Helps catching when a state change is starting and ending.
It is also possible to track the end of state changes by checking the
async-done or state-change messages.
This is particularly important for elements that do async state changes.
Validate that the proxy pad indeed accepts the caps by also
comparing with the pad template caps, otherwise when the pad
had no internally linked pads it would always return true.
https://bugzilla.gnome.org/show_bug.cgi?id=754112
Instead of re-sending sticky events over and over to a not-linked
pad, mark them as sent the first time. If the not-linked came from
downstream, it already received the events. If the pad is actually
not-linked, the sticky events will be rescheduled when the
pad is linked anyway.
There is a similar explanation in gst_caps_make_writable, but the existing
documentation can be misleading since it does not define what 'is already
writable' means.
Also note when this function is meant to be used.
API: GST_BUFFER_DTS_OR_PTS
Many scenarios/elements require dealing with streams of buffers that
might have DTS set (i.e. encoded data, potentially reordered)
To simplify getting the increasing "timestamp" of those buffers, create
a macro that will return the DTS if valid, and if not the PTS
Updated gst_segment_position_from_stream_time and gst_segment_to_stream_time to reflect correct calculations for the case when the applied rate is negative.
Pasting from design docs:
===============================
Stream time is calculated using the buffer times and the preceding SEGMENT
event as follows:
stream_time = (B.timestamp - S.start) * ABS (S.applied_rate) + S.time
For negative rates, B.timestamp will go backwards from S.stop to S.start,
making the stream time go backwards.
===============================
Therefore, the calculation for applied_rate < 0 should be:
stream_time = (S.stop - B.timestamp) * ABS (S.applied_rate) + S.time
and the reverse:
B.timestamp = S.stop - (stream_time - S.time) / ABS (S.applied_rate)
https://bugzilla.gnome.org/show_bug.cgi?id=756810
An ASYNC READY->PAUSED might have failed without the bin code noticing during
the state change, in which case we will never get PAUSED->READY and would leak
messages.
https://bugzilla.gnome.org/show_bug.cgi?id=756611
This way one can define new tracing probes without changing the core. We are
using our own quark table, as 1) we only want to initialize them if we're
tracing, 2) we want to share them with the tracers.
Instead of a single invoke() function and a 'mask', register to individual
hooks. This avoids one level of indirection and allows us to remove the
hook enums. The message enms are now renamed to hook enums.
This way we only expand the structure when we're logging. This allows us to
meassure the pure tracing seperately from the logging.
Also add some comments on further improvements.
Keep tracer base class in tracer and move core support into the utils module.
Add a unstable-api guard to the tracer.h so that external modules would need to
acknowledge the status by setting GST_USE_UNSTABLE_API.
