Apple Compressor (4.0) - Manual (Page 115)

Chapter 5 Custom settings and output formats 115
H.264, also known as MPEG-4 Part 10, is a newer technology than MPEG-4 Part 2, providing up to
four times the frame size of video encoded with the MPEG-4 Part 2 codec at a given data rate. But,
just as MPEG-1 and MPEG-2 are still used in the industry today, MPEG-4 Part 2 continues to be used.
Note: MPEG-4 Part 2 is both a QuickTime codec (MPEG-4 Video) and an output format. This
chapter discusses MPEG-4 Part 2 as an output format.
MPEG-4 Part 2 offers the following advantages:
•
Standards compliance: Output is compatible with MPEG-4 Part 2 devices and other standards-
based (ISMA) players, such as mobile phones.
•
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.
MPEG-4 Part 2 default settings
If you don’t need to customize the video and audio settings of your MPEG-4 Part 2 file, you can
easily transcode your source media files by accepting the default MPEG-4 Part 2 output format
settings. For more information, see
Create MPEG-4 Part 2 settings on page 116.
Default Video tab settings
These are the default video settings for MPEG-4 Part 2 output media files:
•
Video Enabled: Selected
•
Video compression: H.264 baseline profile
•
Frame Rate: 29.97 fps
•
Key Frame Interval: 30 frames
•
Bit Rate: 1000 kbps
Either enter a number in
the Bit Rate field or use
the slider to set the bit rate.