[vdr] Epia tv-out methods (was: EPIA SP + budget hardware mpeg2/4 acceleration?)

Laurence Abbott laz at club-burniston.co.uk
Thu Mar 10 12:49:38 CET 2005


On Thu, 2005-03-10 at 11:21 +0100, Nicolas Huillard wrote:

{snippage}

> Your summary is good.

Cool: it's quite difficult to get answers to things I was looking for!

> What I'd say (I still didn't switch back to softdevice, so I'm not 
> up-to-date wrt the latest release) :
> * use X / vdr-xine / XvMC when you have a regular PC (mouse, keyboard, 
> etc.) : this is actually necessary to run Xine, VDR, X, etc. Xine needs 
> 200MB memory and X approx. 40MB (a lot is shared, and works with 256MB 
> RAM). Add that to the 40MB for VDR...
> * use softdevice / DirectFB / software decoding if you have a STB-like 
> HTPC (no keyboard, no mouse, just the remote) : runvdr will handle 
> running VDR *and* the display, restarting, etc. Software decoding is not 
> a problem for your 1.2GHz processor (indeed, less a problem than running 
> Xine separately)

This is probably the route I will aim for: my current box has a dxr3 for
output but it does have X for doing a bit of coding in front of the
tele'! I can live without that, though.

> Subscribe to the softdevice mailing-list (softdevice-devel at berlios.de). 
> There are interesting developments and skilled developers there.

Doing it now...

> The subject of you post mentions "tv-out" : this is a great subject, and 
> you should really consider the output quality in your planning.
> The TV-encoder on the EPIA board (VT162x) is driven by data tables, 
> present in the frame-buffer kernel module for the CLE266, and also 
> present in the X driver for the CLE266. These tables contains many 
> parameters for the video output (PAL, NTSC, anti-flicker, etc.), and 
> come from VIA. The parameters are actually far less than optimal (in the 
>   versions I have, dated a few months back) : the image has large black 
> borders around (each 4 sides), is largely anti-flickered, thus blurred, etc.
> This lead to a huge loss in resolution. 720x576 should be full PAL 
> display, but is actually far less with these tables. Ville Syrjälä from 
> the DirectFB ML sent me the doc for the VT162x encoders, but I don't 
> have time to dig into better parameters. I can send it if anyone want to 
> improve that.

I saw some posts about that when I was looking for info!

> The alternate TV-out method is to generate SCART RVB signal from the VGA 
> output of the board, which should be good, if one can find the correct 
> timing for the frame-buffer driver and/or X driver.

This is another option I was going to look into. Presumably Epias can't
put out a composite sync signal so I would have to combine the
horizontal and vertical syncs. Component RGB output from my stand-alone
DVD player is noticeably better than S-video output from it. I have seen
modelines for doing this with a PAL or NTSC signal but have never got
around to trying it. I'm hoping that is these boards can drive a PAL or
NTSC output directly, the same sync signals are available at the SVGA
connector!

Cheers,

Laz




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