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Sender Films
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Audio Drifts out of sync.  Why?

Nov 8, 2012 8:26 AM

Tags: #error #audio #blu-ray #encore #encode #sync #cs6 #bluray

Hello,

 

I am completely new to Adobe Encore.  I'm using it to author the first-ever Blu-Ray release by our company.

 

The problem I am encountering is this:

 

The audio and video files that I have are separate.  They were both encoded to the proper specs and came from the same project file, where they were in sync.  The same company that encoded the video for Blu-Ray did it for DVD using the same in and out points, and when I was making the DVD in DVD Studio Pro, the sync worked perfectly.

 

 

Specs:  Video is .m4v at 23.98 progressive 1920x1080 16:9
            Audio is .ac3 (I tried using the LCM .aif that I used to make the ac3, but it didn't work either).

 

I am currently burning a disk image of the Blu-Ray to see if it is just the preview function that is to blame.  However, if the issue doesn't go away, what should I do?  I am 100% certain that the audio and video were handled correctly, so the problem is almost certainly in Encore somewhere!

 

Thanks for help!


Cheers,

Benjamin

 
Replies
  • Currently Being Moderated
    Nov 8, 2012 8:36 AM   in reply to Sender Films

    I do not do BD, so can't help directly... so may only GUESS that something about the audio or video is not 100% compliant

     

    Encore Import Formats http://forums.adobe.com/thread/622722

     
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  • Currently Being Moderated
    Nov 8, 2012 8:44 AM   in reply to John T Smith

    John may be pointing primarily to the chart in the first reply to that thread, and someone mentioning "23.98" rather than "23.976" is always worrisome. It is true that many programs round the number, and what is reported as "23.98" is in fact "23.976." but we also see users who think they have a compliant stream and it is not.

     

    Note that the thread John points to is a good one since the latter parts of the thread illustrate the complexity of compliant audio.

     
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  • Currently Being Moderated
    Nov 8, 2012 11:15 AM   in reply to Sender Films

    That is good news!

     

    Preview is known for many issues; I don't recall hearing the audio sync issue, but not surprising.

     
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  • Currently Being Moderated
    Dec 18, 2013 6:43 AM   in reply to Stan Jones

    I am having a sync problem as well with no clue as to why. I created the first Blu-ray disc of my project with no issues at all. Each chapter in the timeline is an.m4v video file. The audio is one long .ac3 file. I created it by creating a Premiere Project where I dropped all the Premiere projects that make up the movie in the correct order. I then exported the audio as a 5.1 WAV file, and dropped that into WAV to AC3 Encoder 5.0 to generate one .ac3 file (48khz, 6 channels, 640kbps).

     

    I used this method for the first disc and everything worked flawlessly (for once). I used the same Encore file (saved as Disc Two.ncor with the old video video and audio files removed) to keep the exact same menu, and went through the same procedure. Video exported as .m4v files with the same settings, audio produced the same way as described above. Everything starts out fine, but as you get further in the timeline, the audio becomes out of sync. And not by much either. Probably 6-10 frames near the end. It doesn't sound like much, but it is noticable, and when the frame rate is 29.97, being 10 frames off is noticable.

     

    I will double check my settings, but they should all be the same as disc one. I am going to try dropping the 5.1 wav into the encore timeline to see if there is a sync problem with that. If not, then I know it's a setting in the WAV to AC3 Encoder. Has anyone run into this kind of problem and found a way to fix it? I don't know why everything was fine with the first disc but not with this second one.

     
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  • Currently Being Moderated
    Dec 18, 2013 7:25 AM   in reply to eday_2010

    The "usual" issue with this is placing multple m4v's on one timeline. If every video is exact to the gops, then it may make no difference. If not, Encore is challenged, and may fail. Is that what you are doing (putting the m4v's on one timeline with the single audio file)? Are you certain there are no tiny gaps?

     
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  • Currently Being Moderated
    Dec 18, 2013 8:17 AM   in reply to Stan Jones

    Yes, I am putting pultiple m4v files in the same timline, with one ac3 file for the audio to get around the null info that is added to ac3 files that throws things out of sync. It worked perfectly when I did it for the first disc. I am almost certain there are no gaps, since Encore doesn't let you have gaps when you are dropping files in, but I will double check. I didn't see any when I was adjusting the chapter marks.

     

    What is happening is the sound eventually falls behind of the video by a few frames (to about 10 frames near the end of the movie). The movie is one hour and 49 minutes. If the video files are 29.97fps, and somehow the Encore project setting is 30fps, would that cause my issue, or would it cause the audio to get ahead?

     

    I've done the one long m4v file before, but scrubbing through and adding the chapter marks was incredibly annoying.

     
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  • Currently Being Moderated
    Dec 18, 2013 8:25 AM   in reply to eday_2010

    Yes, one long file can have its issues. The primary alternative is for both video and audio to be created in chapter length files.

     

    Encore will happily create gaps...for audio especially when it needs to adjust for tiny differences in video/audio length.

     
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  • Currently Being Moderated
    Dec 18, 2013 8:54 AM   in reply to Stan Jones

    I tried doing both the audio and video in chapter length files. The problem is that the null info at the beginning and/or end of each ac3 file caused Encore to re-encode the audio to stereo.

     

    You are actually the one that suggested I use one long audio file back in September (http://forums.adobe.com/message/5704781) when I was looking at using playlists to get around the null issue, and it worked beautifully. I was expecting to have problems with syncing or something else, but everything was perfect. For some reason it doesn't want to play nice this time.

     

    Encore shouldn't have created any gaps because I did not import any of the individual ac3 files for the clips into Encore.

     

    I will narrow down where the problem is. Everything is in sync in Premiere. I will drop the wav file that I render out of Premeire (to make the ac3 file) into Encore. If there is still a sync issue, then i know i have a problem somewhere in the videos (or the Encore settings). If not, then I know it is something to do with the Wav to AC3 Encoder settings.

     
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  • Currently Being Moderated
    Dec 18, 2013 9:51 AM   in reply to eday_2010

    Ah, yes. Let us know how your troubleshooting goes; those sound like good tests.

     

    In this case the gaps (if any) would be in the video.

     
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  • Currently Being Moderated
    Dec 18, 2013 10:56 AM   in reply to Stan Jones

    Will do. I am 99% there are no gaps as I went through the timeline last night and saw none. But I will double check, and I will also double check the Premiere timeline that I use to export the ac3 soundtrack.

     
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  • Currently Being Moderated
    Dec 18, 2013 8:10 PM   in reply to Stan Jones

    So I checked the Encore timeline for gaps; there were none.

     

    I checked to see if a clip was shorter than it should be from another clipoverlapping it; no dice.

     

    I removed all the clips and put them in again; nope.

     

    I checked the Premiere timeline that I am using for the audio for gaps in the video: none there.

     

    I droppped a two-channel wav file into the Encore timeline to see if that went out of sync; it did.

     

    This last one I do not understand. In Premiere, my nested clips have the audio and video linked to each other so they cannot be placed out of sync. Running through the Premiere Timeline shows that the movie stays in sync the entire time.

     

    One thing I did notice is that in Premeiere, in the Export settings window, The entire timeline is 1:49:16 and 50 frames, but in Encore it's 1:49:17 and zero frames. Then I realized that the Encore timeline is set to 29.97fps, as are the video clips I am dropping into it. But the Premiere timeline that I am using to export the audio was set to 59.94fps. So I made a new Premiere timeline set to 29.97fps, rendered the audio out again and placed it in Encore. Still falling out of sync. Tried with a two-channel wav file again, same problem.

     

    I even tried just pasting the audio tracks into a new premiere sequence and exporting that, but that doesn't work either. That actually made things worse.For some reason the video is playing faster than the audio. At the beginning things are fine, but when you get to the end of the timeline, things are noticably out of sync. It's gradual, so there is no one spot that is causing a problem.

     

    How do I fix this?

     
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    Dec 18, 2013 8:59 PM   in reply to eday_2010

    One thing I did notice is that in Premeiere, in the Export settings window, The entire timeline is 1:49:16 and 50 frames, but in Encore it's 1:49:17 and zero frames.

    If the times are off, I'd track that down. E.g., I would look at the actual exported length of each file.

     

    How did you export each m4v? How do you know that each one and the total is right?

     

    How did you create the Encore timeline? (How do you know it is the right length?)

     
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  • Currently Being Moderated
    Dec 19, 2013 5:39 AM   in reply to Stan Jones

    I exported each m4v individually from their own sequences (and their own Premiere save file/project). The footage is 59.94fps, as is the Premiere timeline, and it is exported as a 29.97fps m4v video file. Reviewing the clips in the Encore timeline nothing is noticable cut off.

     

    I created the Encore timeline the normal way, choosing Blu-ray as the format, 29.97 interlaced. Then I drop my clips in the timeline in the order I want them. It is exactly what I did last time when it worked perfectly.

     

    Last night after playing around with Premiere and Encore some more, I took the Premiere timeline I made to export audio and tried dropping in the 5.1 wav files in the correct order. Exported that as one large 5.1 wav which I then converted to ac3. Plopped it into Encore, and almost success. It still goes out of sync, but it is not gradual, and I have isloated where it goes out of sync, and just have to figure out why and how to fix it. I'll try dropping my long 5.1 wav into Premiere and see if it goes out of sync there too. The easiest solution would be to shorten the audio clip in Premiere by a few frames and export it. Tonight I will give it a whirl. I'll get it eventually.

     

    I am almost tempted to start using Premiere Elements. Much more limited, but also much easier.

     
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  • Currently Being Moderated
    Dec 19, 2013 6:19 AM   in reply to eday_2010

    An alternate method for the timelne, to test this, is to use the audio to create the timeline, then examine the length of the video files.

     

    I would add up the video file lengths.

     
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  • Currently Being Moderated
    Dec 19, 2013 11:40 AM   in reply to Stan Jones

    I will give that a try as well. I will use a two-channel wav file since the ac3 always has null whitenoise at the end.

     
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  • Currently Being Moderated
    Dec 19, 2013 10:16 PM   in reply to Stan Jones

    So after looking at everything carefully, I noticed that some of the audio clips for the movies rendered a frame or two shorter than they should have, which is what caused the drifting of the sync (perhaps the end markers in the render settings wasn't all the way to the end). I got that all sorted out, but now Encore decided to not play audio 95% of the time. It plays fine at the beginning of the timeline, but if I skip to the next chapter or a few after that, I get no sound. There is nothing wrong with the ile since it plays fine in VLC Player, so now I have this problem to solve.

     
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  • Currently Being Moderated
    Dec 20, 2013 5:47 AM   in reply to eday_2010

    This generally indicates an audio file that has no finished conforming. You're talking about a long, single 5.1 audio file, righht. Since Encore should only pass it through it would seem to me it does not need this, but perhaps the Encore preview/mix down that someone else referred to in another thread (Richard?) takes the same sort of processing/time.

     
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  • Currently Being Moderated
    Dec 20, 2013 6:25 AM   in reply to Stan Jones

    I had no problems with this until last night sometime for no apparrent reason. Then when I finally think I have cracked the syncing problem, it decides to start getting wonky. I'll discuss that in the other thread you replied to. No sense in talking about it in two places.

     

    Otherwise, can anyone recommend a different program for doing this kind of stuff? I used DVD Architect to make one disc earlier this year. I liked that it allowed you to have a menu intro, but didn't let you have a multipage menu that kept the background and music going. It also gave me some problems, but it didn't seem to give me as much grief as Encore. I am thinking about going back to Premiere Elements which never gave me problems, but I have never used it for Blu-ray authoring, and the 30-second limit for a menu is annoying.

     
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  • Currently Being Moderated
    Dec 28, 2013 9:30 PM   in reply to Stan Jones

    FINALLY!

     

    I have discovered the problem with the drifting audio. The culprit was Premiere Pro. I decided to go back and drop my rendered m4v video files in a timeline, along with my rendered 5.1 wav files t osee what was going on. Viewing the timeline as close as possible - that is, at the frame-by-frame level - I noticed that about half of the 5.1 wav files that I dropped in would be two frames short in length. They were not rendered short, however. I could grab the end of the audio segment in the timeline and pull it to reveal the two short frames. If you have enough of these, you start to notice the audio drifting.

     

    Why Premiere did this, I have no clue. But now I know to look at everything at the frame-by-frame level when laying out the audio for movies.

     
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  • Currently Being Moderated
    Dec 28, 2013 10:42 PM   in reply to eday_2010

    Thanks for reporting. Very odd.

     
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    Jan 9, 2014 10:58 AM   in reply to eday_2010

    Hi eday,

    It would be great to get a bug report for this. Can you file one here? https://www.adobe.com/cfusion/mmform/index.cfm?name=wishform

     

    Thanks,

    Kevin

     
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  • Currently Being Moderated
    Jan 9, 2014 2:42 PM   in reply to Kevin Monahan

    Done!

     
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  • Currently Being Moderated
    Jan 10, 2014 12:37 AM   in reply to eday_2010

    eday_2010 wrote:

     

    FINALLY!

     

    I have discovered the problem with the drifting audio. The culprit was Premiere Pro. I decided to go back and drop my rendered m4v video files in a timeline, along with my rendered 5.1 wav files t osee what was going on. Viewing the timeline as close as possible - that is, at the frame-by-frame level - I noticed that about half of the 5.1 wav files that I dropped in would be two frames short in length. They were not rendered short, however. I could grab the end of the audio segment in the timeline and pull it to reveal the two short frames. If you have enough of these, you start to notice the audio drifting.

     

    Why Premiere did this, I have no clue. But now I know to look at everything at the frame-by-frame level when laying out the audio for movies.

    Ouch!!

     

    Great catch!

     
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