[GnomeMeeting-list] how to support another capture card? (WAS: experience with the V4L1 compatibility of V4L2)

[Guilhem Tardy <guilhem_tardy yahoo com>]

I added grabber->SetFrameSize(width, height) in videograbber.cpp, and got to
the bottom of this:

Since the Videum card doesn't support 352x288 (but still advertises 640x288 as
maximum frame size), it fall backs on 352x240 (same behavious with 'vctrl'),
and VideoInputDevice::VerifyHardwareFrameSize() doesn't like it at all.

I am a bit confused with the logic here, because
VideoInputDevice::SetFrameSize() first sets the size internally, then verifies
hardware that returns FALSE (at this point, the card is set with 352x240, and
internally to PWLib with 352x288, no converter is configured).

So now, my question is: does the PWLib library behave so by design? Should we
address this in PWLib or work around it in the application (e.g. GnomeMeeting)?

Guilhem.

--- Guilhem Tardy <guilhem_tardy yahoo com> wrote:
> Hi,
> 
> As I found out yesterday, the palette is not an issue. The problem lies in
> the
> VideoInputDevice::Open() function, which gets the device capabilities, sets
> the
> height and width internal values to the maximum values  (i.e. 640x240), and
> mutes the audio.
> 
> In effect, the WinNov video frame size is changed from whatever I set it to
> before (e.g. 352x240x24, via the 'vctrl' utility) to 640x240x8. This is also
> reflected by the 'vctrl' utility after the facts.
> 
> Guilhem.
> 
> --- Damien Sandras <dsandras seconix com> wrote:
> > On Wed, Apr 17, 2002 at 03:45:25PM -0700, Guilhem Tardy wrote:
> > > I found that the problem is actually not the palette, but a subversive
> > change
> > > of frame size (640x288) when you Open() a VideoInputDevice.
> > > Then, the SetFrameColourConverter() calls SetFrameColour(), which calls
> > > SetFrameSizeConverter(), and returns FALSE (640x288 is definitely
> > > non-standard).
> > > Do you know why VideoInputDevice::Open() resets the frame size?
> > > 
> > 
> > I'm not sure I understand what you mean.
> > PWLib only tries sizes CIF (352x288) and QCIF (176x144).
> 
> 
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