Fade out audio after crossing video motion threshold


    Feb 10 2013 | 4:01 am
    I'm having trouble googling this because I don't know what to call it.
    Basically, I'm using a webcam to control the volume of sound in a room. If nobody is in the room, the sound shouldn't play. However, this needs to have a reasonably long time-out value so that it doesn't accidentally stop playing while there are people in the room.
    So I've got a jit.qt.grab, going to a jit.change with a reasonably high threshold value. My playback is controlled by 4 play~ objects through a 4-channel live.gain~ object.
    How do I extract the motion data from jit.change and give it to live.gain with a timeout so as to accomplish my purposes?
    Thanks in advance

    • Feb 10 2013 | 11:17 am
      I'd suggest you using cv.jit externals to perform a more precise tracking. http://jmpelletier.com/cvjit/ In this example, I'm using [cv.jit.label] and [cv.jit.blobs.centroids] to track the presence of people in the room. Then, the output of the [cv.jit.blobs.centroids] triggers a [line~] object connected to a [*~] generating a volume ramp.
      hope it helps.
    • Feb 10 2013 | 11:52 am
      The qmetro can do all this voodoo by itself ? :))
    • Feb 10 2013 | 5:10 pm
      Yes, qmetro is a very powerful object, if you connect it to something else :)
      Sorry for messing with copy & paste.... Here should be the right patch
    • Feb 11 2013 | 12:03 am
      LSka, I'm not sure what your example is--the posted code is just a qmetro.
      I have a metro connected to the qt.grab, which outputs fps (i guess?) Not sure how it does that. However, I'm having a hard time getting reasonable results with the actual fps numbers. It doesn't just nicely decrease to zero, so I can't just pick an fps threshold (I think)
      I'm currently looking into cv.jit; I'll see how that goes.
      edit: sorry, I just saw your updated post.
    • Feb 11 2013 | 1:29 am
      edit: i'm dumb, thank you so much!
      Thanks
    • Jun 30 2013 | 6:14 pm
      Thank you for this patch LSKA !