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80 lines
2.8 KiB
Text
80 lines
2.8 KiB
Text
GST States and Transition Rules (graph to follow)
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-------------------------------
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This should be a map of possible state transitions and what triggers them.
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What the states are:
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GST_STATE_NEW: a new element has this, if it has nothing set except name.
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GST_STATE_INCOMPLETE: any element that has some, but not enough
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information to function is in this state.
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GST_STATE_COMPLETE: if the element has enough data, but is not in any kind
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of running or explicitely stopped state. ready to be used.
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GST_STATE_DISCOVERY: anything the element does in this state must be reset
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after discovery. any data read from sync source must be cached.
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GST_STATE_PREROLL: not a lot different from PLAYING, except sinks don't
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render what they're getting. useful for elements that require
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data to get in sync, such as an MPEG video decoder that needs
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IBBPBB before starting at the next P.
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GST_STATE_RUNNING: this is the normal state of the pipeline, where data
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goes all the way through the pipeline normally.
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GST_STATE_STOPPED: an explicit stop state, different from COMPLETE in that
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the state doesn't get reset.
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NULL -> GST_STATE_NEW
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creating an element (gst_*_new*)
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GST_STATE_NEW -> GST_STATE_INCOMPLETE
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setting anything in the element that isn't sufficient to bring it
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to a useful state (gst_object_set)
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GST_STATE_INCOMPLETE -> GST_STATE_COMPLETE
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setting whatever the last bit of info the element was looking for
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(gst_object_set)
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GST_STATE_COMPLETE -> GST_STATE_INCOMPLETE
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changing anything that invalidates the complete state of the element
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GST_STATE_COMPLETE -> GST_STATE_DISCOVERY
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setting the state to DISCOVERY
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[ used for autoplug ]
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GST_STATE_DISCOVERY -> GST_STATE_COMPLETE
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setting the state !DISCOVERY
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[ used when autoplug is over ]
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GST_STATE_DISCOVERY -> GST_STATE_PREROLL
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setting the state to PREROLL
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[ you can go straight to preroll from discovery if you want ]
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GST_STATE_DISCOVERY -> GST_STATE_RUNNING
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setting the state to RUNNING
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[ you can even go straight to running from preroll ]
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GST_STATE_DISCOVERY -> GST_STATE_STOPPED
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setting the state to STOPPED
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[ normally you'd go from discovery to stopped when you load a src ]
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GST_STATE_PREROLL -> GST_STATE_RUNNING
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setting the state to RUNNING
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[ preroll generally leads straight to running, as in above ]
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GST_STATE_PREROLL -> GST_STATE_STOPPED
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setting the state to STOPPED
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[ it is possible to go to stopped, i.e load file@time ]
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GST_STATE_RUNNING -> GST_STATE_PREROLL
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setting the state to PREROLL
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[ unsure if you'd need this state, you'd go to stopped first ]
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GST_STATE_RUNNING -> GST_STATE_STOPPED
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setting the state to STOPPED
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[ pause. ]
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GST_STATE_STOPPED -> GST_STATE_PREROLL
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setting the state to PREROLL
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[ if you seek to intermediate time while stopped, you'd preroll to
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prepare to start running again immediately ]
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GST_STATE_STOPPED -> GST_STATE_RUNNING
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setting the state to RUNNING
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