Sunday, March 15, 2009

Dirac video







Sequence end code in an own sample



No ctts atom required



Other news



Anonymous said...

Yay! I've been eagerly waiting for a excuse to look further into Dirac. I've big hopes for it.

Although the recent progress from Theora has taken most of my focus ;-)

(That is, end-user focus :-) )

burkhard said...

Libschrödinger is currently focussed on speed rather than encoding quality.
I made some encoding tests (PSNR vs. file size) and they confirm that. Let's wait until more encoding features from the dirac research codec are ported to schrödinger. Maybe todays 1.0.6 release already brings improvements.

Tommy Thorn said...

Very interesting. Your comment is about the Quicktime mapping, but Dirac is mapped to quite a few containers, including MPEG4 and Ogg. I assume the issue doesn't exist there?

Qualitywise, Schrödinger still lags significantly behind dirac-research when encoding, though about 10X faster. I'd hope people aren't making conclusions about the Dirac potential based on Schrödinger.

What is the official/best mailing list for discussing Dirac?

burkhard said...

The mappings for mp4 and quicktime are identical.

The ogg mapping guarantees correct timestamps. But it also demands, that the end-of-sequence code is in an own packet. This makes frame-accurate seeking much more difficult than for theora.

The mapping for MPEG-2 transport streams is similar, but it doesn't hurt much because for the other MPEG codecs it's worse.

There is the schroedinger-devel list, it's low traffic and focused on libschroedinger. Don't know about others.

I really hope that the libschroedinger gets more quality improvements. IMO Dirac is the most promising free video codec. But without a good and fast implementation it's pretty worthless.