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View Full Version : Change (fix) pitch of AC3 or DTS


nada2k
23rd August 2011, 10:23
Hallo

I am living in a german speaking country and as much as I can say the problem I am encountering only appears on the dubs of movies, not the english soundtrack.

For some DVD-Releases in PAL countries pitch-corrected soundtracks were created, meaning the movie was running too fast due to the PAL-Speedup, but had the right pitch.

Unfortunately on some Blu-Ray releases those pitch-corrected soundtracks were taken and slowed down to 23.976 FPS. So on the Blu-Rays the sound is now too deep.

I contacted FOX Germany in regards to that problem on the Robocop Blu-Ray, but they didn't even hear it. Or they didn't want to hear it. :-/

Is there a way to fix it? I have already tried some stuff, ie extracting an AC3 to 6 Mono Wav files and fixing the channels one by one in Adobe Audition, but the result is not satisfying. Voices are moving unnaturally in the Soundfield for example.

As this post is getting pretty long I won't list all the stuff I tried for the moment, but I can, if that helps.

Maybe I am doing something wrong? Did anyone accomplish this task?

Or do I have to do the correction directly on the AC3 or DTS file? I had a look at eac3to, but could not find an option to do this.

Greetings

tebasuna51
23rd August 2011, 15:22
You need decode, change the pitch and after encode.

You can try AviSynth TimeStretch Pitch mode, maybe with BeHappy

nada2k
23rd August 2011, 15:39
Hello

Thx, but I googled TimeStretch and on the info-site is says "Currently the SoundTouch library only supports 1 and 2 channels. When used with more than 2 channels, each channel is processed individually in 1 channel mode. This will destroy the phase relationship between the channels.". Unfortunately most of the time the soundtracks will be 5.1. But maybe this "phase relationship" is also the problem I am encountering with Audition and 6 Mono Wavs?

I have already done an encode to DTS, which had the sound issues. I have now also done an encode to AC3 with my 6 Mono Wavs and a Mux-File in BesweetGUI Wizard , but will have to wait until I get home to hear the result.

I will probably also try a different movie and see what happens. Or in the end I could probably convert the Sound to 2.0, then it should be possible to do the pitch shift in Audition and then encode to DTS or AC3. But it would be a bit of a shame to lose the 5.1 sound.

Midzuki
23rd August 2011, 16:34
For some DVD-Releases in PAL countries pitch-corrected soundtracks were created, meaning the movie was running too fast due to the PAL-Speedup, but had the right pitch.

Unfortunately on some Blu-Ray releases those pitch-corrected soundtracks were taken and slowed down to 23.976 FPS. So on the Blu-Rays the sound is now too deep.

If I were you, I would try another approach:

1) apply Avisynth's "AssumeSampleRate(50050)" plus "ResampleAudio(48000)", then re-encode to AC3 (or DTS, go figure);

2) remux with the BD video @ 25 fps ;

Hopefully in this way the final result "will not suck too much" :o

nada2k
23rd August 2011, 21:46
Thank you too for your input, Midzuki! I also did some more try and error and might have found a way. I did the pitch shift of the mono wavs in Audacity 1.3.13-beta and created the AC3 file with EncWavToAC3 and at least on a quick listen it sounds ok.

ZappoB
10th May 2012, 20:57
How much did you change the pitch? I have the same problem here with Spaceballs, it sounds awful!

Are there till now some more user-friendly tools?

nada2k
11th May 2012, 16:21
For DTS files:

I used eac3to (http://www.videohelp.com/tools/eac3to) to get the 6 mono wavs:

eac3to D:\German.dts German.wavs

Then in Audacity I did the following with every of the mono wav files:

Effect > Change Pitch...
4.271
Export... > Other uncompressed files > WAV (Microsoft) > Signed 24 bit PCM

I then encoded these files to a DTS file with SurCode DVD–DTS Encoder (http://www.minnetonkaaudio.com/index.php?option=com_content&view=article&id=54&Itemid=87) (commercial software, instead of buying more faulty Blu-ray discs I bought this) and to a FLAC (Level 8) file with AudioMuxer (http://www.surroundbyus.com/sbu/viewtopic.php?f=7&t=135) (freeware). It's Tools > "Merge Mono-Wav/Flac to Wav or Flac" in AudioMuxer. The FLAC file is just to have an audio file that isn't compressed lossy two times.

If you use EncWavToAC3 (http://www.videohelp.com/tools/EncWAVtoAC3) to create an AC3 file I think you have to use this option:

Start-of-stream padding: No padding

Else you will get a ~ +5 ms shift (1/48000*256). You would probably not notice this, but anyway.

Btw, I'm not sure if you will get any phasing issues because of the DTS > AC3 format change.