{Spam?} Re: [GEM-dev] pix_record

chris clepper cgc at humboldtblvd.com
Mon Jul 25 18:26:25 CEST 2005

Quoting Thoralf Schulze <thoralf_schulze at yahoo.de>:

> One thing bothers me: Apples MPEG4-Implementation is
> known to be rather inferior when compared to xvid etc.
> What codecs does quicktime actually support? And
> wouln't it be feasible to use a more open platform
> (like ffmpeg or theora) to do this? theora would have
> the added benefit of producing streaming video ...
> Then again, I don't know too much about OSX and even
> less about its multimedia framework, so don't feel
> bothered if I talk bs here.

MPEG4, Divx and the like are not suited for use with this object because they
are designed as delivery and not production codecs.  These do not perform well
in real-time encodng and are so lossy you cannot really do any additional
processing or editing with them afterwards.  This object is designed to be used
with uncompressed 4:2:2, JPEG (Photo and Motion), DVC PAL/NTSC and DVCPRO HD
which are all suitable for further processing.  The open source alternatives do
not really offer the support for production video that Quicktime does.  That
being said, there will be no limitations on the Quicktime codecs available for
use, so you can attempt to use distribution codecs if you wish.

I am working on a way to allow any installed Quicktime codec to be used with
pix_record.  This is more of a user interface problem to be solved than
anything else.  Right now I can dump a numbered list of codecs to the console
and also store them in an array.  The idea is that the user can select the
codec by number and use that.  The list looks like this:

pix_record : codec 0    Animation 1919706400 ctype 65670
pix_record : codec 1 BMP 1465011269 ctype 131253
pix_record : codec 2 Cinepak 1668704612 ctype 65710
pix_record : codec 3 Component Video 2037741106 ctype 65725
pix_record : codec 4DV - PAL 1685480304 ctype 65679
pix_record : codec 5 DV/DVCPRO - NTSC 1685480224 ctype 65678
pix_record : codec 27 Sorenson Video 3 1398165811 ctype 65721
pix_record : codec 28 Sorenson Video 1398165809 ctype 65719

Those numbers after the name are actually constants stored into the array which
really tell QT what to use.  It's a bit of a pain.

Also, as I mentioned in the first post, the standard Quicktime compression
dialog does work by holding down the command key and selecting a compressor
that way.

> I could give it a go with Dev-Cpp (uses the MinGW port
> of the GNU utils), but that would have to wait until
> next week ...

I would wait if you are not familiar with the Quicktime API.  The object
features some non-standard ways of using the API which might cause problems on
Windows (or even OSX as I haven't fully tested it).


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