Hi there,
Was hoping someone can help. I've got some PAL DVD commentaries ripped to mka files that I would like to convert to NTSC speed so that they match the blu-rays. Is there a simple (and ideally free!) program that would do? Many thanks Alex
NTSC speed meaning 23,976 fps?
eac3to can do that, but I'm pretty sure you'd have to convert the files to .wav first.
You can also load the audio track into Audacity (free cross-platform software), use the "Change Speed" option under the "Effects" menu and use a value of "-4.096%" to slow down the PAL audio to a proper NTSC speed, with the pitch correction being done automatically. Then export to any format (ac3, pcm, etc.) that meets your needs. If you don't want a pitch change, use the same value of "-4.096%" but using the "Change Tempo" option instead, also in the "Effects" menu.
The difference between this method and using eac3to, is that you can see the changes right away and adjust any potential timing/syncing issues all in one go before your "final" render. Hope this helps 
eac3to infile.mka outfile.ac3 -XXX -slowdown -25.000
(This post was last modified: 2015-09-09, 03:31 AM by Valeyard.)
Where "XXX" is your bitrate in kilobytes (eg 224 or 448 whatever is close to the source). Alternatively you can do a container slowdown. Open mkvtoolnix and load the video, add the audio track (at 25fps) and in the track properties for the PAL audio put 25/23.976 in the "stretch by" input box and mux. This will cause software to play back the audio at the NTSC speed (stretched by 104.27...%). May not be compatible with all devices. EDIT TO ADD... Note that the "container method" may or may not change the pitch as determined by software - and probably will not change the pitch (for example you can use VLC to play files back at different rates by pressing [ or ] without changing audio pitch). So if you want it pitch correct you have to re-encode.
(2015-09-06, 01:59 PM)jerryshadoe Wrote: You can also load the audio track into Audacity (free cross-platform software), use the "Change Speed" option under the "Effects" menu and use a value of "-4.096%" to slow down the PAL audio to a proper NTSC speed, with the pitch correction being done automatically. Then export to any format (ac3, pcm, etc.) that meets your needs. If you don't want a pitch change, use the same value of "-4.096%" but using the "Change Tempo" option instead, also in the "Effects" menu. This worked perfectly, many thanks!
Happy to help
I'm guessing the PAL video rate would have to be changed as well?
The OP was asking about syncing PAL DVD commentary tracks to BD video, so I don't think there is a PAL video stream to contend with here.
(2015-10-29, 10:10 AM)jerryshadoe Wrote: The OP was asking about syncing PAL DVD commentary tracks to BD video, so I don't think there is a PAL video stream to contend with here. If the video was PAL, how would you convert it to NTSC, if both audio and video needed to be changed?
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