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Synchronizing Audio Files?

Discussion in 'Recording' started by Hello World, Jul 6, 2011.

  1. Hello World

    Hello World Active Member

    Has anyone ever run into this problem?...

    You have a full mix and you need to remove one track?
    You have the separate track, but the files need to be perfectly synchronized.

    I have run into this problem so many times.
    So my question is 2-fold:

    1. Does there exist any software that can completely sync the full mix with the separate track already on the market?

    2. Should I bother to create the program that can do this? In other words, would any of you find this useful if it was an automated process?

    Thanks in advance for ANY replies or advice you can give me. I can write the code. I work in the IT industry for a living and also write programs and dabble in specific need-based software like this.

    By the way, the only software that I know of that can do this easily for the end-user is video-based, I forget the name of it right now but basically it takes the crappy onboard mic from high quality video cameras when you have more than one source and time-synchronizes them, if they are not properly time-coded.

    I know exactly how to write this program -- but it's going to take me a lot of time and if there exists a program (or plugin) that already does this I don't want to waste my time or yours :)
  2. audiokid

    audiokid Staff

    Welcome to RO,

    I'm not sure what you mean. What DAW program?
    If I have a track I don't want, I just hit the mute and its done :), or delete it, period. Please tell us more on why we would need your concept. Sorry, I don't get it?
  3. Hello World

    Hello World Active Member


    Imagine this only: You have been provided a single mixed down .wav file for mastering. The vox is way too low to work with. So you are only provided with the vox separate track. So now you have exactly 2 .wav files in your possesion only. But the only problem is that the vox track is out of sync with the full mixdown. Now comes the tedious and time consuming task of synchronizing the 2 files you have until they are perfect down to the sample level. Hasn't this ever happened to you?

    This is just one example I can think of but by far not the only one. Sometimes I get mixing projects and the tracks are all out of sync. I have a reference mixdown from the client that is a rough mix only. Everytime this happens to me, which is almost always, I think to myself I should just write an application that would auto-sync all the tracks to the reference rough mixdown.

    Sorry this is difficult for me to explain, but the idea is to synchronize tracks that are out of sync. Does this clear things up at all? Thanks in advance for your reply.
  4. audiokid

    audiokid Staff

    Ah, very cool. But if you are able to get the Vox track, why not get the entire mix, again? Doesn't overlapping the exact vox track cause some null and/or weird phasing problems?
  5. Hello World

    Hello World Active Member

    Cool -- I'm glad you get was I was trying to say -- Overlapping the exact vox track actually does not cause null and/or weird phasing problems as long as you get it perfectly synched down to the sample believe it or not, in fact that's the whole beauty of it -- you can even remove the track altogether if you want by inverting it (assuming that you can also get the amplitude perfect also.) There's a ton of other uses for this. It's just that I have been doing it manually for years and it's time I write the app that can do it for me. So can I assume that there is not something almost identical already on the market? And do you think this is something that other people would even want, or is it just me?
  6. audiokid

    audiokid Staff

    Your idea sound brilliant. If you can perfect it, it could serve a few purposes. Removing a track that you don't want as well?
  7. dvdhawk

    dvdhawk Well-Known Member

    If I sent you a completed mix and sent you any alternate track(s) a year later both sound files would start at 0:00:00 in the DAW and export the exact same length audio file. If nobody truncates the beginning of either of these files, you can drag the new track into the timeline starting at 0:00:00 and it's done.

    I just contributed a part to a friends recording project via the internet. He sent me an mp3 of the rough mix of his latest song. I imported his entire mp3 file into my different brand DAW and played along with it without cutting and intro or silence at the begging. I tracked my part and emailed him the uncompressed WAV file of my part starting from the beginning. He slid my track into his DAW in a few seconds. Both tracks were the same length and started at 0:00:00 - done.

    If your clients are exporting just the new vocal track minus the time that elapses before the vocals come in.... tell them to export the files from the beginning of the song 0:00:00.

    I might be missing something, but this just seems like a procedural problem to me.

    If this is happening 'almost always', it's time to insist the people sending songs do a better job from a procedural point of view. Or provide a combination of pulses at the beginning of the recording. Much like the test tones we used to have to put on our final mixes back when dinosaurs roamed the earth and tape machines had to be calibrated every time you gave your tape to someone.

    Best of luck to you.
  8. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    I agree that it's a procedural problem as dvdhawk said. That said, invert the polarity on the vocal-only track and slide it around until you cancel out the one in the mixed track. You should be able to get the alignment perfect as long as there is no difference in eq applied to the two tracks. Then flip the polarity back.
  9. Hello World

    Hello World Active Member

    I completely agree with the last two posts. It is a procedural problem for sure. But, it's difficult to change people. By the way, mp3 adds padding silence which does in fact throw off the sync. We've all dealt with sync problems caused by many different reasons. I just want to write an app that synchronizes the tracks automatically and quickly. If anyone wants to alpha test it, feel free to let me know. Thanks everyone!
  10. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    The data reduction algorithm of MP3 will probably make syncing without phase or similar interaction impossible.
  11. dvdhawk

    dvdhawk Well-Known Member

    You are absolutely right about people being hard to change. Billing them by the hour (and telling them what portion of that was avoidable) usually keeps them from wasting your valuable time and their own money doing something they could correct.

    What program are you using that adds silence to the front of your mp3's? (just curious, I've not had that issue.) Good luck with the app though - I'm sure there are others with a need.
  12. hueseph

    hueseph Well-Known Member

    Aren't there already formats within most DAWs that allow you to export a file with it's time stamp in tact? Ogg?
  13. Hello World

    Hello World Active Member

    For anyone who cares...


    Hopefully I can use some of this code
  14. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Okay, wait a second. First you say:

    Then without explanation:

    You drop that "by the way" on us as if you had called it an MP3 from the start, which you didn't. Then you post something (addressed to me) about cancelling a track being a good use of sync but not what you were after when I had said that inverting was a good way of syncing the two files, which is completely different. Then you edit the post to put a link to some software. If you are going to change the facts and your posts every few hours there's no point for us (me, anyway) to waste our time on whatever the question is.

    If someone came to me with the original request (using WAV files) I'd be reticent about taking the project. If they had MP3 files I almost certainly wouldn't take the job because the results would almost certainly be disappointing.
  15. Hello World

    Hello World Active Member

    I'm sorry for the confusion. I'm new to recording.org. I actually joined specifically to ask the question if anyone thought that an automatic sync program would be useful and if there was already one available. Again, sorry for the confusion. It's my fault.
  16. hueseph

    hueseph Well-Known Member

    I'm still confused. You still haven't mentioned what DAW you are using. I'm not saying this problem doesn't exist but I personally haven't experienced it. The only issue similar to this would be working in a program that doesn't have ADC. Like ProTools LE. But that is finally a thing of the past. So, what DAW are you using.
  17. IIRs

    IIRs Well-Known Member

    Broadcast wavs (BWAV)

    If the files are timestamped they can be automatically moved to their original positions on the timeline, assuming your DAW supports it.
  18. hueseph

    hueseph Well-Known Member

    Well, there you go. Thanks for clearing that up. Most DAWs already support this these days. Even ProTools, though very late in the game:rolleyes:. AFAIK Cubase, and Logic both are capable of BWF.

    EDIT: Here's the Wiki just to clarify.

  19. hueseph

    hueseph Well-Known Member

    And just to add to the confusion, I've done quite a few internet collaborations using MP3 files as the bed and sending WAV files over the web. I've never had any issues with sync other than latency induced by plugins.
  20. lambchop

    lambchop Active Member

    This is a very interesting discussion. I just got Sony Vegas for working with some of my band's videos of performances. We recently performed an outdoor concert and the audio from the video was less than perfect. My bass player also recorded the audio with a portable recorder of which I downloaded multiple instances to my DAW program and manipulated the tracks with narrow band eq and some multiband compression, then rendering it to a new wav file and importing it into Sony Vegas. I must've spent about a half hour aligning the new track to the video's audio. Hopefully there is a function built into the Vegas software to perform exactly what Hello World is referring to and I just didn't find it yet. If not, a software program like he's talking about would be a great thing!

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