Apple Final Cut Pro 7 - Manual (Page 1433)

• Graphics card speed and memory: Many video filters in Final Cut Pro use your computer’s
graphics card to process effects, leaving the computer processor free to perform other
tasks. A faster graphics card with more RAM allows more real-time playback.
• Level 2 and Level 3 processor cache: The sizes of a computer processor’s level 2 and 3
caches affect its real-time playback capabilities. The larger these caches are, the more
real-time performance is available.
• RAM: The more RAM you have available in your computer, the more potential real-time
performance your computer has.
• Memory bus speed: Computers with a faster memory bus allow better real-time
performance because data can be sent more quickly between RAM and the computer
processor.
• Hard disk speed: The faster your hard disk can read data, the more video data
Final Cut Pro can access in real time. With some video formats, such as uncompressed
video, hard disks may not be able to keep up with the video data rate, making real-time
playback impossible. Multiclips and multiple video layers require many video streams
to play back simultaneously. A faster hard disk allows more streams to play back
simultaneously in real time.
• Codec: Not all codecs are supported by RT Extreme, but the most commonly used ones
are. Some codecs require more processing power and RAM to play back than others.
For example, the long-GOP MPEG-2 compression used by HDV requires more RAM and
processing power to decompress than I-frame-only codecs such as DV. For more
information, see
“Supported Real-Time Playback Codecs.”
• External video monitoring: Enabling output via FireWire or other video interfaces requires
additional processing power and may limit the number of effects you can play back in
real time. For more information, see
“External Video Monitoring.”
Real-Time Audio Mixing in Final Cut Pro
Final Cut Pro can mix and play back multiple audio tracks in a sequence in real time, even
while you make adjustments to levels, stereo pan, and audio filters. The number of tracks
that can be played back depends on the number of filters applied to your clips and your
computer’s capabilities and settings, including:
• Your computer’s processor speed
• The seek time and sustained transfer rate of your hard disk
• The amount of RAM available to Final Cut Pro
• The Audio Playback Quality setting in the General tab of the User Preferences window
Note: For information on this setting, see “Choosing Settings and Preferences.”
1433 Chapter 84 Using RT Extreme