Re: [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:
> 
> You shouldn't have added that method, but used SetFrameSizeConverter
> and add a HINT in video4linux.cxx for your card to force the size.
> That way, VerifyHardwareFrameSize will ignore the problem and it will work.

There's no HINT that I can see which matches the problem with Videum
card/driver: the card is set at 352x240 while PWLib still keeps 352x288
internally (IMHO it is a bug of VideoInputDevice::VerifyHardwareFrameSize,
which should update the internal variables to what is returned by the driver).

> You have to add a HINT in PWLib. That works this way because all Video4Linux 
> drivers do not respect the API. So you set a HINT, to force the required size
> for your specific driver, and then it will work.

I can't force a driver to take 352x288 if it happily falls back on 352x240, can
I? Now, I elected to modify GnomeMeeting (in videograbber.cpp) like this:

Open()
SetVideoDeviceParameters()
->   SetFrameSize(320,240)
SetColourFormatConverter()
SetFrameSizeConverter(352, 288)

That was a bad idea, indeed. So I will revert to the original videograbber.cpp,
and try to add a new size converter (352x240 -> 352x288).

Guilhem.


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