Re: [gentoo-user] large .avi video files, re-encode ?

[Dan <dan@spore.ath.cx>]

On Thu, 28 Dec 2006 18:27:16 +0000
Dave S <gentoo@pusspaws.net> wrote:

> On Thursday 28 December 2006 17:40, Strong Cypher wrote:
> > could you give us the original format of your video ?
> 
> The .avi files were directly generated by a screen capture program
> 
> Dave
the avi format is a container format that can work with multiple codecs
(see below).   perhaps you just need to re-encode them so that either
they use a better codec or they are lower qualilty in the same codec
(quality is directly proportional to size). Or use a better file format
alltogether if you wish.  

to do video stream editing i recommend the transcode package, as that's
the only one I know if.  

some quick info on avi's

http://en.wikipedia.org/wiki/Audio_Video_Interleave says:

(quotes)

Audio Video Interleave, known by its acronym AVI, is a multimedia
container format introduced by Microsoft in November 1992 as part of
the Video for Windows technology. AVI files contain both audio and
video data in a standard container that allows simultaneous playback.
Like DVDs, AVI files support multiple audio and video streams, although
these features are rarely used. Most AVI files also use the file format
extensions developed by the Matrox OpenDML group in February 1996.
These files are supported by Microsoft, and are known unofficially as
"AVI 2.0".
...
By way of the RIFF format, the audio/visual data contained in the
"movi" chunk can be encoded or decoded by a software module called a
codec. The codec translates between raw data and the data format inside
the chunk. An AVI file may therefore carry audio/visual data inside the
chunks in almost any compression scheme, including: Full Frames
(Uncompressed), Intel Real Time Video, Indeo, Cinepak, Motion JPEG,
Editable MPEG, VDOWave, ClearVideo / RealVideo, QPEG, MPEG-4 and others.
...
AVI is considered by many to be an outdated container format.There is
significant overhead when used with popular MPEG-4 codecs ...The
container has no native support for those codecs' modern features...
cumbersome hacks (in a programming context) are used,
causing incompatibilities in some players. Hacks are also used to
implement subtitles. The highly efficient H.264 codecs use even more
compression tricks, and thus are even more ill-suited to the format,
particularly Main and High Profile.
(end quotes)
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