4.2

Main: Similar to the Baseline profile, with additional support
for standard-definition (SD) video requirements.
Baseline: Primarily for video conferencing and mobile
applications.
Entropy mode: Use the pop-up menu to set the entropy mode
to CABAC, which provides higher-quality output, or CAVLC,
which is faster.
Key frame interval: Enter a value in the text field to set the
(number of frames) at which you want key
frames created in your output file. Alternatively, you can select
Automatic to have Compressor choose the key frame interval
rate (the displayed value is 0 with Automatic on; the actual
value is determined during the encoding process).
Data rate: This pop-up menu allows you to choose a data rate
for your video based on any of three options:
Custom: Enables a slider to set the number of kilobytes
per second (kbps) to which you want to limit your video
signal. Higher rates allow higher-quality video, but generate
larger files that are slower to download or transmit.
Computer playback: Creates a larger file with higher
quality.
Web publishing: Creates a smaller file (of lower quality)
suitable for hosting on a website.
Important: When you set a data rate, you override other
codec-quality properties because the codec compresses the
file as much as it needs to based on its data-rate limit.
Multi-pass: Select this checkbox to turn on multi-pass
encoding that uses additional analysis of video frames to
key
frame interval