Mixing Sample Rates and Using Real-Time Sample Rate Conversion
Ideally, the sample rate and bit depth of your audio files should match that of your
sequence settings. When you play a sequence in Final Cut Pro, any audio files with
sample rates that don’t match your sequence sample rate are converted in real time.
This is known as sample rate conversion, and it requires additional processing power.
Clip items that require real-time sample rate conversion appear with a green render bar
within the clip item. For more information, see Volume III, Chapter 29, “Rendering and
Video Processing Settings.”
Even though Final Cut Pro can perform real-time sample rate conversion, conversions
can reduce your audio mixing and effects performance. The quality of this conversion is
controlled by the Audio Playback Quality setting in the General tab of the User
Preferences window. Higher-quality conversions reduce the number of audio tracks
that Final Cut Pro can mix together in real time.
Logging, Capturing, and Importing
If the sample rates of all the audio in your sequence match, sample rate conversion is
not necessary and the number of audio tracks that can play in real time increases. If
you are working with someone who is creating music or audio files specifically for your
project, you can request audio files at the settings you need to match your sequence.
However, If your audio clips don’t match your sequence settings, you can improve
audio playback performance by converting your audio files to the sample rate and bit
depth of your sequence.