[QLab] Video Fade Stutter

[Marc Ray]

Glad to see I am not the only one using the BBC footage as a test  
case :)  I usually pull stuff off of the Apple Quicktime site.

Marc
-- 
Marc Ray
FSU Dance
Maggie Allesee National Center for Choreography
dance.fsu.edu
mancc.org
mrray at fsu.edu
850-645-1996 Office
850-645-1900 Dance Computer Lab
850-644-1277 Fax


On Oct 8, 2007, at 4:37 PM, Paul Gotch wrote:

On Mon, Oct 08, 2007 at 04:03:59PM -0400, studioinabox at aim.com wrote:
> starts, and the fade up of that video. These both seemed to help in  
> some
> cases. So why are my fades stuttering? is the video too big? (1280x720
> Photo - Jpg codec quicktime files) is my processor too slow?  
> (2.16ghz MBP)
> Ram? (2 gb) I do not have this issue fading from a picture to video.

I don't know why everyone keeps recommending using Photo JPEG, when  
using
Photo JPEG it's going to be.
     - Trying to pull a high data rate from the disk as it's not  
doing any
       temporal compression of the video.
     - Using significant amounts of host CPU power to do the decode,  
as it's
       not using the acceleration on the video card.

I would hazard a guess that it's the disk in the MBP not being able  
to keep
up with pulling two HD PhotoJPEG compressed streams of video that's  
causing
your stuttering not processing power problems.

I've tried using full HD (1920x1080) H.264 encoded files downloaded  
from the
BBC and doing video fades between them. This is on a 2.33MHz Core 2 Duo
MacBook Pro. It can do stutterless video fades between them, probably
because most of the legwork for decode *and* the video fade is being  
done on
the graphics card. It appears to take about 30% of the host CPU per  
video
playing back.

If you need to more than this then you are going to need to spring  
for a Mac
Pro and load it up with processors, video cards and RAIDed disks.

-p
-- 
Paul Gotch
--------------------------------------------------------------------
________________________________________________________
WHEN REPLYING, PLEASE QUOTE ONLY WHAT YOU NEED.  Thanks!
Change your preferences or unsubscribe here:
http://lists.figure53.com/listinfo.cgi/qlab-figure53.com