MJPEG playback problems

[Emmanuel]

I use a G400Max with RR card. When I capture in RGB mode I have no problem: all is fine. When I capture in MJPEG: I can't have a good image, the video is fine during a few seconds then I have colored blocks, slow motion, etc. Even when I try in very low resolutions it didn't work (my system is a Celeron 366@550, 192Mb RAM, 17Gb fast UDMA66 HD).
Another question: Is there a way to capture in full-screen, full-motion in RGB mode ?

Thank you and Happy New Year!

[Werner]

.... but it WILL be fixed....

[Emmanuel]

Well it seems that I'll have to reply to my own post...
After reading some FAQs (from Matrox and this user's site) I find why I'm losing so much frame: it seems that WinFaxPro (v8) was the culprit (seen in the Matrox FAQ). After closing WinFax I lose almost no frame. But sometimes the MJPEG playback is really bad and I'm disapointed by the lack of quality (colored blocks, slow motions, black & White, pixelisations...)

Second question: Is there a way to capture in full-screem, full-motion, RGB mode ?
Yes there is, you have to hack the registry (thanks Matrox FAQ again) to change the speed of your hard disk: If I put 40Mb/s, I get the option to record 640x480x16.7@30fps. Of course, I need a HD able to do 30Mb/s of sustained rate or 19Mb/s if I reduce the colors to 16bits. My Fujitsu 17Gb, UDMA66, 5400RPM is just able to do 9-12Mb/s...

[This message has been edited by Emmanuel (edited 04 January 2000).]

[delrue.luc]

Hmm;

I had this problem on my G400max too; it did go better when I got into lower quality settings!?
Now I do capture on 352 x 288 (PAL) ;25fps and a compression ratio of 5.2:1
It doesn't look too bad once it is played on TV and it does allow faster rendering with U-lead viedeo editor.

I wander what would happen if you did capture in RGB (in a small window) and after the editing convert it to MJPEG full screen?
I don't even know if this is possible; hehe, it leaves me with something to try out this evening.

Greetings;
Luc

[delrue.luc]

OK; I did the test.
I did a capture from my TV (the RR-G TVset)in RGB-16.7 mil colours at 320 x 240 /25 fps with a datastream of 6.922kb/sec. The audio quality was CD quality.

The duration of the video was about 24 sec.
It did get me a file of 138 Mb.

After this I put the file into Ulead video editor; and transformed it to a MJPEG file; 704 x 576/25 fps (PAL). As a result I got a file with a max datastream of 3.156 kb/sec ;
It had a size of 71.3 Mb.

When I played it full screen I must say the quality was better then when I do the capture in MJPEG.
Maybe it is important to know that I do not use the matrox codec but the picvideo codec instead.

There's one disadvantage however; for transforming this file I needed 08:47 minutes; for only 24 sec of movie.
The work was done on a K7-500 128 Mb SDRAM.
The graphic card is a MatroxG400max.

I don't know wheter this info may be usefull for someone; but I let you ppl know this anyway.

Greetings;
Luc