Mpeg-2 files, Mpeg-2 overview, 84 mpeg-2 files 84 – Apple Compressor (4.0) User Manual
Page 84
Chapter 5
Custom settings and output formats
84
Stereo playback
Even with the popularity of 5.1 systems, you should always address stereo reproduction. There
are three basic ways to do this:
•
Prepare a new stereo mix from the original multitrack elements (using conventional stereo-
mixing sessions).
•
Prepare a studio-adjusted downmix from the multichannel mix. This method takes advantage
of the work that has gone into mixing the 5.1 version. It retains flexibility in the exact
proportions of each channel represented in the final stereo mix.
•
Let the decoder derive a stereo downmix, based on preset formulas in the decoder. Downmix
options and dynamic range control effects can be previewed and adjusted in the production
studio, and a range of adjustments are possible.
Always check the mix on an inexpensive surround system to evaluate how well it sounds on
modest playback systems.
Note: For more information about Dolby Digital Professional, visit the Dolby Laboratories Inc.
website a
.
MPEG-2 files
MPEG-2 overview
MPEG-2 is an internationally accepted compression standard developed by the Motion Picture
Experts Group (MPEG). MPEG-2 allows you to create broadcast-quality video files and was
designed to support high-resolution, high-bit-rate video. It’s the video compression format used
for high-quality video titles on DVD, high-definition (HD) broadcast, and home satellite dish
systems. All DVD players contain the hardware required for MPEG-2 playback.
The Compressor MPEG-2 encoder can create MPEG-2 video streams for the DVD-Video format.
To create DVD-Video discs, you can use a DVD authoring application in conjunction with
Compressor, or you can use the Create DVD job action, which is part of the Create DVD template.
For more information, see
Post-transcoding actions overview
on page 184 and
page 18.
Standard-definition (SD) MPEG-2
Standard MPEG-2 is full frame rate (23.98 to 29.97 fps) and full-screen resolution (720 x 480 for
NTSC and 720 x 576 for PAL). SD MPEG-2 has the following characteristics:
•
Support for interlaced video: MPEG-2 can support either interlaced or progressive video.
Because MPEG-2 streams are generally played from a local DVD drive rather than over a
network with variable bandwidth, video frame rate usually stays constant, and the video
normally looks completely smooth.
•
No streaming support: MPEG-2 is not suitable for streaming video files over the web because it
requires a high bit rate (2 to 9 Mbps) to maintain acceptable image quality.