Originally posted by: Gillean
That is easily explained, and probably should be done before other people make the same mistake!
Take this example. Our film source is 100,000 seconds long, we make that faster by 4.096% which leaves us with a PAL version at 95,904 seconds. Now if we slow the 95,904 version down by 4.096% we end up with a copy that is 99,832 seconds long, not 100,000 seconds. The reason is that 4.096% of 95,904 is obviously less than 4.096% of 100,000.
So the problem was you were thinking in terms of the original source where SoundForge is correctly thinking in terms of the current source. Easy mistake and something I hadn't thought of until you mentioned it! So whenever you are adjusting PAL material to 24fps then if my maths is right then you need to slow it down by 4.2709376043%. Been way to long since I've done that sort of maths!
Originally posted by: pupil
Just playing in SoundForge, to pitch shift up by 4.096%, you need to increase the pitch by 69.5 cents, and to pitch shift it down by 4.096%, you need to decrease it by -72.4 cents. In my mind they should be plus and minus the same value, but Sound Forge doesnt seem to think so, I'm going by the transposition ratio at the bottom of the window, either up to 1.04096, or down to 0.95904.
Just playing in SoundForge, to pitch shift up by 4.096%, you need to increase the pitch by 69.5 cents, and to pitch shift it down by 4.096%, you need to decrease it by -72.4 cents. In my mind they should be plus and minus the same value, but Sound Forge doesnt seem to think so, I'm going by the transposition ratio at the bottom of the window, either up to 1.04096, or down to 0.95904.
That is easily explained, and probably should be done before other people make the same mistake!
Take this example. Our film source is 100,000 seconds long, we make that faster by 4.096% which leaves us with a PAL version at 95,904 seconds. Now if we slow the 95,904 version down by 4.096% we end up with a copy that is 99,832 seconds long, not 100,000 seconds. The reason is that 4.096% of 95,904 is obviously less than 4.096% of 100,000.
So the problem was you were thinking in terms of the original source where SoundForge is correctly thinking in terms of the current source. Easy mistake and something I hadn't thought of until you mentioned it! So whenever you are adjusting PAL material to 24fps then if my maths is right then you need to slow it down by 4.2709376043%. Been way to long since I've done that sort of maths!
eeeek, please dont tell me you worked that our in your head!
Right, I see where I went wrong now, simple mistake, thanks for clearing that up Gillean. So would I be correct in saying that you would change the pitch plus/minus 72.4 cents, depending which way (NTSC to PAL or PAL to NTSC) you are going. I think thats right now.