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  1. Member
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    Yeah. Here's the story. The original mpeg file I had was in perfect sync. I do my encoding, which is done using DGIndex/DGMPGDec, Avisynth, and AutoMKV. I convert the video and the quality is great. But halfway through the video, it looses audio sync. So, is there a way to sync the audio without re-encoding the MKV file I have? If so/not, what do I do to fix this?
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  2. Banned
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    Need more info.

    Are you converting the audio to another format? If yes, give us details about that format. VBR (Variable Bit Rate) audio is notorious for going out of sync.

    Is it an HDTV capture? They can sometimes have changing framerates and this cause various problems during conversions.

    Are you changing the frame rate of the source to something different in your encode?
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    No, not HDTV. Yes, changing audio. Converting audio to Nero AAC with 1.0 quality setting in AutoMKV. And yes, I believe I changed the framerate, although not directly. The original file was interlaces, and so I did an IVTC. Thus, the original 29.97 fps was cut to 23.379 or whatever the 23.something is.
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  4. How did you do the 29.97=>23.976 conversion? I suspect that is where the problem started. What is the duration of the audio & video of the .MPEG (before) and the duration of the audio & video after? (use mediainfo)
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    Did you read? I did and IVTC. Used TFM and TDecimate.

    Duration of mpeg: 27 minutes 55 seconds
    Duration of converted MKV: 27 minutes 55 seconds

    When I used DGMPGDec, when I saved the .d2v, it also created an .ac3 file that stated it used a -19ms delay. But that didn't work obviously. How would I be able to manually detect how long of a delay there was? The audio is in sync for about the first 10 minutes, but after that, it goes out of sync.
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  6. Member
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    Well, I just put the MKV file in Mediainfo, and it doesn't tell me that there's any audio delay at all I'm in the Tree mode, and the Audio stops at Resolution. Don't know why.

    EDIT: I hope you guys are still reading this topic. I just saved the audio as wav, and it has a different length than the aac audio!

    AAC audio length: 27 minutes 54.940 seconds
    WAV audio: 27 minutes 54.667 seconds

    Oh, and I found out the times by using Vdubmod > Stream list and then I added the wav to the list and then I saw the audio lengths.
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  7. Banned
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    I guess the IVTC process was done "incorrectly".
    I mean, you may have gotten the correct framerate and
    the correct framecount, but perhaps the method you used
    has kept the "wrong" frames and discarded the "right" ones ---
    --- which would explain the gradual loss of sync.
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  8. Banned
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    Nightshiver - I find your attitude to be troubling. Nobody pays us to help. I sympathize with the frustration but saying "Did you read?" (by the way, "I did and IVTC" is grammatically incorrect and should be "I did an IVTC") isn't giving me a lot of optimism about you. I hope you are not yet again one of those closed minded people who is resistant to suggestions. Look you said you need help. If you don't like what we say, then go away.

    OK, now assuming you still want help, my suggestion would be to do your conversion process but DO NOT convert the frame rate from 29.97 to 23.976 and see if it stays in sync. If it's in sync, then your process of converting the frame rates is wrong. If it's not in sync with 29.97 fps, then something is wrong with your audio process.

    You still don't give enough details. WHAT is your source? If it's a TV show on DVD, then it's probably wrong to convert the frame rate as the source was most likely never progressive to begin with. Note too that TV shows on DVDs have some oddities that can cause audio problems, such as having introductory studio logos show up. I've seen Divx conversions fail from DVD TV show sources because the video stream had a studio logo at the beginning but the audio stream somehow skipped that and started with the episode, leading to horrible sync issues.
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  9. Did you read what was suggested above?

    Mediainfo gives you the delay of the original AC3 audio when you use it on the .MPG. It will also give you the duration. No need to export as a .WAV or extra steps that may complicate the troubleshooting process.

    It seems like you did the video conversion correctly. Now does the duration of the demuxed AC3 (from dgindex) and the duration of your video match? If it does, you should be able to merge it together with mkvmergegui, entering the delay given from mediainfo from the original MPEG. If this is in sync then you are most certain that the error was caused by the conversion of audio to AAC.

    Also are you using a recent build of dgindex?

    How are you doing the AAC conversion? If you just used automkv, try doing the AC3=>AAC conversion with belight, MeGUI, or another application; Do you get the same duration?
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  10. Member
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    I know I made a grammar error, but didn't feel like changing it, so why bring up something as insignificant as that? Anyway, the original file came from a TiVo recording. It seems that you are keen for the frame rate conversion to be wrong. This is the script for IVTC that I used:

    deint = TDeint(mode=2, mtnmode=3, blim=100)
    TFM(order=-1,mode=5,PP=7,field=-1,slow=2, clip2=deint)
    TDecimate(mode=1)

    Works better than most things. No, I did not only use automkv as I said that I used Avisynth also.
    Demuxed the MKV with MKVextractGUI. I'd really like to be able to TRY and fix this problem without re-encoding.
    Yet another edit. Since I've now demuxed the video/audio, isn't it now possible that I can sync up a fixed audio stream back into the video? The only problem will be to try to keep the same audio size as the demuxed audio. (Which is 73mb) So, I know there's a way to do this, I just don't know how. How can I correctly make a delay that will fix the audio sync problem?
    EDIT Number 134: Re-encoded just for you guys. Nope. This time I let automkv do an Auto De-int, and the audio is still out of sync. As I said before, the original file was not out of sync.

    Nother Edit: Sweet. Ok, at 11 minutes 42 seconds in the video, there's a strange "hiccup", where the video blocks up and from there on out, the audio is out of sync. I hope some of this info is helpful.

    Edit: I suppose it's good to experiment. Well, with Mkvmerge GUI, I added the demuxed .h264 video file and the audio file accordingly. Well, since the audio sync issue occurs at 11:42, I went to the Global tab, Checked "Enable Splitting", clicked on "....after this duration" and entered in the seconds, which would be 702. Well, it created 3 files, because evidently, I didn't know it would continue to split the file every 702 seconds. Anyway, the first file was in sync, which it should have been. But the second file, which should have been out of sync, is now in sync. I played it repeatedly just to make sure I wasn't seeing things. Unfortunately, I'm afraid that if I append them/put them together again, it may still have the sync issue. I'll edit again to tell you what happens after I do that.

    Heh, you guys having fun reading all this? I fixed the problem. When I used the "append" command in mkvmerge, it merged all 3 files and now there it no audio sync problem. Very odd, but it works for me.
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  11. Member
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    Damn. I'd still like you guys help. Now instead of the last half of the movie being out of sync, the first half is.
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