audio out of sync with AVCHD video

[mikelt]

Hello there!

I've reached a braking point, I'm making simple videos for youtube, I usually record with my camcorder and use an external microphone plunged in a usb port to my laptop, today I've decided to make a video with an AVCHD file format instead of the regular mp4 which I usually use, now that made my life a nightmare today..

I'm using Sony movie studio 13.0 and sync the audio on start with 3 claps I made during the recording, it all seemed all right at the start, but when I checked the video file to the end of it (around 22 min long video) I've saw a delay between audio and video, it's getting there quite noticeable during the end of the video..

So I tried readjusting the sync at the start with no vail, the problem is deeper, where the video will get delayed during the playback, so no matter where you put the sync it will be out of it in some point of the video, so I tried to split the audio and move it slightly to sync right with the video, it can help for some point where I notice the delay but worse for other point, so to make it perfectly right I have to split it in numerious places during the video and attach the audio correctly, a procces I'm not willing to do or waste time on, I want ti figure where's excalty the problem and fix it from there, may you help me pls? * pulling out my hair*

for info- video is AVCHD format at around 17mbps bitrate, recording at 60i
Audio is exported with audacity in wav format 32bit (highest quality, no compassion)

never notice that problem before while using mp4, altought I've been using AVCHD previously I might have not used and external audio from my mic, which didn't recognize me with the problem, pls help

AVCHD never again !

[hech54]

Audio is exported with audacity in wav format 32bit (highest quality, no compassion)

But it was recorded @ 16bit?

[mikelt]

Audio is exported with audacity in wav format 32bit (highest quality, no compassion)

But it was recorded @ 16bit?

Oh I'n not sure, I recording with the Blue Yeti, never had sync problem with it, I just export in highest quality from audacity

[manono]

Oh I'n not sure, I recording with the Blue Yeti, never had sync problem with it...

His wasn't just an idle question as that's probably the source of the problem. Check the source audio/video in MediaInfo and if the audio is 16bit - as it almost surely is - then export the same.

Are you doing anything to the audio - making cuts, transitions and the like?

[mikelt]

Oh I'n not sure, I recording with the Blue Yeti, never had sync problem with it...

His wasn't just an idle question as that's probably the source of the problem. Check the source audio/video in MediaInfo and if the audio is 16bit - as it almost surely is - then export the same.

Are you doing anything to the audio - making cuts, transitions and the like?

Hey thx to the help so far, I think I tried exporting the audio as wav of 16 bit with no difference, I will try it again later on just to make sure, the original audio is in audacity and it's being soften on side as 32-bit, I will get that info with the program you mentioned tomorrow.
Yes I do, with no problems as I group the video and the external audio together after I sync them.

[smrpix]

Does the audio not align only on playback, or is the waveform out of sync when you stop and examine it.

I'm leaning toward your having an underpowered playback issue. If I'm right, your exported final video should be fine.

[mikelt]

Does the audio not align only on playback, or is the waveform out of sync when you stop and examine it.

I'm leaning toward your having an underpowered playback issue. If I'm right, your exported final video should be fine.

the original camera audio waveform is hard to notice, except the claps, im pretty sure the external audio is drifting a bit faster, which cause it to be heard before the original, especially noticeable at the end of the video//

OK,so I tried the 16-bit export through audacity with no vail, I tried to change tempto in audacity, and I played with it for a while, I managed to make it better at the end point but the audio during the all video somehow gets echo altough it's aligned perfectly, it's nerve wrecking, So I dropped out of it as the non edited audio is somehow good during most of the video and only drift away a bit at the end//

With mediainfo, I checked my audio file it is 44.1 hz while the audio from camera is 48hz, so I export the external audio with 48hz, no difference, what the hell is causing that drift?

[smrpix]

It's actually pretty easy in Vegas.

Find a sync point near the beginning --- your three claps for instance -- and actually cut the audio right before there. Add an edit to the video too so you know exactly where the audio should line up.

Now go to the end and find a sync point. Cut the audio after that distinctive sound then stretch or shrink the audio until it aligns perfectly. Zoom in close on the timeline to be sure.

Now that the audio is in sync and the right length you can extend out the head and tails if you need to.

If you can find a specific percentage that you've stretched or shrunk the audio, keep that for future projects.