Adobe 65008009 - After Effects CS4 Using Manual page 642

Last updated 12/21/2009
Because antivirus software operates by monitoring every read and write operation, such software can decrease
rendering speed, especially with the Render Multiple Frames Simultaneously preference selected.
Minimum Allocation Per CPU
process, each of which runs on its own CPU (processor core). Setting this value lower can allow more CPUs to be used
simultaneously with a limited amount of RAM. However, if you set this value too low for the kinds of frames that you
are rendering, then the background processes will fail to render frames at all, and only the foreground process will be
used to render frames. For example, you should not set this value to 0.5 GB if you are rendering frames with the pixel
dimensions of high-definition television or digital cinema.
The optimum amount of RAM to allocate for each of the background processes varies according to project settings
(such as color bit depth), composition settings (such as pixel dimensions of the composition frame), and what effects
are applied. For a typical 8-bpc project with HDTV-sized compositions, at least 1 GB per background process is
recommended. For a 32-bpc digital cinema project, at least 2 GB per background process is recommended. Start with these
settings, but run some tests with your own computer systems and projects to determine the best settings for your specific
needs.
Longer RAM Preview / Faster Rendering
be stored in the RAM cache. The RAM cache exists in the address space of the foreground After Effects process. By
allocating more memory to the foreground After Effects process, less memory is allocated to the background processes.
This allocation of memory to the foreground process can cause fewer background processes to be used to render
multiple frames simultaneously, so there is a tradeoff between faster rendering and longer RAM previews. Drag the
slider to adjust the memory allocation to a balance that suits your work and computer system.
CPUs To Leave For Other Applications
of the CPUs (processor cores) in your computer system. For example, if you have a computer with 8 CPUs, setting this
value to 2 leaves 6 CPUs for After Effects.
When After Effects temporarily disables multiprocessing with Render Multiple Frames
Simultaneously
If After Effects can't use background processes to render multiple frames simultaneously, a message appears in the Info
panel and After Effects uses only the main foreground process to render all frames. These messages include the
following:
• "Incompatible composition. Multiprocessing is off."
• "Incompatible effect. Multiprocessing is off."
• "Incompatible preview mode. Multiprocessing is off."
In general, the reasons for After Effects temporarily disabling the Render Multiple Frames Simultaneously
multiprocessing feature fall into these categories:
• The rendering of a single frame requires more RAM than is available to the individual background processes.
• The project uses OpenGL for rendering of previews or final output. The Render Multiple Frames Simultaneously
multiprocessing feature works by using background processes on multiple CPU processor cores to render frames,
whereas rendering with OpenGL works by moving processing to the GPU. (See
page 703.)
• The composition uses an effect that relies on GPU processing. These effects are generally effects implemented with
Pixel Bender.
• The composition contains a live Photoshop 3D layer. (See
Specifies the minimum amount of RAM that will be allocated to each background
The length of a RAM preview is determined by the number of frames that can
Set this value to a number other than 0 to prevent After Effects from using all
Memory, storage, and performance
"Render with
"3D object layers from Photoshop" on page 185.)
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USING AFTER EFFECTS CS4
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