boolean indicating whether the pad should be blocked or unblocked
GstPadBlockCallback that will be called when the operation succeeds
user data passed to the callback
TRUE if the pad could be blocked. This function can fail if the wrong parameters were passed or the pad was already in the requested state. MT safe.
Blocks or unblocks the dataflow on a pad. The provided callback is called when the operation succeeds; this happens right before the next attempt at pushing a buffer on the pad. This can take a while as the pad can only become blocked when real dataflow is happening. When the pipeline is stalled, for example in PAUSED, this can take an indeterminate amount of time. You can pass NULL as the callback to make this call block. Be careful with this blocking call as it might not return for reasons stated above.