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Help choosing a processor
http://forum.linhes.org/viewtopic.php?f=2&t=15333		 Page 1 of 1
Author:  s0127786 [ Wed May 23, 2007 11:40 am ]
Post subject:  Help choosing a processor
Sorry if this is in the wrong place but I cant find anywhere really appropriate.

Im buying up components for a new mythtv box, the front end and back end will all be in one box and I want dual tuners to be able to record more than one channel.

However afaik to convert mpeg2 (what the pvr-150? gives out) to mpeg4 for storage requires a lot of processor power? I was going to use an ageing XP3000 I have but would this find it impossible to cope?

If not does anyone have any recommendations for a good processor thats:

1. Supported by Myth
2. Can be relatively easily silently cooled (air only)
3. Is relatively inexpensive
4. Has good m/b support which is also supported by myth

Hope thats not to many questions. :)

Michael
Author:  bigbro [ Wed May 23, 2007 12:39 pm ]
Post subject: 
I would say the new dragon would be a good reference to consider.

There are multiple options available and everyone I am sure has a flavor.

A good place to start looking for a system would be the Hardware Tier 1 references here.

Bigger is always better and "Transcoding" mpeg2 to mpeg4 does take some horsepower.

I typically take some of my 720x480 files captured to produce around 1 gig per hour and transcode those down to play on my Pocketpc.
That takes some serious time, because I use such a low bitrate for the mpeg4 to get a small file.

If I do multipass, noise reduction and a bitrate around 256 kb. It can take 6 hrs to transcode that file.
With much less compressed settings say 756kb, and not using all the options I can do the same file in around 2 hrs.

All the options you select adjust how long it takes as well.

My main processor is an AMD 3400 and of course it makes a difference how many othe things the box is doing at that time.

If I were building a new box today, because of Transcoding files I would look at Dual Core Whatever your flavor.

It isn't necessary, but I have seen in here that folks report it makes a difference in transcoding or even some of the post processing of mpeg2 files.

ymmv.

Hope this is helpful.
Author:  tjc [ Wed May 23, 2007 5:56 pm ]
Post subject: 
This is exactly the right place for this. :-)

Along with what bigbro said check out the hardware pages on the wiki: http://www.knoppmythwiki.org/index.php?page=HardwareConfigs Some of these are mildly out of date but they're still mostly right.
Author:  benotto [ Sat May 26, 2007 4:05 am ]
Post subject:  Re: Help choosing a processor
s0127786 wrote:
However afaik to convert mpeg2 (what the pvr-150? gives out) to mpeg4 for storage requires a lot of processor power? I was going to use an ageing XP3000 I have but would this find it impossible to cope?


If you have a pvr-150 (or any hw encoding or DVB card), transcoding is probably the only use that needs some processing power. I personally decided to save on the CPU and keep my XP1900+ underclocked to 1200 mhz and spend on an additional hard drive.

Even my lowly configuration yesterday managed to record a program (DVB-T so no encoding to do), show a divx video on TV and also run a P2P program on a separate vnc session all at the same time; total CPU usage was around 50% (Recording and P2P run on the same disk while the video is on a different one).

Considering that a XP3000 is probably twice as fast as my configuration, I would probably keep it and buy a large disk and not worry about transcoding (except maybe some lossless transcoding that manages to save 30% space in around 3 minutes per hour of recording from DVB-T).
Author:  mogator88 [ Sat May 26, 2007 4:58 am ]
Post subject:  Re: Help choosing a processor
s0127786 wrote:
Sorry if this is in the wrong place but I cant find anywhere really appropriate.

Im buying up components for a new mythtv box, the front end and back end will all be in one box and I want dual tuners to be able to record more than one channel.

However afaik to convert mpeg2 (what the pvr-150? gives out) to mpeg4 for storage requires a lot of processor power? I was going to use an ageing XP3000 I have but would this find it impossible to cope?

If not does anyone have any recommendations for a good processor thats:

1. Supported by Myth
2. Can be relatively easily silently cooled (air only)
3. Is relatively inexpensive
4. Has good m/b support which is also supported by myth

Hope thats not to many questions. :)

Michael


An older cpu like that will not transcode so fast. But if you only have a few hours of shows per day to archive, it should manage fine. You can set up the box so it does this overnight, so it won't affect playback. Get a good graphics card or you'll have problems playing HD shows.

Some people have used VIA processors with vayring degress of difficulty and success. And some people have used Turion processors, but they all seem to have attached fans.

I use a Sempron 2800+, and with a good case and drive its really quiet, you don't even know its there. I'd go for something stronger though, better CPU's and mobo's are so cheap there's no reason not to. Good Luck!
Author:  gatorback [ Sun May 27, 2007 11:00 am ]
Post subject: 
I posted a link for CPU data here (power \ temp):

http://mysettopbox.tv/phpBB2/viewtopic.php?t=15359

I also posted a link on VIA processors here, however, the community has not seen fit to respond:

http://mysettopbox.tv/phpBB2/viewtopic.php?t=15329

Via processors and their boards can be found in a fanless configuration. Unfortunately they are not cheap and they do not offer the horsepower needed for HD playback.

I was lucky enough to find a Hauppage dual tuner card with Philips (as opposed to Samsung) tuners. So far so good.
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