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Matrix789
15th May 2014, 17:01
Hello everybody, I have a blu-ray of an american tv show and a dvd of the same tv show from Europe. The blu-ray is ntsc with 23,976 fps, while the dvd is pal with 25,000 fps.
I have extracted the episodes from the blu-ray (video + audio) and I've put them into .mkv containers, and the audio track from the dvd.
I would like to mux the audio track from the dvd, which is in a different language, with the tracks taken from the blu-ray.
I usually use audacity to convert audio tracks from 25,000 fps to 23,976 fps with the command "change tempo", setting -4,096 as value of stretch. But this time I can't sync the tracks perfectly, I always have a delay (or an anticipation) somewhere and I don't understand why, considering that the content of the dvd audio track is identical with the blu-ray one.
I have another low quality version of that audio track, with 23,976 fps and in the same language of the dvd; I'm trying to compare and align this version with the dvd one, even changing a little the -4,096 value, but I can't match them perfectly.

This is the dvd version (25,000 fps):
https://www.dropbox.com/s/ptjil85kez0mely/DVD%2018min.ac3

And this is the low quality (23,976 fps):
https://www.dropbox.com/s/pf40kqj8msl5hm8/HDTV%2018min.ac3

I was wondering if somebody could check them and tell me why they don't match and how to solve the problem.
Thank you in advance and please forgive me for my bad english.

tebasuna51
15th May 2014, 20:33
...But this time I can't sync the tracks perfectly, I always have a delay (or an anticipation) somewhere and I don't understand why, considering that the content of the dvd audio track is identical with the blu-ray one.

If there are different delay at the begin than et the end, after change the duration 25 -> 23,976 then the BD video is different than DVD video.

I have another low quality version of that audio track, with 23,976 fps and in the same language of the dvd; I'm trying to compare and align this version with the dvd one, even changing a little the -4,096 value, but I can't match them perfectly.

If this HDTV track is in sync with your BD video and you want this duration for your DVD track the factor to stretch is -4,060 instead the theoretic one -4,096.

Matrix789
15th May 2014, 20:55
If there are different delay at the begin than et the end, after change the duration 25 -> 23,976 then the BD video is different than DVD video.



If this HDTV track is in sync with your BD video and you want this duration for your DVD track the factor to stretch is -4,060 instead the theoretic one -4,096.

The silence at the begin and at the end of the dvd is shorter, in fact I add silence at the begin so the two tracks start at the same moment, and I cut the silence at the end, so I only stretch the dialogs.
I've tried almost all values from -4,000 to 4,1000 but noone gives me a perfect result. -4,060 is quite good but in some parts the two tracks are synced and in some parts there is a little echo/delay

tebasuna51
16th May 2014, 13:13
Sometimes the HDTV tracks can be different because non exact cuts for commercials, you must compare the italian DVD track with a BD track even in other languaje.

Matrix789
16th May 2014, 14:06
Sometimes the HDTV tracks can be different because non exact cuts for commercials, you must compare the italian DVD track with a BD track even in other languaje.

I did it but it's not easy comparing two different languages, especially for me that I'm not expert. If you want I can upload a sample of the original dts-hd ma english track.
Anyway every episode seems to be a little different from the others and it would take hours to fix all of them. I'm looking for a "standard rule" valid for each one.

EDIT: I compared the hdtv audio with the blu-ray one and they match perfectly, I don't understand how is it possible. Never found this sync between dvd and blu-ray

mariner
17th May 2014, 09:18
......
considering that the content of the dvd audio track is identical with the blu-ray one.
....

Not if the BDs and DVDs are produced from different master tapes. Typically a few ms cuts here, few ms insertions there, usually at scene change. You'll need to compare the two audio tracks.

It took me a few weeks to add English audio to the first six Asterisk BDs.

Matrix789
17th May 2014, 09:25
Not if the BDs and DVDs are produced from different master tapes. Typically a few ms cuts here, few ms insertions there, usually at scene change. You'll need to compare the two audio tracks.

It took me a few weeks to add English audio to the first six Asterisk BDs.

I understand..now I'm trying the opposite method, converting at 25 fps the bd and hdtv tracks..maybe it would help me to better understand the differences

Matrix789
18th May 2014, 07:49
I discovered a program called Audition by Adobe. It allows me to match perfectly two similar tracks:

-I import the dvd audio track and the hdtv one
-I use the automatic align option to match the dvd track to the hdtv one
-I use mkvmerge to set the delay found when I demuxed the audio track from the dvd

It seems working perfectly, but I still have some problems:

-I can't export the track in the .ac3 format and with the same settings of the input track
-I don't know yet how to generate silence at the end of the track like I do with Audacity
-I can't do the alignment with a 5.1 track (in english), because I can compare just one channel and this way I lose some parts, and in any case I'm not sure that I would have the same result comparing two tracks of two different languages
-I can't import dts-hd ma tracks

tebasuna51
18th May 2014, 10:37
-I can't export the track in the .ac3 format and with the same settings of the input track

Export in .wav or .w64 uncompressed format an after use a AC3 encoder.
There are a free one: Aften (used also with eac3to).

-I can't import dts-hd ma tracks

Use eac3to with ArcSoft decoder to decode the dts-hd to wav or w64 (if > 4GB).

Matrix789
18th May 2014, 10:41
Export in .wav or .w64 uncompressed format an after use a AC3 encoder.
There are a free one: Aften (used also with eac3to).



Use eac3to with ArcSoft decoder to decode the dts-hd to wav or w64 (if > 4GB).

Thank you!
I was wondering if converting a 5.1 track to a 2.0 track could be useful for me because Audition would be better able to compare it with the dvd track. But in case I don't know how to do it with audacity