Audio help

[John R. Hart]

I am finishing/starting an older project. It consists of mini DV tapes from a canon gl2 and separate audio recordings made with a Nady wireless lavalier mic plugged into my laptop.
Using Sound Forge 7, The original files are wave 64 and have been saved as mp3 files and wav files at various bit and Hz to try and match the audio from the mini DV. I am using Vegas 6 with Sound Forge 7.
I am overlooking something simple. I have had to deal with this in the past, I just can’t remember. Any help/suggestions would be appreciated.
Thanks John

[Seth Bloombaum]

Exactly what problem(s) are you experiencing?

Typically saving in different formats is not needed, keep the recordings as wav. It is helpful to have the laptop recordings at the same sampling rate as the original GL2 recordings, eg. 48KHz or 32KHz.

[John R. Hart]

I don’t remember what the sample rate was when originally recorded. When I drop the extra audio on the time line it only stays in sync for about 15 seconds. When I rendered the original recording I most likely did not change the default settings, and most likely did not change the defaults when recording in sound forge. Between changing the project properties in Vegas, and resaving the wave 64 file with different properties, I can’t seem to match the audio files.

[Tim OBrien]

Saving as MP3 probably changed the sample rate to 44.1khz.

Video is always 48k.

You should always keep your audio in .wavs at 16bit/48k.

[John R. Hart]

This is what I have

wave 64 audio files 32,000 Hz, 24 Bit, Stereo

and DV audio, Bit rate 1536 kbps, 16 bit sample, PCM format

Can the two audio files be mach on the time line?

[Edward Troxel]

There frequently is a little drift. The main two methods of fixing this is to every so often split and resync or just do a CTRL-Resize of the audio so that it matches. It should be a very small adjustment.

[Seth Bloombaum]

Originally Posted by John R. Hart

This is what I have

wave 64 audio files 32,000 Hz, 24 Bit, Stereo

and DV audio, Bit rate 1536 kbps, 16 bit sample, PCM format

Can the two audio files be mach on the time line?

You've not included the sample rate for your DV audio, but at 1536 Kbps bitrate I believe that's 48KHz sampling rate - you can confirm this in media properties. This is the most common for DV. (Although many cameras also have a 32KHz mode it is almost never desireable.)

If so, your first step is to convert your audio-only files to 24bit or 16bit 48KHz sampling rate, then see how they perform and sync on the timeline prior to using the techniques Edward describes above.

When recording projects in the future on your laptop, it is best to match the sampling rate of the video audio for easier sync.

[John R. Hart]

I have pull up an old VEG file, and to my dismay the procedure that Edward mentions is exactly what I did in the past. That project was a small 20 minute promo.

The current project is documentary with hours of interviews. As it is, I have set the vegas audio project properties to 16bit 48Hz, dropped the video on the time line (vid was shot in 16bit 48Hz audio). Than dropped the extra audio on the time line (converted to 16bit 48Hz wav) and it only stays in sync for about 15 seconds.

The original recording attributes in sound forge were 24bit 32Hz.

Well thanks for all the help, I best get haken and slashen.
John

[John Cline]

Even though both the camera and laptop are crystal controlled, they aren't running at _exactly_ the same frequency. Therefore, they are guaranteed to drift. Fixing the problem is fairly easy in Vegas, align the audio files at the beginning and then grab the end of the audio track and hold down the Control key and lengthen or shorten it to match the video's audio track.

[John R. Hart]

Yes. Thanks. It seemed a little overwhelming when I put up 80 minutes of video and a 110 minutes of additional audio.
Once I calmed down and set all properties to the same settings and trimmed the events down to match and resized the additional audio event, it was all good

Thanks again
John