Apple Motion 4 - Manual (Page 1410)

Note: DVCPRO 50 movies cannot have alpha channels.
Apple M-JPEG
There are two Apple M-JPEG codecs, M-JPEG A and M-JPEG B. These are variable data
rate codecs similar to the ones used by video capture cards. If you need to deliver more
heavily compressed material to keep files small, consider these codecs. M-JPEG is a lossy
codec and results in artifacts in your final video. The severity of these artifacts depends
on the data rate you choose.
Several capture and playback cards on the market can play back either M-JPEG A or
M-JPEG B in real time without re-rendering the material, or at most, doing minimal
re-rendering. This makes file interchange very fast. Before you use either M-JPEG A or B,
consult the manufacturer of the capture card you’re using to find out which one you
should use.
Note: Apple M-JPEG movies cannot have alpha channels.
JPEG
JPEG is similar to M-JPEG, except that the compression artifacts can be less severe at
similar data rates. JPEG movies may play back in real time on your system, depending on
your system’s speed and the data rate of the movie.
Note: JPEG movies cannot have alpha channels.
Third-Party Codecs
There are several manufacturers of video-editing solutions, most of whom use different
variations of the M-JPEG codec. Many make software-only QuickTime codecs that you
can install in your System folder, enabling you to play back movies with little or no
re-rendering. For more information, contact the manufacturer of the editing system.
Note: Most third-party codecs cannot have alpha channels.
What Is Field Order?
All video displays, whether analog or digital, work by breaking a single frame of video
into individual lines of horizontal resolution running across the screen. Standard definition
NTSC and PAL are both interlaced video formats, as opposed to high definition video, or
video displayed on a computer screen, which are progressive-scanned video formats. With
progressive scanning, these lines are drawn one at a time, from the top of the screen to
the bottom.
1410 Appendix B Video and File Formats