Imagine the following 'pipeline'
--------------
p1/| 'fullqueue' |--- 'laggy' downstream
--------- / | |
-| demuxer | | multiqueue |
--------- \ | |
p2\| 'emptyqueue' |--- 'fast' downstream
--------------
In the case downstream of one single queue (fullqueue) has (a lot of) latency
(for example for reverse playback with video), we can end up having the other
SingleQueue (emptyqueue) emptied, before that fullqueue gets
unblocked. In the meantime, the demuxer tries to push on fullqueue, and
is blocking there.
In that case the current code will post a BUFFERING message on the bus when
emptyqueue gets emptied, that leads to the application setting the pipeline state to
PAUSED. So now we end up in a situation where 'laggy downstream' is
prerolled and will not unblock anymore because the pipeline is set to
PAUSED, the fullequeue does not have a chance to be emptied and
the emptyqueue can not get filled anymore so no more BUFERRING message
will be posted and the pipeline is stucked in PAUSED for the eternity.
Making sure that we do not try to "buffer" if one of the single queue
does not need buffering, prevents this situtation from happening though it lets the
oportunity for buffering in all other cases.
That implements a new logic where we need all singlequeue to need
buffering for the multiqueue to actually state buffering is needed,
taking the maximum buffering of the single queue as the reference point.
https://bugzilla.gnome.org/show_bug.cgi?id=734412
After EOS there will be no further buffer which could propagate the
error upstream, so nothing is going to post an error message and
the pipeline just idles around.
When the first segment has position != 0 and position > max-size-time
it will immediatelly cause the multiqueue to signal overrun.
This can happen easily with adaptive streams when switching bitrates
and starting a new group. The segment for this new group will have
a position that is much greater than 0 and will lead to this issue.
This is particularly harmful when the adaptive stream uses mpegts
that doesn't emit no-more-pads and it might happen that only one
of the stream pads was added when the multiqueue overruns and gets
the group ready for exposing. So the user will only get audio or
video.
The solution is to fallback to the sink segment while the source pad
has no segment.
https://bugzilla.gnome.org/show_bug.cgi?id=729124
They are very confusing for people, and more often than not
also just not very accurate. Seeing 'last reviewed: 2005' in
your docs is not very confidence-inspiring. Let's just remove
those comments.
Use the last result as a default when pushing a item from a single queue,
otherwise the status gets reset to _OK when pushing events.
This causes problems when mistakenly activating a not-linked stream
that is being ignored upstream as it is not being used (adaptive
scenarios), it will make the multiqueue post a buffering message
on a pad that won't receive buffers
https://bugzilla.gnome.org/show_bug.cgi?id=725917
When the single queue size was just bumped by 1 to allow more buffers to
be added, the buffers limit could be reduced to the current level when
setting the max-size-buffers property. This would result in a stall
since the queue would not grow anymore at this point.
Prevent this by not reducing a single queue size below the current
number of buffers + 1.
https://bugzilla.gnome.org/show_bug.cgi?id=712597
In the case where one singlequeue is full and all other are not linked, the
growing of the full queue does not work correctly. The result depends on if
the full queue is last in the queue list or not.
https://bugzilla.gnome.org/show_bug.cgi?id=722891
When prerolling/buffering, multiqueue has its buffers limit set
to 0, this means it can take an infinite amount of buffers.
When prerolling/buffering finishes, its limit is set back to 5, but
only if the current level is lower than 5. It should (almost) never be
and this will cause prerolling/buffering to need to wait to reach the
hard bytes and time limits, which are much higher.
This can lead to a very long startup time. This patch fixes this
by setting the single queues to the max(current, new_value) instead
of simply ignoring the new value and letting it as infinite(0)
https://bugzilla.gnome.org/show_bug.cgi?id=712597
This makes buffering stop in case a stream switch happens. This is
important for adaptive streams that can disable not-linked streams
to avoid consuming the network bandwidth.
https://bugzilla.gnome.org/show_bug.cgi?id=719575
After patch bda406c4, the state of the singlequeue was set to OK, but nothing
would then wake up the thread, as the other wakeup functions only look at
singlequeues that are marked as having received as not-linked.
https://bugzilla.gnome.org/show_bug.cgi?id=708200
If the multiqueue has automatically grown chances are good that
we will cause the pipeline to starve if the maximum level is reduced
below that automatically grown size.
https://bugzilla.gnome.org/show_bug.cgi?id=707156
We must be certain that we don't cause a deadlock when blocking the serialized
queries. One such deadlock can happen when we are buffering and downstream is
blocked in preroll and a serialized query arrives. Downstream will not unblock
(and allow our query to execute) until we complete buffering and buffering will
not complete until we can answer the query..
https://bugzilla.gnome.org/show_bug.cgi?id=702840
The control of wheteher a SingleQueue is full is not correct.
Rewrote single_queue_overrun_cb() so it checks the correct variables
when checking if the queue has reached the hard limits, and to
increase the max buffer limit once for each call.
https://bugzilla.gnome.org/show_bug.cgi?id=690557
We reset all the waiting streams, let them push another buffer to
see if they're now active again. This allows faster switching
between streams and prevents deadlocks if downstream does any
waiting too.
Also improve locking a bit, srcresult must be protected by the
multiqueue lock too because it's used/set from random threads.
