Unpacking AVI without reencoding

[enim]

Every where I go, I only hear pack-up, pack-up and pack-up. But, somehow I always like to unpack.

I am in a middle of writing a switch /unpack for unpacking packed-bitstream AVI without re-encoding. So far tried two different methods/algorithms but results in hard to notice jerks.

Anybody ever came across full-proof and free to share code for unpacking packed-bitstream AVI without re-encoding.

As I know microscopic structure, please do not provide links to the truck-wagon loads of information.
I can appreciate if any GuRu can focus a light on this.

[Baldrick]

Unpack?

If you have a shrinked avi(like an avi divx/xvid etc) so can't your restore any information.

[enim]

Baldrick you caught me. I am modifying my text.
What I meant was unpacking packed-bitstream AVIs.

My baby does not pack anything, loves to scatter everything here-n-there in to pieces and leaves un-packed.
Knowledge of cleaning up others shit would be better idea.

[Baldrick]

Okey. I have no idea.

[Selur]

'MPEG4 Modifier' (from: http://moitah.net/) is able to unpack 'packed-bitstreams' without reencoding and it is open source,...

[enim]

Downloaded MPEG4 Modifier binary and source.

Modifies MPEG-4 ASP videos (XviD, DivX) without re-encoding (change aspect ratio, edit userdata, remove or add packed bitstream, and change interlaced field order). It can also show information about the video such as the amount of I/P/S/B-VOPs used, whether or not QPel/GMC were used, etc. The video must be in an AVI container.

Running a quick test on various samples, this one seems to cause little flicker and mine causes little jerk. As it has many other features, I liked it. Anyway later on I will have a detailed look into it.
Thanks!