[pvrusb2] [patch] 24xxx capture window cropping support

[Carsten Meier]

Am Tue, 8 Sep 2009 10:37:23 -0500 (CDT)
schrieb Mike Isely <isely at isely.net>:

> On Tue, 8 Sep 2009, Carsten Meier wrote:
> 
> > Am Mon, 07 Sep 2009 22:51:14 +0200
> > schrieb Bernhard Geier <geierb at geierb.de>:
> > 
> > > vdb128 at picaros.org schrieb:
> > > > Here below is a patch for the setup: 
> > > > Linux 2.6.29.6, 24xxx device, cx25840 decoder, firmware
> > > > 2.06.039. 
> > > Works! Thank you!
> > > 
> > > This settings elimiate the black borders at top & bottom:
> > > 
> > > echo "16x9" > ctl_video_aspect/cur_val
> > > echo 428 > ctl_crop_height/cur_val
> > > echo 72 > ctl_crop_top/cur_val
> > > 
> > > Bernhard
> > > 
> > 
> > I don't have the ability to test it yet, because I'm currently
> > connected to a satelite dish, but shouldn't the aspect-ratio of the
> > stream be automatically calculated from the cropping settings?
> 
> The driver does not internally attempt to set that control, and I 
> seriously doubt that the mpeg encoder would do that on its own
> either.  
> 
>   -Mike
> 

The video aspect control should not change, because it specifies the
aspect ratio of the input signal, which remains constant. But the aspect
ratio of the MPEG stream should be adapted accordingly to preserve pixel
dimensions. E.g.: A 4:3 letterboxed TV broadcast (with square pixels)
contains an 2:1 image with black bars at the top and the bottom. If I
set the crop-controls to remove the black bars, shouldn't the MPEG
stream have an aspect ratio of 2:1? (A value that is not even settable
through controls, because of the enum) Otherwise the square pixels get
streched.