Mixing Videos/ Audio

Mar 17, 2009 at 1:55am

Mixing Videos/ Audio

Hey Everybody,

I kinda new to Max/MSP and I’m trying to work through a problem. I know there is probably a simple solution, but I’m not familiar enough with Max or Jitter, and wondered if anyone could give me a hand.

I’m making a program that takes a bunch of video files and mixes them together into one using random selection. The end result is supposed to resemble flipping through channels on a tv really fast. I used jit.qt.movie and random numbers to successfully mix all of the video feeds into one, but the all of the audio plays at once in one big, garbled mess. I’ve attached the patch I’m working in. The window all the way at the bottom is the end result. Is there a way i can mix the audio signal along with the video? And, I’m hoping to do this with up to 16 videos in the end, so can anyone suggest a more efficient way of building this? I know using a tree of switches and drunk numbers is very messy. I appreciate any help you could give. Thanks a lot!

#42891
Mar 17, 2009 at 2:42am

jit.qt.movie plays by default the sound through your system, not through MSP, that’s why you can’t easily mix.
You could:
-look at jit.qt.movie help file, see the “track sound” subpatch, and use the commands to mix.
-mix in MSP, using [spigot~] object to steal the movie sound.
-import the sound into a [buffer~] then play with it in MSP.
Jean-François.

#153536
Mar 17, 2009 at 5:36am

kahood wrote on Mon, 16 March 2009 20:55
I’m making a program that takes a bunch of video files and mixes them together into one using random selection. The end result is supposed to resemble flipping through channels on a tv really fast. I used jit.qt.movie and random numbers to successfully mix all of the video feeds into one, but the all of the audio plays at once in one big, garbled mess. I’ve attached the patch I’m working in. The window all the way at the bottom is the end result. Is there a way i can mix the audio signal along with the video? And, I’m hoping to do this with up to 16 videos in the end, so can anyone suggest a more efficient way of building this? I know using a tree of switches and drunk numbers is very messy. I appreciate any help you could give. Thanks a lot!

You might also look into [router] for easy control of multiple banks of movies. The [router] is compact and handy, and can be preset with multiple configurations, so for any kind of performance, you can do a lot with just a few clicks.

Also you can use [jit.xfade], but you might not need it for the “tv channel switching” effect.

For volume you may want to just play the files separately from buffer~ and groove~ as mentioned, this has been much smoother in my experience, plus you have total control over it. I’m not sure of the difference processor-wise between (say) 8 jit.qt.movie-plus-audio-track objects, and 8 jit.qt.movie (no audio track) and msp playback through 8 buffer~/groove~ pairs. Probably this takes a considerably bigger hit, though I’m not sure (and it may be a different kind of hit). However, as mentioned on other threads, changing speeds a lot (esp. going backwards) and skipping around madly can be stuttery using the jit.qt.movie soundtrack due to audio decompression and stretching, but these kinds of actions are rock-solid with groove~.

– Pasted Max Patch, click to expand. –
#153537

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