Syncronize two audio track in different languages

[TrueScreen]

I want to sync two audio tracks from a TV Series. I basically want to take the existing 1080p Blu-ray rips with English audio that i already have and add English+Italian+Forced Italian subtitles and Italian audio from a DVD Rip.

However, when trying to OCR the vobsub subtitles to have them in SRT format, I've discovered that the Blu-ray episodes have a "trailer" of the episode before the opening, while the DVD episodes do not. The trailer length changes slightly from episode to episode so it's not possible to sync it manually once and copy-paste the delay to every audio track.

I've tried to import a Blu-ray rip with the corresponding DVD rip into a video editor to try and sync the two tracks together and used the first scene cut in the opening to align the clips, but after that point, the video went out of sync and the DVD audio followed. Probably because the Blu-ray rip are 23.976 FPS while the DVD ones are 25. Attached is a 20 sec video with a second of the episode trailer, the Blu-ray opening and the DVD opening layered on top.

I should also emphasize that the Italian audio is not "remove vocals from original and re-dub", but "recreate the general atmosphere and dub", after all the dub from the mid '80s. But, since the DVD has an English track I suppose we can figure out the delays and everything else from that track and apply them to the Italian one since they are synced between them (yes, the English DVD track is a lower quality than the English BD one)

Any idea on how i could accomplish such a task. Also, since a have 22 episodes per season (and 4 seasons), I'd love a way to do everything somewhat automatically

[TubeBar]

I want to sync two audio tracks from a TV Series. I basically want to take the existing 1080p Blu-ray rips with English audio that i already have and add English+Italian+Forced Italian subtitles and Italian audio from a DVD Rip.

However, when trying to OCR the vobsub subtitles to have them in SRT format, I've discovered that the Blu-ray episodes have a "trailer" of the episode before the opening, while the DVD episodes do not. The trailer length changes slightly from episode to episode so it's not possible to sync it manually once and copy-paste the delay to every audio track.

I've tried to import a Blu-ray rip with the corresponding DVD rip into a video editor to try and sync the two tracks together and used the first scene cut in the opening to align the clips, but after that point, the video went out of sync and the DVD audio followed. Probably because the Blu-ray rip are 23.976 FPS while the DVD ones are 25. Attached is a 20 sec video with a second of the episode trailer, the Blu-ray opening and the DVD opening layered on top.

I should also emphasize that the Italian audio is not "remove vocals from original and re-dub", but "recreate the general atmosphere and dub", after all the dub from the mid '80s. But, since the DVD has an English track I suppose we can figure out the delays and everything else from that track and apply them to the Italian one since they are synced between them (yes, the English DVD track is a lower quality than the English BD one)

Any idea on how i could accomplish such a task. Also, since a have 22 episodes per season (and 4 seasons), I'd love a way to do everything somewhat automatically

Not easily. Decide which frame rate you want, I assume 23.976 since it's the Blu-ray.

1. Any SRT's you create from a 25fps source need to change them to 23.976. https://www.videohelp.com/software/Subtitle-Edit will do it.

2. Any 25fps audio also needs to be slowed down by about 4% and it sounds like you need to do some additional editing by trimming. https://www.videohelp.com/software/BeSweet will change it from 25 to 23.976

3. You need to trim the audio edit off the trailers. That can be done on video first or after.

I've done this but it was a pain and time consuming.

[Subtitles]

Deleted reply

[ProWo]

First of all, you need to bring the Italian DVD audio track from 25fps to 23.976 fps.
As you probably heard, both audio tracks have not only different length, but also different pitch.

You can adjust this with clever FFmpeg GUI.
Load your DVD movie, click main, click encode audiostream, click go to the encoder, choose the codec of your choice (you can also leave the source codec) and then choose the changes as shown in the picture. Click encode.


[Attachment 72468 - Click to enlarge]

Your new audio track is ready.

To adjust it exactly you need a second program, Mpeg Video Wizard DVD 5.0.
Move your Bluray Movie to the top line, the converted DVD Audio to the third.
Right click both tracks, select Audio, Audio Peaks Display.
Set the bluray audio track to silent.
Move the lower track until the peaks exactly match the upper ones.
Choose peaks that are not related to the language, e.g. doors closing, bang, explosion.
Play the video. If everything fits, right-click the first line in the gray link area, select all and delete the Bluray stream from the program.
Then press the red button at the bottom right and save the adjusted audio track.


[Attachment 72469 - Click to enlarge]

You can then add it to the Bluray movie with clever FFmpeg GUI.

[TrueScreen]

I assume 23.976 since it's the Blu-ray.

Yes, i want to conform everything to 23.976 FPS

1. Any SRT's you create from a 25fps source need to change them to 23.976. https://www.videohelp.com/software/Subtitle-Edit will do it.

Never though of that, but thank you!

2. Any 25fps audio also needs to be slowed down by about 4% and it sounds like you need to do some additional editing by trimming. https://www.videohelp.com/software/BeSweet will change it from 25 to 23.976

Thank you for pointing me in the right direction!
I've ended up using FFmpeg with the rubberband filter:

rubberband=tempo=0.959:pitch=0.973

For the tempo value I've divided the destination frame rate (23.976) with the source one (25). Source: https://superuser.com/questions/1502456/ffmpeg-changing-frame-rate-without-re-encoding...504299#1504299

For the pitch, just some trial and error

3. You need to trim the audio edit off the trailers. That can be done on video first or after.

Is there a way to use Matroska/mkvmerge's delay feature? How will it play with demuxers/players?
I've read that a cross correlation algorithm can be used to sync the audio together. Do you have any experience with it or something similar?

I should also note that, even after a perfect synchronization, there will be a need to edit the DVD audio a little bit because the time between the end on the opening and the begging on the episode is shorter than the Blu-ray one. Obliviously importing the two into a video editor and manually editing will do the job, but is there a way to do this editing automatically.

[TrueScreen]

I repeat my questions: Is there a way to use Matroska/mkvmerge's delay feature? Or maybe a way to prepend the audio with some silence?

Is there a way automate the editing of the DVD audio

[fsherty]

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