Video and audio?

Quote: Little Bear wrote on Thu, 01 May 2008 18:12
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> I don't know what forum to put this under. I am kinda new to Max MSP Jitter. I am trying to get into video scrubbing. I was wondering if there is an easy way to control treble, and bass levels coming out of a jit.qt object that is play an .mp4,

look at the spigot~ object (assuming it's working on your platform and max version). otherwise, extract the audio as an aif or wav, and load it in a buffer controlled by a groove~ object. fairly trivial to sink a qt.movie to the right output of groove~.
then send this output (either spigot~ or groove~) to an fffb~ object.

> also lets say there is music being played by two jit.qt's how would someone go about creating a beat matcher for the audio outputs.

not sure what you mean here. please be more specific. you mean two movies, each with their own soundtrack (music videos), and you want an automatic way to sync their bpm? there's no automatic way to do that in msp, and it would be very complicated for a beginner to implement something.

maybe others have more suggestions.

Thank you for the reply.

I don't necessarily want to make them match automatically. I simply need a way to determine the beats per minute from the video file. Is there an external object that I can stick into the spigot~ object that will give me the bpm?

> Is there an external object that I can stick into the spigot~ object that will give me the bpm?
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nope.
requires spectral analysis and some math, and probably heuristics to get it to really function.
take a look at the cnmat externals, if you're up to the challenge.
http://cnmat.berkeley.edu/downloads

better off creating your own tap tempo mechanism (bang -> timer -> !/60000, probably throw in some averaging math as well).

if you're just dealing with loops, then it's much easier to get the bpm upon loading the file.

Quote: Little Bear wrote on Fri, 02 May 2008 02:12
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> I don't know what forum to put this under. I am kinda new to Max MSP Jitter. I am trying to get into video scrubbing. I was wondering if there is an easy way to control treble, and bass levels coming out of a jit.qt object that is play an .mp4, also lets say there is music being played by two jit.qt's how would someone go about creating a beat matcher for the audio outputs.
>
>
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I always advize people to load the audio of a movie separately into a buffer~ and use msp to control the playback of jit.qt.movie instead of using spigot~.

Since this request comes up a lot on the forum, I decided to make a template that shows what I believe is the optimal way to use msp together with a quicktime movie.

I attached it. If you have any questions, please let me know.

Best,
Mattijs

What is the advantage of using the buffer? I cannot see the video, I can only hear the audio?

While jitter is equipped to mess with audio, it is much easier and more
efficient(?) to mess with the audio in msp. I think the idea is to use
jitter to play back the movie, but load the aiff from the video into the
buffer, and to use the phasor output of [groove~] to control the video
playback of the [jit.qt.movie] object. This way both video and audio will
be playing and you'll be able to manipulate the audio without having to
capture it from the movie file first.
Beat detection seems difficult. I have a friend who figures out the bpm
(and sometimes key center) of samples beforehand, and labels them with the
info. When he loads them into his patches, the information is parsed out
from the file name and the appropriate adjustments are made. Perhaps
something like that would make beat matching videos easier?

On Sat, May 3, 2008 at 2:59 AM, Miles wrote:

>
> What is the advantage of using the buffer? I cannot see the video, I can
> only hear the audio?
>

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Ahh... Right now I have a patch that can loop video through an rslider. So is groove~ the way I can set up that feature? Sorry for all the questions, jitter seems to make more sense to me. I am trying to mix two videos together while being able to control the audio. So the most effective way would be to have two jitter object go through two buffers that controls the rate, and volume of both the music and the video. By doing this I can control different variables of the sound, I could use a groove~ that would change the music loop, which changes the video loop? Then finally have an out put of both jitter objects that go through video fadersRGB and other bells and whistles to control the visual?

Ha. The only part that I seem to have control over is the beat. I came up with a solution for the BPM.

Quote: Little Bear wrote on Sat, 03 May 2008 08:59
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> What is the advantage of using the buffer? I cannot see the video, I can only hear the audio?
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Hmm, maybe this general solution is a bit over your heads for now, sorry for that. When you start building more complex programs with audio and video processing you'll see what I mean. I'll try to put this template online somewhere.

Best,
Mattijs

I think I am slowly getting the hang of it.

Are there any tutorials I can read to help me understand it a better, other than the ones on Max? I have been messing with your patch and I was able to put in looping via groove~, the only problem is that when I do this function it speeds up the video instead of looping it with the sound. Any ideas?