[theora-dev] More introductions

Thu Jul 18 15:05:29 PDT 2002

wow -- turn aside for a moment, and things heat up.  Glad to see some
interest here.  I'll answer what I can from my perspective over a few
posts.

First, for those who don't know, I am one of the original VP3 developers.
As CTO of On2, I was involved in the decision to release VP3 as open
source, and in the recent decision to migrate the codebase to Xiph.  I
will be making myself available to Theora, time permitting, to help with
the integration effort, documentation of the VP3 bitstream, and future
versions of the codec.  Note however that I am not a Xiph employee; Monty
et al will be the final arbiters of what transpires on their servers.

My understanding at present is that Xiph will continue to host the QT and
VFW versions of VP3.  There are a number of good reasons for this, which
are mentioned in some of the recent posts.  We feel it is important to
have a clean workflow path from common source formats such as .MOV and
.AVI, into the OGG format.  Eventually we hope that there will be a
thriving set of tools that support OGG natively; but that will of course
take time.  In the meantime, it will be critical for there to be an easy
conversion path from today's formats into OGG.

I am willing to support these components as I have at On2 for a while,
until others get up to speed and take my place.  Presently, the theora CVS
repository has a recently updated version that builds all the platforms we
presently support, which are as follows:

* VFW for Windows
* QT for Windows
* QT for MacOS
* QT for OSX

Please post any build, compile, or install questions to
theora-dev at xiph.org and I will try to answer them.

<p> ___  Dan Miller
(++,) CTO and founder, On2 Technologies

On 18 Jul 2002, Eric M. Kidd wrote:

> --- Ralph Giles wrote:
> I don't see why we wouldn't be interested in hosting continued
> development of the quicktime and vfw plugins; however, I've not looked
> closely enough at the current packet structure to be able to guess how
> much (if at all) we'd want to change it for ogg. If there are
> significant bitstream changes, that might complicate maintenance.
> --- end of quote ---
>
> The various existing VP3 codecs all seem to run in a "packet-per-frame" mode.  QT or VFW justs tosses them a blob of data (and requests an output pixel format), and a thin glue layer munges stuff around a bit and calls into VP3 itself.
>
> I can think of two advantages of preserving this architecture:
>
>   1) It's probably less work.
>
>   2) Nearly all professional video editing systems support QuickTime/MPEG-4 container files.  If Ogg Theora uses the existing VP3 packet format, it would probably be possible to convert QuickTime container files to Ogg container files, and leave the data unchanged.  This would be a quick&dirty way to get some decent tool support for Theora.
>
> VP3 internally supports quite a few pixel formats, with a couple of caveats:
>
>   A) The supported pixel formats are slightly different on Mac and Windows.
>
>   B) The assembly code for many of the pixel formats is heavily optimized and CPU-dependent.  Under Windows, you need to install a variety of assembler upgrades and MSVC service packs just to compile the code.  So porting the assembly code to GCC/gas is likely to be a pain, if that's the plan.
>
> But anyway, that's enough theory--on to development stuff. :-)  If you don't mind hosting the VP3 QuickTime codecs (at least for now), to whom would you like me to send patches?
>
> Once again, thank you for all your cool multimedia work!
>
> Cheers,
> Eric
>
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