Apple Compressor (4.0) User Manual
Page 98
Chapter 5
Custom settings and output formats
98
MPEG-2 video frame sizes and formats
Because MPEG-2 uses fixed video frame sizes, Compressor enters the output frame size in the
fields in the Geometry pane based on your video format selection.
The video format you choose in the Video Format pop-up menu determines the options for the
associated characteristics such as frame size and rate, aspect ratio, and field dominance. For more
information, see
on page 89.
Video format
Frame size (pixels)
Frame rate (fps)
Aspect ratio
Scanning method
NTSC
720 x 480
23.98 (progressive
only), 29.97
4:3 or 16:9
Interlaced,
progressive
PAL
720 x 576
25
4:3 or 16:9
Interlaced,
progressive
720p
1280 x 720
23.98, 25, 29.97, 50,
59.94
16:9
Progressive
HD 1440 x 1080
1440 x 1080
23.98 (progressive
only), 25, 29.97
16:9
Interlaced,
progressive
HD 1920 x 1080
1920 x 1080
23.98 (progressive
only), 25, 29.97
16:9
Interlaced,
progressive
640 x 480 (1.33)
640 x 480
23.98, 25, 29.97
4:3 or 16:9
Interlaced,
progressive
640 x 360 (1.78)
640 x 360
23.98, 25, 29.97
4:3 or 16:9
Interlaced,
progressive
640 x 352 (1.82)
640 x 352
23.98, 25, 29.97
4:3 or 16:9
Interlaced,
progressive
640 x 384 (1.67)
640 x 384
23.98, 25, 29.97
4:3 or 16:9
Interlaced,
progressive
640 x 320 (2.00)
640 x 320
23.98, 25, 29.97
4:3 or 16:9
Interlaced,
progressive
About 24p (23.98p)
For DVD authoring and encoding, 24p refers to a video sequence that contains 24 progressive
(non-interlaced) frames per second, with NTSC-related standard-definition (SD) frame dimensions
(720 x 480 for MPEG-2). Film-based movies have a native frame rate of 24 fps, and because the
MPEG-2 format is able to represent 24 fps video internally, many commercial movie DVDs are
encoded in this way. But any time you use NTSC video in your project, the frame rate of film-
transferred material is slowed down from 24 fps to 23.976 fps (rounded to 23.98) and a 2:3:2:3
pulldown is added. So, the more accurate term is actually 23.98p.
Compressor can also do this for 24p source video files. For such material, the 23.98 frame
rate option (in the Video Format tab) compresses each source frame one-for-one, without
compressing repeated frames or fields in order to achieve a 29.97 fps display rate. This results in
higher quality at a lower compressed bit rate than would be possible if the 24p material were
converted to 29.97 fps prior to transcoding. Compressor also sets internal MPEG-2 frame flags
correctly, so that DVD players will properly apply the 3:2 pulldown process for display on 29.97
fps interlaced NTSC TV sets.
Note: If your source video has a frame rate of 24.00 fps rather than 23.98 fps, Compressor skips
one out of every 1000 source frames. If the 24p source video is 23.98 fps, Compressor transcodes
all source frames, without skipping (or repeating) any of them.