MPEG-4 Audio Export Options
When you export a movie to MPEG-4 format (by choosing File > Export and then
choosing “Movie to MPEG-4”), you access the following options by clicking Options and
then clicking Audio.
Exporting Files with QuickTime Pro
Â Audio Format: Choose your audio compressor (codec) here. If your source movie has
only one audio track and it is already compressed, you can choose “Pass through” so
that the audio doesn’t get compressed again.
Â Data Rate: As with video, the more kilobits per second, the better the audio quality.
Â Channels: Choose between mono (1 channel) or stereo (2 channels).
Â Output Sample Rate: Available only with AAC audio. It’s best to match the sample
rate to that of the target device.
Â Encoding Quality: Available only with AAC audio. The Good setting is optimized for
the highest-speed encoding, for higher-quality, choose Best for 16-bit audio, or Better
if your audio source is 24-bit.