CPU usage & DivX 5.02

[4lex]

Hi all - I'm having a bit of trouble with DivX 5.02 playback on a shuttle spacewalker SV24 box. It had a celeron 533 in when I was using DivX 3.11/MP3 and seemed to cope fine, however since I went to 5.02 & AC3 sound it struggled, in fact was unwatchable. I do all the movies at about 700x280 ish and go for about 1.5gig completed filesize.

I've just upgraded the processor to a cel 667 which is running at 750 (tweaked bios to allow overclocking), and it still seems to top out in scenes with loads of movement. BSPlayer (0.85) seems to work best, but still not quite fast enough.

I'm decoding the AC3 in software as well, by way of an ABit au10r 5.1 soundcard, so I would have expected a higher cpu overhead, but is 750mhz still not enough, or is something wrong?

Cheers,
Alex

[Acaila]

Indeed 750MHz is not enough for that resolution. Things you could do to drop cpu load:
- encode without B-frames & Q-Pel
- drop resolution to 640 or lower
- try the ffdshow decoder instead of DivX 5's
- buy a faster cpu :)

[ppera2]

Playback depends much from Graphic card too. Your CPU should be enough fast, but if Graphic card has not support for video playback poor CPU must do all...

[theReal]

I'm not sure how much CPU power it costs to decode 5.1 AC3 in software, but I guess mp3 costs a little less.

ppera2, I don't think a 750MHz CPU is fast enough, not with that high resolution and high bitrates.

I just checked the CPU usage on my machine with a 704x288 Divx 5.02 file (file size 1400MB, AC3 Audio 5.1 Surround). I was using BSPlayer 0.8, Divx 5.02 decoder, medium post-processing, Moonlight Odio Dekoda for AC3 4-channel downsampling. The average cpu usage on the short part I checked was about 35%, peaks up to 45% on action scenes (might be more on other scenes, I don't know). In addition to that I had ~3% Kernel and ~2% INT+DPC processor usage (I played the file from CD on an ATAPI DVDRom)

My system:
Thunderbird 1400@1500 (10 x 150MHz FSB)
Mainboard: Epox 8K7A+ (AMD761)
2 x 256MB PC2100 Crucial Micron (8-8-6-2-4-2-2 timing)
ATI Radeon 7500 retail
Philips Acoustic Edge PSC706
Win2k SP3

I'd say you if you're using a system with half the cpu speed, slower chipset and memory and an onboard Savage 4 graphics chip, it's most probably too slow, at least on action scenes.

However, that SV24 box is very nice (and probably not 1/4 as loud as my system...)

[sarahjh69]

a p3 450 plays any resolution DiVX perfectly
the graphics card make no difference to DiVX playback AT ALL!

your problem is easily fixed!

divx 5.02 installs with a default playback quality
set way too high (athlon 1000+ level)
right click on a running movie
select filter properties/divx decoder
and set the quality to minimum and hit apply
all your movies will play fine then!

[4lex]

The problem seemed to be ineffective use of processor time, enabling 'smooth playback' has fixed it.

Thanks for all the replies anyway.

Cheers,
Alex

[ppera2]

Originally posted by sarahjh69
a p3 450 plays any resolution DiVX perfectly
the graphics card make no difference to DiVX playback AT ALL!
!!!

Maybe you are expert for pose 69 :D , but, come on...

[MvB]

Got a celeron 533Processor and I can play every divx to a resolution of 720x480very well since i installed the ffdshow decoder. With the divx5 decoder my cpu was to slow.

(edit) sorry, that was an error :(
Had 2 computers looking absolutely the same so i was using the wrong one (Duron 800 Mhz). There it runs smoothly.

[beta447]

Originally posted by ppera2
Playback depends much from Graphic card too. Your CPU should be enough fast, but if Graphic card has not support for video playback poor CPU must do all...

very true. the more powerful your video card is, the less work your cpu will have to do, and the better the output video will be. 750mhz is way more then enough as long as your video card's powerful enough.

[sarahjh69]

Doom9 and others had this discussion with me
over a year ago in this forum. They all said no
performance gain in DiVX due to graphics card!

I had to agree (in the end)
Graphics cards make no difference to 2d performance (DiVX)
(extra memory = higher resolutions available but thats it)
(some have mpeg2 hardware built in....this does not help DiVX)

tell me why you think it helps
maybe its doing a few vertex calcs for you?
maybe you think it does some textures???

[theReal]

Graphics cards make no difference to 2d performance (DiVX)Well, if you have a really bad, old graphics adapter you might have problems with all kind of video playback in fullscreen, not only with Divx. An older card with slow RAM might not refresh quickly enough to make fast camera movements look smooth (try an ATI Rage IIC, for example...).

But of course every fairly new card should be able to play video in fullscreen (I say "should" because I really don't trust some of the onboard graphics chipsets...)

[Fox Mulder]

A friend had a lousy 1MB PCI card for a week waiting for a replace for a GeForce card that he bought and failed, and could't watch any video smoothly in his P3 1Ghz, because the overlay and the drivers of this old card sucked.

[4lex]

On and off I've been getting an 'overlay failed, switching to RGB' error, which works fine in a window, but is very very slow for fullscreen.

A reboot seems to remedy it, are the VGA drivers my prime suspect here?

[auenf]

Originally posted by sarahjh69
Doom9 and others had this discussion with me
over a year ago in this forum. They all said no
performance gain in DiVX due to graphics card!

I had to agree (in the end)
Graphics cards make no difference to 2d performance (DiVX)
(extra memory = higher resolutions available but thats it)
(some have mpeg2 hardware built in....this does not help DiVX)

tell me why you think it helps
maybe its doing a few vertex calcs for you?
maybe you think it does some textures???

acutally, if the playback runs thru DXVA, then mpeg-2 decoding routines that the video card has can increase playback speed (mpeg4 does have capability for more advanced stuff, but the MS mpeg-4 codecs only implement a part of the mpeg-4 spec.

im not sure if divx5 can be accelerated thru DXVA or VMR tho.

Enf...

[Zhnujm]

some gfx cards (or was it a driver problem ?) dont use overlay if the x-resolution is not dividable by 32. and that will make a big difference in cpu usage.
i tested that some time ago with my old gforce2mx card, the difference was around 30% on a 900MHz Athlon cpu.

[qwasyx23]

Hi,

I looked at the different threads and I didn't find something about my pb except this one though what was said didn't help me much. So here is my problem:

I encoded "The Game" in Divx 5.0.2 with 2 passes, Bframes, Qpel and GMC. I used a 720x576x25fps and a bitrate of 1086. The whole thing without sound. (To make it simpler) And now when I play the movie it is barrely fluid : 90-100 % CPU. I tried the smooth playback, and the movie freezes at the begining. The quality setting of the playback doesn't change anything (I don't know why) wether it is at min or max quality. When I add the sound (AC3) then it becomes unwatchable.

My configuration :

Athlon 1200
512 MB DDR
A7A266
Radeon VE

Also even with a P4 2.4 Ghz, the movie with the sound in AC3 is not fluid.

I was wondering if I did something wrong, or if it is normal with the quality I am using. Anyone could tell me please.

Thank you very much, best regards

Miles

[Acaila]

Trying to play a 720x576x25fps video encoded with both B-frames and Q-Pel is certainly asking for trouble. Those are the most cpu intensive features combined with the highest resolution you can get.
Not to mention it's a waste of bitrate because 1) it's most probably got black borders and 2) it's not in a correct Aspect Ratio. But that's beside the question asked.

While an Athlon 1200 will have serious trouble playing this video, a P4 2.2GHz should be more than adequate. The fact that it plays ok without audio can be an indication that something might have gone wrong with the audio interleaving process (although AC3 decoding draws quite a lot from the cpu as well).
What settings did you use to interleave the AC3 with your video? If you used GKnot then the settings should have been ok; in this case you can try it manually with Nandub and some of the interleaving settings mentioned in the AC3 FAQ (http://forum.doom9.org/showthread.php?s=&threadid=18318).

Ps. Enabling the "Smooth Playback" setting usually results in freeze frames. I highly recommend not using it. Ever.

[qwasyx23]

Hi,

Thanks for you're answer. It cleared the doubt I had about a bad ripping & encoding. It is just that I've always been doing 720x576x25fps with Divx3.11 on a Celeron 800Mhz and had no trouble. So I was wondering about the Athlon. Since you're saying about Qpel, GMC and B-frames I took a look at the different forums and found out I shouldn't use Q-pel, though for GMC it doesn't seem clear. Anyway it will save me the trouble of this slow decode.

Also I was decoding with DivX 5, and then I tried ffdshow, and the CPU usage dropped even if it still rockets up to 99% sometimes. Sorry about not seeing this before.

Finally about the AC3, I have trouble because on my computer it is not jerky only when I put a synchronisation of 1 frame. But then it is not synchronized (Maybe too slow). I also tried 160ms and it was nearly ok on the P4 2.4Ghz though I am not entirely sure (made too many test in too little time). The interleaving was done with VirtualDub. I haven't tried Gknot yet (Still a newbie here as you must have seen :-( ). I also took a look at what was said on the AC3 FAQ and I think I have to do more test.

Finally about smooth playback I noticed the frame freeze so I am not using it anymore ! ;-)

Thanks again for all this information and sorry for the trouble.

Miles

[qwasyx23]

Hi,

Thanks for you're answer. It cleared the doubt I had about a bad ripping & encoding. It is just that I've always been doing 720x576x25fps with Divx3.11 on a Celeron 800Mhz and had no trouble. So I was wondering about the Athlon. Since you're saying about Qpel, GMC and B-frames I took a look at the different forums and found out I shouldn't use Q-pel, though for GMC it doesn't seem clear. Anyway it will save me the trouble of this slow decode.

Also I was decoding with DivX 5, and then I tried ffdshow, and the CPU usage dropped even if it still rockets up to 99% sometimes. Sorry about not seeing this before.

Finally about the AC3, I have trouble because on my computer it is not jerky only when I put a synchronisation of 1 frame. But then it is not synchronized (Maybe too slow). I also tried 160ms and it was nearly ok on the P4 2.4Ghz though I am not entirely sure (made too many test in too little time). The interleaving was done with VirtualDub. I haven't tried Gknot yet (Still a newbie here as you must have seen :-( ). I also took a look at what was said on the AC3 FAQ and I think I have to do more test.

Finally about smooth playback I noticed the frame freeze so I am not using it anymore ! ;-)

Thanks again for all this information and sorry for the trouble.

Miles

[Vanos_b]

The video card DOES matter. I know because I hava a Cirrus Logic now (PCI 2 MB - I had to give up my AGP TNT2 M64 / 32 MB for a few days) and I can't watch a movie encoded with B-frames and Q-Pel (640x352/25fps + Vorbis) not even withought any postprocessing and with ffdshow (the best I could get was 22 fps). Before I could use postprocessing at 4 and noise (both in ffdshow and DivX Decoder) and worked great. I think it's because newer cards have some support for IDCT (for MPEG-2 decoding, but it works for MPEG-4 about the same way (maybe, it's just a guess)). BTW Q-Pel is the one that has the most impact on CPU load from all DivX features (both on encoding and decoding).
Edit: And that's for playback in a window, because in full screen - no point of discussing it. And in full screen you can really see the speed (2D) and the QUALITY of a card (the qulity difference is huge - try watch a movie resizing it to full screen using SiS :scared: and Matrox :D ).

[Bluedan]

Uh, well, similar post here: http://forum.doom9.org/showthread.php?s=&threadid=34710

Mine is more XVid related. So, my contribution here is that movies at a resolution of 704x384 (XVid) drive my Pentium3 @667MHz with 256 MB RAM to the edge in bright moving scenes.
For Fullscreen 4:3 it must not exceed a resolution of 640x480.
Only with darker movies I can add 'noise' or even 'unsharpen' through ffdshow.
Video chipset: TNT2 pro, 32MB, AGP4x