[Techtalk] VHS to DVD

Anthony de Boer adb at adb.ca
Wed Jul 25 15:04:31 UTC 2012

David Sumbler wrote:
> On Mon, 2012-07-23 at 16:28 -0400, Anthony de Boer wrote:
> > That continuous stream might be one of encoded video, if it's anything
> > like the capture card I used.
> > 
> > Type 'cat /dev/video0 > mycapture.mpg', feed some video into the card,
> > and then ^C it.  At this point running something like mplayer on the
> > file should show you video.
> I have now tried this.  About 10Mb per second were written to the file.

So it's definitely getting *something*.  Big question is what.

> When I entered 'mplayer mycapture.mpg' I got the following output:
> MPlayer SVN-r33713-4.6.1 (C) 2000-2011 MPlayer Team
> mplayer: could not connect to socket
> mplayer: No such file or directory
> Failed to open LIRC support. You will not be able to use your remote
> control.
> Playing mycapture.mpg.
> Invalid seek to negative position ffffffffffffffff!
> libavformat file format detected.
> [mp3 @ 0x10b47e0] Header missing
> ...

And it seems that it's not finding a video format it understands,
though maybe somehow it thinks there's an MP3 audio stream in it.

Possibly the glossy docs on the device you have, or searching the web,
might reveal what format it's supposed to do.  Raw video can be
particularly tricky because you have to know how much data to stuff in
each frame, and in what format.  Some formats have helpful headers,
especially in container formats that include audio.

Some distros give out stuff like ffmpeg and mplayer with codecs that
have patent claims against them disabled, to avoid potential lawyer
enrichment, though having MP3 support suggests that's not the case for
what you're running.

The file(1) command might be able to tell you something about the sample
file you captured, if it has headers it can recognize.

Best o'luck, eh?

Anthony de Boer

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