PAL / NTSC Pitch Correction

[Tormentor667 16]

I am currently watching Star Trek TOS Remasters and the pitch of all voices is a little too low. I guess the reason herefore is the difference between PAL and NTSC (FPS, PAL Speedup).

Currently there is no way to fix this in Emby so some kind of a new feature would be cool that fixes the pitch or with which you can somehow fix the pitch yourself.

Kind regards,

Dan

[ebr 16169]

Hi.  I've never heard of video frame rate affecting audio.  Are you sure this wasn't just a bad encode of some sort?

[visproduction 315]

British TV makes video playback 25fps for PAL TV playback.  Sometimes, they take original US TV and film media shot at 24fps and just speed it up about 4%.  This results in higher voices and incorrect pitches for any music.  Your average viewer usually doesn't notice.  This is a much cheaper way to work in the UK for TV broadcast for older media.  It still shows up today on BBC and other broadcasters.  I notice when the note A is not 440 Hz., from my sound engineering days.  To me, it's like fingernails on a chalkboard.

Fixing this is complex and I am not really sure what video editor can handle it.  You probably need a top timeline type editor.  Maybe ffmpeg can do something.  Just converting from 25 fps back to 24 fps and reencoding, often puts the audio out of sync.  And you lose a generation in quality.  I've tried pulling out the audio and using Audacity, stretching it exactly to the fraction of a second to be correct for 24 fps and then adding the audio back to a converted 25 fps to 24 fps video.  I think I got it to work, once.  Audio and video are no longer synced with original timecode in this newly edited version, so it's tricky.

Personally, my solution is whenever I see this 25 fps on original 24 fps media problem is to discard the media entirely and not bother anymore.
see: https://duckduckgo.com/?q=25fps+PAL+encode+24fps+original&ia=web

and: https://superuser.com/questions/320127/converting-movie-from-25fps-pal-back-to-24fps-without-recompressing

One person in a forum listed in the above search, suggested reclock which is software from 2018, no longer in development as a solution:
 https://www.videohelp.com/software/ReClock-Directshow-Filter
Reclock looks promissing.
 

===

Related:
Audio adjustment is not an issue when you take 29.97 fps from interlaced standard def or DVD and convert it, by removing the 3:2 pulldown stuttering and blending the frames back to 23.976 fps. (29.97/5*4). ffmpeg, AVIDemux and many video editors can do that fairly well.  In this case, the audio is not pitched higher. So that's good.
See: https://duckduckgo.com/?q=29.97+frames+per+second+3%3A2+pulldown&ia=web

Edited February 22, 2025 by visproduction

[visproduction 315]

Aha, I found another forum post detailing this fix to change from 25fps and slow down to 24fps so people sound correct and music is at the right pitch.
https://forum.fanres.com/thread-2278.html

I am sure that it's a surprise how crazy this fix is.  It would have seemed to be only a quick single button and easy code to make it work... but no... Ha!

From: SpaceBlackKnight    2018-09-07

Quote

Download the latest version of Avidemux (freeware) http://avidemux.sourceforge.net/download.html

Load up your video, then in the video output column on the left. In order to access filters for what we're going to do, it requires a re-render. Click "Copy" and scroll down to the video codec you want to render in and hit "Configure" to set it's perimeters/bitrate to whatever you like.

Next, go to "Filters" underneath the configure tab and the video filter manager window pops up and should put you at the "Transform" selection of filters. Scroll down to the "Change FPS" filter, top source FPS should be set at "Custom" and the lower would denote the actual frame rate of the source. Since our source is "25fps", leave the top two as is and tick "Destination FPS" and select "23.98". Note: if your 25fps source has some odd interlace or top field/bottom issues, I would try the "Deinterlace" filters after you have the Change FPS filter on and find one that works best (if you do it before, you're gonna have field blended shit). Otherwise, I would deinterlace your 25/50i video in a different program that you're familiar with first. Now, if you want to speed up a 24fps source to 25fps, put 25 in the Destination FPS box and don't do anything else unless you need to have audio in sync which will require a lossy rendering in the next step.

Then press OK and it should show up in the "Active Filters" window and close the filter manager. Next, we're gonna have to render audio too if you do choose to keep the original track in sync. Hit "Copy" and choose the audio codec of your choice and whatever rate you like under "Configure". Next, go to "Filters" and in the audio filters window "Frame Rate" change is set to none. Click the drop down and select "PAL to Film" (or "Film to PAL" if converting 24fps to 25). Now, your files audio sample rate should be ether 48000hz or 44100 if the audio was from a CD or LD. If it's the latter, the you'd have to re-sample it in the tick box to 48000hz or the synced audio will have this weird garbled ghost effect. Note: you can hit the "Shift" check box to shift your track several ms to however you want and can set gain to your choosing. I would not recommend using the mixer tick box, as that's for folding down "untouched" multi channel audio and may cause problems with your sped down or up.

Now in the output format, choose the container you want to render in. I highly recommend "MKV" or "AVI", as all the others may not handle the audio correctly depending on the audio codec used. Click the save floppy icon to select your destination and render away. When your file finishes, you should notice a run time difference in your video compared to the original, in addition to a slight motion change (should be no blended fields) and a pitch change in audio.

I understand this method may not be ideal for those who use Avisynth and such, but this is a easier way to speed up or down footage without any blending/frame judder for those who aren't up to the steep learning curve of AS.

 

[crusher11 1101]

On 2/22/2025 at 7:01 PM, Tormentor667 said:

I am currently watching Star Trek TOS Remasters and the pitch of all voices is a little too low. I guess the reason herefore is the difference between PAL and NTSC (FPS, PAL Speedup).

 

PAL speedup would pitch voices higher, not lower.

[Tormentor667 16]

Well my problem is actually only the audio to be honest. I watch the german remasters of Star Trekt TOS and it sounds as the pitch is just a little off too low. Is there no easy way to fix this?

[visproduction 315]

Tor,

The info above would seem to have already given you an answer.  You should understand that changing the pitch for audio by lengthening or shortening the number of seconds for the audio file will also change the sync of the audio to the video.  To fix a wrong pitch, you normally would need to change both video and audio together.  Technically there are software programs that can change the pitch of audio and keep the same duration.  It's called pitch adjustment.  This is a recording tweak for music and vocals and was not used on media editing.  That is not the source of this issue.  Pitch issues with video are a result of shifting original 24 fps to 25 fps or possibly shifting 29.97 interlaced.

You cannot just change the audio and leave the video alone.  They will no longer be in sync.  The answer of how to do it correctly is already mentioned above.

[crusher11 1101]

13 hours ago, Tormentor667 said:

Well my problem is actually only the audio to be honest. I watch the german remasters of Star Trekt TOS and it sounds as the pitch is just a little off too low. Is there no easy way to fix this?

Again: if it was NTSC-to-PAL conversion, the pitch would be too high. So no, there's no easy way to fix this, because either it's just in your head or there's something wrong with your source and there's no way of knowing how the issue was caused or what needs to be done to remedy it.

[rexerm 36]

On 3/6/2025 at 12:11 PM, Tormentor667 said:

Well my problem is actually only the audio to be honest. I watch the german remasters of Star Trekt TOS and it sounds as the pitch is just a little off too low. Is there no easy way to fix this?

I just had to do with for another show with some seasons I could only find in PAL. I used ffmpeg's rubberband function to change just the pitch in the audio of the MKVs. Hit up your favorite AI bot and it will write a batch file to automate this for a folder full of files.

[visproduction 315]

On 3/9/2025 at 2:18 PM, rexerm said:

I just had to do with for another show with some seasons I could only find in PAL. I used ffmpeg's rubberband function to change just the pitch in the audio of the MKVs. Hit up your favorite AI bot and it will write a batch file to automate this for a folder full of files.

That is interesting.  If someone finds a script for this, please post it here.  It would be nice to not reencode the video, but just change the frames per second.  If ffmpeg script doesn't work,  online posts are claiming that the other software can do it.  https://www.videohelp.com/software/ReClock-Directshow-Filter