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Audio Glitches

CloudsClouds Posts: 1,599Member
edited December 2011 in Tech Support
The audio in GameSalad seems to have a few little idiosyncraticies I've come across which can be a little annoying. A lot of them you can get around - some of them you can't (or at least I have not worked out a way as yet).

For example when interpolating audio to fade a piece of music up - the music jumps up in volume at the end of the fade . . . So let's imagine you are interpolating 'Music' volume from 0 to 1 (sound off to full volume) you'd expect it to go:

0 1 2 3 4 5 6 7 8 9 0 0 0 0 0

But it actually goes something like this:

0 1 2 3 4 5 6 7 0 0 0 0 0 0 0

ie: after 7 in our sequence it just jumps up to full volume, which sounds a bit crap to be honest and ruins a nice subtle fade-in, here is the waveform of a sine wave stuck through game salad with it's volume interpolating from 0. - I recorded it back out into Logic Audio to check what was going on, you can clearly see where the volume leaps up (and you can certainly hear it too!) - the problem is much worse when interpolating to values below 1 (eg: interpolating from 0 to 0.5 is much worse than interpolating from 0 to 2):

image

Comments

  • CloudsClouds Posts: 1,599Member
  • CloudsClouds Posts: 1,599Member
    This interpolation issue also 'pops up' when you are interpolating the alpha channel of an actor (to fade an object in) - it fades smoothly for the first portion of the interpolation and then suddenly jumps up a level.

    So . . . . it's most probably something to do with the interpolation algorithm rather than audio per sa.

    Interpolating the position of an actor (for instance across the width of an iPad screen) doesn't seem to display the same problem.
  • CloudsClouds Posts: 1,599Member
    edited December 2011
    SOLUTION (or workaround at least):

    For the alpha channel interpolation issue you can get around the 'lumpy' fade by making your target alpha channel value higher than 1, putting in 1.2 gives me a smooth fade up, although you might have to play around with various values depending on your project , the same deal with audio fades not being smooth, try fading to values higher than 1**, it seems to mitigate the worst of the issue.


    ** You might have to go back to your original source audio file and attenuate it so when fading to higher values it doesn't get too loud in Gamesalad,
  • CloudsClouds Posts: 1,599Member
    edited December 2011
    This information applies to both Music volume and Alpha channel value when used with the interpolate behaviour.

    Interpolating from -0.2 to 1.2 gives you a smooth fade in.
    Interpolating from 1.2 to -0.2 gives you a smooth fade out.

    Interpolating from 0 to 1 gives you a fade in with noticeable steps/glitches.
    Interpolating from 1 to 0 gives you a fade out with noticeable steps/glitches.
  • gyroscopegyroscope I am here.Posts: 6,577Member, Sous Chef, PRO
    edited February 2013

    Hi Tynan, hey, what a great workaround. The interpolate fade in of alpha has always been particularly annoying to me, something which never seems to get fixed (at least not in the last 3 GSC updates). it used to work perfectly at one time).

    Anyhow, excellent and thanks!

    ""You are in a maze of twisty passages, all alike." - Zork        temp domain http://spidergriffin.wix.com/alphaghostapps

This discussion has been closed.