A 450 MHz processor is never going to decode 1080p. I know this. My 500 MHz G4 upgrade can play 720i in some formats, but with occaisional drops. It also depends what player you use and what video card. OS 9 has funny limitations on playing back various file and container types. AVI *can* work, but many (most?) files will be problematic with mp3 audio. It's crazy how you can play an mp3 audio file in Quicktime 6, but not an mp3 audio track to an AVI movie!
Here are your best bets for OS 9 video:
If you can re-code the media files yourself to make sure they play, AVI might be ok. Maybe demux and transcode the audio to .aifc or something else Quicktime likes.
If you don't mind huge file size, encode uncompressed. Motion JPEG video and AIFF audio to a .mov file. It will be huge - perhaps gigabytes - but QT will play it without a hitch and since your CPU won't need to decompress anything you will get the largest possible playback size. Limited only by the throughput of your bus and video card. This could yield 720p or better on your CPU, but YMMV. If you need a compressed .mov lossy MPEG1, Cinepac, or Sorenson will play nicely, but don't count on large screen sizes.
Here are your best bets for OS 9 video:
If you can re-code the media files yourself to make sure they play, AVI might be ok. Maybe demux and transcode the audio to .aifc or something else Quicktime likes.
If you don't mind huge file size, encode uncompressed. Motion JPEG video and AIFF audio to a .mov file. It will be huge - perhaps gigabytes - but QT will play it without a hitch and since your CPU won't need to decompress anything you will get the largest possible playback size. Limited only by the throughput of your bus and video card. This could yield 720p or better on your CPU, but YMMV. If you need a compressed .mov lossy MPEG1, Cinepac, or Sorenson will play nicely, but don't count on large screen sizes.