The video files created by the Sony DCR-SR72 Handycam are not playable on MacOS if you just copy them from the camera in USB mode. VLC will play them, but they can’t be opened by Quicktime, iMovie or iDVD:
The document "filename.mpg" could not be opened. The movie is not in a format that Quicktime Player understands
The videos can, however, be imported to iMovie if the camera is connected in “Disc Burn” mode. It may also be called “DVD burn” or something similar.
Connect the camera in disc burn mode, then open iMovie and select the “Import Movies…” option. Navigate to the folder on the camera where the MPG files are located, and click the import button. iMovie will then import all the files and save them as MOV files in the event library. This can take quite a long time if you have many movies. Also be aware that the resulting MOV files are larger than the original MPG files, and iMovie creates thumbnail versions which consume quite a lot of disk space. Make sure you have plenty of space available before starting.
Now the files are playable in iMovie and Quicktime, but there is still one more issue to fix. If you have recorded movies in 16:9 format, they will be rendered as 4:3 when you add them to a project in iDVD. To make them work properly you have to export them from iMovie to yet another MOV file.
This whole process is very frustrating. Not only does it take a lot of time and effort, but the double conversion of the files ends up consuming around 3 times more disk space than if the original files could be copied off the camera and used directly.
Apple offers a Quicktime MPEG2 Component which might make the original files playable, but it’s not clear to me if that will remove the need to import/convert them before using in iMovie/iDVD. Also it’s a bit annoying that it costs USD19.99 on the US store, but JPY3400 (almost double!) on the Japanese store.