Timewarping in chops and audio problem

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Hello all
I'm playing around with mocap data brought in as bclips inside chops.
I thought it would be fun to see if the data could play an oscillator ,
as if the limbs of my characters bones where playing a virtual theremin.
All worked well. I attached my file to a maths chop to get the data in an audible range then attached that to the oscillator node, all good this works.
My first problem is that when I save the results as an aiff the result doesnt match the length of my rendered images , this is frustrating as I'm yet to see if there is any correlation between the movement of my characters and the audio, boo.
The second problem I have is that I've time warped the data to freeze the character in certain poses then start him off again. Now the audio output is just a constant drone with intermittent intervals (sounds like a john cage title).
I'll attach a reduced version of it. Any ideas would be well appreciated.
Cheers
John
Edited by - March 3, 2010 08:58:27
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here's the file
bclip's for initial pose and move included
Any suggestions for taking the idea further ?
John

Attachments:
warpaudio.zip (174.9 KB)

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Sorry, I don't have time to look at your file. But a few things come to mind.

HUGHSPEERS
My first problem is that when I save the results as an aiff the result doesnt match the length of my rendered images

This is probably due to a FPS/sample rate mismatch. Say you have 240 frames at 24 FPS of rendered images, ie. 10 seconds. Then for the equivalent audio of 10 seconds at 8KHz, you should have 80,000 samples in the CHOP that you save to the .aiff to.

Now the audio output is just a constant drone with intermittent intervals (sounds like a john cage title).

This might be due to the fact that Houdini isn't able to cook fast enough for real time. Try rendering out the sequence and audio separately and combine them in a NLE.
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I had a short look in the hip, and I can say that, regardless of the fact, that I don't know what an oscillator does, whichever FPS I used, there was always just an offset of one frame. See I have time to test the .aiff export, too.
IMHO
Lorenz
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So, I don't know how long the sequence of the last audio part, where you've attached the exporter, should be, but if I export it I get a 6.240s clip. Maybe it's your compositing program, which samples not with 25 FPS. As I say that I recall, that your scene is rendered 24FPS. Maybe that is the deal.
IMHO
Lorenz
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thanks both of you
I think the timing issue was down to two things.
1. Firstly I'd keyframed my constant value which was controlling the index lookup in my warp node, I'm looking into doing this in an alternative way now, but if I manually adjust the samples in the constant chop instead, it sorts itself out.
2. The second was the sampling rates. I resampled my post warped mocap data to the 441000 rate the oscillator was set to and it works.
I'll also check whether my import frame rate is right in the compositor
I'll post a minimized working version of it later if anyone's interested.
Thanks again for the heads up pointers
John
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