in stream timebase according to demuxers and utils.c,
> >>>btw doxy is also wrong in avformat.h.
> >>
> >>But 1/sample_rate is the stream timebase in this case, so 1 frame is
> >>equivalent to 1 timebase unit.
> > 
> > 
> > no, 1 frame is long as how many samples are in your frame, being said,
> > one ac3 frame contains 1536 samples at 48khz, duration of one frame is
> > 1536/48000, and assuming you have 50 frames, you have 76800 samples, and
> > duration is 76800 / 48000, not 50 / 48000.
> I think we're having a terminology mixup here.  The CAFF specification
> uses the term "frame" to refer to 1 sample over all channels.  WAVE
> calls this a block.  The frame you're referring to is at the codec
> level, and is called a "packet" by CAFF.  Multiple CAFF packets can be
> put in one AVPacket.

1 AVPacket should be 1 (codec) frame/packet, if not a AVParser is needed
to split the AVPackets, the exception is raw audio

> > libavformat version bump is missing also.
> ok. Just so I'm clear about this, what are the criteria for a
> libavformat version bump?

depends on who you ask ...

major version must be bumped on ABI breaks (=anything that could break a
properly written application which has been compiled against an old

minor version must be bumped on ABI extensions (=anything that could break
a properly written application which has been compiled against the new
version but linked against the old)

patchlevel can be increased whenever you like

for adding a codec/(de)muxer increasing the patchlevel is correct IMO some
(IIRC roberto/diego though argue that the minor version should be bumped ...)

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I know you won't believe me, but the highest form of Human Excellence is
to question oneself and others. -- Socrates
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