does Graphics Card help DivX?

[BHard]

Hi,

I am wondering.... I've got an old mobo (socket 7) with a k6III+550MHz CPU. This rig does everything I want, except certain games and sometimes a choppy divx playback.

Doe anybody know if upgrading my old TNT card to a Geforce2 Ti card will help playing Divx movies?
I know it will help a lot playing games!

Is a geforce 2 Ti an overkill for my old system??? Possible problems with this upgrade?

Thanx for your help,

BHard


My system:
Asus P5A socket 7, 100MHz
K6III+550Mz
Diamond Viper 550 TNT 16 MB
448 MB SDRAM Cas3
20GB Quantum 72000rpm
Windows XP

 

[vss1980]

Yes graphics card can effect how well the playback is in terms of speed and not just quailty.
Upgrading from the TNT might give an improvement, but if the video gets really badly choppy or out of sync with the sound, then a new video card may not help out enough.

 

[Workin']

I would say the video card has virtually nothing to do with Divx playback. ALL the processing is done by the CPU; NO graphics card has MPEG4 acceleration built in.

The system you have should play Divx without too much trouble. Maybe the movies that are choppy would be choppy on any system, due to flawed encoding or other glitches in the file?

At any rate, the best way to improve Divx performance is with a faster CPU.

 

[BHard]

thanx for the replies!

I was already afraid a better graphics card wouln't help playing divx... o well... only a couple of movies are choppy, so not a big problem...

I still want to upgrade though... playing games like 'return to castle wolvenstein' with my TNT is possible, but not great.

Unfortunately, they only have ASus Geforce 2 Ti in my neighbourhood (the Netherlands) and no leadteks or other brands... Asus is expensive!
I'll be looking at all kinds of GF2 GTS or GF2-Ti for the next couple of weeks!

BHard

 

[Ksnif]

BHard,
As "vss1980" said, the graphic card does effect video playback, while video playback uses DirectShow (which is part of DirectX) .And something else. All MPEG formats are based on iDCT (inverse Discrete Cosine Transform). So if a graphic card has a hardware iDCT (ATI cards for example) it will vastly improve video playback performance and quality.

 

[BHard]

okay...new information! thanx ksnif!

I've thought about the directshow...thought it was not of great influence....

never heard of IDCT though....only ATI cards (radeon) have hardware IDCT?

I don't know about buying an ATI... drivers any good (and up to date), especially for windows XP?
Do ATI cards use a lot of power? My rig is not very good at that...

thnanx for the help,

Bhard

 

[vss1980]

There are a lot of things actually that the graphics card could effect performance with.
iDCT is an example, but there are other things such as its ability to handle different colour space and other transforms applied to video.

I dont think that the ATI cards are major users of power compared to the all time greats like the Voodoo3 and original Geforce cards.

 

[Workin']

<< All MPEG formats are based on iDCT (inverse Discrete Cosine Transform). So if a graphic card has a hardware iDCT (ATI cards for example) it will vastly improve video playback performance and quality. >>

MPEG4 uses different transforms than MPEG2, so any current video card with iDCT support won't help Divx one bit.

 

[vlieps]

Wasnt there some native problem with K6III CPU and DivX playback? I remember something about incompatibility, crashes on those CPU's. Correct me if I am wrong. Might be that Your CPU gives some kind of choppines to the picture etc. But, if You have downloaded some movies from the net (here I mean pirated versions of the new movies then just for information they all use slow motion compression that makes the files smaller on the sacrifice of quality. So, if You see a fast motion in the movie, it MUST be choppy).
You must compare with a video file that You know is of good quality (have seen on other PC without being choppy).

 

[BHard]

Hi,

I know about the divx codec... fastmotion, slowmotion. Most movies play well on my rig, but I can see it is on the limit.
CPU usage is 100%, responsiveness gets very bad and such... the problem is not the quality of the movies. They all (few exeptions) should play without any problem.

About incompatibilty with k6 cpu's... I believe the divx codec doesn't use the 3dnow capabilities, or at least not completely... but he, I can not change that!

I've done everything else to optimize the system for divx (drivers, software optimizations)... that already helped a lot. I just want that small extra boost, without buying a new system.

BHard

 

[Ksnif]

What Divx are you using? If it is DivX;-) 3.11, then I have to say that they are very CPU consumptive. Try DivX 4.11 instead (www.divx.com). They are 100% compatible with the old DivX (although they come from a completely deferent team) and speed & quality are vastly improved.
Regarding to your question about video cards, I?m afraid that only ATI cards have a decent iDCT hardware support. I heard that nVidia?s NV17M supports hardware iDCT. Geforce 2/3 cards have only ?motion compensation? ,that is used (as far as I know) only for MPEG2 playback.

PS1: Workin?, could you please define your sentence ?MPEG4 uses different transforms than MPEG2?. In what form do you believe that they differ. As far as I know DCT/iDCT functions are used in the majority of Video/image compression/decompression. JPEG, for example, uses DCT/iDCT. I?m not trying to start a wrangle here. Just interested in your opinion/knowledge.
PS2: For one more time I agree with ?vss1980?. YUV and YV12 are 2 of widely used color spaces on Videos. DivX for example makes the use of YV12. Video cards do handle those color transforms.
PS3: I?ve seen an improvement on performance while upgrading to a Readon 32DDR from a Rage Pro, on a Celeron 433Mhz. And keep in mind that both had iDCT hardware support. It?s just that Readon has a better one.
PS4: I?m not trying to convince you to purchase an ATI card. I prefer nVidia. I have a TNT on a Duron650Mhz and it performs quite well, although there are some aliasing problems on WinXP. Of course I can?t compare Radeon?s (nor Rage?s) quality with TNT?s.

 

[Workin']

I do not know the math involved but I know for absolute truth that iDCT support built into current graphics cards (i.e., ATI) supports only MPEG2, not MPEG 4. It is a bit of an assumption on my part that it is because the algorithms are different.

 

[Superwormy]

I was almost positive also that all vid cards only support MPEG-2 and lower...

I can say FOR SURE that gonig from a Radeon 32mb DDR to a Matrox G400 32mb didn't affect DivX performance WHATSOEVER on a Celeron 533mhz.

Also, 550mhz K6-2 is probably not a fast enough CPU to run DivX movies at high res at fullscreen. My Celeron stutters once in a while on em too. Bus speed (66mhz for you and me) greatly affects DivX playback.

 

[StandardCell]

<<

<< All MPEG formats are based on iDCT (inverse Discrete Cosine Transform). So if a graphic card has a hardware iDCT (ATI cards for example) it will vastly improve video playback performance and quality. >>

MPEG4 uses different transforms than MPEG2, so any current video card with iDCT support won't help Divx one bit. >>



Knsif et al: MPEG-4 (and JPEG-2000) uses "wavelets" which are basically functions that describe certain complex aspects of the picture in a simple way. This can actually be used for audio compression also, although you are choosing a different wavelet with different behavior. See http://mpeg.telecomitalialab.com/mtx/mtx97_tebrahimi/ppframe.htm for a more thorough explanation.

As far as the video, you need good floating point capability in your processor. I know the K6 processors were NOT particularly noteworthy, which is amazing since Athlons and Durons bench faster than Pentium 3s/4s/Celerons in FP ops. Funny thing, I installed DivX 4.11 on my K6-200 and it runs but VEEEEEERY slowly.

 

[BHard]

Well, I tried installing divx 4.11.... that was no good; video looks good but the audio has a delay.... and still 100% CPU usage.... I changed back to 3.11, it works the best!

I'll borow a GF2 GTS form a friend... lets try out if it makes any difference (without IDCT)!

BHard

 

[vss1980]

I appreciate that the CPU is heavily used decoding MPEG4 as well as MPEG2 or other highly compressed video formats, but the video card is still a factor as to how well the playback is.

If you graphics card doesn't support the ability to scale the video, run it in its native colour space and anything else that could be optimised by the hardware/DirectShow filter, its all processed by the CPU during playback, and this hurts performance even more.

Worst case scenario is that the DirectShow filter doesn't work and it has to be played back through the GDI, in which case it would take all of those 500MHz to probably process just the playback at 30 fps let alone decode DivX. Of course, this is not likely on pretty much any graphics card made in the last 5 years, but if the graphics card doesn't support scaling and YUV colour spaces, it can hurt performance (CPU has to do YUV->RGB conversion).

EDIT: Also, I am fairly sure that the DivX 4.0 codec is not as efficient or is working harder on something to playback the video as others have commented on it being a bit slower or having stutters where the old Divx 3.11 (M$ hack) didn't.

 

[Ksnif]

StandardCell,

Thank you for the information that you provided. Although they give you a deep enough analysis of MPEG-4?s structure, they seem to describe the way that MPEG-4 works in theoretical bases.
I?m not an expert on this field, so there maybe some flaws on my analysis/explanations. I?m not ether good at English, so please show some understanding. Things work much like an OSI-like structure. There are certain levels of processes. So depending on your view sight, you have a bottom level heading towards a top level. What I ?m trying to say is that when looking from CPU?s side, you see in a very close level the functions of iDCT?s algorithm (decoding). These functions provide higher levels with a useful tool for calculating their appropriate mathematics. This ?wavelets? you mentioned, are described as cosine functions. Ultimately, as you can understand, any kind of mathematic calculation, conclude in the use of iDCT?s functions. That is the reason why iDCT algorithm has such an influence on video playback performance.



PS: It?s strange to hear that DivX 4.11 doesn?t work fine on your system, while I?ve seen the results on a Celeron 433Mhz and I can tell you, there were breath taking.

 

[Ksnif]

Bhard,

Judging from your system?s specifications, I would say that that your rig is strong enough to handle DivX titles. K6III has an improved FPU over earlier K6s. So in maters of Video playback performance, it should be equally strong as a PII-450Mhz at least.

I had a PII-350MhZ(466Mhz@133Mhz!!!) and my TNT could play any DivX title (even with the old DivX 3.11 decoder. I tell you once again that DivX4.11 is much faster than its ancestors). So I believe that there must be some kind of a software problem (OS, Drivers, etc.). WinXP have some incompatibilities with TNT based card (I have noticed some aliasing problems). Try Win98SE with some old detonator drivers (like 3.68 that I believe are the best for TNT). For WinXP I guess that 7.76 work better than others. Give them a try (www.guru3d.com)

There is something else you should be aware of. Super Socket has some incompatibilities with some later graphic cards (1.5V vs 3.3V on AGP). So be careful on what you are sticking on your AGP slot! You could easily harm the card and/or the motherboard.

 

[BHard]

well... I have done it. I've bought a Asus GF2 Ti 64MB and put it in my socket 7 mobo.

First of all, the system instability problems I've always had are gone now!!! Great! The card works great in games, but unfortunately divx playback hasn't improved...maybe just a little.

I still have some problems with the drivers.... the card came with 14.62 drivers from Asus (based on 14.62 Nvidia)... but they looked quite slow on my system... and above all directX did not work!!! Opengl worked great though.

I tried to install the 7.58, 7.76 or the 12.90 nvidia drivers (they're the best for my system) but that gave 2 problems: those drivers do not recognise my GF2 Ti, instead I van choose between a GTS, Pro or an ultra.... which one should I choose???
second problem: when I do install these drivers, the system boots up in 8 bit color, 640x480, and there's no way I can change this... very strange!


So I tried the latest asus drivers, and the latest drivers from nvidia... directx only started working again with the latest nvidia drivers: 23.11. these drivers are the ones I am using at the moment. They are faster than the 14.6x drivers so it is quite okay for the moment.


Anybody knows why the old nvidia drivers (before 14.6x) are giving me only 8 bit color 640x480, why nvidia drivers 14.6x till -22.80 messes up my directX?

I also thied the Technogarb drivers for asus cards... they just gave me instand reboots...


About DivX 4.x.... the movies do play a little better with divx4.x instead of 3.x but I get problems with the sound! The pictures and the sound do not match! Sound first, matching picture later... I do not have this problem with divx 3.x....


I have read some great replies here.... keep on the good work!

BHard