G400 and MPEG-4 Video

[huMMer]

I heard DivX codec uses somehow certain hardware acceleration features of latest Matrox cards. Does anybody have any specific information as to how to configure G400 DH to maximize the efficiency of the use of hardware acceleration.

[huMMer]

Yep, thanks for the answer and I already brought my excuses in the other forum for cross-posting. So, the bottomline is - there is no way to use Matrox hardware capabilities for MP4 video? Too bad...

[huMMer]

And... Is it really that much MS?

[Gurm]

Well if you get one of the hacked (pirate) DivX/MPeg4 codecs it doesn't have the overlay issues that MS's does.

But no, none of them uses any "acceleration" features from Matrox (or any other) video card (well maybe ATI).

- Gurm

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Listen up, you primitive screwheads! See this? This is my BOOMSTICK! Etc. etc.

[dZeus]

#1: there are no hardware MPEG-4 decoders available as far as I know. And MS MPEG4 is too different from the ISO MPEG-4 specifications anyway to be accelerated by a MPEG-4 accelerator that can accelerate ISO MPEG-4

#2: YES. The 'devide-by-32' problem is a MS MPEG-4 codec bug, which shows up on the G4x0 because it has pitch restrictions that are needed for proper functioning of the hardware.

Gurm: DivX ;-) _IS_ MS MPEG-4. DivX and all other incarnations of the MS MPEG-4 codec suffer from this bug.

[This message has been edited by dZeus (edited 09 February 2001).]

[huMMer]

Well, GURM, eh,... that's exactly what I have So what's the story with DivX codec? What do I have to do to at least have the overlay properly running on my G400 DH?

[dZeus]

the specific steps? only unregister the directshow filter by typing "regsvr32 /u "directshowfilter.ax". Where directshowfilter.ax is the name of the MPEG4 direstshow filter you want to unregister. The official MS one is called MPG4DS32.AX

Not that you want to do this, because it will look worse than video blitting, and now even movies that have a horizontal res. devidable by 32 don't use overlay in 32bpp desktop

[This message has been edited by dZeus (edited 09 February 2001).]

[huMMer]

Can I play with something else (Desktop bit depth, resolution, or anything else)? I am so persistent because I think I HEARD somewhere that with DivX MP4 movies Matrox card is a good thing to have. Although now I am starting to think it was not true...

[dZeus]

Matrox has very good image quality with overlay surfaces, so any codec should look relatively good on the G400. And the dualhead feature is very usefull for outputting it to the tv.

But, again, other cards won't help you either with MPEG-4 playback. The only thing that the G400 has is this problem with the MS MPEG-4 codec where you can't use overlay when the horizontal res. isn't a multiple of 32. Consider it a small price to pay for a great feature like DVD-MAX

[Maggi]

Hi huMMer,

I think what you have in mind is the DVD Max feature which ports the MPEG-4 video stream to fullscreen TV ...
(given the horizontal resolution is a multiple of 32 and your desktop is set either to 16 or 32bpp colordepth)

This is of course a hardware feature and the resulting picture quality is way superior compared to a VGA monitor playback.

If you have clips in 720 pixels width, you should crop them to 704 (=22*32), configure the driver to use DVD Max mode in the DualHead tab and enjoy your DVD backups on your big screen ...

[xortam]

Maggi wrote:

<font face="Verdana, Arial, Helvetica" size="2">... and the resulting picture quality is way superior compared to a VGA monitor playback.</font>

Au contraire! You know better than that.

[dZeus]

really! video content looks so much better on a good TV! Video content often is too dark on a monitor, plus that a TV has motion blur and it's made in such a way that low resolution video (like VCD) doesn't look that bad at all on it!

[dZeus]

MS MPEG-4 uses overlay just like most other video codecs. That's about the only hardware acceleration you'll get.

But then there is the issue with the MS MPEG-4 codec that it won't use overlay when the horizontal resolution of the MPEG-4 encoded video isn't a multiple of 32.

If you unregister the MPEG-4 directshow filter, and set your desktop to 16bpp, it'll use the codec .dll for decoding, and it will use overlay on all videos now, but will look like crap, because the codec dll can't dither properly in 16bpp (and it won't use overlay in 32bpp desktop mode)

ah, and please don't crosspost!

[This message has been edited by dZeus (edited 09 February 2001).]

[xortam]

O.K. We really need to detail what resolutions we're talking about. I'll give you the possibility that low resolutions may look better on TV due to the reasons you prescribe (I've only tried desktop and DVD playback on TV). A monitor or RGB driven TV will look better at higher resolutions where you're not limited by the bandwidth of PAL/NTSC standards.

[Wombat]

dZeus,
I used to think that DivX ;-) was MS MPEG-4 implementation, but the group that put it out has denied it.
I didn't believe them, but now there is reason to. You can go to their website and download the beta of their new DivX codec. It's unstable, but from people I've heard that have used it, it offers a lot of improvements. Faster, better visual quality, and it switches between fast-/slow-motion implementations within the same encoding, as it sees fit.