Compressibility check is wrong on PC generated frames?

[Nel]

I'm trying to make a movie of the 3DMark03 nature demo using the image quality capture function and had limited success so far. I've tried divx5 and xvid. Basically what it does is capture 2038 frames of the demo in bitmap form and says it will run at 30 fps.

So after I capture frames, I go to vdubmod and make a full frames uncompressed avi out of it. Plays back perfectly although it's like 4.5gb for only 68 seconds of video. Then I open the avi in gknot and it comes up. If I have the resolution set to anything higher than 640x480 then it won't read the length of it correctly. No problem, I just type it in manually. I also found out I can go to virtually unlimited resolution by manually changing it in avisynth since it only goes up to 800x600 in gknot. A 1600x1200 movie looks stunning although even a high-end pc can't run it too well.

Anyways, when I go to do a compressibility check, it does 112 frames only and it's supposed to be 2038 frames. So I'm sure I'm getting an inaccurate reading. When it actually encodes the movie though, it does all the frames. I try and encode it anyway around a size of 30 megs and it's a bit blurry. The bitrate is really high compared to a movie and still doesn't look like it's enough. I've tried up to over a 10k bitrate and it doesn't seem to keep the original quality that well but it doesn't look bad at all. Also if I don't change the length when it detects it wrong, I get a warning after the first pass saying the settings are for something else and it detected 2038 frames and it changes it. No problem though if I set it myself.

Is there some trick to getting it to check it properly on bitmap frames? I'd like to record some other movies like this too or even make a higher res version of this demo.

[manono]

Hi-

...it does 112 frames only and it's supposed to be 2038 frames.

The default setting for the compress test does 5% of the movie.

I go to vdubmod and make a full frames uncompressed avi out of it.

You should probably use MJPEG for that. It's lossless also and will be a good deal smaller in size.

...it's a bit blurry.

Maybe it's just hard to compress. What was the compress test percentage? Isn't the Nature Demo the one with all the tree leaves moving? Those are very complex scenes. At 640x480 I think you would need a much higher bitrate than an average movie. You have non-stop movement in that scene. And it's also full-screen, while the average movie is widescreen. You have a whole lot of pixels to compress.

[Nel]

The default setting for the compress test does 5% of the movie.

Ah I never really paid attention when I did movies. I thought it went through the whole thing quickly.

You should probably use MJPEG for that. It's lossless also and will be a good deal smaller in size.

Cool. I thought using vdubmod uncompressed would be lossless but maybe that's where I'm losing the quality.

I don't remember the percentage off hand because I deleted everything for the moment to do some more movies I rented. It was pretty low though. Around 40% for a 5000 or so bitrate I think. I went up to 10000 bitrate and it was closer to 80%. I'll experiment again tonight and let you know what happens. Thanks for the help.

[Sastraxi]

MJPEG most definately isn't lossless by default, only if you use the rare uncompressed JPEG options which many (most?) things don't support.

Anyway.

If you're looking for a nice lossless compression tactic, look into Huffyuv. Though you may not have much luck with such a complex scene (think: PNG). It would probably be OK in this case to use MJPEG as manono has suggested, I just thought I'd point out that little issue :)

[Nel]

I tried it and the master avi certainly looked a lot sharper but when I go to make a divx out of it, the colors are messed up almost like the tint is wrong or the RGB is switched. It looks fine in the window when I hit open in gknot though. Just when I hit preview or make the divx it does that. If I disable the mjpeg codec and preview it, then the colors are right but it looks out of focus.

Anyway, after I did the compress check, I needed about 130 MB at near max bitrate of 16000 to get around 80% at 1024x768. Pretty crazy for only 68 seconds. I'll try huffy and some others. I might be able to get away with a smaller size and still be happy.

[manono]

Hi-

MJPEG most definately isn't lossless by default

My mistake. Thanks for the correction, Sastraxi.

If you still want to use the MJPEG, Nel, then adding SwapUV() to the .avs will fix the colors being off. And yes, maybe it's time to try a lower resolution. LanczosResize(512,384) might be just the thing.

[Nel]

Ok getting better. The avi looks perfect now and the swapuv fixed the colors but now it looks jagged like I have antialiasing off and I used 6X. It looks good in the gknot window though.

[Sastraxi]

If you're previewing in VirtualDub, I believe the XviD codec, by default, halves the resolution. I always had thought that it automatically did this to make the movie more compressable at lower bitrates, but it's actually at the correct size.

I'll try to make a screenshot of what I mean, though it may be hard as I have ffdshow now that (to my knowledge) doesn't do that.

Oh and manono, when looking at my post I sounded unreasonably harsh. I apologise if it came off looking that way to you too.

[Nel]

I tried xvid and divx and they both looked like that. I encoded it once just to be sure and it came out looking jagged still. Maybe it just doesn't work with such a high resolution? I've only tried 1024x768 using this method so far.

[Sastraxi]

The same decoder will probably be used for both DivX and XviD. Encode the first 1 or 2 seconds and see how it goes, when viewed in WiMP or something of the sort.