Apple Final Cut Pro 7 - Manual (Page 1710)

The QuickTime framework supports codecs that are commonly used today as well as
codecs that were once popular. When you go to export a QuickTime movie file, the long
list of available codecs demonstrates how extensive QuickTime codec support is. At the
same time, this list can be potentially daunting. Look for the codec you need and ignore
the rest.
Distinguishing Between File Formats and Codecs
A file’s format specifies the unique way data is stored and organized in a file, regardless
of what the content of that data represents. A codec is an algorithm that transforms
image or sound data into a more compact, albeit temporarily unintelligible form for the
purpose of compression (reducing data size for transmission or storage). The codec must
be reversed in order to see the original content of the media data.
A file format determines consistent guidelines for where information is stored and found
in a file. For example, a Microsoft Word file will always store the name of the creator in a
particular location in the file’s structure. On the other hand, a codec is specific to
media-intensive data, such as video or audio, and is used simply to reduce the data size.
Understanding Codec and File Format Naming Conventions
The distinction between file formats and codecs is often confused by shared naming
conventions. For example, MPEG-2 defines both a file format (a structure for organizing
video and audio data within media tracks) and a codec (an algorithm for encoding and
decoding video and audio data for the purposes of compression).
The following codec and file format examples may help to clarify the distinction.
• TIFF: This refers to a graphics file format. TIFF files may or may not use a codec, or type
of compression called LZW compression.
• JPEG: This is a type of compression that can be used on any still images or individual
video frames. Images encoded with JPEG compression can be stored in the JPEG file
format. QuickTime can open files in the JPEG file format as well as decode images
compressed with the JPEG codec.
• QuickTime: This refers to the QuickTime movie file format, which can contain multiple
media tracks, each containing data encoding with a number of possible codecs.
QuickTime is not a codec, but rather has the ability to present images and sound stored
with a number of codecs.
• AIFF and WAVE: These are audio file formats that contain uncompressed audio data.
1710 Chapter 103 Learning About QuickTime