Need to bounce output at exact length

[furrytoes]

Hi,

 

I need to bounce a mastered track out at *exactly* 1.51.67 (the length of my video)

 

Below is a screenshot of a video in Quicktime, with a Logic screen, showing the region I'm bouncing, above it.

 

The region is 1.51.666 (which seems close enough).

Unfortunately, this bounces at the length 1.51.72 (ie "Sound Track 2" in the screenshot)

 

(I render audio from the video editor, master it in Logic and then use Quicktime to "copy" the audio track in).

 

The reason I need my output m4a/wav file to be exactly 1.51.67 is for iPad compatibility. If I don't get the soundtrack at exactly the length of the video - it's basically not playable (by ordinary means) on the iPad (or at least in Dropbox).

 

I can't figure out a way to guarantee the length of my output file (1.5.1.67) or even just get Logic to output 1.51.666 as it says is the length of the region. Incidentally, before I bounce, I select the region and leave the settings based on that.

 

Am I asking for too much precision?

 

[furrytoes]

Actually, it's only the .m4a that's 1.51.72.

I just loaded both the .wav and .m4a files that I bounced, into Audacity - and the .wav is absolutely correct at 1.51.666.

The .m4a is "wrong" at 1.51.723

So this must be the vagaries of mp4 compression...