[mythtv-users] Stability and quality questions

steve at nexusuk.org steve at nexusuk.org
Mon Jan 26 13:46:00 EST 2004


On Mon, 26 Jan 2004, Tor Hovland wrote:

> * The Hauppauge PVR-250/350 is clearly regarded as a top-notch tuner. Are
> there other tuners that are equally good, for instance the cheaper Hauppauge
> ones? I'm talking strictly tuner here, no video out, no hardware
> encoding/decoding, etc.

the PVR250 has a hardware MPEG2 encoder - if you don't care about the 
encoder then you may as well get a plain bttv card (e.g. Hauppauge WinTV 
or similar) whcih are dirt cheap.  Obviously if you don't get a card with 
a hardware encoder on it then you need a much meatier CPU and you won't 
get such high quality.

The only reason for going for the PVR350 over the 250 seems to be that the 
350 has a radio tuner in it and also a MPEG2 decoder (again means you need 
less CPU).  But from what I can tell (I don't have a 350 ATM) the 350 
drivers don't have XV support (not even sure if the hardware allows for 
this either?) which means you can basically only play MPEG2's (which may 
be fine for you if you're always using MPEG2's but it does mean you 
probably won't have much luck transcoding stuff to MPEG4 format to save 
disk space).

I'm thinking of getting a 350 at some point but wouldn't mind 
clarification from the techies who own 350's as to whether it will ever 
get XV support since I like to use my Myth box to play various AVI's and 
MPEGs as well as running Myth.

> * The PVR-350 is regarded to have the best tv-out quality, but as noted the
> drivers are not sufficiently stable. Which other video cards have good
> tv-out? It doesn't have to be as good as the PVR, but it must be quite hard
> to detect that the tv signal is running via the computer. Are there even
> motherboards with sufficiently good tv-out? Does the Asus Pundit have
> sufficiently good onboard tv-out?

If you want to run without deinterlacing turned on (better quality) then I 
think you're pretty much tied to an nVidia card since you'll need vsync 
support.
Personally, I use an S3 Savage (onboard my motherboard) and a little VGA 
-> SCART sync converter that I built.  However, the S3 drivers don't 
support vsync so you will get minor tearing and won't be able to run 
without deinterlacing turned on.  I've written a small kernel module to 
provide a /dev/nvidia style device to do the vsync for the card but it's 
less than perfect because there is no way for the driver to determine 
which field is being scanned (and S3 have completely ignored my request 
for technical information to resolve that problem).  Other than the vsync 
problem, the quality of this method is very good because it's a direct RGB 
connection to the TV without any scaling required to convert from 800x600 
down to the TV's resolution (768x576 for PAL).

-- 

 - Steve                                             http://www.nexusuk.org/

     Servatis a periculum, servatis a maleficum - Whisper, Evanescence



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