CPU requirements for HDTV MythTV

Someone asked this question a while back and I've been doing some testing.
I'm not sure what the bare minimum is but I can tell that a Duron with SSE
running at 1200MHz is plenty fast enough with an Nvidia card using XvMC.
To be perfectly honest, it kind of shocked me too with all the talk
(which turns out to be BS) around about needing a 3Ghz P4. So there you
go. I didn't check the amount of CPU usage with the Duron at 1200MHz, but
at 2000MHz, it's about 50%. That's running MythTV with the monitor set for
1600x1200 FX5200 128M Nvidia card. 512M system ram.

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Wes Newell ) wrote in alt.tv.tech.hdtv:
To be perfectly honest, it kind of shocked me too with all the talk
(which turns out to be BS) around about needing a 3Ghz P4. So there you
go. I didn't check the amount of CPU usage with the Duron at 1200MHz, but
at 2000MHz, it's about 50%. That's running MythTV with the monitor set for
1600x1200 FX5200 128M Nvidia card. 512M system ram.

What did you use to check for dropped frames?

--
Jeff Rife | "The only petitions that I sign are to bring back
| canceled sitcoms, thank you. America needs the
| wisdom of 'Herman's Head' now more than ever."
| -- Comic Book Guy, "The Simpsons"

On Sat, 04 Feb 2006 21:31:38 -0500, Jeff Rife wrote:

Wes Newell ) wrote in alt.tv.tech.hdtv:
To be perfectly honest, it kind of shocked me too with all the talk
(which turns out to be BS) around about needing a 3Ghz P4. So there you
go. I didn't check the amount of CPU usage with the Duron at 1200MHz, but
at 2000MHz, it's about 50%. That's running MythTV with the monitor set for
1600x1200 FX5200 128M Nvidia card. 512M system ram.

What did you use to check for dropped frames?

The only thing that matters, my eyes. Couldn't tell the difference with
the cpu at 1200MHz or 2000MHz while watching. There was flicker with the
OSD, but it didn't effect the picture. Now, I certainly wouldn't recommend
slowing your CPU as slow as it will go, but it will work at a lot slower
speeds than people thiink. And I pretty nuch just threw this machine
together out of spare parts, except for the $30 video card. FWIW, I paid
$39.99 for the CPU with a MB at fry's during a sale about a year ago.

--
Want the ultimate in free OTA SD/HDTV Recorder? http://mythtv.org
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My server http://wesnewell.no-ip.com/cpu.php

Wes Newell ) wrote in alt.tv.tech.hdtv:
What did you use to check for dropped frames?

The only thing that matters, my eyes.

So, in other words, you have no idea if you were watching 30fps or 25fps.
This is especially true if you used film-sourced material...dropping a lot
of frames doesn't make as much difference, especially when you have a
monitor set at 60Hz (or greater) refresh.

Couldn't tell the difference with
the cpu at 1200MHz or 2000MHz while watching.

Chances are you are dropping a lot of frames and just don't notice it.
See http://www.avsforum.com/avs-vb/showthread.php?p=6857651 for some more
details about someone who is dropping frames with MythTV and the same
video card and a processor that is a lot more powerful than yours.

--
Jeff Rife | Coach: What's doing, Norm?
|
| Norm: Well, science is seeking a cure for thirst.
| I happen to be the guinea pig.

Jeff Rife wrote:
Wes Newell ) wrote in alt.tv.tech.hdtv:
What did you use to check for dropped frames?

The only thing that matters, my eyes.

So, in other words, you have no idea if you were watching 30fps or 25fps.
This is especially true if you used film-sourced material...dropping a lot
of frames doesn't make as much difference, especially when you have a
monitor set at 60Hz (or greater) refresh.

Couldn't tell the difference with
the cpu at 1200MHz or 2000MHz while watching.

Chances are you are dropping a lot of frames and just don't notice it.
See http://www.avsforum.com/avs-vb/showthread.php?p=6857651 for some more
details about someone who is dropping frames with MythTV and the same
video card and a processor that is a lot more powerful than yours.

--
Jeff Rife | Coach: What's doing, Norm?
|
| Norm: Well, science is seeking a cure for thirst.
| I happen to be the guinea pig.

Unless it is dropping frames in a perfect rythm, anybody still
breathing would notice. I don't mean to offend, Wes. I'm with you on
this because I've seen sporadic frame drops and they stick out like a
sore thumb. Even 'rythmic' drops are very apparent. Example is a 1" C
(analog) deck running true frame mode but in speed-up (30 fps to make
time for more commercials). Motion is mostly smooth but with cyclic 1
frame jumps -- VERY noticable in end credit rolls.

GG

GG

On Sun, 05 Feb 2006 14:58:04 -0500, Jeff Rife wrote:

Wes Newell ) wrote in alt.tv.tech.hdtv:
What did you use to check for dropped frames?

The only thing that matters, my eyes.

So, in other words, you have no idea if you were watching 30fps or 25fps.
This is especially true if you used film-sourced material...dropping a lot
of frames doesn't make as much difference, especially when you have a
monitor set at 60Hz (or greater) refresh.

I'm pretty sure I'd notice those kind of problems, but the monitor is
running 85Hz. So you tell me how you want me to check this and I'll do it
even though it has no bearing on the quality a person can actually see
while watching.

Couldn't tell the difference with
the cpu at 1200MHz or 2000MHz while watching.

Chances are you are dropping a lot of frames and just don't notice it.

And chances are I'm not.;-)

See http://www.avsforum.com/avs-vb/showthread.php?p=6857651 for some
more details about someone who is dropping frames with MythTV and the
same video card and a processor that is a lot more powerful than yours.

Well, there's a big difference here. He states his system is jerky to
begin with.

"I got fed up with jerky video playback on my Linux HTPC and Plus UP-1100P
projector, so I wrote this program today to help me solve the problem."

Mine isn't. The OP wrote the software said he dropped 23 frames out of
1481. Why? How would I know? Maybe it was because he was also running the
test software and that put extra strain on the cpu. Still doesn't matter.
And then there's this there.

Some common causes of judder a

1. Projectors and other displays that have a fixed update rate running at
a refresh rate different from their fixed update rate

2. Computers with insufficient processing power to keep video and audio in
sync

3. Poor quality sound cards that cause video software to have a hard
time keeping audio and video in sync

4. Video card refresh rate that isn't an integer or 3:2 multiple of the
video frame rate (i.e. 59.94Hz is the ideal rate for 29.97Hz NTSC and
23.976Hz NTSC telecine - if displays could do it, doubling that rate to
~120Hz would be the best).

Number 1 and number 4 are the biggest problems. This Judder Test program
is designed to help track down #1.

So the whole test program isn't even designed to test CPU problems. And
since he mentions NTSC, I assume they are testing with an analog NTSC
card. I don't use NTSC, just ATSC, which requires no conversion to digital
or compression as it comes in as mpeg2 already. So in the end, that thread
is about worthless as most frame drops occur on the incoming signal
conversion and compression if I'm not mistaken. At least that where every
mention of dropped frames has ocurred when I searched the subject.

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G-squared ) wrote in alt.tv.tech.hdtv:
Motion is mostly smooth but with cyclic 1
frame jumps -- VERY noticable in end credit rolls.

Some things like this will make it more obvious, but again if the source is
24fps, you already have some frame doubling involved, so losing one frame
might not be as noticable.

And, unless you get display all the pixels, losing a frame isn't noticable.

--
Jeff Rife |
| http://www.nabs.net/Cartoons/Dilbert/TokenRing.gif

Wes Newell ) wrote in alt.tv.tech.hdtv:
See http://www.avsforum.com/avs-vb/showthread.php?p=6857651 for some
more details about someone who is dropping frames with MythTV and the
same video card and a processor that is a lot more powerful than yours.

Well, there's a big difference here. He states his system is jerky to
begin with.

No, actually, he doesn't.

"I got fed up with jerky video playback on my Linux HTPC and Plus UP-1100P
projector, so I wrote this program today to help me solve the problem."

The thread starter said this...jay_cee is the one who found out he was
dropping frames and didn't realize it until he ran the test software.

So the whole test program isn't even designed to test CPU problems. And
since he mentions NTSC, I assume they are testing with an analog NTSC
card. I don't use NTSC, just ATSC, which requires no conversion to digital
or compression as it comes in as mpeg2 already.

You are focusing on the wrong writer.

Try this URL...maybe it will help your reading comprehension:

http://www.avsforum.com/avs-vb/print...5481&p=6857651

--
Jeff Rife |
| http://www.nabs.net/Cartoons/OverTheHedge/HDTV.gif

On Mon, 06 Feb 2006 03:23:08 -0500, Jeff Rife wrote:

Wes Newell ) wrote in alt.tv.tech.hdtv:
See http://www.avsforum.com/avs-vb/showthread.php?p=6857651 for some
more details about someone who is dropping frames with MythTV and the
same video card and a processor that is a lot more powerful than yours.

Well, there's a big difference here. He states his system is jerky to
begin with.

No, actually, he doesn't.

Actuallly, he does. this was the message you link took me to.

"I got fed up with jerky video playback on my Linux HTPC and Plus
UP-1100P projector, so I wrote this program today to help me solve the
problem."

The thread starter said this...jay_cee is the one who found out he was
dropping frames and didn't realize it until he ran the test software.

Yeah, And I included that info in my reply too. You just seem to have
conveniently snipped it out the parts you wanted to to make it look like
I overlooked it. I can see you practice the same BS here as you do in
other groups.

So the whole test program isn't even designed to test CPU problems. And
since he mentions NTSC, I assume they are testing with an analog NTSC
card. I don't use NTSC, just ATSC, which requires no conversion to
digital or compression as it comes in as mpeg2 already.

You are focusing on the wrong writer.

No. I didn't focus on the wrong writer. You just cut that portion out of
your reply to me to make it look that way.

Try this URL...maybe it will help your reading comprehension:

Now that's the Jeff I know. Lay off his own incompetance on others. You
know I already covered that in my original reply. You know, the part you
snipped out.

--
Want the ultimate in free OTA SD/HDTV Recorder? http://mythtv.org
http://mysettopbox.tv/knoppmyth.html Usenet alt.video.ptv.mythtv
My server http://wesnewell.no-ip.com/cpu.php

Wes Newell ) wrote in alt.tv.tech.hdtv:
Well, there's a big difference here. He states his system is jerky to
begin with.

No, actually, he doesn't.

Actuallly, he does. this was the message you link took me to.

OK, here goes again:
http://www.avsforum.com/avs-vb/showthread.php?p=6857651

This link, on a correctly configured browser, goes to this post:

================================================== ==================
jay_cee

I'm running an Athlon 2500 w/ an Nvidia 5200 based graphics card.
My display is a a 37" Sceptre at 1920x1080. My refresh rate is set to
~53 Hz to work around a judder/tearing issue with the Sceptre display.
Here are my results:

frames drawn: 1458
traces elapsed: 1481
frames dropped: 23
frame ratio: 0.984470
seconds elapsed: 27.729266
approximate fps: 52.579827

It looks like my system is actually dropping a few frames which is
surprising. I think I can see the slight judder when a frame is dropped.
Does this sound right? The 5200 is the standard g-card and an Athlon
2500 isn't that puny...
================================================== ==================

The thread starter said this...jay_cee is the one who found out he was
dropping frames and didn't realize it until he ran the test software.


Yeah, And I included that info in my reply too. You just seem to have
conveniently snipped it out the parts you wanted to to make it look like
I overlooked it.

Um, you seem to have overlooked it, since you don't seem to understand
the contents of the post.

jay_cee is surprised that his system is dropping frames. He knew his
monitor wasn't perfect, but had worked around those. He did not notice
the effect from the dropped frames until it was pointed out by the test
that his system is dropping frames, but, even so, he still isn't 100%
sure he can see it.

Despite the fact that he isn't sure that he can see it, his system (which
is much faster than yours) *is* dropping frames. This is exactly what I
suggested might be happening to you without you realizing it, but you are
too thick to see that.

Thus, I stand by my call that you need to improve your reading
comprehension.

--
Jeff Rife | "He's an investment banker from Amsterdam.
| Apparently he handles a lot of Bill Gates'
| money, so, don't say anything derogatory
| about the Netherlands or Microsoft."
| "Oh, damn...there goes my opening joke about
| the Dutchman trying to install Windows 95."
| -- Niles and Frasier