Apple Compressor 3 - Manual (Page 222)

• High-quality video: A versatile transcoder that can be set to a target data rate and—using
one-pass variable bit rate (VBR)—can maximize the highest-quality output or speed
for the fastest possible transcode.
• Advanced Audio Coding (AAC): MPEG-4 audio accommodates a wide variety of source
audio, and brings true variable bit rate (VBR) audio transcoding to QuickTime. It uses
the Advanced Audio Coding (AAC) codec, which provides more clarity than MP3 audio
at the same bit rate with smaller file sizes, or files of the same size at higher quality.
You can also include podcasting information, such as chapter and podcast markers
with artwork and URLs, as well as a variety of text annotations.
• Hinting for streaming: Hinting refers to how a video stream is divided into streamable
pieces. To create streaming video, the streaming server needs some hints about what
data to send out and when. These hints consist of defining a maximum packet size and
maximum packet duration. A hint track contains information needed to stream your
output file. A hint track is created for every streamable media track in the output file
(video and audio), and the streaming server uses the hint track to turn the media into
real-time streams.
About the MPEG-4 Part 2 Encoder Pane
The MPEG-4 Part 2 Encoder pane allows you to select a variety of streaming types and
options.
MPEG-4 Encoder Pane General Settings
The MPEG-4 Part 2 pane contains the following items:
• File Extension field: Displays the MPEG-4 Part 2 file extension (.mp4) as soon as the
MPEG-4 output format is selected from the File Format pop-up menu or the (+) pop-up
menu in the Settings tab.
222 Chapter 19 Creating MPEG-4 Output Files