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Ian Rosaaen
Video as background
on Jan 18, 2013 at 5:36:42 pm

I'd hoped that I could import a video and use it as a background.

It seems to me that the best way to match the particle effects to the video is to play them together in real time. If this is not the correct approach, I'd appreciate knowing how others do it. So far, I haven't been successful.

The problem is that PI slows to a crawl after I import the video. The video plays at about 2 frames per second. The PI program controls are very slow to respond. This is the case when no particle emitters have been added.

Any help would be greatly appreciated. Thank you.

Here is a description of the conditions and computing environment:

HP Z820 workstation
Windows 7 Professional
64 bit
Service Pack 1
Intel Xeon CPU E5-2665 0 @ 2.40GHz 2.4Ghz

Graphics hardware:
NVIDIA Quadro 4000 graphics card
NVIDIA Tesla C2075

Particle Illusion 3.0, stand-alone.

Through trial-and-error, and technical support assistance, I've manipulated these variables:


Video display resolution: 1280 X 720
Video frame rates tested: 30fps, 29.97fps
The video is 4 seconds in length.
Video formats tested (with high / low bit rates):
AVI (uncompressed);

OpenGL settings (selected / deselected)

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Alan Lorence
Re: Video as background
on Jan 18, 2013 at 6:03:53 pm

pI's video support is not very good. Some things to try:

- In Preferences there is a "use old method of loading AVIs" checkbox. Check that and see if it speeds things up. Note that you won't be able to use DV AVIs -- if you get an error message that tells you that the codec the clip uses is not supported by the "old method of loading AVIs".

- Avoid WMV.

- Try converting the AVI into an image sequence (JPG or PNG).

- Convert the AVI to another codec.

- In the OpenGL page of Preferences, toggle the "use texture RAM for bg images" and see if it makes a difference.

None of those may help much, so you may be stuck doing this:

- Create a lower-resolution version of the clip, use that to setup your particle effects, then use the "Scale Project" function in the "Action" menu to scale up to the final resolution as a last step.

For best quality, use the video in pI as a reference only. As a final step turn off the bg image and render just the particles with an alpha channel. Then bring the particle footage into your video editor and overlay on the original video.



Alan Lorence
Product Manager
GenArts, Inc.

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Ian Rosaaen
Re: Video as background
on Jan 18, 2013 at 6:18:07 pm

Thanks, Alan. I'll give all of it a try.

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