[vlc-devel] CVS Commit (fenrir)

cvs at videolan.org cvs at videolan.org
Sat May 31 03:23:29 CEST 2003

Update of /cvs/videolan/vlc/modules/access/v4l
Modified Files:
	Modules.am v4l.c 
Added Files:

Log Message:
 * mjpeg grabbing added, thanks to Paul Forgey <paulf at aphrodite dot com>
 that had done all the work.

Paul Forgey's notes:

Unfortunatley, the v4l interface shows how much it sucks here.  I can't
wait for v4l2 to become more common.  Anyway, the mjpeg mechanism
captures completely differently than the uncompressed frame capture
mechanism.  This means the code has to split off a bunch to do similar
things depending on mjpeg being set or not.  For some reason, I can't
use non v4l2 calls to capture uncompressed frames from the lml33,
however I do have another bttv card on my system to test that I didn't
break the non-mjpeg stuff.

The Zoran encoders don't use square pixels.  So the 4:3 (or 16:9)
picture is going to show up as 720x480.  I don't know my way around the
code well enough to know how to specify a non-square pixel aspect
ratio.  If there isn't a way to do it, it would be nice to be able to
specify as an option the aspect ratio of the sourc.  Either 4:3 or 16:9
in the case of anamorphic S-Video, which does occur.

I stole the videodev_mjpeg.h header from the lavrec project.  Despite
the linux kernels having support for the Zoran cards, there doesn't seem
to be a reliable way to pick up this header, which is probably why
lavrec did it this way.  Since it only defines ioctl definitions, I
don't think using it is a legal problem.

I also modified the audio handling a bit.  If the card supports audio,
great, we'll set the card's parameters as we did before.  But if adev=
is specified, use it regardless.  The reason to do this is to capture
audio from the sound card with video coming from, say, a web cam or in
my case, an encoder card which doesn't have any audio capabilities at

This is the vlc-devel mailing-list, see http://www.videolan.org/vlc/
To unsubscribe, please read http://developers.videolan.org/lists.html
If you are in trouble, please contact <postmaster at videolan.org>

More information about the vlc-devel mailing list