I want to export some QuickTime movies from iMovie to put on a CD-ROM. So, I am not too concerned about the size of the movie files, but I want them to look as good as possible at the largest window size as possible.

I have found, however, if I use the default "large, CD-ROM" export settings my iMac DV/SE cannot play back the movies very smoothly and the resolution isn't all that high.

Does anyone have any preferred export settings you can recommend? I guess my priorities are:
1. High quality image
2. Large window size
3. Audio quality
...in that order.

Thanks in advance.

a)If you want smooth playback, keep the bitrate below about 3.5M/sec (that's megabytes) so it's 28Mbits/sec.
b)If you're not actually making VCD's you could drop the framerate from 25/30fps down to about 20/24, anything below that starts getting jerky.
c) Get Quicktime 4.1Pro (If you haven't already) gives you more control over compressions settings etc.
d) Again, if it's CD-ROM for your own use, try the frame size 384x288 (VCD/MPEG1 size, approx), it's a reasonable size for full speed playback, unless you really want 640x480/768x576 blown up to full-screen! Remember you're also dealing with IDE/ATA max data rates from your CD-ROM not just the capabilities of the CPU/Graphics Card.
e) Use Sorensen Compression (If you're not already) definitely the best quality vs bitrate compressor. (I'm sure 3,500,000 will now disagree with me!!!)
f) Sound, for quality try to leave sound alone (ie: uncompressed) it's already been sampled once, you could go from stereo to mono, or integer halve the sampling rate, or go from 16bit to 8bit. Compressors can give the sound a strange hollow phased effect. Compared to the video bit-rate, the sound is almost insignificant. I'd sacrifice a few K of video to keep reasonably listenable sound!

N.B. These are statements of personal opinion, I'm not trying to pass them off as fact, Gospel, a quotation from the Torah or even an extract from the Dead Sea Scrolls (2nd edition, addendum to Section 2, St.Paul's Letter to Sorensen)

[This message has been edited by Feathers (edited 03-24-2000).]

I disagree with Feathers about the sound compression. I have found audio compressed with IMA 4:1 is very good. It gives much better quality than going from 16-bit to 8-bit, and it is more compressed. You could also use ULaw or ALaw, which will cut the size of the output in half without sacrificing quality. 16-bit sound can become VERY big uncompressed.

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Simon Kornblith
Computer Consultant
Programmer

[This message has been edited by Simon Kornblith (edited 04-01-2000).]

!!!