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aspect ratio A lm or video frame’s width-to-height ratio on any viewing screen.
Standard-denition (SD) video (used for regular television screens) has an aspect ratio
of 4:3. High-denition (HD) video has an aspect ratio of 16:9.
Audio Animation Editor You can show the Audio Animation Editor for clips in the
Timeline to adjust eect parameters, create fade-ins or fade-outs, or change eects
over time using keyframes.
audio sample rate The number of times an audio signal is measured, or sampled, per
second. A higher sample rate produces higher-quality audio and larger le sizes, and a
lower sample rate produces lower-quality audio and smaller le sizes.
Audio Units The standard real-time audio lter format for audio applications used
with Mac OS X.
audio waveforms Audio waveforms are visual representations of the actual sound. An
audio waveform’s amplitude and length change according to the underlying sound’s
volume and duration. A short, loud sound such as a drum beat has a sharp, peaked
waveform, whereas low-level crowd noise has a lower, more uniform waveform.
These properties make it easier to nd specic edit points when trimming clips or
keyframing eects.
audition In Final Cut Pro you can organize related clips into sets, called auditions,
from which you can choose one clip to use. You can create an audition composed of
dierent clips to try out multiple takes, or you can create an audition composed of
multiple versions of the same clip to preview dierent eects. Auditions appear in the
Event Browser and Timeline as clips with an Audition icon in the upper-left corner.
AVCHD A high-denition (HD) video format that uses Advanced Video Coding (AVC)
compression (also known as MPEG-4 part 10 or H.264). Many Blu-ray players can play
red laser discs with AVCHD format content, making this a common way to distribute
short HD video projects using a standard red laser disc.
Background Tasks window The Background Tasks window shows the progress of
importing, transcoding, analysis, rendering, and other tasks.
batch Compressor uses a batch to contain one or more source media les that you
want to convert, or transcode, to another format. Each source media le creates its
own job. This means that a batch can contain multiple jobs, with each job based on its
own source media le. Each job also has at least one setting that denes the format of
the transcoded le.
bit rate The number of bits per second that makes up a digital video or audio asset.
The higher the bit rate, the better the quality. However, higher bit rates require larger
le sizes.
534 Chapter 18 Glossary