Videomaker – Learn video production and editing, camera reviews › Forums › General › Video and Film Discussion › Video File Incorrectly Interpreted as 4:3 and not 16:9 › 720×480 is a 4:3 format,
720×480 is a 4:3 format, believe it or not, because the pixel aspect ratio is not 1:1, it's actually .9. That is to say, the individual pixels aren't square, they're rectangular. That's why DV is a 4:3 frame aspect ratio even though the pixels are 720×480, which is closer to 16:9.
If there's somewhere in your editing software to change the sequence pixel aspect ratio to 1:1, you should have your widescreen aspect ratio back.