[QLab] Video Fade Stutter

[Paul Gotch]

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
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