Audio Sync Question for you experts. at DVinfo.net

Alastair Brown · June 23rd, 2008, 01:49 AM

Here is one for you audio experts.

I recorded some Audio using an Olympus DS-30 Digital Voice Recorder. It was at it's highest quality setting recording in wma format at 44.1 kHz / 128 kbps.
My problem arose when I then tried to sync this up to my XH-A1 HD Footage.
The sync very quickly drifted out.
I'm a Vegas user.
Only solution I could get was to go to the clip properties for the Olympus track and do the following:-
Go to Time stretch/pitch shift
Method Classic
Set the new length value to approx 99.76% of the original length. (too tired to work it out exactly..sorry!)
You then have to go back and re-sync the start of the clip.
After that you go to the end of the clip and just adjust the new length a fraction at a time until you are in sync.
Took a few attempts having to adjust/re-sync the start and check but it's now spot on.

So…….anybody got an explanation for what goes or a more elegant non hit or a miss solution?

Jeff Harper · June 23rd, 2008, 02:26 AM

Jon Fairhurst is very knowledgeable about this stuff...he might check in with some tips for you. I would also suggest checking in the audio forum...those guys are pretty knowledgeable about this stuff...this is a very common problem that is brought up over there all the time....unfortunately I don't think there are any quick and easy answers....as I recall I ended up not using my digital voice recorder except for backup, as the audio drift issue with digital voice recorders, even some high end ones, seems to be an inescapable problem.

I remember a recommendation of using the Sony mini-discs (device is only sold used now) and then downloading audio analog instead of copying files, which seemed to work for one guy.

Alastair Brown · June 23rd, 2008, 03:14 AM

Perversely, I bought this to replace a Mini-disc recorder that worked perfectly! Capturing time was my only problem. I believe the Sony NET MD recorders let you drag the file across.

Edward Troxel · June 23rd, 2008, 05:53 AM

Can't you just hold down the CTRL key and stretch it to match?

Alastair Brown · June 23rd, 2008, 06:58 AM

It's an hour long clip and no matter how hard I tried using that method to match the peaks, I just wasn't happy with it. It ended up going to frames button in the time/pitch adjust was what got me there.

Heard someone mentione re-sampling at 48k but that made no difference. Not sure whether the anti-alias setting would have made any difference on/off?

Bill Ravens · June 23rd, 2008, 07:09 AM

have you tried turning off "quantize to frames"?

Alastair Brown · June 23rd, 2008, 09:07 AM

http://www.mfbb.net/myvideoproblems/...s-about25.html

Some good info on the subject.

Hadn't tried the quantize to frames.

June 23rd, 2008, 01:49 AM	#1
Alastair Brown Major Player Join Date: Aug 2006 Location: Glasgow/Scotland Posts: 626	Audio Sync Question for you experts. Here is one for you audio experts. I recorded some Audio using an Olympus DS-30 Digital Voice Recorder. It was at it's highest quality setting recording in wma format at 44.1 kHz / 128 kbps. My problem arose when I then tried to sync this up to my XH-A1 HD Footage. The sync very quickly drifted out. I'm a Vegas user. Only solution I could get was to go to the clip properties for the Olympus track and do the following:- Go to Time stretch/pitch shift Method Classic Set the new length value to approx 99.76% of the original length. (too tired to work it out exactly..sorry!) You then have to go back and re-sync the start of the clip. After that you go to the end of the clip and just adjust the new length a fraction at a time until you are in sync. Took a few attempts having to adjust/re-sync the start and check but it's now spot on. So…….anybody got an explanation for what goes or a more elegant non hit or a miss solution? Last edited by Alastair Brown; June 23rd, 2008 at 03:15 AM.

June 23rd, 2008, 05:53 AM	#4
Edward Troxel Sponsor: JET DV Join Date: Dec 2001 Location: Southern Illinois Posts: 7,953	Can't you just hold down the CTRL key and stretch it to match? __________________ Edward Troxel [SCVU] JETDV Scripts/Scripting Tutorials/Excalibur/Montage Magic/Newsletters

June 23rd, 2008, 02:26 AM	#2
Jeff Harper Inner Circle Join Date: Jun 2005 Location: Cincinnati, OH Posts: 8,425	Jon Fairhurst is very knowledgeable about this stuff...he might check in with some tips for you. I would also suggest checking in the audio forum...those guys are pretty knowledgeable about this stuff...this is a very common problem that is brought up over there all the time....unfortunately I don't think there are any quick and easy answers....as I recall I ended up not using my digital voice recorder except for backup, as the audio drift issue with digital voice recorders, even some high end ones, seems to be an inescapable problem. I remember a recommendation of using the Sony mini-discs (device is only sold used now) and then downloading audio analog instead of copying files, which seemed to work for one guy.

June 23rd, 2008, 03:14 AM	#3
Alastair Brown Major Player Join Date: Aug 2006 Location: Glasgow/Scotland Posts: 626	Perversely, I bought this to replace a Mini-disc recorder that worked perfectly! Capturing time was my only problem. I believe the Sony NET MD recorders let you drag the file across.

June 23rd, 2008, 06:58 AM	#5
Alastair Brown Major Player Join Date: Aug 2006 Location: Glasgow/Scotland Posts: 626	It's an hour long clip and no matter how hard I tried using that method to match the peaks, I just wasn't happy with it. It ended up going to frames button in the time/pitch adjust was what got me there. Heard someone mentione re-sampling at 48k but that made no difference. Not sure whether the anti-alias setting would have made any difference on/off?

June 23rd, 2008, 07:09 AM	#6
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	have you tried turning off "quantize to frames"?

June 23rd, 2008, 09:07 AM	#7
Alastair Brown Major Player Join Date: Aug 2006 Location: Glasgow/Scotland Posts: 626	http://www.mfbb.net/myvideoproblems/...s-about25.html Some good info on the subject. Hadn't tried the quantize to frames.