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MacBrian

Audio/video Sync Frustration

Question

:)

 

I feel about how this little icon-guy looks.

 

What's the deal with SOME XVID AVI files and the lack of audio sync if you try to do ANYTHING with the files?

 

I was happily converting XVID AVI files to DVDs via the wonderful new video capabilities of Toast 7.0.2. Thank you Roxio for making it so easy with the latest version of Toast! These capabilities are awesome and well implemented...when they work.

 

BUT, I've run into several files that, no matter what I do, always end up with the audio and video out of sync...and it's NOT just Toast. It's **anything** I try!

 

Things I've tried so far:

 

Toast > DVD disc image = sync failure

ffmpegX > DV, DVD, MPG, or another AVI = sync failure on any conversion I attempt

Quicktime Export to .DV (which almost always has worked in the past) = sync failure

VLC Media Player > Open File > Stream to MPG file = sync failure

 

My frustration is that these AVI files play JUST FINE in Quicktime and VLC, but if I try and convert them to anything else, the audio and video go out of sync.

 

If the players can play the files with proper audio and video sync, then why can't they be encoded to something different and remain intact?

 

Quicktime 7.0.4

OSX 10.4.4

PowerMac G4, 1.3 Ghz PowerPC, 2 MB L3 cache, 1.25 GB SDRAM

 

I thought surely using VLC to stream the file to a new format would solve the problem but it didn't.

 

Any suggestions, anyone? HELP! Where's the key to unlock this mystery?!

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DVD video requires 48 khz audio. Is the audio in your out-of-sync AVIs 44.1 khz?

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I think you found the problem, tsantee. I just checked and Amadeus II can resample sounds, but I don't know what will happen with the recording's time scale. Any audio-freaks around who can check this out? Amadeus II is a great app and it's cheap, so would be a nice solution if it would work in upsampling CD to DAT...

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DVD video requires 48 khz audio. Is the audio in your out-of-sync AVIs 44.1 khz?

 

tsantee:

 

The audio in the source files that give me sync problems is listed by ffmpegX as mp3, 48000 Hz, stereo, 112 kb/s.

 

I just don't get how many different players can play these files in sync, but encoding them with ANYTHING breaks the audio sync.

 

:)

 

--Brian

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I don't know if this will help but I have had a similar prob. with video mpg2, video not syncing with audio. Following some great advice from Tsantee, the orig encoded mpg2 had audio at 44khz, Toast recognizing only 48 khz. Toast will burn file but will not be able to sync up the audio when it muxes the file. The orig file needed to be resampled, in my case I used Mpeg Stream clip by Squared 5 (free) and apple's mpeg playback component. Exported the file as a DV file, with a resample to 48 khz....toast burns new dv file, and now the video syncs up with the audio. Note that here, in my case, Toast encoded the file instead of multiplexing of which I have set to 'never encode'.

 

It may sound like apples to oranges but its a similar concept and may offer a new path to help you find some software so resample the audio. (Maybe? I hope, since I understand your frustrations, it took me two weeks to resolve my issue) Check out the discussion thread in Forum Toast 7, "My TV.PVR and Audio" that may offer some kind of spark or added insight.

 

also I have never heard of the file that you are describing but maybe Mpeg Streamclip can help?

 

Squared 5

 

(I hope I added the above link alright, bear in mind I am a Newbie!)

 

eek wrong url....dropped the 'l' ... here it is!

 

Squared 5, Mpeg Streamclip

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I have never heard of the file that you are describing but maybe Mpeg Streamclip can help?

 

Hmmm. I had tried Mpeg Streamclip but it said the AVI was an "unsupported format." After reading your comments I checked and found I was a couple of versions old on Mpeg Streamclip, so I downloaded the current version. It now accepts the troublesome AVI files, but haven't tried anything with it yet because my CPU is maxed out right now exporting .DV from iMovie.

 

Yup, why use a precision tool when a blunt object will work? :) I discovered I could drop the AVI into iMovie HD, then after an hour or so of waiting it finally appeared as a clip. I dragged the clip into the timeline and extracted the audio. Then I unlocked the audio and pushed it to the right of the video until voice and lips seemed to sync pretty well. Now I'm exporting .DV from iMovie (3+ hours for a 48-minute clip).

 

I'll definitely give Mpeg Streamclip a try after my 3-hour time in the penalty box expires.

 

Thanks for the tip! I'll let you know if it worked.

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Thanks for the tip! I'll let you know if it worked.

 

 

(Later)

 

:)

 

Nope. MPEG Streamclip did it's magic but in the resulting .DV file the audio is still out of sync, even though the source AVI file plays in Streamclip's preview window perfectly in sync. The Stream Info reported by MPEG Streamclip is:

 

===========================

Duration: 0:53:48

Data Size: 344.95 MB

Bit Rate: 0.90 Mbps

 

Video Tracks:

Generic MPEG-4, 608 × 336, 23.976 fps

 

Audio Tracks:

MPEG Layer-3 Audio stereo, 48 kHz

===========================

 

I tried checking and leaving unchecked the option "Resample Audio to 48 kHz" -- neither made any difference, the end result was still out of sync.

 

The EDIT > Fix Timecode Breaks menu item doesn't appear to do anything when the movie is open. Is that a clue??

 

Anyway, I'll manually fix the sync in iMovie and then take the resulting .DV files into Toast to create the DVD image. If that doesn't work, I'll try iDVD.

 

--Brian

Edited by bljohns@swbell.net

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Hi!

 

I don't know if this will help (and my english is not very good), but when you do some video editing, many software use MPEG-2 Playback Component, add-on to QuickTime Player or QuickTime Pro. If you have bought this software, I can tell you that there is good chances that this is your problem... MPEG-2 Playback Component has a bug that create out of sync audio/video files. Apple know this bug but don't talk about it on his site and there is not update available now.

 

I am not working very often with AVI files, but I know that the use of software not using MPEG-2 Playback Component (like Diva) can help. You must compressed de video file with Diva and save with none compression, and after that put back the audio track with Quicktime pro, and then save it as AVI.

 

There is a chance that your problem will be gone after that.

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Hi!

 

I don't know if this will help (and my english is not very good), but when you do some video editing, many software use MPEG-2 Playback Component, add-on to QuickTime Player or QuickTime Pro. If you have bought this software, I can tell you that there is good chances that this is your problem... MPEG-2 Playback Component has a bug that create out of sync audio/video files. Apple know this bug but don't talk about it on his site and there is not update available now.

 

Thanks for the reply! Yes, I do have the MPEG-2 Playback component. Is this what causes the sync to break when I export from AVI to .DV? Kind of a catch-22 -- I gotta have the MPEG-2 component in order to play my Tivo files, so I can't disable it.

 

I am not working very often with AVI files, but I know that the use of software not using MPEG-2 Playback Component (like Diva) can help. You must compressed de video file with Diva and save with none compression, and after that put back the audio track with Quicktime pro, and then save it as AVI.

 

There is a chance that your problem will be gone after that.

 

Hmmmm. Sounds like that'll take just as long as importing the AVI into iMovie, extracting the audio, offsetting it to regain sync, and then re-exporting as .DV.

 

However, if the QT MPEG-2 component were the cause, why would VLC also write an out-of-sync file? VLC wouldn't be using the QT component, would it? It's my understanding that VLC is self-contained and that everything it uses to play audio/video comes from within itself.

 

The offset to correct the out-of-sync audio is almost always 1.2 seconds. Does anyone know of a way to demux an AVI file and remux it with an audio offset correction? I haven't had much luck figuring out how to do this precisely with QT Pro. I'm sure ffmegX could do it if I could just figure it out... :)

 

--MacBrian

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Sorry for not reading the whole thread (again), but I don't have any AVI-sync problems. They go straight into Toast 702 Video window. I clean out the text and set a button picture in the Edit window and that's about it. No sync problems yet burning PAL discs.

 

But then, are we talking AVI files or AVI containers with XVID or whatever in them? Anyway, if they don't show up in Toast or it balks I whip them through ffmpegX first. The only ones that still give me trouble are the ones with Ogg Vorbis sound. Yes, there is a way to get the sound playing but that means installing yet more software and I really can't be bothered at the moment. Oh well, still learing...

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