Video Assets for HD-Based DVD Video Streams
All assets on an HD-based DVD stream must use the same aspect ratio (4:3 or 16:9), the
same resolution, the same video standard (PAL or NTSC), and the same MPEG type
(MPEG-2/HDV or H.264).
All non-HDV and non-H.264 QuickTime video assets you import into an HD projects are
encoded as MPEG-2.
Note: Because HDV is actually HD MPEG-2, you can combine HDV assets with other HD
MPEG-2 assets, including those encoded from the integrated MPEG encoder, as long as
they are the same resolution.