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67 lines
1.6 KiB
Text
67 lines
1.6 KiB
Text
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1) transitions
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--------------
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There are four states, NULL, READY, PAUSED, PLAYING. state transitions only
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happen from once neighbouring state to another.
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NULL: the element is just being created, the initial state.
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!
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! the element creates all of its resources (a thread will create
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! its pthread etc..)
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! - most used by bins to set up thread context for its children
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v
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READY: the element is ready to start processing.
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!
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! the element sets up its state so it can start processing buffers.
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! - open devices
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v
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PAUSED: the element is paused
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!
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! the element starts spinning
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!
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v
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PLAYING: the element is playing
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!
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! the element stops spinning
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! the element frees resources from other plugins (bufferpools)
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!
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v
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PAUSED
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! element removes caps from pads
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! reset internal state
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! - close devices
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!
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v
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READY
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!
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! the element frees all of its resources (eg: pthread_join)
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!
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v
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NULL
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2) bin transition
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-----------------
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the state of a bin is equal to the maximum state of its children.
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3) interaction with the scheduler
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---------------------------------
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elements in the !PLAYING state are disabled in the scheduler.
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4) action that can be performed by the app in the different states
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------------------------------------------------------------------
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PLAYING: nothing, only iterate on the pipeline, some properties can
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be changed.
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PAUSED: elements can be connected, removed, disconnected. some
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properties can be changed
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READY: as in PAUSED but *all* properties can be changed.
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NULL: everything.
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