Disk Image Audio Drifting Out of Synch

Hello, I've searched and can't find a relevant audio synch thread, although I've read several in the past.
My issue:
I export from FCP a QT file that is perfectly in synch. However, once making a disk image in iDVD, it gets 1 or 2 frames out of synch towards the middle of a 75 min project.
I've ensured that all chapter markers are at least 3 seconds from any transition or keyframe, etc. I also have fully rendered all video 100% and mixed-down all audio. I also preloaded the "text" track in QT to try and head off the synch issue. I am exporting a sequence that has several sequences nested-in from an older (much larger) file. I've further edited, requiring up to 6 audio tracks, but only 2 video tracks. But, again the QT file is perfectly in synch. It only happens when making a Disk Image.
Why is iDVD disk image putting it out of synch? Any more thoughts, suggestions for settings in FCP, QT, or iDVD?

There was a similar issue in an earlier version of compressor to DVD Studio Pro.
You don't say which versions of softeare you are using but it might be related.
The issue was that when a movie was compressed with aif audio as the chosen output this resulted in a loss of sync as time went by on the DVD.
The problem was rectified in later versions of compressor and a workaround until the update was to select AC3 audio as the preferred compression method.
It may be that iDVD uses AIF audio to construct the DVD and is the source of your problem.
HTH's

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Audio drifts out of synch

For me, this is a very inexplicable problem.
Concert video. Video taken with 5 HD cameras, camera's audio at 48KHz. Audio was also separately recorded in a Pro Tools system, also 48 KHz.
The video was later captured into FCP using the standard HD 1080 50i. Syncing up the videos was no big hassle. When adding the ProTools audio, it drifts out of sync.
I found in the FCP manual about the fact that if audio and video is not synced using a master sync / time generator, the audio can drift.
But how is this possible? I want to understand. I can understand the need for an external sync during recording, to more easily sync up the start point for each track when editing, but one second is one second long, exactly and 48000 samples is 48000 samples, wether recorded on one device or another. 48KHz is 48KHz and 1 second is one second, whatever the device.
In my mind, the master program (in this case FCP) should read exactly 48000 / second regardless if the audio is captured on the cam or on any other 48KHz device. But it does not do this... it reads maybe 48090 - or whatnot - samples per second. The result is that the audio drifts ahead of the video. Why does it do this?
This is not just in FCP. My friend is composing music on Logic Pro. The bas player (who lives in another city) records his bas lines on Logic Pro and sends the files (uncompressed). When my friend imports the bas recording into the master Logic project, the same thing happens... the imported file drifts.
In my mind, a bit is a bit, a byte is a byte, a sample is a sample... the master-program should read each sample in its place, 48000 / second, in a quantified "time grid". So, in my mind, this just cant happen, but it does. Can anyone explain why, and if there is anything one can to in the program (FCP or Logic) when reading the files to ensure actual sample-time accuracy when reading imported files?

Hi Per:
I have been through this many times. The reason that the devices go out of sync is that their master clocks (the digital equivalent of a crystal in an analog device) are all beating to their own drummers, so to speak. The internal master clocks are all off from each other the second that they began recording. It's just how long does it take before those offsets become greater than one frame of video or film, right?
This is why genlock and video TC sync were invented. What is more frustrating is that the devices do not all slip at the same speed either so usually, one nudge of the audio in one direction or another may line it up for a while, but later down the timeline, you may discover that the devices (camera tracks and the ProTools track) have all lost sync again. On a long show, you may have to do a lot of slicing and dicing to make everything stay in sync. This is the price you pay for not using really big, expensive, professional cameras, there has to be a trade off somewhere.
The best way to mitigate this is to shoot with genlocked cameras with locked TC with the PT rig or a quality TC generator as the master clock. If the projects are shot with non-genlock prosumer type cameras, the next best solution is to rent a giant TC display and position just out of frame in a position that all five cameras can easily pan to, but won't pan to it accidentally as they frame their shots. The master TC display is driven by the PT system. You instruct the cameras ops to quickly photograph just a second or two of it every "whatever length you had before it slipped, probably once every five to ten minutes". In this way, when using multicame to edit, you can quickly locate the TC display frames and slip and slide the tracks accordingly.
This can happen with any non-genlocked, non-TC reading devices. Usually I can get about 20 minutes between my cheap MD recorder and prosumer cameras before I see sync slip. Some devices have better, more steady master clocks, some have really lousy ones that slip quickly.
You just have to bite the bullet and deal with it.
Dan

Audio & Video Out Of Synch after Editing

I edited a clip, and the audio went out of synch with the video. What did I do wrong? How do I fix it?
Kate

Kate,
Tell us more about this Clip. What format is it in? Be as specific as possible. AVI doesn't tell us enough. What CODEC is inside? G-Spot is a great freeware program for giving you that info www.headbands.com/gspot
How does it go out of sync, i.e. drifts from beginning until it's way out at the end, or starts out of sync in the beginning?
There are likely workarounds for getting it back into sync, but those methods will depend on your answers.
Good luck,
Hunt

Importing 24p audio falls out of synch

Hello,
I was just capturing two tapes of a musc video, using a panasonic GS500 to import, shot in 24p on a DVX100, and captured on the standard DV NTSC 48 kHz preset. When I watched my clips afterwards, I found that the audio falls out of synch in the longer clips. I don't understand why this has happened, because I thought the 24p was still recorded on the tape as DV NTSC but with a 3:2 pulldown effect on it. My question is how can I fix this importing problem so it doesn't fall out of synch again when I re-import?
Thank You,
Kyle

This can happen with long captures. Better Camera/deck seems to be key here.
For now, you could select the clips that drift and do a 'File'/Export as AIFF...48khz/16bit. Then re-link/replace the new audio with the original video files.
Recapturing in shorter clip length may avoid funky Aud Rates. Either way, you'll likely need to create new multi-clips and edit with those.
Within current multi-clip sequences, you can control-shift/drag left or right on an angle in the viewer to bring the sync back in line. This should only affect the angle/clip following a cut, and not the sync prior to a cut.
If you've already made many cuts througout the timeline, you could use the 'slip' tool on out of sync clips after you've collapsed the multiclip.
Hope that helps,
Kevan

I am having trouble playing MFX files in Premiere Pro CC. The audio is out of synch. Is there a way to monitor the audio correctly?

I am having trouble playing MFX files in Premiere Pro CC. The audio is out of synch. Is there a way to monitor the audio correctly?
Many thanks

Chances are the pinnacle is producing .avi files or MPEFG1/2 streams - iTunes may know how to decode the audio but not the video. Download Handbrake and try running the Pinnacle files through it and adding to iTunes - use Universal format unless you have a specific device in mind.
Keep copies of the originals.
Another option might be to try to install Perian. Can't remember if the Apple MPEG2 plugin allows MPEG2 to be played in iTunes.
AC

Audio drifts out of sync since Quicktime 7.6 update!

Help!
Seems like ever since i updated the Quicktime to 7.6 my uncompressed 8 or 10 bit sequences for playout to digital betacam drifts out of sync over time!
But when i just go to the end of the sequence and hit play, everything seems fine.
I just restarted to my old Tiger system and there the problem doesn't seem to be there.
Any ideas??
I use the blackmagic Multibridge Extreme.
Another strange thing is that when i playout to HD, there is also no problem!
Thank you for your time,
Steve Pittoors

I have had my audio drift out of sync also, not with Betacam, but DV. I basically send the audio from FCP to STP and tweek the audio, and then on export back to FCP it adds about 10 frames worth of audio. It starts in sync and then drifts by the end of the sequence. I have had no problems with shorter sequences - ie. 30 sec. The one I am working on now is just over 6 minutes. What is weird is that the sequence length in both FCP and STP are the exact same, but when I export back it drifts and adds in the extra frames.
I tried fiddling with all the framerate settings in STP and it still does it.
I posted last night in FCP and STP forums and haven't had any luck.

Audio drifts out of sync in QT

I have just completed a 30 min., 20 sequence piece. When I create the reference movie the audio drifts out of sync.
It plays fine in FCP (5.1.1). The properies are matched at 1080i50 and 48k in FCP and QT.
Would appreciate some help.

Thanks for taking an interest, Studio X.
I didn't do the capture, but the media and sequence settings are matched and the QT properties are too at 1080i50 and 48k. I'm not using an external monitor, just viewing from the timeline. I'm done with the project, I was just trying to save myself a copy before it goes to the compositor and composer.
I think I remember reading a post on the same problem somewhere else and it came right when it was encoded for MPEG 2. I'm trying that now, will post the result.

Audio Drifts Out of Sync After Demux

Hi,
I demuxed an hour-long program from DVD to .m2v and .ac3 using MPEG Streamclip. The audio drifts out of sync very gradually, and by the end is way off.
I don't want to re-compress the audio, as it is already AC3. According to Quicktime, the video is 29.97 fps, and the audio is 16-bit 48 khz.
When I used to Export to DV option, everything stayed in sync. I can't go this route, however, since I can't afford to re-compress anything (I'm making a new DVD from this old one). Just an FYI that this worked.
Ever run into this problem before?

I am using version 1.9. In the preferences pane, I don't have anything checked.
To reiterate, all I'm trying to is demux the DVD as-is and bring those assets into DVD Studio Pro for an updated project. Not using FCP anywhere in this workflow.
Looks like I left out an important piece of info, though...When I demux the audio stream to AC3 (its original format), and try to import it into DVD Studio Pro, I get the error message: "Variable bit rate audio assets cannot be imported." I am not sure how the client originally encoded their audio, but the fact that it stays in sync on the DVD led me to believe they didn't do anything wrong. Could this VBR be throwing the audio off during the demux? The only instances where I've noticed it's out of sync are when I export to an uncompressed format like AIFF or WAV, and can actually view it.

Simple AUDIO & VIDEO OUT OF SYNCH

Lots of out of synch stuff out there, but all specialized. Mine is SIMPLE. COnnect a Canon Vixia HV40 HD DVD, do a capture, and audio and video are out of synch. It starts fine, but as it goes it drifts away gradually. I have NO IDEA what to do. I am not an expert at this, just an ameteur who loves HD DVD.
It happens upon capture - not when buring to Blu Ray, not when converting WMD files to Torpedo or artillery or atomic or U Tube files, or any other fancy stuff. It's not my brand of BVlu Ray disks, it's not the label I stick on it. I don't do - don't even know how to do fancy editing.
Just copy and burn is REALLY hard.
Just seems so strange that basic capture is so damn difficult and should be so simple - audio just will not line up with video.
HELP!!
I have Win 7 64 Bit, al;l kinds of processor power, latest biggest hammer bought for video editing and gaming. If you need specs I can send.

First, a clarification... Capture is what you do via Firewire from a (usually, as far as I know) tape camera
Please provide EXACT step-by-step details of what you are doing
Also, provide details about the file
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037?tstart=0
What is a CODEC... a Primer http://forums.adobe.com/thread/546811?tstart=0
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037?tstart=0
For PC http://www.headbands.com/gspot/ or http://mediainfo.sourceforge.net/en
For Mac http://mediainfo.massanti.com/

Audio Drifts out of sync. Why?

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

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?

PE3 - Audio & Video out of synch on imported VOB files

I have tried adding some footage imported from DVD & is saved in a folder on the PC (by the PE process).
The file is stored as VOB 1 & VOB 2. When I import this file into the PE project the first half plays OK. When it plays onto the second file, the audio is lagging behind the video by a considerable amount.
If I view the file separately (where it is stored) with Windows Media Player, it plays back fine.
When I view the file in PE in the preview window, the out of synch fault occurs.
Something is happening in the import process to the PE project.
Anyone, have any ideas on the problem?

Here is a reply that I posted to a past thread that will give you options for fixing the Out-of-Sync issues when trying to use VOB files within PE.
In all cases it is better to not import VOB directly to PE, but convert to DV-AVI via one of these methods and then use the AVI format.
The last bullet below sends you to a Muvipix link describing how to combine multiple VOB's from one disc to a single file, this will cure the Sync problem, then convert this file to DV-AVI for import to PE:
I take the min-DVD directly from camcorder to my PC, and capture the disk via Power Director.
PD will convert the VOB's directly to DV-AVI Type 2 on one pass.
I then load this DV-AVI into PE7.
(PD v7 was pre-installed on my new PC from HP, or it can be purchased from Cyberlink).
Other options to try:
Copy the VOB's directly from the mini-DVD to your PC and use Prism to convert these to AVI.
Prism is a free convert utility and can be found here:
http://forums.adobe.com/thread/415317?tstart=0
Or load the VOB or Mpeg into PE, then use that to convert to AVI.
(Export to DV-AVI with PE8 is done with SHARE/PC, not Export under the File Menu, which is greyed out).
I've had many issues trying to work with Mpeg's and VOB's when loaded directly to PE with limited success.
So if you can get it converted successfully to AVI outside of PE, I've found this to be a better approach.
Post results, if any of this works for you...
Note: One other thing, if you are working directly with VOB's to PE, especially multiple VOB's from a single DVD, you can encounter out-of-sync issues between video and audio. If this occurs, review this link from Muvipix:
http://muvipix.com/phpBB3/viewtopic.php?f=38&t=2469:

How do I backup my MacBook Pro when the disk image is grayed out?

I have a MacBook Pro (15 inc. four years old) running OSX 10.6.8 and last night I got the color pinwheel of death. I could not force quit anything and had to manually power down.
When I powered back up I got the folder with the question mark. I ran Disk Utility and tried to Repair Disk, but I got:
Disk Utility stopped repairing "diskOs2"
...Back up as many of your files as possible
Details: Invalid B-tree node size
The volume could not be verified completely
Volume repair complete
Error: Disk Utility can't repair this disk, Back up... at the disk, and restore your backed-up files
I hooked up an external hard drive and tried to make a copy of the disk image, but it is grayed out. I also tried to partition the main Hitachi drive and make a "New Image" but I got: "Unable to create backup (input/output error)
So I now have a Genius Bar appointment for tomorrow, but I can't even back up my computer before going. I can have them tell me what to do, but then I'll have to go home and do it, and then make a second appointment.
Any suggestions? Oh, and I backed up this computer about six weeks ago on Time Machine, but I'd love to make a copy of all new files I've created since then.
Thanks!

You have two options. Purchase Disk Warrior or erase the drive. The former would require your ability to install a download of DW on a bootable disk so you could repair your hard drive. And, DW costs $99.00. The latter requires a Snow Leopard installer DVD from which you can boot, erase the hard drive, then reinstall Snow Leopard. Then download and install Mac OS X 10.6.8 Update Combo v1.1. You can then restore from your Time Machine backup. There is no way now for you to backup files unless you can access the drive. Open Disk Utility, select the entry for your disk volume then click on the Mount icon in the toolbar. If your volume mounts on the Desktop then you may be able to copy files to an external drive or even run a Time Machine backup.

When exporting separate audio and video streams, the audio drifts out of sync

So this is my first slightly larger project in Final Cut Pro X.
When I export my finished project (around 12 minutes long) straight to quicktime, it plays back perfectly.
When I export using compressor, the resulting audio and video streams are two different lengths. The audio comes out a full second longer. If you try to lay them down in a program like Adobe Encore, the audio starts out perfectly in sync. Two minutes in you notice the video is slightly out of sync with the audio. By the end of the video it's comically bad, over a second out of sync.
What's even more vexing is if I try to take the quicktime file that IS in sync upon playback, and try to convert it burn that to a dvd or blu-ray using toast, the problem re-emerges.
I triec searching around, but most of the suggestions that came up were vauge, like, "Upgrade to a real program like Final Cut." (This was in reply to people who were using free software programs.)
I did see one idea surface where 44 and 48 kHz sampling rates don't play well together. So I combed through my project and found all the 44.1 songs that were used, and swapped them out with upsampled versions. Nothing changed. It didn't sound like it would fix it, as people usually said it was a specific amount of frames off, not something drifting out of sync.
So the question is, does anyone have any suggestions on what could be causing this? Thanks! :-)

Project settings can be accessed and changed by selecting the project and pressing command-J. Then, in the inspector, click on the little gear in the lower-right hand corner to access the settings.
Why are you trying to output video/audio separately? If the content plays in-sync when exporting a quicktime movie (using current project settings), you could try separating the video/audio using MPEG Streamclip as a second step instead of using compressor. For audio, don't change the sample rate from the project settings, and use uncompressed audio (AIFF) as the output format.

When Viewing Adobe Connect Training, why are Audio/Video out of synch

I am a new Captivate 5.5 user and I have been using the Adobe Connect Training material to come up to speed on the product. However, I have noticed that when viewing presentations in Connect, over time, the audio and video eventually are completely out of synch. What is being discussed (in the audio) has nothing to do with what is being shown on the screen. This happens on all Connect Training videos. I have a high-speed Internet connection and I never have problems with streaming content from other sources such as YouTube, etc. What am I doing wrong?

Dang, though it was worth a shot.
Now, one user here, Jim Simon, uses similar, and has worked out a percentage that he adjusts the remote mic's material to fit with his camera. Cannot recall exactly now, but it seems that he alters the Audio by a factor of about 104%. My memory is cloudy on the exact figure, and Jim seems to be on extended holiday. Not sure now, if he uses the Rate Stretch, or runs his mic's audio through Audition. Sorry that the memory is so fuzzy now.
Good luck, and maybe Jim will show up with his exact figures, to give you a starting point.
Hunt

QT exports but audio goes out of synch... Fixable?

I'm exporting some rather large timelines to QuickTime from FCP 6 and all of the resulting QT files are losing audio synch. Actually the audio tracks are stretching, it seems: the audio tracks are LONGER than the corresponding video track, each time. Longer by 1 to 2 seconds.
SOME FACTORS
My files are around 25 minutes long.
I'm preserving my current settings when exporting with QT.
codec XDCAM EX 1080p24 35mbs VBR
frame rate 23.98
frame size 1920x1080
48.0khz audio
Is it simply that I shouldn't try to export files that are this big? I searched the existing archives. One person had the exact same problem, apparently, but there were no replies.
Anyone know the situation here?
Shanked

Hey Venturesome,
I've heard of things "floating" out of synch whenever you're exporting to QT with files of a particular length or longer. Back in the day, this magic file length was 5 minutes. I have no idea what the current magic maximum is... or if there even IS a maximum. If you've got synch issues inside your timeline without even exporting, I wonder if it may be you're using mixed media.
But I defer to the forum at large on this -- anyone know why our audio and video tracks float out of synch upon exporting (or in this other case, non exporting)?
Shanked

Disk Image Audio Drifting Out of Synch

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