[MPlayer-users] record from TV ( v4l ) with sound

Jindrich Makovicka makovick at kmlinux.fjfi.cvut.cz
Wed Oct 23 13:50:02 CEST 2002


On Wed, Oct 23, 2002 at 11:36:59AM +0200, Emmanuel Anne wrote:
> Oh, it was just to force the audio recording from /dev/dsp even with a
> v4l card without audio capabilities : 
> s/param_noaudio = 1/param_noaudio= 0/ in tvi_v4l.c.
> I'll try the cvs version later instead. It works with alsa and oss
> emulation, but not with oss only with this card.
> 
> By the way you are right, it was an intel sound card based on an ac97
> chip.

Could you try to specify explicitly a samplerate of 48kHz with the "real"
OSS ?

> > AFAIK no. I currently use VirtualDub under wine for this purpose. It doesn't
> > work optimally but at least it can do the direct stream copy. The scene
> > change detector is usually smart enough to put a keyframe at the start and
> > end of the commercials so it can be cut out very easily.
> 
> ???
> Sorry, I am a little lost here. How can you use these key frames for
> cutting a sequence ???
> I mean, with mencoder there does not even seem to be a way to cut
> sequences : you can start and end at specific points to define a
> sequance, but then you can't join the resulting files. You have to use
> another program and it becomes a mess (avicat works, but it is very
> sensitive to what you have for the audio track - it does not like mp3,
> and it hates mp3 vbr).
> 
> Is there something special to do to use these keyframes, or is it just
> an external program to use ? (by the way AFAIK, there is no program able
> to edit divx files in linux) 

Sorry, this was really confusing. I just meant that the main problem with
cutting DivX (or any MPEG) is that you can cut the video only at the
keyframes. But as mencoder (or libavcodec) does a pretty good job detecting
the scene changes, it's possible to cut the ads out clearly, without having
to cut a bit of movie or leaving a bit of the commercial.

To be honest, I didn't look for any native Linux video editing tools yet as
I was used to VirtualDub and its only feature I use works even under Wine.
(VirtualDub is a GPL'd point-and-click video editing tool for Windows). The
only disadvantage is that you have to encode audio as CBR. VD is unable to
cope with vbr audio like most of the other video editors.

--
JM




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