[rescue] Video encoding

[Joshua D Boyd]

On Wed, Apr 24, 2002 at 04:23:50PM -0400, Big Endian wrote:
> >On Wed, Apr 24, 2002 at 03:56:53PM -0400, Kurt Huhn wrote:
> >
> >> An Octane is nice, but it typically lacks the A/V option - Personal
> >> Video Option (PVO) is the official name.  If you find one at an
> >> affordable price with the PVO, you scored big time!  Otherwise, it can
> >> cost a couple grand just for the PVO, on top of the price for the
> >> Octane.
> >
> >Note, the PVO lacks compression.  I believe there is a seperate compression
> >board available, but it is darn expensive, and can be done without if you
> >throw enough hard drives at the problem.
> 
> I/O channels also.  The octane only has 2x UW scsi channels, which 
> won't do 100MB/sec.

He is only trying to capture, not do multi stream editing, so 30.12 MB/s, 
plus overhead is all that is needed.  One UW chanel, with enough drives on
it, should be able to handle the load.  But, with that, about 108gigs of 
hard drive space will be needed per hour.

You only need 100+ MB/s if you are doing multistream editing, and/or using
more than 8bit graphics.  To my recal, the PVO can do 10bit, which is a good
idea because NTSC and the RGB used on screen clash badly, especially when
being mixed with CG elements.  That is why I make a point of using 32 bit
floating color depth.  32bit floats help leave you headroom to work, and allow
you to delay choosing what gets lost.  

Note, for anyone who has watched it, the recent Time Machine starring that guy
from LA Confidential.  The time bubble wouldn't have looked anywhere near as
good if it was done in 8bit color.  For the time bubble, they used custom 
software that allowed them to generate graphics that would overload the film
it was being written to (essentialy, on a scale of 0 to 1, they used whites
higher than 1).  Very impressive.  They used 32bit floats for the CG work. 
I'm guessing they used cineon 10bit files for output, but the CGW article
didn't say.

Anyway, back to work.

-- 
Joshua D. Boyd