Register a callback on the given GstClockID id with the given
function and user_data. When passing a GstClockID with an invalid
time to this function, the callback will be called immediatly
with a time set to GST_CLOCK_TIME_NONE. The callback will
be called when the time of id has been reached.
Register a callback on the given GstClockID id with the given function and user_data. When passing a GstClockID with an invalid time to this function, the callback will be called immediatly with a time set to GST_CLOCK_TIME_NONE. The callback will be called when the time of id has been reached.