[mythtv-users] PVR350 TV-OUT (PAL) not Working (probably X-Server Config?)

Michael T. Dean mtdean at thirdcontact.com
Fri Jul 23 13:04:38 EDT 2004


Stephen Longhurst wrote:

>>On Thursday 22 July 2004 06:14 pm, Frank Bertling wrote:
>>    
>>
>>>I've seen the color pattern clearly on the screen. So far so good. So in my
>>>opinion there is no problem with the card or the modules. But when I start
>>>the X-Server I get a "running" picture (like one might have had in former
>>>computer times when resolution was wrong) So I can guess that the X -
>>>Server is running, becaus I know the look from the desktop, but I cannot
>>>get a clear picture.
>>>      
>>>
>I don't know if I had the same problem or not, but I'll describe it
>and the solution.  It might give you some ideas.
>
>On my machine (using originally ivtv 0.1.9 and now
>ivtv-0.1.10-pre2-ck71), when the saa7127 module is loaded, I get a
>scrambled picture. It has diagonal lines running around on it with
>flashes of colour. If I load it with the test picture, that was
>perfect. If I loaded X, it would start up, but the picture on the tv
>out was similarly garbled... until I played some video using the ivtv
>decoder. Once an mpg video had been sent to the decoder (either from
>mythtv or simply "cat something.mpg > /dev/video16", everything
>corrected itself.
>  
>
If that is the same problem, it's due to the transparency (alpha) 
settings on your framebuffer.  When you see a "garbled" screen (with 
"diagonal lines running around on it with flashes of colour"), your 
framebuffer is partly transparent (each pixel having a different 
transparency), and the random bits in the framebuffer (the 8-bits/pixel 
above the 24-bits written by the fbdev driver) are creating a strange 
pattern on screen.

Fix it for video output with
    ivtvfbctl /dev/fb1 -globalalpha -nolocalalpha -alpha 0
and for framebuffer (X output) with
    ivtvfbctl /dev/fb1 -noglobalalpha -nolocalalpha

Note that your programs (i.e. MythTV) will take care of this for you, so 
this only really applies when testing using non-ivtv-aware tools (i.e. 
cat/dd).

>Your XF86Config is almost identical to mine, apart from I use the
>ivtvdev driver from Mathias Badaire.  Get it from
>http://membres.lycos.fr/badzzzz/ and change the Driver "fbdev" line
>above to Driver "ivtvdev".  I never tried the standard framebuffer
>driver, but everyone says the ivtv one is much better, and it works
>great for me.
>  
>
Definitely a must--especially since the newest CK patches disable direct 
framebuffer output to the PVR-350 framebuffer.  It is not safe to do 
framebuffer writes while the decoder is running--data must be transfered 
using DMA or it will lock up the card (and possibly the system).  Note 
also that these ck releases (the .tgz files, not the .diff files) have 
provided an updated ivtvdev driver (with some bugfixes).  I can't tell 
you whether the updated ivtvdev works with older ivtv drivers.  See 
patches/README for more information about installing ivtvdev.

I'll also mention that the newest CK patches autodetect settings--even 
the PAL settings automatically.  For example, with 
ivtv-0.1.10pre2-ck100b, the only required settings in modules.conf (or 
modprobe.conf) should be:
    alias char-major-81 videodev
    alias char-major-81-0 ivtv
    # Only if using the ivtv framebuffer
    # Even then, optional, could manually be inserted
    #add above ivtv ivtv-fb
And the ivtv modules are loaded with:
    modprobe ivtv

ck100b has been very stable for me, but it is a "bleeding-edge" 
development snapshot, so, if you decide to try it, be prepared for 
problems (and sign up for the ivtv ML's at 
http://sourceforge.net/mail/?group_id=73219 ).  Also, I stopped using my 
PVR-350's TV out (the disadvantages--no Xv, no OpenGL acceleration, 
lower system stability--outweighed the advantages--great picture).  I'm 
very content with my PVR-350 for recording and my Chaintech MX440 for 
playback.

Mike


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