Adobe 12040118 Tutorial - Page 529

Caches: RAM cache, disk cache, and media cache To the top 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 (CS5.5 and later) 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. Enable the Layer Cache Indicators option by selecting it 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. Disk cache After Effects can store rendered items to your hard disk when the RAM cache is full during standard previews. Blue bars in the time ruler of the Timeline, Layer and Footage panels mark frames that are cached to disk. Note: 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 CS5.5 and later, Disk Cache is enabled by default. For disk cache preferences, and to enable, or disable disk caching: Choose Edit > Preferences > Media & Disk Cache (Windows) or After Effects > Preferences > Media & Disk Cache (Mac OS), and select, or deselect Enable Disk Cache. Disk cache preferences allow you to select a folder to contain your cache. Click the Choose Folder button, and then click OK (Windows) or Choose (Mac OS). To empty the disk cache: Click the Empty Disk Cache button. Note: Even when disk caching is enabled, each frame must be able to fit into a contiguous block of RAM. Enabling the disk cache doesn't help with limitations regarding inadequate RAM to hold or render a single frame of your composition. For the best performance with disk caching, select a folder that's on a different physical hard disk than your source footage. If possible, the folder should be on a hard disk that uses a different drive controller than the disk that contains your source footage. A fast hard drive or SSD with as much space allocated as possible is recommended for the disk cache folder. The disk cache folder can't be the root folder of the hard disk. As with the RAM cache, After Effects only uses the disk cache to store a frame if it's faster to retrieve a frame from the cache than to rerender the frame. The Maximum Disk Cache Size setting specifies the number of gigabytes of hard disk space to use. In After Effects CS6, the default disk cache size is set to 10% of the volume's total size, up to 100 GB. In After Effects CS5.5, this amount is 20 GB, by default. Because of this, many more frames are eligible for disk caching than in previous versions. Note: In After Effects CS5.5, the application checks to make sure that you have 10 GB free above what is set in Preferences > Media & Disk Cache. After Effects warns you if there is not enough room for the disk cache. Note: Roto Brush frames are not persistently cached.