Changing audio pitch to match a different frame rate

[steptoe]

Right, trying another method for 'converting' NTSC to PAL or PAL to NTSC, I ain't giving up that easily

All I need it by what amount to speed up/slow down the actual audio track, which will be/has been extracted using VirtualDub into a WAV, which I then convert to 48000khz, 16-bit stereo, 187kb/sec using dbPowerAmp, so that I have the exact same audio rates across all my movies before encoding to MPEG2

They are in synch, just end up in whatever rate the source is. If its PAL, its gets encoded to PAL, and if its in NTSC, then its encoded into NTSC, with the audio track added back in, so any problem with the audio track in the source AVI "should" be eliminated using that method as recommended by quite a few users on here

Basically, can somebody supply the figures/formula that I need to convert an audio track that is used in one framerate to another, so that when they are encoded, then it will synch as good as the original it came from

I don't care what audio program to use, whichever does the results I'm looking for ................

I need the figures for the following framerates from/to


29.970 to 25
29.762 to 25

23.977 to 25
23.976 to 25

25 to 29.970
25 to 23.976

And what program to apply this figures in


Much appreciated, maths ain't my strong point, its years since I have actually had a need to think !!

[flaninacupboard]

uh......
the only time you should even consider doing audio length adjustment is going from 23.976(24fps) to 25, or 25 to 24. in either case the difference is 4%. so to go from 24 to 25 you want the sound 4% faster. bsweet will do this for you, it actually has a "23.976 -> 25" option. converting 25 to 30 or 30 to 25 is -not- reccomended. you won;t notice a 4% difference in speed of the picture from 25 -> 24, but 25-> 30 is a fifth faster. it's not watchable.

[steptoe]

maybe so, but if somebody can provide the figures, there is something I want to try out ..............

4% means nothing to me, I want the actual figures, so I could tap them into say Cool Edit Pro pitch shifter, or SoundForge, whatever, but the figures will be better, then I can see for myself

At least its another step closer to me getting a guide started for us poor saps that are insisting on trying to convert a PAL AVI to NTSC DVD or NTSC AVI to PAL DVD

I have quite a bit of info on various methods, but sitting down and sorting out a guide isn't going to be easy, there is quite a lot of conflicting advice from various sources

So thats why I want to try for myself, this other method I'm looking into may do it, it may not

[flaninacupboard]

uh, just enter 4% in timestretch in cooledit. make sure you select to adjust the time and not the pitch, this way music stays the same notes, it's just slightly slower or faster.
as i said, if you want a one click solution, use Bsweet, it does the time calculation for you.

[mats.hogberg]

Here's a small but impressive app specially made for stretching/compressing wav files when changing frame rates. My personal fav, when it comes to this kind of job.

/Mats