Encoding XVID from 10 FPS source

[dilly323]

Hi all,
I want to compress a file to XVID and I'm using AutoGK.

My source is an uncompressed 35GB AVI, 47 minutes long, 640x480, and only 10 FPS.

I'm do a 2 pass encode with the target file set to 350MB.

The result is a 350MB file at 464x362 and 1046 bitrate. But the quality loss is visibly dramatic. I would have thought that being under an hour and 10 FPS, the quality at 350MB would be much better.

Any thoughts or suggestions?

Thank you,
Dilly

[jman98]

Oh dear Lord! 10 fps? You have run into either a dumbass who foolishly thoght that using 10 fps would make the file tremendously smaller than 29.97 fps (it really won't - it will actually make it larger!) or you ran into an evil genius who deliberately encoded it at 10 fps knowing that it would not convert accurately to DVD or other formats. I don't know much about camcorders, but I've heard of some new ones that do really weird things so maybe this is some weird kind of DV, which I would know absolutely nothing about.

Your bit rate should have been OK for the size you propose. Try using a higher bit rate (I suggest 1500), but you're screwed on the fps. NOTHING you encode it to will look right. Not 10, not 24, not 25, not 29.97 fps.

[dilly323]

Thanks for the reply. The truth is closer to dumbass than the evil genius unfortunately.

Basically the video was shot on a crappy Cannon Powershot digital camera that only records video at 10 FPS. Nothing I can do about that.

But I have the source movie edited together in Sony Vegas. I COULD export the video from Vegas with a higher framerate. I'm not sure that would help though.

The result is watchable, it's not too jumpy or anything, but just has that look of over compression. The 35GB file looks much nicer.

[jagabo]

I wonder if AutoGK isn't good at handling unsual frame rates like that? Although it's hard to see how it would mess up since Xvid is doing the hard work. Try compressing the file with VirtualDub (included as part of AutoGK). Start VirtualDub then:

1) File -> Open Video File
2) Video -> Fast Recompress
3) Video -> Compression, hilite Xvid, press Configure, press the "Load Defaults" button in the Xvid config dialog.
4) Files -> Save as AVI.

That will give you a single pass target quantizer encoding with a quantizer of 4. The frame size and the frame rate will be the same as the source. See how big the file turns out. If it turns out very large your video may have too much noise and/or too much motion to get good compression.

[dilly323]

Thanks jagabo, I'll give that a try. It's true that there is a lot of motion (walking with the camera) in this video.

[guns1inger]

I suspect that the issue isn't so much Xvid under AutoGK, but the avs script. Probably does some funky AssumeFPS or ConvertFPS stuff to the file first.