SONAR for Film Sound Editing

Sonar can handle long projects just fine. That's not where you'll have any problems. It also supports 5.1 just fine.

I'm currently using Sonar to score a film. And what you describe is entirely possible, though there are some pitfalls.

My working process is that I am importing short sections into Sonar for composing to, which is all fine and dandy. I then export out these individual pieces of music. I'm also creating sound effects and recording VO in Sonar, again, to short sections and individual scenes.

I'm then importing all these bits into another project to assemble them to the full length cut of the film.

The painful part of this is that Sonar's video support is a bit unsophisticated. The only control you have over where a piece of video appears in the time-line is "Trim-in" time, meaning you can make it start further into the video than the very beginning of the video. But aside from that, the video will always start at 00:00:00... you can't slide it around or anything.

This is in some ways a minor detail, but it does mean setting up your tempo and time signature for composing to video is an unintuitive hassle a lot of the time.

Once you've got set up to work, it's fine, and of course, once you're compositing ready-made pieces of music into a full length project, then tempo doesn't really matter at all.

Attempting to compose everything directly in one project is just about possible, but it's no fun whatsoever, and not an approach I would take.

Hope this is of some use.