How to convert mp4 video to be more efficient?

[Matt Graham]

From: joe
> The video that I referred to in my previous message today
> turned out to be an mp4 with a file size of 33,978,499
> and it was only 27 seconds long.
> 
> Surely there must be a way to convert a video like that
> to a more efficient format (requiring less file space for
> such a short video.
> 
> What would you recommend?

There's a very useful utility called ffmpeg that can re-encode audio
and video to a ton of different formats.  However, it's not really
friendly.  I used the file at http://crow202.org/~mhgraham/presets.xml
(originally part of a frontend written in some bizarre dialect of
Pascal) and a bit of shell to come up with this:

#!/bin/bash
# converttoflv.sh
# no error checking at all.  Converts first arg to second arg
ffmpeg -i $1 -vcodec flv -f flv -r 29.97 -s 320x240 -aspect \
4:3 -b 300kb -g 160 -cmp dct -subcmp dct -mbd 2 -flags +aic+cbp+mv0+mv4 \
-trellis 1 -ac 1 -ar 22050 -ab 56kb $2

...which, when invoked as "converttoflv.sh thing.mp4 thing.flv", will
turn thing.mp4 into a 320x240 FLV with a low bitrate audio stream at
22KHz and a 29.97 frames/sec framerate.  The resulting videos are
suitable for FlowPlayer and probably YouTube.  There are a metric
ton of reasonable presets in the XML file above, and they have
descriptions.  You can roll your own script(s) from that in about
30 seconds depending on your needs, or modify the command lines to
get something different.

There's probably something more polished out there, but the video
re-encoding projects I found via freshmeat/sourceforge were all
half-finished or special purpose.

-- 
Matt G / Dances With Crows
The Crow202 Blog:  http://crow202.org/wordpress/
There is no Darkness in Eternity/But only Light too dim for us to see