Subject:Frame Boundaries - what gives?

Posted by: Shaun

Date:7/7/2001 10:14:19 AM

I burn CD's from WAV files I master in SF5B. I burn using Adaptec (Roxio) ECDC 4.5, DAO. Often I work on a big WAV from one side of a tape, then create regions for each CD track, break out the regions into WAV files using the Extract Regions tool, then burn the CD. I recently learned that small clicks occur between tracks on audio CD's when tracks don't end on frame boundaries. To cure this I use status format "Absolute Frames" to set the region boundaries for each track, then Extract Regions tool to create the individual WAV files. I set the default frame rate to 75/second, the Red Book Standard setting.

Now here's the problem: when I create regions on frame boundaries, I get a region length that is 0.002 frames larger than the selection. Here's an example:

Region starts at 0.000 frames
Region ends at 94,262.000 frames
Region length: 94,262.002 frames
Input format: Absolute frames

This setting produces an audible click on DAO CD's.

If I set the length to 94,262.000, I get a region end of 94,261.998 frames and no click.

So why is this .002 tagged on the length of the WAV, and how should I go about creating my regions?

Subject:RE: Frame Boundaries - what gives?

Reply by: Sonic

Date:7/9/2001 12:38:15 PM

The region end points are sample inclusive, e.g. a selection from sample 0 to sample 10 is 11 samples long.

So a region from 0.000 to 94262.000 is actually (588*94,262) + 1 = 55,426,057 samples, or 94,262.0017 frames in _length_. If you want your length precisely at 94262.000, then the region end should be at sample index 55,426,055 or 94261.9983 frames.

J.