Apple Final Cut Express HD - Manual (Page 982)

982 Part XII Output
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.
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.
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.