I've never tried a side by side comparison.... perhaps you could do a test trying it both ways.

I would imagine that since no one answered your post that no one knows. This is a fairly simple test to do and you could have answered this yourself. Since you didn’t, I ran a test and found that it is indeed *much* slower to use video with opacity of zero. Here’s what I did:

Stack two video clips on two tracks, one above the other, at 100% opacity and render one minute of NTSC DV avi. Took 00:00:26. Now set the opacity of the top track to zero (0%) and render again. This time it took: 00:01:53 !!! (That's on my Pentium 4 3.0Ghz PC, your PC may be slower of faster)

That’s a 4X hit in performance! So I would strongly suggest that you should cut out the video you don’t want instead of setting the opacity to zero. You should see a significant performance improvement when rendering.

~jr

I've just tried repeating ~jr's experiment on a 933 Mhz PIII - it produced a 10x difference in render time! I'd expect some difference, but not that much - is the P4 inherently better for video production (ignoring the clock speed)?

Ian G.

I don’t think know the answer but I suspect it has more to do with the fact that your P3 @993Mhz is one-third the speed of the P4 @3000MHz rather than the difference between the P3 and P4 itself. If performance was linear because it’s just compute intensive, you would expect it to take 3x longer than the 3.0Ghz at 4x, which would be 12x (3 x 4) so 10x isn’t bad. I know that doesn’t make you feel better but it is logical. ;-)

Don’t forget, rending DV AVI to DV AVI is not compute intentive at all because it’s just a disk copy from source to target so you’re measuring disk i/o at that point.

~jr