I need to mux an audio and video track of different lengths...

[Lathe]

I extracted the AC3 5.1 Audio from my DVD of 'HACKERS 2' which runs 1:35. However I would LIKE to mux it with a superior HD video print that I have that runs 1:31. The audio from my DVD is far superiour. The video track is at 24 FPS. Since the AC3 track came from my DVD I'm assuming that it is quite different since the two running times are about 4 minutes off.

I tried using Audacity, but it doesn't accept multichannel AC3 files (I THINK that it has a setting to change the length but not the pitch) What would be easier, to alter the video file somehow and re-encode it to make it longer to match the audio, or is there some easier way to alter the 6 channel AC3 track to run shorter?

This one has been puzzling me most of the day so far

Thanks kindly for any help or suggestions!

___________________L@the

[jman98]

I don't think I've ever seen a film with as many names as this one has. It's known as both Track Down and Takedown with Hackers 2 being used in a very small number of places.

There doesn't seem to be a Blu Ray release of this anywhere, so your HD copy is likely from TV. The HD version could be edited and if so you will not ever be able to align the soundtrack and audio once you hit the spot where the film is edited. Multiple sources confirm 96 minutes (1:36) as the official running time, but that's close enough to your DVD time that I suspect the DVD is not edited.

If you place no value at all on your spare time, you could spend days if not weeks or months doing a painstaking comparison of exactly what is missing in the HD version and attempt to edit the audio file to match, but I don't recommend this. The odds of you making the exact edits needed are poor, but then again I don't know you and we have a lot of people who place no value on their spare time and would try to do this anyway. Maybe you should ask yourself if it's REALLY and truly worth all the incredible effort for a film you may not ever watch again in your life or may only watch 1 more time.

[Lathe]

I don't think I've ever seen a film with as many names as this one has. It's known as both Track Down and Takedown with Hackers 2 being used in a very small number of places.

There doesn't seem to be a Blu Ray release of this anywhere, so your HD copy is likely from TV. The HD version could be edited and if so you will not ever be able to align the soundtrack and audio once you hit the spot where the film is edited. Multiple sources confirm 96 minutes (1:36) as the official running time, but that's close enough to your DVD time that I suspect the DVD is not edited.

If you place no value at all on your spare time, you could spend days if not weeks or months doing a painstaking comparison of exactly what is missing in the HD version and attempt to edit the audio file to match, but I don't recommend this. The odds of you making the exact edits needed are poor, but then again I don't know you and we have a lot of people who place no value on their spare time and would try to do this anyway. Maybe you should ask yourself if it's REALLY and truly worth all the incredible effort for a film you may not ever watch again in your life or may only watch 1 more time.

LOL!!!

Heh, I loved your post man; so practical and true

Well, you DID bring up one thing that I hadn't thought of which is very important. I hadn't considered that the HD print (yes, from the Telly) would have been edited. DAMN good point mate! I guess I just naively thought that they were different frame rates or PAL vs. NTSC or something benign like that. How bloody funny!

Well, I guess you are quite right. I am NOT by any means a perfectionist like some people who are into this kind of thing, but the Audio / Videophile in me really nags at me to have the nice 5.1 448 sound with my nice HD video print. (sigh...) Oh well... I guess that if I REALLY looked SUPER DUPER hard, I SUPPOSE that I could MAYBE find another movie that might merit my time a little more...

Thanks so much!

[johns0]

Just like to point out that audacity does accept multichannel ac3 files and it also lets you change the pitch,speed as well as tempo,you just need to install the Ffmpeg For Audacity to get the ac3 export as well as change the settings to multichannel output.

Then you can try and the time length to match and see if it syncs,i doubt it will since the scene changes usually have different length of time from the original as well as other edits.

[Lathe]

Just like to point out that audacity does accept multichannel ac3 files and it also lets you change the pitch,speed as well as tempo,you just need to install the Ffmpeg For Audacity to get the ac3 export as well as change the settings to multichannel output.

Then you can try and the time length to match and see if it syncs,i doubt it will since the scene changes usually have different length of time from the original as well as other edits.

Hey thanks Mr. Hamster, uh, I mean John

Actually, that is excellent to know because I'm SURE that I will have MANY more useful things to use that for in the future.

Cheers!

______________L@the

[manono]

I guess I just naively thought that they were different frame rates or PAL vs. NTSC or something benign like that.

They could very well be differing framerates. Did you check the framerate of the Hi-Def version?

And why would you want to speed up the AC3 audio anyway?

[Lathe]

I guess I just naively thought that they were different frame rates or PAL vs. NTSC or something benign like that.

They could very well be differing framerates. Did you check the framerate of the Hi-Def version?

And why would you want to speed up the AC3 audio anyway?

Yeah, that was the first thing I checked; although I'm a little fuzzy on PRECISELY how that affects the timing. The HD video is at 24 FPS and the audio came from my US DVD, so I'm assuming that would be about 29.xxx, right? But, as far as I know, the only way to adjust the video is to re-encode it, which would be just fine, but I don't know how or what to do or IF that would definitively fix it anyway. So, I thought since the running time of the audio is about 1:35 and the video is 1:31, the simplest way would be to match the timings.

Actually, for the hell of it I did what Hamster said above and I used Audacity (with the ffmpeg download) and I adjusted the 'tempo' of the sound track to where I TRIED to match it to the video track (this changes the overall speed without changing the pitch) Well... as the other quite practical fellow above said, you can imagine how that worked... So, I synced up the audio / video after adding the 'new & improved' 1:31 soundtrack so that they at least STARTED in sync. Heh, after about a minute the audio was starting to be early. I DO think the guy above is right that it likely is a lost cause; but, it SURE would be nice to have the MUCH better 5.1 448 AC3 soundtrack than the Stereo 256 that is on the HD print...

Just for 'fun' I wrote down the audio timings of the first spoken word where I could sync it to where the end credits start. I did this with the original HD print audio, the DVD audio, and the 'new & improved' audio. I muxed all 3 together with the video so I could switch back and forth between the 3. So, I know the approximate length from the first spoken sync point to almost the last (the credits run about 4 minutes after the sync point that I could mark) There was about a 48 second disparity between the 'new' track and the HD track. It being about 48 seconds early. I SUPPOSE I could redo the audio (talk about TRIAL & ERROR) and try to adjust the overall timing by adding 48 seconds.

Heh, the data sure is kinda fascinating; now, if I just KNEW what the hell to do with it! It's like if I can get it really close so that it stays in sync for a decent amount of time and then SOMEHOW, I don't know how, maybe make small corrections at scene changes to bring it back into sync, it SOUNDS like that could almost work. I do that with subtitle files, but that is a WAAAAAAY different animal...

It's like it is SO temptingly close, and yet so bloody far. For what it worth, it doesn't LOOK like it was edited, surely not for content because the HD print has the naked dancing girls in the bar at the beginning. Of course, what do I know...?

Oh well...

Thanks though!

_______________________L@the

[manono]

The HD video is at 24 FPS and the audio came from my US DVD, so I'm assuming that would be about 29.xxx, right?

First, although the output framerate has to be 29.97fps, the 'base' framerate for a movie on NTSC DVD is 23.976fps with repeated fields to bring it up to 29.97fps. If the HD version is really 24fps, the difference would be under six seconds due to the differing framerates alone. Therefore the longer version has additional content (scenes, logos) and you can't simply stretch the audio to fit. My advice is either to forget about doing this, or be prepared to spend an ungodly amount of time working out where the extra material is and cutting, stretching, and otherwise manipulating the audio to fit.

I've done this a number of times for short music videos (matching soundtrack audio with a video of a song from a movie) and it's taken 2-3 hours per song. And I already know how to do it. I don't think I'd want to attempt similar for an entire movie.

[Lathe]

The HD video is at 24 FPS and the audio came from my US DVD, so I'm assuming that would be about 29.xxx, right?

First, although the output framerate has to be 29.97fps, the 'base' framerate for a movie on NTSC DVD is 23.976fps with repeated fields to bring it up to 29.97fps. If the HD version is really 24fps, the difference would be under six seconds due to the differing framerates alone. Therefore the longer version has additional content (scenes, logos) and you can't simply stretch the audio to fit. My advice is either to forget about doing this, or be prepared to spend an ungodly amount of time working out where the extra material is and cutting, stretching, and otherwise manipulating the audio to fit.

I've done this a number of times for short music videos (matching soundtrack audio with a video of a song from a movie) and it's taken 2-3 hours per song. And I already know how to do it. I don't think I'd want to attempt similar for an entire movie.

My friend, you are of course quite right IF that were the case. However, although there MAY very well be different content, when I sync the DVD audio with the HD print, IMMEDIATELY within one minute the sync is WAAAAAAY off and late. Therefore, the two are definitely NOT that close in rate. Perhaps I have not understood or explained it properly. But, that alone shows me that if the rate is that far off after one minute from syncing and the content is not any different (I WILL hafta check the DVD to make sure that nothing is different in that minute to be sure), then it absolutely HAS to be at a far slower rate.

I guess in my little Fantasy world, I was HOPING that just MAYBE the content is the same and if I can find the right relationship, I can match them. Here's the deal, if I can get the rate at least close, then I will easily be able to tell if there is any content difference. When comparing the HD and DVD audio tracks, it SEEMED to me that the time lag appeared to be uniform (after about 10 minutes from beginning sync the audio was behind about 8-10 seconds - after 30 minutes the audio seemed to be behind by 30 seconds, etc.) But, if I COULD at least get close, then I could tell easily by sliding the progress bar along the film to see if there are any abrupt changes (at which point I think to keep my sanity I likely SHOULD throw it in about then )

If I can determine that overall, or at least say within the first several minutes that there are no edits or differences, then I can compare the entire film quickly to see if that is consistant.

BUT... with that said, you STILL are right in that there is a HUGE probability that I am not gonna be able to fix this easily....

Thank you!

_______________________L@the

[johns0]

Hey thanks Mr. Hamster, uh, I mean John

Not sure where you saw a hamster,never watched the angel episode where he got turned into a puppet?

[manono]

My friend, you are of course quite right IF that were the case. However, although there MAY very well be different content, when I sync the DVD audio with the HD print, IMMEDIATELY within one minute the sync is WAAAAAAY off and late.

OK, then possibly it's a bad NTSC2PAL conversion. Would you be able to upload some short samples, 10 seconds of the same scene, one with steady movement? The difference between 95 minutes and 91 minutes is roughly the same as between a film source and a PAL video with everything speeded up to 25fps. That's why I thought at first it might have been an NTSC/PAL framerate difference and was hoping you'd tell me the HD version was 25fps.

[Lathe]

Hey thanks Mr. Hamster, uh, I mean John

Not sure where you saw a hamster,never watched the angel episode where he got turned into a puppet?

No, sounds like a good one though

[Lathe]

My friend, you are of course quite right IF that were the case. However, although there MAY very well be different content, when I sync the DVD audio with the HD print, IMMEDIATELY within one minute the sync is WAAAAAAY off and late.

OK, then possibly it's a bad NTSC2PAL conversion. Would you be able to upload some short samples, 10 seconds of the same scene, one with steady movement? The difference between 95 minutes and 91 minutes is roughly the same as between a film source and a PAL video with everything speeded up to 25fps. That's why I thought at first it might have been an NTSC/PAL framerate difference and was hoping you'd tell me the HD version was 25fps.

I know, I know... That is EXACTLY what it seems like, but when I click on the file MediaInfo shows it to be 24.00 FPS, unless of course it is mistaken. I've had occasional bad reads on it before (perhaps the 'tags' within the encode are wrong...? Just a guess; I really DON'T know what I'm talking about...)

Listen, just for experimental purposes (No drugs involved... ) Let's just assume that is the situation and that the HD print is in PAL and of course my US DVD would be in NTSC. NOW... what do I do if I want to add the NTSC audio to the PAL video? If I can just TRY whatever one would do in that situation, I have a feeling that might be it...

Thanks!

[manono]

Me, I'd use the NTSC video and slow the audio from a PAL source. But we'd need samples to understand better what you're working with. Anyway, audio can be speeded up or slowed down easily. It's a movie, though, so forget about the 29.97fps stuff. Your important framerates are 23.976fps, 24fps and 25fps.

[Lathe]

Me, I'd use the NTSC video and slow the audio from a PAL source. But we'd need samples to understand better what you're working with. Anyway, audio can be speeded up or slowed down easily. It's a movie, though, so forget about the 29.97fps stuff. Your important framerates are 23.976fps, 24fps and 25fps.

Yeah, you are right; however, I want to keep the superiour HD video print and add the NTSC audio from my own DVD. I guess there is no magic formula; if I wanna spin the roulette wheel, all I can do is keep guessing at and adjusting the length of the audio using Audacity until I hit close enough to see if it consistent throughout the film.

Thanks again mate!