So far I have always converted my HDV footage to NTSC before editing. For a small project I’m working on now, I’ve decided to try working directly with the raw HDV footage.

This thread explains why my m2t files show up as 1440×1080 even though they can be edited as 1920×1080 (aka 1080i). It has to do with square vs. rectangular pixels — or something — it doesn’t really matter. More general info on formats is here.

In Cinelerra, you must set the project format to 1440×1080, 16:9 ratio, then make sure you select “match output size” by right-clicking on the video track(s). This looks okay in the compositor window in Cinelerra, but the resulting file plays by default at 4:3 aspect ratio. You can set this manually when you open the video in VLC and see that everything looks okay. The only method I have found so far for getting the rendered video to play as 16:9 by default is by using a command such as this on to re-encode it after the fact:

ffmpeg -i -aspect 16:9 -sameq

For rendering in various formats, follow the instructions here as usual.