This is my first post and I've done a bit of digging around the forums before I asked this but I wasn't able to find the answer that I was looking for so I figured I'd ask.
I am a big fan of the John Woo HK classics with Chow Yun-Fat. I bought a laserdisc player and am trying to sync the PCM mono tracks from the laserdisc to the Anchor Bay R1 NTSC DVD video that I own. The LD is NTSC and so is the DVD so I figured there would be no issues syncing the video and audio other than an initial delay as the DVD has longer opening credits than the LD.
I ripped the DVD's mono AC3 track as a reference guide and am trying to get the LD audio to sync up with the DVD audio in Audacity. It's also nice that I can play the two tracks at once to see if they are in sync or not and/or zoom into the waveforms to see if they line up.
1. Like I said, there's a longer opening credit on the DVD compared to the LD. No problem, I just place silence at the beginning of the LD audio so the two tracks are in sync at the start of the actual movie. So far, so good.
2. The tracks stay in sync for about 4 minutes and get progressively worse throughout the movie. I tried synching the tracks together using The laserdisc splits the movie onto two sides of the disc so I know I have some work to do there but the first side doesn't end until 45 minutes into the movie so I honestly have no clue as to why the audio gets out of sync so quickly, unless the DVD is stored at 23.976 fps vs 29.976 fps for the LD?
3. The two movies are identical and have the same cuts, audio mix, etc. The LD's ending credits are a bit longer but other than that they are identical.
I'm really lost on this one. Any help would be greatly appreciated!
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1. Near the end of the laserdisc (approximately 47min 15 sec into the movie), the LD audio lags the DVD audio by approximately 302 msec.
2. The length of the LD audio after inserting silence at the beginning to sync with the DVD audio and trimming the silence between laserdisc side changes and stopping where the ending music stops on the DVD is 01:33:51.940 (hours : min: sec), the DVD's running time from start to the end of the music is 01:33:52.033.
If you want the length of the movies where the ending music stops (LD has longer music) the LD is 1:35:30 and the DVD is 1:33:55.
I have attached two segments of audio at the beginning and end of the movie. Do you want those to detect pitch changes?
Thanks for your help so far! It is most appreciated.
Last edited by singhcr; 23rd Feb 2013 at 15:06.
Then it's not as I thought. It's not a PAL/NTSC issue nor even a 29.97/30fps issue as the difference is less than 100 MS at the end. With that small of a difference can you really tell it's out of synch? And you know that after the beginning where you synched the audio, the framecount for both versions is exactly the same? It probably isn't, and there may be a couple of frames that are missing from one version that the other has. That's about all it takes.
My suggestion is to stretch one audio to fit the second (which you know to be in synch). Audacity (as well as other WAV Editors) can do that. No, I wasn't asking for audio samples but for video samples, but it's academic now because it isn't a PAL/NTSC issue it seems.
I did some comparisons throughout the movie and found this:
2 min: PCM lags 45 msec
10 min: PCM lags 276 msec
20 min: PCM lags 164 msec
30 min: PCM lags 110 msec
56 min: 83 msec
60 min: 100 msec
80 min: 241 msec
90 min: 314 msec
93 min: 317 msec
I think the music I used at the end for a comparison point was incorrect because it was hard to find the exact same point by looking at the waveforms. These new estimates are much more accurate. Do you still think there is no FPS difference here? It seems odd that the lag is changing so unpredictably within the same LD side. Or is that just because a few frames here and there are missing?
In general, how do you know if there is an NTSC/PAL issue? How do you resolve it, typically? Also, what would I use as a reference for what segment of the LD audio to stretch to the DVD audio? Do I just insert silence to sync the beginning of the track up, clip the end music to what the DVD audio has and then stretch it to make the LD and DVD segments the same length?
Last edited by singhcr; 24th Feb 2013 at 00:31.
Audacity can do that - stack waveforms and cut small sections and add silence in strategic places to make the waveforms line up better. However, this is one helluva lot of work and you had better love this movie or whatever it is to make it worthwhile to you.
In general, how do you know if there is an NTSC/PAL issue?
How do you resolve it, typically?
Also, what would I use as a reference for what segment of the LD audio to stretch to the DVD audio? Do I just insert silence to sync the beginning of the track up, clip the end music to what the DVD audio has and then stretch it to make the LD and DVD segments the same length?
What I don't understand is why you're tackling the the project in the first place. Is the audio on the DVD so bad that you want the much better laserdisc audio to replace it? And those films are classics. Won't there be Blu-Ray versions of these films with cleaned up video and audio out one of these days? Hard Boiled, Better Tomorrow, and The Killer are already out on Blu-Ray. I'd think it would be just a matter of time for Bullet In The Head, Better Tomorrow 2 and whatever other ones you're interested in. The reviews aren't all that good for the Blu-Rays but the audio should be decent.
The DVD audio is OK (at least for ABT, The Killer's mono audio is full of hiss and pops) and I have enjoyed the movies despite that but the LD audio was so much better and I figured this would be a straightforward process but I guess that isn't the case now.
I didn't realize this would be such a chore. I've already spent many hours working on this and the player and discs weren't cheap either. I did some looking around for Blu-ray editions and it looks like Hard Boiled has a faithful 24-bit 5.1 lossless audio track but The Killer (DD 2.0) and ABT I, II and Bullet in the Head (really crappy 5.1 remixes with "piercing highs and distortion" and having "the main score in the surround channels instead of the fronts" according to one review of the HK BD's) don't fare so well. Maybe, just maybe, I'll have better luck with the LD track of The Killer. If it doesn't sync right away, I'm not going to waste my time with it. It is unfortunate that these classics have been released on Blu-ray with upconverted SD material and having very poor audio tracks for all of Woo's main movies save for Hard Boiled.
Thank you very much for your help on this, I do appreciate it. Now I have some tips and tools I can use if I want to try something like this again.
Last edited by singhcr; 24th Feb 2013 at 05:56.