GstPtpClock implements a PTP (IEEE1588:2008) ordinary clock in
slave-only mode, that allows a GStreamer pipeline to synchronize
to a PTP network clock in some specific domain.
The PTP subsystem can be initialized with gst_ptp_init(), which then
starts a helper process to do the actual communication via the PTP
ports. This is required as PTP listens on ports < 1024 and thus
requires special privileges. Once this helper process is started, the
main process will synchronize to all PTP domains that are detected on
the selected interfaces.
gst_ptp_clock_new() then allows to create a GstClock that provides the
PTP time from a master clock inside a specific PTP domain. This clock
will only return valid timestamps once the timestamps in the PTP domain
are known. To check this, the GstPtpClock::internal-clock property and
the related notify::clock signal can be used. Once the internal clock
is not NULL, the PTP domain's time is known. Alternatively you can wait
for this with gst_ptp_clock_wait_ready().
To gather statistics about the PTP clock synchronization,
gst_ptp_statistics_callback_add() can be used. This gives the
application the possibility to collect all kinds of statistics
from the clock synchronization.
https://bugzilla.gnome.org/show_bug.cgi?id=749391
gst_clock_wait_for_sync(), gst_clock_is_synced() and gst_clock_set_synced()
plus a signal to asynchronously wait for the clock to be synced.
This can be used by clocks to signal that they need initial synchronization
before they can report any time, and that this synchronization can also get
completely lost at some point. Network clocks, like the GStreamer
netclientclock, NTP or PTP clocks are examples for clocks where this is useful
to have as they can't report any time at all before they're synced.
https://bugzilla.gnome.org/show_bug.cgi?id=749391
There are gstmemory's available that operate in two memory domains
and need to ensure consistent access between these domains.
Imagine a scenario where e.g. the GLMemory is mapped twice in both
the GPU and the CPU domain. On unmap or a subsequent map, it would
like to ensure that the most recent data is available in the memory
domain requested. Either by flushing the writes and/or initiating a
DMA transfer. Without knowing which domain is being unmapped, the
memory does not know where the most recent data is to transfer to
the other memory domain.
Note: this still does not allow downgrading a memory map.
https://bugzilla.gnome.org/show_bug.cgi?id=750319
Now that locking exclusively dows not always succeed, we need to signal
the failure case from gst_memory_init.
Rather than introducing an API or funcionality change to gst_memory_init,
workaround by checking exclusivity in the calling code.
https://bugzilla.gnome.org/show_bug.cgi?id=750172
gst_memory_lock (mem, WRITE | EXCLUSIVE);
gst_memory_lock (mem, WRITE | EXCLUSIVE);
Succeeds when the part-miniobject.txt design doc suggests that this should fail:
"A gst_mini_object_lock() can fail when a WRITE lock is requested and
the exclusive counter is > 1. Indeed a GstMiniObject object with an
exclusive counter 1 is locked EXCLUSIVELY by at least 2 objects and is
therefore not writable."
https://bugzilla.gnome.org/show_bug.cgi?id=750172
DllMain should not be relied on for anything except storing the DLL handle.
It should also not be defined for static builds, but doing so is not
straightforward and is mostly harmless, so let's just add a comment about that
for now.
GstFlagSet is a new type designed for negotiating sets
of boolean capabilities flags, consisting of a 32-bit
flags bitfield and 32-bit mask field. The mask field
indicates which of the flags bits an element needs to have
as specific values, and which it doesn't care about.
This allows efficient negotiation of arrays of boolean
capabilities.
The standard serialisation format is FLAGS:MASK, with
flags and mask fields expressed in hexadecimal, however
GstFlagSet has a gst_register_flagset() function, which
associates a new GstFlagSet derived type with an existing
GFlags gtype. When serializing a GstFlagSet with an
associated set of GFlags, it also serializes a human-readable
form of the flags for easier debugging.
It is possible to parse a GFlags style serialisation of a
flagset, without the hex portion on the front. ie,
+flag1/flag2/flag3+flag4, to indicate that
flag1 & flag4 must be set, and flag2/flag3 must be unset,
and any other flags are don't-care.
https://bugzilla.gnome.org/show_bug.cgi?id=746373
Just create the cancellable fd once and keep it around instead
of creating/closing it for every single packet. Since we spend
most time waiting for packets, an fd is alloced and in use pretty
much all the time anyway.
We were segfaulting because g_sequence_search was returning the iter_end,
and that iterator does not contain anything and thus should not be used
directly
The old gst_object_has_ancestor will call the new code. This establishes the
symetry with the new gst_object_has_as_parent.
API: gst_object_has_as_ancestor()
In basesink functions gst_base_sink_chain_unlocked(), below code is used to
checking if buffer is late before doing prepare call to save some effort:
if (syncable && do_sync)
late =
gst_base_sink_is_too_late (basesink, obj, rstart, rstop,
GST_CLOCK_EARLY, 0, FALSE);
if (G_UNLIKELY (late))
goto dropped;
But this code has problem, it should calculate jitter based on current media
clock, rather than just passing 0. I found it will drop all the frames when
rewind in slow speed, such as -2X.
https://bugzilla.gnome.org/show_bug.cgi?id=749258
Since frame->priv->discont was cleared earlier,
GST_BASE_PARSE_FLAG_LOST_SYNC was never being set.
Take the chance to refactor the frame creation a bit to
organize the flags setting and reset.
https://bugzilla.gnome.org/show_bug.cgi?id=738237
