[pvrusb2] [patch] capture window centering via VIDIOC_S_CROP

[Mike Isely]

On Sat, 10 May 2008, Mark Goldberg wrote:

> On Fri, May 9, 2008 at 8:21 PM, Mike Isely <isely at isely.net> wrote:
> > On Fri, 9 May 2008, vdb128 at picaros.org wrote:
> >
> >> The pvrusb2 patches here below implement capture window centering
> >> by adding the controls crop_left and crop_top.  They call the v4l2
> >> ioctl VIDIOC_CROPCAP and VIDIOC_S_CROP to get the capture
> >> rectangle default and to set the margins.
> > I briefly scanned through the pvrusb2 part of the code and it appears
> > that you have really nailed down how the controls work in the driver.
> > Great job.  I will play around with this a bit (in NTSC-M BTW) and if
> > there aren't any issues I'll merge it in.
> >
> > The cx25840 driver part is a different issue.  I don't maintain that
> > driver.  However I will see about getting those changes reviewed and
> > pushed up into the V4L-DVB repository.
> >
> > Thanks.
> >
> >  -Mike
> 
> It looks like this will solve the issue I had where too much of the
> vertical interval shows in your latest versions of the driver.
> Maybe it will also help trouble shoot it. Please post the patches when
> you have them for NTSC and I'll try them out. If you
> could point me to instructions how to rebuild only one kernel module
> (cx25840), I'd appreciate it. It would be much faster
> and less disruptive than building the whole kernel.
> 
> Thanks Mike and thanks vdb128 at picaros.org whoever you are. I had
> pretty much given up on this problem.
> 
> Mark

Looking at the cx25840 patches, it looks like some basic geometry is 
being calculated based on the current video standard.  I'm not sure if 
this is exhaustive enough.  If it is, then NTSC should "just work".  
Certainly worth trying.

On the other hand, these cx25840 changes are only going to help 24xxx 
PVR USB2 devices.  Older 29xxx devices have an saa7115 instead of the 
cx25843.  So if you are using a 29xxx device then the changes won't 
help.  I will have to figure out what to fix there (or someone else more 
of an expert on the saa7115 will need to work this issue).

  -Mike


-- 

Mike Isely
isely @ pobox (dot) com
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