settings advice for very low quality encodes

[junglemike]

Hi everyone. For some time alredy i'm encoding movies to watch them on palm. It has to be max 320x320 res and about 15fps (my zire71 can't hendle more) But even under such settings it is very hard to put full movie to about 80-90mb (free space on my sd-card) I know that i'm asking too much but i have no choice. I must say that i tried other codecs, and xvid performs best under such brutal conditions. I don't understand much in advanced stuff like quant matrixes. I just follow the guides and everything works perfect (with encodes to watch on pc) But now i need to put 2-2.5 hours with audio (mp3 24kbps 22khz mono) to 80-90 mb. What are the best setting you would recommend in such case?

[Prettz]

For quant matrices, if you want to stick to "tried and true" ones rather than some of the more recent amateur matrices, I would definitely go with the hvs-good matrix (as opposed to the standard lower-bitrate matrix, H.263). You can find somewhere to download that matrix by searching this forum.

I assume that whatever it is you're playing these on doesn't have the CPU power to handle b-frames (if I read you right), so none of those. No QPel or GMC, for the same reason.

Using adaptive quantization will probably give you better quality than without it for the same file size.

Definitely use chroma motion, trellis quantization, and VHQ-4 so you can squeeze every bit of quality possible out of your small file size.

Finally, and this is only an uneducated guess, enabling chroma optimizer MIGHT help overall quality, although it might just as easily hurt it. I really couldn't say since I don't know what the video you're encoding is like, or really even how chroma optimizer helps/hurts at extremely low bitrates. If you have the time you might make two identical encodings, but with one using chroma optimizer and one without and compare the two.

I hope I was able to help.

[pogo stick]

Here (http://forum.doom9.org/showthread.php?threadid=74879) is my attempt to make XviD look good at very low bitrates.
I failed. :(

[Teegedeck]

I'd downsize the resolution to 160x160. :p
No, I mean it.

[crusty]

Another solution would be to use more than one sd card. ;)
Consider it just like a two cd rip. Halfway, you switch to the other memory card.

[scharfis_brain]

If you are encoding movies, set the framerate to

11.988 fps for NTSC
or 12.5 fps for PAL

this ensures smooth motion and loweres the filesize.

15fps would yield to a non-continous motion, because it isn't a divider of 23.976 or 25 fps.

[junglemike]

I tried some Hvs matrix, also set 1 b-frame (i tried more - but the output is garbded, probably mmplayer (for palmOS doesn't support more b-frames), also tried vhq-4, chroma-on, and trellis thing. The quality is definitly better than default xvid settings, altough all these setings make file harder to play, so i overclocked the ARM processor from 144mhz to 192 mhz. Everything works flawlessly. Thanks.

[Alxemi]

vhq4, chroma optimizer/motion and trellis doesn´t make the movie harder to play; gmc, qpel, matrix choosed and bframes configuration do, so you must be carefull with this settings, the others (including adaptative quantzation) are safe (from the decoding-power point of view).