On every film I work on we always run into the question of where do we apply our matte so that the editors' client monitors are hard-masked to 2.40 or whatever aspect ratio we're working in. Sometimes you can do it on the client monitor itself, other times with a downstream key on a 3rd-party I/O card, and sometimes in the timeline itself with a dedicated matte track. 

It'd be nice if Media Composer had a user setting for applying a matte on any output from the system, or if it was an option that could be enabled when a Mojo or Nitris is attached. 

+1

I have often suggested such a thing.

I think there should be an output module that should be configurable for each sequence. It would operate precisely as if you had added extra video tracks to your timeline and put some effects on them, only you don't see these effects in your timeline and you can't keyframe them.

Every timeline should have the options to enable resizing, blanking, grids, burn-ins and watermarks. You could just toggle on/off what you need and store presets for different projects.

The module would effect the entire sequence just before it is output to the client monitor. You could have switches to toggle the display for desktop/client monitor/export.

It would be super usefull IMHO.

Absolutely. Longstanding request. Even more so with the arrival of first Super35 and now all digital cams that need to be cropped to 2.39.