[mythtv-users] video cards, processor, etc.

Ray Olszewski ray at comarre.com
Thu Oct 23 18:39:45 EDT 2003


At 04:09 PM 10/23/2003 -0700, Chris Haumesser wrote:

>I have an old Pentium-200 that I want to put to good use for a very 
>limited task, and I'm wondering if it would be up to it.
>
>On my primary PC, which is a 3.06GHz P4 in my bedroom, I have a number of 
>movies, mp3's, etc.  Upstairs in the living room, we have a TV, stereo 
>etc.  Simply put, I want to use the old P200 to watch music and video 
>upstairs, coming over a network connection from my downstairs PC.
>
>We don't even have cable, so I am not interested at all in the PVR 
>functionality of Myth, and the P200 would not be used for any encoding 
>whatsoever.  Basically, what I want is a front-end, which looks and 
>behaves similarly to the on-screen menus people are so familiar with on 
>PVRs/VCRs/DVD players, for this weak linux box to play movies and music on 
>the TV/stereo.

I'm not sure that you gain much by using Myth in this setting. Running a 
straight X setup with xine or mplayer for video, xmms for audio, may serve 
you about as well. It might be less confusing than a UI like Myth's, with a 
lot of functionality that your setup doesn't actually provide.

>Here are my questions:
>
>1.  First of all, would a P200 be capable of decoding/playing high-quality 
>DVD and/or Divx-encoded video, given a sufficient video card?

I would not say "no" for certain, only because I've been astounded to see 
how little CPU load DivX decoding can take (in contrast to the far more 
demanding task of encoding). But I seriously doubt a P200 could handle even 
this (by today's standards) low load. Perhaps a card with hardware decoding 
could work for DVDs (which are MPEG-2), but not DivX (which is a type of 
MPEG-4). Unless I am mistaken, the hardware decoders are only MPEG-2 (which 
means they handle MPEG-2 and MPEG-1, but nothing else).

The rest of the answers below assume you are using a more capable system. 
The wimpiest I've actually used with success is a K-3 200, running xine to 
play DivXs on a monitor (not a TV). This was just a stunt, though ... for 
everyday use, I'd concur with JAC that you want a 500 MHz Celeron as a minimum.

>2.  What kind of network bandwidth would be needed?  We currently have 100 
>Mbps cat5 ethernet, and are planning to add dual-band 802.11a/b 
>wireless.  Ideally, I would like to use the 802.11a (the access point will 
>be in the same room as the P200), which should in theory provide 54 Mbps, 
>as wireless would prevent me from having to drill a hole in the living 
>room floor.

Do the arithmetic; it depends on how compressed the image is. If, as an 
illustration, you are playing a DivX that is captured at 600 MB/hour, that 
translates to 10 MB/minute, or about 1.3 Mbps.

With wireless, what it will provide "in theory" is less usefult than what 
it will provide in your house. Bitrates drop off as the signal degrades (at 
least 802.11b does; I assume .11a works the same way), so the floor may 
cost you some capacity. And across a lot of LAN technologies, I've found 
that the actual maximum for any one connection is around 50% of the nominal 
speed of the LAN.

>3.  What is the best video card (must naturally have TV-out) for this 
>application, in terms of:   a. price (restricted budget);  b. linux 
>compatibility/driver availability/ease of configuration;  c. xv- and 
>general decoding performance?

Various nVidia cards seem to be the best bet, though some favor other 
cards. You don't need a top-end card, as you don't need the acceleration 
they offer for gamers. As an example, I've used a GeForce4 MX440-SE and 
been happy with it.

>4.  Does anyone else have experience with this type of setup?  What is the 
>crappiest hardware on which anyone has been able to successfully play (NOT 
>encode) video with MythTV?
>
>5.  Is there a different app I should consider that doesn't have the PVR 
>features of Myth, which I don't need?  I need something that is very easy 
>to use, functioning like onscreen menus of a VCR or DVD player.  I don't 
>really want to have to teach my roommates how to use Linux to watch 
>movies/play music.

Myth is going to use mplayer to play this stuff anyway, so you might use 
either it or xine directly, mounting the other system's video directory 
locally.

>6.  What would be the most efficient file-sharing protocol in this 
>case?  I am tempted to to go with SMB, since I could then make everything 
>available on the network regardless of whether the PC downstairs is booted 
>into Linux or Windows, but I almost always stick to Linux, and I wonder if 
>NFS or some other protocol would provide any efficiency gain?

There might be a difference between smb and nfs on efficiency grounds. If 
there is, though, it is not a dramatic one, at least not in my experience. 
In your case, since the video server is dual boot, I'd probably use smb for 
the same convenience reason you mention.





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