[mpeg2] Re: MPEG encoder code (was: Kfir Mpeg2 to SVCD)

[Dan Hollis <goemon@anime.net>]

On Thu, 1 Feb 2001, Andrew Stevens wrote:
> - A rather efficient (o.k. I invented it) hierarchical sub-sampling
> based motion compensation search algorithm.  Gets to within a % or two
> of optimal matching and delivers legit VCD MPEG-1 at 13 frames/sec
> (352*288 PAL) at a motion compensation search radius of 16 p.p.f.d. on
> a Duron 700.

I'm not so concerned with compressor speed, I'm more concerned with
quality and I'll spend extra cpu if needed to compress better quality.

> (Yes, I *did* spend a lot of time gathering data and testing
> alternative algorithms).

I assume you've already read the motion estimation papers from
http://citeseer.nj.nec.com/Compression/ ?

> - For low bit rate work scene-change detection / automatic GOP length
> adjustment needs to be added (this should help quite a bit for
> low-bit-rate applications).

I've been told one of the best commercial mpeg encoders dynamically
modifies GOP structure to best fit the material. Eg It can vary IPPPBP
or IPBPB or IPBBBB or any other combination depending on the dynamic
content.

> - For SVCD work it would probably make sense to add multi-threading
> for folk with SMP machines like Adam did on mpeg3movie.

Clustering? Tsunami mpeg allows this, you can throw a cluster of machines
on 100bt and have them all crunch video.

> If I thought Adam were interested I'd *love* to merge all the MC and
> rate-control stuff into mpeg3movie.   Save a lot of redundant effort.
> Perhaps I should email him again?

Certainly, at least you can share techniques of compression.

-Dan