add FrameDescriptor to the wiki

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Christian Thaeter 2007-06-27 03:54:02 +02:00
parent b7d6f074e8
commit 7c9c181a04

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@ -816,10 +816,12 @@ FileMap objects are transparent to the application, it will only requests [[Fram
Whenever a FileMap is in use, it is checked out into a in-use list where it is not subject of aging. Whenever a FileMap is in use, it is checked out into a in-use list where it is not subject of aging.
</pre> </pre>
</div> </div>
<div title="Frame" modifier="CehTeh" modified="200706202206" created="200706202115" changecount="4"> <div title="Frame" modifier="CehTeh" modified="200706270152" created="200706202115" changecount="5">
<pre>'Frames' are the smallest datablocks handled by the Backend. The application tells the Backend to make [[File]]s availabe and then only requests Frames from the Backend, all other datastructures of the backend are private. <pre>'Frames' are the smallest datablocks handled by the Backend. The application tells the Backend to make [[File]]s availabe and then only requests Frames from the Backend, all other datastructures of the backend are private.
Actually Frames are blocks of continous memory, they can be anything depending on the usage of the [[File]] (Video frames, encoder frames, blocks of sound samples). Actually Frames are (references to) blocks of continous memory, they can be anything depending on the usage of the [[File]] (Video frames, encoder frames, blocks of sound samples).
Each [[Frame]] points to a [[FrameDescriptor]] which describes the shared properties of [[Frame]]s of the same kind. For video frames this [[FrameDescriptor]] will define the policies of the used color modell, resolution, aspect ratio and so on, for example.
Frames are referenced by a smart-pointer like object which manages the lifetime and caching behaviour. There are 3 states such a frame reference can be: Frames are referenced by a smart-pointer like object which manages the lifetime and caching behaviour. There are 3 states such a frame reference can be:
# readonly: the backing FileMap is checked out from the aging list, frames can be read # readonly: the backing FileMap is checked out from the aging list, frames can be read