[mythtv-users] PVR-350 TV-out distorted

[Thomas Börkel]

HI!

Michael T. Dean wrote:

>> The test picture comes out OK from the PVR-350, but if I play MPEG 
>> (either with the dd command directly from /dev/video0 or with MythTV), 
>> the output is totally distorted. You can guess, that it's a TV 
> 
> Sounds like the "teared" picture you're getting is actually a 
> semi-transparent view of your framebuffer's "picture" on top of the TV 
> picture.  Since you haven't set up X, the framebuffer's "picture" is 
> actually garbage (some semi-random initial bits in the framebuffer).  
> Most instructions I've seen refer to this as "about 20 colored lines in 
> the picture," but for me it was a mess of garbage (sometimes opaque and 
> sometimes semi-transparent) obscuring the view of the TV picture.  Note 
> that the test picture works because it actually uses the framebuffer 
> instead of the TV "underlay."

The picture looks like it is teared or ripped apart diagonal.

> Basically, try these commands:
> 
> # Assuming NTSC via S-Video input
> test_ioctl -u 0x3000 -p 6

My input comes from tuner and is PAL. The input is OK, because I can use 
mplayer /dev/video0 and MythTV works with the GeForce TV-out.

> # This makes the framebuffer image transparent
> ivtvfbctl /dev/fb1 -globalalpha -nolocalalpha -alpha 0
> dd if=/dev/video0 of=/dev/video16 bs=64k
> 
> (Note the slight difference in the ivtvfbctl line from most posts which 
> use:
> 
> ivtvfbctl /dev/fb1 -alpha -on -globalalpha -nolocalalpha
> 
> Interestingly enough, that command works, also, but only by "accident."  
> The -alpha option requires a value for alpha from 0 (transparent) to 255 
> (opaque) and uses the first "word" after "-alpha"  That word happens to 
> be "-on" (which is supposed to mean "turn on the framebuffer" and is 
> never required), but it's not a numeric value "-alpha" expects, so 
> "-alpha" goes with its default of 0. )
> 
> Then, once you have set up X, you can set the framebuffer's background 
> using your normal background changer (i.e. I use chbg ( 
> http://chbg.sourceforge.net/ ) because it has very few library 
> dependencies).  Once you have a "pretty" picture (instead of garbage), 
> use the following to go back to an opaque framebuffer (and see your 
> picture):
> 
> # This makes the framebuffer image opaque
> ivtvfbctl /dev/fb1 -noglobalalpha -nolocalalpha

OK, I'll try that. But shouldn't MythTV clear out the framebuffer and 
set the alpha values right? I have activated "use PVR-350 TV-out" in 
MythTV and I get the same distorted picture when I try to watch TV with 
MythTV.

Thanks!

Thomas