Re: Converting HD Video for Video On Demand - Bad Quality Loss - Advice please!

Compression is all about finding the balance between quality loss and file size.

I would target something like:
Export to Quicktime
Compression: H.264 (multipass if you have the time)
I would use the Limit Bitrate option instead of the Quality slider. It'll give you a file size estimate. I would start at 8mbps for 720 or 25mbps for 1080. Depending on the complexity of your footage and the need for quality you can adjust up or down to taste.
Sound: MPEG-4 AAC, Stereo, Auto, 192kbps
Frame Size - I would leave it at unscaled, but if you're at 1080 you can shave off a lot of size by dropping to 720.
Frame Rate - Don't type one in and it will be unchanged.
Interlaced scaling should be OFF
Deinterlace video should be on if your source is 1080i, otherwise it should be off.

Remember, if you're testing for quality you can work with a sample of the video instead of ten minutes. Pick a portion with a lot of motion in the frame.

When you find settings you like, save a preset.