mythtv noob - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 13 Old 04-28-2007, 03:03 PM - Thread Starter
Newbie
 
milodesc's Avatar
 
Join Date: Nov 2005
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hi -

I've just started playing around with Linux and am considering enhancing the my linux box so that it has some htpc functionality.

i'm currently running Ubuntu 6.06 on a machine with the following specs:
CPU - PIII 863mHz
RAM - 256 MB (133mHz)
HDD1 - 8GB
HDD2 - 40 GB
Video Card - Nvidia Riva TNT2 Model 64

can i just get a hauppauge pvr-150 tuner and install mythtv (or mythdora/knoppmyth) on this box?

anyone forsee any trouble?

thanks for the help!
milodesc is offline  
Sponsored Links
Advertisement
 
post #2 of 13 Old 04-29-2007, 01:22 AM
AVS Special Member
 
CT_Wiebe's Avatar
 
Join Date: Nov 2003
Location: San Jose, CA
Posts: 6,437
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
I don't have my (Ubuntu 7.04) installed yet. I do have the PVR-250 card and I don't anticipate any problems. Your CPU is on the slow side for playing video and your 40GB drive is small also. The PVR-150 has it's own hardware encoder, so that should not be a problem. Playing video with MythTV requires a lot of CPU power (usually at least around 1.3+ GHz, if I remember correctly). Your PC is pretty old (from your description of the hardware), so you might want to think about upgrading it first, before installing and trying to use MythTV. It doesn't need to be an expensive one, just one that has a newer, much faster, CPU and more memory.

However, from what I've read on this forum, you should upgrade to Feisty (7.04) as it will make the integration of the PVR-150 and MythTV much easier (although it will work with 6.06 - Myth just requires more work to get it functioning, see the mythtv-howto: http://www.mythtv.org/modules.php?name=MythInstall).

NOTE: You do have to upgrade to Edgy Eft (6.10) first (according to the Ubuntu "How_To" pages, before doing the Feisty upgrade).

One note, recording video is a memory hog. When I record at, DVD (SD) quality, the files are about 2.5GB/hour (before editing). After I edit out the commercials from a 2 hour show, I get a 4.28GB file which just fits on a single layer DVD-R disc. Your 40GB HDD won't hold much video. I've easily filled up a 500GB HDD and have several external 400G drives for backup files and additional video files.

- Claus {non-Santa model}
CT_Wiebe is offline  
post #3 of 13 Old 04-29-2007, 06:24 AM - Thread Starter
Newbie
 
milodesc's Avatar
 
Join Date: Nov 2005
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Thanks CT!

Just need some clarification on your response...

ABOUT THE CPU:
First you say that since the PVR-150 has a hardware encoder, so my slow CPU shouldn't be an issue for playing video:
Quote:
Originally Posted by CT_Wiebe View Post

Your CPU is on the slow side for playing video and your 40GB drive is small also. The PVR-150 has it's own hardware encoder, so that should not be a problem.

Then you say that playing video with MythTV requires a lot of CPU power (1.3+ GHz):
Quote:
Originally Posted by CT_Wiebe View Post

Playing video with MythTV requires a lot of CPU power (usually at least around 1.3+ GHz, if I remember correctly). Your PC is pretty old (from your description of the hardware), so you might want to think about upgrading it first, before installing and trying to use MythTV.


Which is it? Does the PVR-150 alleviate my need to upgrade my CPU? Am I misunderstanding something?
milodesc is offline  
post #4 of 13 Old 04-29-2007, 07:09 AM
Advanced Member
 
blackoper's Avatar
 
Join Date: Sep 2006
Location: Louisville, KY
Posts: 553
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 23
it only alleviates recording. playback still requires cpu cycles to decode the video. You could get away with 863mhz cpu with xvmc hardware decoding with a nvidia 5200 probably but I don't know honestly.
blackoper is online now  
post #5 of 13 Old 04-29-2007, 07:13 AM
Rgb
AVS Special Member
 
Rgb's Avatar
 
Join Date: Apr 2000
Location: SE Michigan
Posts: 6,881
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 17
Quote:
Originally Posted by CT_Wiebe View Post


One note, recording video is a memory hog. When I record at, DVD (SD) quality, the files are about 2.5GB/hour (before editing). After I edit out the commercials from a 2 hour show, I get a 4.28GB file which just fits on a single layer DVD-R disc. Your 40GB HDD won't hold much video. I've easily filled up a 500GB HDD and have several external 400G drives for backup files and additional video files.

I currently use PVR150 cards on a few Xp Pro boxes to record analog cable. I plan to migrate them to Ubuntu + Myth over the coming months.

On the XP Pro boxes, I use the WinTV 2000 app for recording. WinTV2000 has encoding settings in a preferences dialog box.

For all my analog cable recordings, I use 352x480 (half D1) at 2Mbps MPEG2, which yields about 1GB per hour of recording.

Analog cable sources have no more useful resolution than this, and it is easily verified by comparing 720x480 vs 352x480 recordings.

Cutting the horizontal resolution encoded in half reduces the needed bitrate in half. There are only mild MPEG artifacts in these Half D1/2Mbps recordings during fast motion transitions- no normal person has ever mentioned it, and artifacts are far less than the digital compression artifacts I have seen on digital cable or satellite.

Is there a way to change the encoding parameters for the PVR150 in MythTV? I would like to use the same 352x480 at 2Mbps when I switch to MythTV.
Rgb is offline  
post #6 of 13 Old 04-29-2007, 08:46 AM - Thread Starter
Newbie
 
milodesc's Avatar
 
Join Date: Nov 2005
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by blackoper View Post

it only alleviates recording. playback still requires cpu cycles to decode the video.

Does this mean I would have a hard time watching live tv as well?

From reading the Hauppage site it doesn't seem like the hardware decoder on the pvr-350 would help much either for watching live/recorded video on my PC.

From the hauppage site:
WinTV-PVR-350 uses the hardware MPEG encoder for watching live TV, for pausing live TV and for recording. The encoded MPEG-2 video is... decoded in software for display on the PC screen. When playing recorded video onto an external TV monitor, the on-board hardware MPEG-2 video decoder is used.

Since it says that the encoded MPEG-2 video is decoded in software for display on the PC screen, i guess that means that my CPU would be hit pretty hard for showing live TV on my PC? The decoder only comes into play when watching recorded video on a TV?

are there any tuners available that would encode/decode in hardware to my PC monitor?
milodesc is offline  
post #7 of 13 Old 04-29-2007, 09:01 AM
Rgb
AVS Special Member
 
Rgb's Avatar
 
Join Date: Apr 2000
Location: SE Michigan
Posts: 6,881
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 17
Quote:
Originally Posted by milodesc View Post

Does this mean I would have a hard time watching live tv as well?


Since it says that the encoded MPEG-2 video is decoded in software for display on the PC screen, i guess that means that my CPU would be hit pretty hard for showing live TV on my PC? The decoder only comes into play when watching recorded video on a TV?

are there any tuners available that would encode/decode in hardware to my PC monitor?

In my opinion, your machine should be fine for MPEG2 playback using your CPU.

It has long been known on these forums that MPEG2 standard definition video can be played fine on CPU's as low as 500Mhz P3 or lower.

The issue is, front ends like MythTV use CPU for housekeeping and GUI control.

I don't know how much overhead MythTV requires, but I am certain your machine will handle any recordings from hardware encoder cards like the PVR350/250/150.

I think your best bet is to just try it with your hardware, and upgrade if you need it, though I recommend 384MB-512MB
Rgb is offline  
post #8 of 13 Old 04-29-2007, 01:38 PM - Thread Starter
Newbie
 
milodesc's Avatar
 
Join Date: Nov 2005
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Rgb View Post

I don't know how much overhead MythTV requires, but I am certain your machine will handle any recordings from hardware encoder cards like the PVR350/250/150.

I think your best bet is to just try it with your hardware, and upgrade if you need it, though I recommend 384MB-512MB

Thanks Rgb, i'll probably upgrade the RAM as you suggested. Am I correct in thinking that the PVR-350 won't give me any performance gains while playing live or recored video on my PC monitor?
milodesc is offline  
post #9 of 13 Old 04-29-2007, 05:36 PM
Rgb
AVS Special Member
 
Rgb's Avatar
 
Join Date: Apr 2000
Location: SE Michigan
Posts: 6,881
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 17
From
http://www.mythtv.org/wiki/index.php/Hauppauge_PVR-350

"(PVR350) Well Suited for: a single-card solution for input/ouput of video and audio to a standard television, running only MythTV and recordings. Also well-suited for underpowered systems, since the onboard mpeg encoding and decoding mean your CPU has very little to do. As a single data point, consider that the utilization on 750 Mhz PIII is only 20% while watching live tv."

It appears the PVR350's hardware decode works under MythTV, so it reduces CPU utilization. If the link info is correct, you shouldn't have any CPU related playback issues.

I also believe you wouldn't have playback issues on a PVR150, either, though CPU utilization would be higher while watching TV or MPEG2 recordings, though it shouldn't affect recording as the hardware encoder would alleviate recording related CPU utilization.
Rgb is offline  
post #10 of 13 Old 04-30-2007, 10:27 AM - Thread Starter
Newbie
 
milodesc's Avatar
 
Join Date: Nov 2005
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Rgb View Post

It appears the PVR350's hardware decode works under MythTV, so it reduces CPU utilization. If the link info is correct, you shouldn't have any CPU related playback issues.

I also believe you wouldn't have playback issues on a PVR150, either, though CPU utilization would be higher while watching TV or MPEG2 recordings, though it shouldn't affect recording as the hardware encoder would alleviate recording related CPU utilization.

Unfortunately, i think the decoder is only used for the TV-out, not PC-Out.

from hauppage's PVR-350 site:
Quote:


The encoded MPEG-2 video is... decoded in software for display on the PC screen. When playing recorded video onto an external TV monitor, the on-board hardware MPEG-2 video decoder is used.

but, like you said rgb, even w/o the hardware decoder i should be able to play live tv albeit with higher cpu usage.

it's worth a shot.

If anyone else has a similar setup, please let me know your opinion.
milodesc is offline  
post #11 of 13 Old 04-30-2007, 10:57 AM
AVS Special Member
 
newlinux's Avatar
 
Join Date: Oct 2006
Location: Parts unknown
Posts: 1,540
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 14
I wish I could get analog output from my imac G3 PowerPC 600Mhz (or 700Mhz, don't remember). It just doesn't seem to be able to cut it in MacOS or ubuntu even with already encoded (recorded) shows... But I don't know how PowerPCs compare to Pentium IIIs, but the link below seems to suggest you should be able to do it.

http://www.mythtv.org/docs/mythtv-HOWTO-3.html
newlinux is online now  
post #12 of 13 Old 05-01-2007, 09:28 AM
Newbie
 
Lockman99's Avatar
 
Join Date: Oct 2001
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by milodesc View Post

Hi -

I've just started playing around with Linux and am considering enhancing the my linux box so that it has some htpc functionality.

i'm currently running Ubuntu 6.06 on a machine with the following specs:
CPU - PIII 863mHz
RAM - 256 MB (133mHz)
HDD1 - 8GB
HDD2 - 40 GB
Video Card - Nvidia Riva TNT2 Model 64

can i just get a hauppauge pvr-150 tuner and install mythtv (or mythdora/knoppmyth) on this box?

anyone forsee any trouble?



thanks for the help!

You have a low powered system but it may be ok for mp2 play back. also PVR 150/250/350/500 dual tuners are supported out of the box. I just built my MythTV this passed weekend on Ubuntu 7.04 and it was painless and easy for a noob like me.

If it wasn't for the new release of Ubuntu I would still be breaking my head trying to get it to work.
Lockman99 is offline  
post #13 of 13 Old 05-01-2007, 11:08 AM - Thread Starter
Newbie
 
milodesc's Avatar
 
Join Date: Nov 2005
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Lockman99 View Post

You have a low powered system but it may be ok for mp2 play back. also PVR 150/250/350/500 dual tuners are supported out of the box. I just built my MythTV this passed weekend on Ubuntu 7.04 and it was painless and easy for a noob like me.

If it wasn't for the new release of Ubuntu I would still be breaking my head trying to get it to work.


yea from what i hear feisty is the way to go. hopefully my hardware can keep up!
milodesc is offline  
Reply HTPC - Linux Chat

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off