[vdr] vdr and YUV output

Nicolas Huillard nhuillard at e-dition.fr
Tue Jun 7 12:52:47 CEST 2005

Andreas Holzhammer - Privat a écrit :
> Nicolas Huillard schrieb:
>> Andreas Holzhammer - Privat a écrit :
>>> I'm in the course of converting my home cinema equipment from S-Video 
>>> (Y/C) to YUV connection.
>>> Currently I use vdr with a full-featured card and s-video output 
>>> through the j2 connector. What is the "recommended" way to move vdr 
>>> to YUV output, as the FF cards are not capable of doing so? I don't 
>>> want to shell out to much money, so RGB->YUV converters are probably 
>>> out of the range.
>>> Would a cheap (PCI) ATI (Radeon 8500/9x00) card with an YUV adapter 
>>> be suitable, and what picture quality is achievable through this 
>>> setup? Are there any other options? The PC is a 1.3GHz celeron 
>>> MediaPortal, so I can't spare to many CPU cycles on either X or 
>>> software mpeg decoding.
>> Your Celeron have enough power for softdevice (if you don't plan on 
>> HDTV before softdevice make use of hardware accelerated decoding).
>> Well supported card are Matrox, with DirectFB. Maybe they are capable 
>> of YUV output.
>> If you plan to convert your equipment, why don't you go the RGB way ? 
>> Do you already have a special output device with YUV input ?
>> In fact, a VGA card with an overlay is actually an YUV to RGB 
>> converter, and a typical display device is in fact RGB by design (CRT, 
>> LCD, DLT, Plasma). So why convert from YUV (MPEG2 stream) to RGB, then 
>> output in YUV and convert back to RGB inside the display device ?
> Nicolas,
> thanks for your recommendations, I will have a look into the Matrox 
> route as well. I'm somewhat concerned on CPU power especially when 
> playing back mpeg4, but I could offload this to a pinnacle showcenter 
> type box.
> There are three reasons to use YUV:
> - progressive scan is possible through YUV

VGA/RGB output can also be progressive... It all depends on your display 

> - DVD media is natively YUV

Though YUV is converted to RGB at the display stage...

> - most important, my amp (Yamaha AX1) is capable of switching YUV input 
> signals (and add his OSD to it), but can't do RGB

That's *the* real reason... if you have more than one YUV device (VDR + 
something else) *or* you really need the OSD from the amp.
My amp only switch S-Video, and does not add OSD, and it would not be a 
problem for me to directly connect the VGA output from the VDR to the 
display device, since the VDR is in fact the only valuable video device 
(VCR does not count as "valuable" : composite only, mono audio, etc.).

> So the highest achievable quality for me is YUV

I googled for YUV + Matrox + DirectFB, but can't find anything else than 
overlay specifications : nothing about output signal type.


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