Audio Progressively Out of Sync

[FreeMrBone]

Alright so I looked for over two days all around the internet and couldn't find anything that helped me. So I decided to register and post my own problem. I recently bought a Game Capture for recording gameplay off my TV and I record live commentary separately through audacity. Problem is whenever I edit the video and import audio into a video editing program the audio always seem to get more and more out of sync the further the video goes. I tried changing the FPS in the video, changing tempo in audio, and messed with virtualdub mod (but virtualdub mod won't let me add seperate WAV audio file to my video. I'm pretty new to the program to. Might need a step-by-step lesson to tell me how to fix on VirtualDub Md). I can't find out how to fix my audio syncing problems. I literally spent over $300 for recording gameplay and I really want to make sure it was worth but so far it's such a hassle with the audio that I don't even know anymore. Please, any help is appreciated.

[awgie]

I have not done anything with Game Capture, but I do a lot of video editing with external audio, so this may or may not be of any value to you.

Check to make sure the frame rate you are capturing matches the frame rate of your editing. For example, if you were capturing at 30FPS and editing at 29.97FPS, the video would not LOOK slower by enough to notice while watching the video itself (a 60:00 video at 30FPS would be 60:04 at 29.97FPS), but it would be enough to throw off the timing when compared to a separate wav file (which is not frame-rate based).

Something else I've had to resort to when I simply can't get the files to agree is to either insert or remove a fraction of a second of audio in the external file in order to re-sync it whenever the timing gets off by enough to notice. This is usually only when I'm trying to edit video from different cameras that recorded at different speeds (e.g. an SD camera recording 720x480x29.97FPS and an HD camera recording 1920x1080x60FPS) or if the video source dropped a frame or two, but the audio didn't.

[manono]

...but virtualdub mod won't let me add seperate WAV audio file to my video.

Sure it will. Go Streams->Stream List->Add.

I agree with awgie that it's probably a framerate issue. If you can tell us the framerate of the video and its length, along with how much the audio is off by the end, and if it's too short or too long, it may help to figure out the problem.

[FreeMrBone]

...but virtualdub mod won't let me add seperate WAV audio file to my video.

Sure it will. Go Streams->Stream List->Add.

I agree with awgie that it's probably a framerate issue. If you can tell us the framerate of the video and its length, along with how much the audio is off by the end, and if it's too short or too long, it may help to figure out the problem.

Oh sweet thanks. How can I cut a piece off of the video? I hit the record button first so it begins sooner than my audacity recording. My video length is 14 mins 54 sec. That's not including the cut of the beginning of the video I plan to do. Audio is 14 min 52 sec.

[FreeMrBone]

I have not done anything with Game Capture, but I do a lot of video editing with external audio, so this may or may not be of any value to you.

Check to make sure the frame rate you are capturing matches the frame rate of your editing. For example, if you were capturing at 30FPS and editing at 29.97FPS, the video would not LOOK slower by enough to notice while watching the video itself (a 60:00 video at 30FPS would be 60:04 at 29.97FPS), but it would be enough to throw off the timing when compared to a separate wav file (which is not frame-rate based).

Something else I've had to resort to when I simply can't get the files to agree is to either insert or remove a fraction of a second of audio in the external file in order to re-sync it whenever the timing gets off by enough to notice. This is usually only when I'm trying to edit video from different cameras that recorded at different speeds (e.g. an SD camera recording 720x480x29.97FPS and an HD camera recording 1920x1080x60FPS) or if the video source dropped a frame or two, but the audio didn't.

I messed around a bit on virtuadub and I seen what you were talking about. My video is naturally 25 fps in MPEG II. But to match my audio and video it has to be 25.053 fps. Which I believe would solve the problem but I need to edit out a ew seconds in the beginning to sync the audio just in general At 30 fps the video gets cut ridiculously short to 12 mins and 45 secs. Nearly 3 minutes short than audio so I'm hoping 25.053 is going to help. Any idea how to delete a segment off video while leaving audio untouched?

[awgie]

I messed around a bit on virtuadub and I seen what you were talking about. My video is naturally 25 fps in MPEG II. But to match my audio and video it has to be 25.053 fps. Which I believe would solve the problem but I need to edit out a ew seconds in the beginning to sync the audio just in general At 30 fps the video gets cut ridiculously short to 12 mins and 45 secs. Nearly 3 minutes short than audio so I'm hoping 25.053 is going to help. Any idea how to delete a segment off video while leaving audio untouched?

I use avidemux in copy mode to do simple trimming of my MPEGs (cutting on I Frames). It's possible that either your capture software isn't recording at a true 25fps (especially if you have limited RAM), or that Audacity isn't accurately recording in real-time. I wouldn't change the framerate of the video, since 25fps is a standard framerate, and 25.053 isn't. Rather, I would adjust the external audio file in a separate audio editor (like Audacity). You could stretch or compress the full audio stream, but you lose quality that way. It's much simpler to insert little bits of silence when necessary to keep the external audio in sync with the natural video length.

EDIT: you could also try different software for recording the audio to see if it makes any difference. You could also actually time the source (with a stopwatch, or even anything with a second hand) as it's being captured to see if the actual time agrees with the reported length of the recorded video.

[manono]

My video is naturally 25 fps in MPEG II.

You're in the US and have recorded 25fps off of your television?

Any idea how to delete a segment off video while leaving audio untouched?

Just setting an audio delay would allow it to synch up at the beginning. Or remove the delay entirely using DelayCut.

[Bjs]

more out of sync the further the video goes

Beware ... the application in all forms has this issue in "preview" playback.

Mark a sample, output, playback in any other player to confirm audio sync issue.

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If audio is from another source it must match the video length or additional editing will be required to sync.

Aviutl might be a better app to use as you can shift the audio back and forth in the timeline then simply apply cut edits to be left with the correct aligned video segment.