Disk Caching in PFClean

14 Jun, 2016 | PFCLEAN, TUTORIALS

In cases where, due to the complexity of applied effects or hardware limitations, processing time can be high, intermediate results can be cached to disk to improve interactivity. This functionality is available in both, Workbench and Standards conversion nodes.

Contents

01. Specifying Disk Cache Locations

– Cache Standard Resolutions

02. Disk Caching in The Workbench

– Caching Effects

– Caching The Effects Stack

03. Clearing a Disk Cache

– Automatically Clearing Effects Caches

04. Use for Standards Conversion Node

Tutorial Footage

To learn this tutorial you will need to download and use the footage below.

Footage: Chanti.zip

Download

Footage: Chanti_Stack.zip

Download

01. Specifying Disk Cache Locations

Before you will be able to use disk caching in PFClean, you need to define locations where the data should be written to disk. You can create multiple cache locations and set rules for when a certain cache path should be used. For example, you can specify a location on a fast drive for high resolution clips, whilst caching SD footage on a slower drive.

Cache locations can be created and managed in the PFClean preferences. Click the settings_pfclan button in the top right corner of the application to open the preferences. The preferences window will appear with the Caching tab visible.

A cache location must have a name, a path, and a rule for what type of clip should be cached in that location. You can choose one or more resolutions to store in a location. You can also have one location with the standard resolution Undefined. The Undefined location will store all resolutions that don’t have a specific location set. Once these values have been set, click the + button to add the cache location.

Make sure you have at least a 2K or Undefined cache location if you follow the steps in this tutorial with the Chanti footage.

Cache Standard Resolutions

UndefinedCache all resolutions in this location, unless a different location has been specified for that resolution (see below)
SDCache all Standard Definition resolution clips in this location
HDCache all High Definition resolution clips in this location
2KCache all 2K clips in this location
4KCache all 4K clips in this location

02. Disk Caching in The Workbench

The Workbench takes a “deferred” approach to caching, meaning no action is immediately taken when caching is enabled but rather frames are cached to disk as and when they are subsequently created. You can decide whether you want to cache the result of individual effects or the full stack.

Caching Effects

In cases where your effects stack gets complex and the time to display a frame increases, you can cache the result up to a selected effect to disk by pinning a cache to the effect.

Click the C button to “pin” a disk cache to the effect you want to cache. Pinning a cache to an effect does not trigger any immediate action, but rather marks the results of this effect to be cached to disk whenever they are subsequently created. If you play through a clip with a cache pinned to an effect, the blue bar and percentage figure in the effect show how the cache is being filled as the effect is being processed.

Caching The Effects Stack

You can also pin a cache to the full effects stack. Click the C at the bottom of the Stack Manager to pin the stack for disk caching, then play through the clip to fill the stack. Stop playback again once the whole clip has been cached.

If you add an effect to a cached stack, the cached version written to disk is no longer up to date and has been cleared and the stack cache progress is back to 7%*.


*
Note: In the example given in the video, 7% is the equivalent of 1 frame. Since the first frame is displayed in the Cinema, and the cache is pinned to the stack, it has also been cached to disk. That’s why the cache progress is 7% rather than 0%.

03. Clearing a Disk Cache

Disk caches are automatically cleared and disk space freed when the underlying data changes and the caches are no longer up to date.

Effects and Stack caches can also be cleared by unpinning them from the effect or stack respectively.

You can also clear disk caches in the PFClean preferences. Click the Clear button in the Standard node row to clear all caches created by the Standards node. Effect Stack clears all Workbench stack caches while Effect clears all Workbench effects caches.

Automatically Clearing Effects Caches

The effects caches’ main purpose is to increase interactivity whilst adding and setting up effects on a clip. In order to keep disk usage at a minimum, you can choose rules to automatically clear effect caches when they are no longer needed. The available rules are:

Clear ManuallyDo not automatically clear effect caches
Clear on Project ExitClear all effect caches when closing the project, e.g. switching to another project or exiting PFClean
Clear on Node ExitClear all effect caches when exiting the Workbench node, e.g. returning to the Workflow Manager or closing the project
Clear on Clip ExitClear the effect cache of the current clip when switching to another clip in the Workbench e.g. selecting a different clip in the current Worklist or exiting the Workbench node

04. Use For Standards Conversion Node

Unlike disk caching in the Workbench, disk caching a Standards node is an “immediate” operation meaning pressing the cache button triggers the creation of the cache files on your hard disk. This is done from the cache control, which is attached to the Standards node icon in the Workflow Manager. The white number at the top left of the control illustrates the number of clips ready to be cached in the node. The blue number below illustrates the number of clips that are already cached. Click this button cache_butotn_standards_node to start caching the clips. Please note that this button will be disabled unless a cache location has been defined for the output resolution. Also note that unlink the Workbench, Standards node caches are not automatically recreated should they become invalidated. To re-cache the Standards node you have to manually start the caching.

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