Adobe 12040118 - After Effects Standard, Руководство

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Layer Cache Indicators (CS5.5 and later)
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Note:
Global RAM cache
D1/DV PAL (720x576) frame in an 8-bpc project: 1.6 MB
HDTV (1920x1080) frame in a 16-bpc project: 16 MB
4K digital cinema (4096x2304) frame in a 32-bpc project: 144 MB
Because video is typically compressed during encoding when you render to final output, you can’t just multiply the amount of memory required for
a single frame by the frame rate and composition duration to determine the amount of disk space required to store your final output movie.
However, such a calculation can give you a rough idea of the maximum storage space you may need. For example, one second (approximately 30
frames) of uncompressed standard-definition 8-bpc video requires approximately 40 MB. A feature-length movie at that data rate would require
more than 200 GB to store. Even with DV compression, which reduces file size to 3.6 MB per second of video, this storage requirement translates
to more than 20 GB for a typical feature-length movie.
It is not unusual for a feature-film project—with its higher color bit depth, greater frame size, and much lower compression ratios—to require
terabytes of storage for footage and rendered output movies.
Caches: RAM cache, disk cache, and media cache
As you work on a composition, After Effects temporarily stores some rendered frames and source images in RAM, so that previewing and editing
can occur more quickly. After Effects does not cache frames that require little time to render. Frames remain uncompressed in the image cache.
After Effects also caches at the footage and layer levels for faster previews; layers that have been modified are rendered during the preview, and
unmodified layers are composited from the cache.
When the RAM cache is full, any new frame added to the RAM cache replaces a frame cached earlier. When After Effects renders frames for RAM
previews, it stops adding frames to the image cache when the cache is full and begins playing only the frames that could fit in the RAM cache.
Green bars in the time ruler of the Timeline, Layer and Footage panels mark frames that are cached to RAM. Blue bars in the Timeline panel mark
frames that are cached to disk.
Layer cache indicators allow you to visualize cached frames on a per-layer basis. This is helpful when
trying to determine which layers are cached in a composition.
In After Effects CS5.5, enable the Layer Cache Indicators option by selecting it in the Timeline panel menu.
In After Effects CS6, enable the Layer Cache Indicators option by pressing Ctrl (Windows) or Command (Mac), and then choose Show Cache
Indicators in the Timeline panel menu.
The Show Cache Indicators option must be enabled in the menu to see the indicators.
Once Layer cache indicators are enabled they will be visible underneath each layer in the composition. Each layer becomes slightly narrower to
allow for the indicators. Like Timeline, Layer, and Footage panels, cache indicators may appear as one of the following colors:
Green: frames are cached into RAM
Blue: frames are cached to disk
Showing the cache indicators decreases performance slightly.
The RAM cache is automatically purged when you quit After Effects.
In After Effects CS6, you can choose to purge the RAM cache, or the RAM cache and the disk cache from the Edit > Purge menu.
The global performance cache
In After Effects CS6, disk cache, and other performance enhancements are referred to as the global performance cache, bringing major
improvements to workflow. The Global Performance Cache consists of these features:
Global RAM cache : RAM cache is still available, even after you perform a function that would have erased it in past versions of After Effects.
Persistent disk cache : Frames cached to disk are still available, even after closing After Effects.
Cache work area in background : It is now possible to cache the work area of multiple compositions in the background.
Faster graphics pipeline : OpenGL now enhances the way interface items are drawn, including overlays.
For more information about the global performance cache, see the blog post entitled, "GPU (CUDA, OpenGL) features in After Effects CS6" on the
After Effects Team blog.
In this video by Todd Kopriva and video2brain, learn about the global performance cache and persistent disk cache, and see how these features
make rendering and re-rendering layers much quicker and easier in After Effects CS6.
The disk cache is not used for RAM previews. It is only used for standard previews. (See Use standard preview to play video.)
In After Effects CS6, RAM caching is vastly improved over previous versions. Global RAM Cache, offers these advantages: