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On the Web
Since MPEG-1 was one of the first widely adopted compression standards, it has an
advantage of being compatible with most media players. This makes MPEG-1 attractive
for use on the web when you need maximum compatibility with relatively high quality.
Audio-Only
You can use MPEG-1 Layer 2 audio compression as an alternative to Dolby Digital
Professional or DTS compression. While there is no Apple setting for MPEG-1 audio-only
files in this release of Compressor, you can easily create a setting yourself. See
“Configuring the MPEG-1 File Format for DVD Use” on page 175 for details.
MPEG-1 Specifications
Compressor supports all the MPEG-1 specifications for frame sizes, frame rates, video
encoding, and audio encoding.
MPEG-1 Frame Sizes and Frame Rates
Compressor can produce full frame rate video (25 fps and 29.97 fps for DVD and 23.976
fps, 25 fps, and 29.97 fps for the web) with SIF resolutions dependent on the use:
 Web: 320 x 240
 NTSC: 352 x 240
 PAL: 352 x 288
While the NTSC and PAL resolutions are roughly half the full resolution of MPEG-2
video, when played on a DVD player they automatically expand to fill the entire screen.
MPEG-1 File Format Specifications
MPEG-1 video encoding uses a process very similar to that used in MPEG-2 encoding—
many of the same terms and settings apply. In Compressor, the encoding settings are
set as follows:
 Encoding mode: One pass
 GOP structure: Open
 GOP pattern: BBIBBP
 GOP length: 15 frames for NTSC; 12 frames for PAL
These settings are fixed and apply to all Compressor MPEG-1 video output files.
See “GOP Tab” on page 195 for information about Group of Pictures (GOP) settings.
See “Quality Tab” on page 190 for information on the encoding mode.
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Chapter 14 Creating MPEG-1 Output Files