[mythtv] Re: [XFree86] Relationship of XVideo to V4L

Billy Biggs vektor at dumbterm.net
Tue Jul 8 15:12:03 EDT 2003

Michael J. Hammel (mythtv at graphics-muse.com):

> MythTV seems to want to work with V4L devices.  My understanding is
> that XFree86's v4l module will provide an Xv interface to V4l devices.
> Is that correct?  This assumes the TV is accessible through a V4l
> driver, ie Xv sits atop V4L - is this also correct?

  XVIDEO does two things.  It provides an API allowing applications to
draw their own video to the screen, and it also provides an API to have
X talk directly to the capture card simply for displaying on the screen
(no capture).

  The driver you're using, afaict, can _only_ display video to the
screen, and not capture.  This means that mythtv CANNOT record using it.

> If I'm right about this, the only way to support my hardware would be
> either:
> 1. write a V4l driver for the TV hardware and make the X server not
> manage that hardware


> 2. Add direct Xv support to MythTV

  No.  The XVIDEO API for displaying video does not provide a usable
interface for recording video streams.

  Send the output of 'xvinfo' and you'll likely see that no capture
capabilities exist anyway.


More information about the mythtv-dev mailing list