The various wait implementation have a latency ranging from 50 to 500+
microseconds. While this is not a major issue when dealing with a low number of
waits per second (for ex: video), it does introduce a non-negligeable jitter for
synchronization of higher packet rate systems.
The `clock_nanosleep` syscall does offer a lower-latency waiting system but is
unfortunately blocking, so we don't want to use it in all scenarios nor for too
long.
This patch makes GstSystemClock use clock_nanosleep (if available) as such:
* Any wait below 500us uses it
* Any wait below 2ms will first use the regular waiting system and then
clock_nanosleep
# modified: gst/gstsystemclock.c
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/688>
In order to support the symbol g_enum_to_string in various
project using GStreamer ( gst-validate etc.), the glib minimum
version should be 2.56.0.
Remove compat code as glib requirement
is now > 2.56
Version used by Ubuntu 18.04 LTS
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/199>
... and update meson file so that enable it only using required headers.
"dependency(...)" is unlikely successful for Windows SDK libraries
since it doesn't ship pkg-config file. So it needs to be changed
to "find_library()" to link corresponding .lib file. That would
result to most MSVC build system will link dbghelp.dll. However,
one drawback of the change is that gstreamer-1.0.dll will mandate
dbghelp.dll although it should be optional. So g_module_open() way
can be the most safe way in this case.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/626>
Since bash-completion 2.9, it was no longer possible to override
the completionsdir through prefix. [1] In 2.10, the overridability
was re-estabilished but this time through datadir variable. [2]
This should not really matter except for developers installing the project
into a custom prefix or distros using per-package prefixes like NixOS.
[1]: 81ba2c7e7d
[2]: https://github.com/scop/bash-completion/pull/344
Problem:
multiple aggregator elements (audiomixer, compositor) in a live
pipeline use a lot of CPU waiting each other up. This is because
of the previously unused clock entry unscheduling during regular
operation.
Clock entry unscheduling has the potential to wake up every clock entry
waiting using the system clock which may be a large number.
Solution:
Implement waiting per entry and only wakeup the unscheduled entry.
While this may be possible using GCond, theoretically GCond only gives
us microsecond accuracy and uses relative waits in a number of places.
We can unfortunately do better poking at the platform specifics
ourselves by using futexes on linux and pthread on other unix. Windows
may have a possible implementation using Waitable timers but that is
not implemented here and instead falls back to the GCond implementation.
GCond waits on Windows is still as accurate as the previous GstPoll-based
implementation.
When this `_strnlen` internal method was added, strnlen (in glibc)
was not available yet (appeared in 2.10 it was released that same
year).
If available, use the much more optimized strnlen
GST_CLOCK_TYPE_TAI is GStreamer abstraction for CLOCK_TAI. Main
motivation for this patch is support for transmission offloading features
- when network packets are timestamped with the time they are deemed to
be actually transmitted. Linux API for that requires that time to be
in CLOCK_TAI coordinate.
With GST_CLOCK_TYPE_TAI, applications can use CLOCK_TAI directly on
their pipelines, avoiding the need to cross timestamp packet times. By
leveraging system's CLOCK_TAI, applications also don't need to keep track
of leap seconds - less burden for them. Just keep system's CLOCK_TAI
accurate and use it.
This can be made to work in certain circumstances when
cross-compiling, so default to not building g-i stuff
when cross-compiling, but allow it if introspection was
enabled explicitly via -Dintrospection=enabled.
Fixes#454 and #381.
Ensure that the code paths for HAVE_UNWIND and HAVE_DBGHELP are never
taken at the same time, even if the build file code changes.
Prefer DbgHelp over libunwind on Windows in case both are somehow
available because DbgHelp is only available when building with the
MSVC toolchain, and libunwind won't give us debug symbols from objects
built with the MSVC toolchain.
Also, print slightly more useful messages for the level of stack trace
support enabled, and document what each if conditional does.
This means we can use some newer features and get rid of some
boilerplate code using the `G_DECLARE_*` macros.
As discussed on IRC, 2.44 is old enough by now to start depending on it.
This suppresses the annoying 'g-ir-scanner: link: cc ..' output
that we get even if everything works just fine.
We still get g-ir-scanner warnings and compiler warnings if
we pass this option.
We need a nested extern in our init section for the scanner binary
so we can call gst_init to make sure GStreamer types are initialised
(they are not all lazy init via get_type functions, but some are in
exported variables). There doesn't seem to be any other mechanism to
achieve this, so just remove that warning, it's not important at all.
Add new GST_API_EXPORT in config.h and use that for GST_*_API
decorators instead of GST_EXPORT.
The right export define depends on the toolchain and whether
we're using -fvisibility=hidden or not, so it's better to set it
to the right thing directly than hard-coding a compiler whitelist
in the public header.
We put the export define into config.h instead of passing it via the
command line to the compiler because it might contain spaces and brackets
and in the autotools scenario we'd have to pass that through multiple
layers of plumbing and Makefile/shell escaping and we're just not going
to be *that* lucky.
The export define is only used if we're compiling our lib, not by external
users of the lib headers, so it's not a problem to put it into config.h
Also, this means all .c files of libs need to include config.h
to get the export marker defined, so fix up a few that didn't
include config.h.
This commit depends on a common submodule commit that makes gst-glib-gen.mak
add an #include "config.h" to generated enum/marshal .c files for the
autotools build.
https://bugzilla.gnome.org/show_bug.cgi?id=797185
