Pipewire 0.3.52 via commit a1f33a99 introduced a change that affects how
long pipewiresrc holds onto the pw_buffers it dequeued. Before that
change the pw_buffer was held until the end of the videoconvert element
at the beginning of the pipeline. After that change the pw_buffer was
held onto until the filesink at the end of the pipeline. This was
starving MetaScreenCastStreamSrc of pw_buffers to record new frames
into, resulting in the majority of frames being missed, especially in
situations in which the encoder was taking longer.
Pipewire 0.3.57 via commit 1ea1d525 will allow queuing the pw_buffer
early again via the `always-copy` option. This however is only a
workaround until a proper solution is found in either pipewire or
gstreamer that does not depend on copying the buffer contents and
instead queues the pw_buffer again after videoconvert as prior to
a1f33a99.
Since it is not clear yet when a proper solution will arrive, this makes
use of `always-copy` as a workaround for now and should be reverted once
it is no longer needed.
Related: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5585
Related: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/2461
Related: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/283
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2436>
Screenshots use `%Y-%m-%d %H-%M-%S` for the timestamp, which has the
advantage of allowing proper lexicographical sorting.
The screencast file name pattern, on the other hand, uses
locale-dependent expansions, which break sorting based on file name, and
introduces the chance of potentially invalid characters on different
file systems.
Fixes: #5115
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2300>
We currently decide at build time whether to include screencast
support, based on whether the required gst/pipewire library headers
are installed.
That check is imprecise, because having the library headers available
at build time doesn't necessarily mean that the libraries are there
at runtime, or that the corresponding typelibs are installed.
It makes more sense to check the requirements at runtime, so prepare
for that by installing the screencast service unconditionally, but
bail out early if the dependencies aren't met.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2297>
If one of these libraries breaks its GIR API in future, then upgrading
packages unrelated to gnome-shell might pull in the newer version,
causing gnome-shell to crash when it gets a newer GIR API that is
incompatible with its expectations. For example, this seems to be
happening in Debian testing at the moment, when GNOME Shell 41.4
imports GWeather and can get version 4.0 instead of the version 3.0 that
it expected.
Adding explicit API versions at the time the newer version is released
is too late, because that will still let the newer version of the GIR API
break pre-existing GNOME Shell packages. Prevent similar crashes in
future by making the desired versions explicit.
This is done for all third-party libraries except GLib, similar to the
common practice in Python code; if GLib breaks API, then that will be
a disruptive change to the whole GLib/GObject ecosystem, regardless.
Gvc, Meta, Shell, Shew, St are not included because they're private
(only exist in a non-default search path entry).
Clutter and Cogl *are* included, because we need to import the fork of
them that comes with Meta, as opposed to their deprecated standalone
versions.
Signed-off-by: Simon McVittie <smcv@debian.org>
Bug-Debian: https://bugs.debian.org/1008926
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2261>
Instead of testing if the videos directory exists and using the home
directory otherwise, just try to create the target directory. This
aligns with how the screenshot UI handles the screenshots folder, and
it's convenient for putting screencasts into a subdirectory.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2102>
If parsing the pipeline fails for some reason, we currently end up
with a zombie session that leads to a stuck recording indicator in
gnome-shell.
Instead, properly tear down the session to allow mutter and gnome-shell
to correctly update their state.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1878>
The current gstreamer pipeline performs quite bad on slower machines and
is dropping lots of frames, improve the pipeline by changing a few
things:
- Use threads for videoconvert and improve speed of videoconvert by
disabling some unneeded things
- Add a queue before the encoding step, this allows the encoder to work
at its own pace and will lead to a lot more stability
- Remove the fixed quantizer and only set a max quantizer, this helps
quite a bit with performance
- Change the deadline parameter of vp8enc to 1: This makes the encoder
go into real time mode, which will make it a lot faster
- Set cpu-used to 16, the maximum possible value.
- Set static-threshold to 1000, static-threshold is the motion detection
threshold, and while a value of 100 is recommended for screencasting in
the gstreamer documentation (see [1]), using 1000 appears to perform a
lot better and still outputs fairly good quality
- Set a larger buffer size than the default size, this seems to get a
bit more stability during high load scenarios
All in all, those changes make the pipeline drop no more frames when
recording at 30 FPS and 2K screen resolution. That was tested on a
fairly recent mobile core-i5 processor.
Also, because we now have two %T replacement strings for the number of
threads, we need to switch to replaceAll(). For that to work, we have to
put the %T matching expression into quotes.
[1] https://gstreamer.freedesktop.org/documentation/vpx/GstVPXEnc.html?gi-language=c#GstVPXEnc:static-threshold
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1633>
Move the screencasting into a separate D-Bus service process, using
PipeWire instead of Clutter API. The service is implemented in
Javascript using the dbusService.js helper, and implements the same API
as was done by screencast.js and the corresponding C code.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1372
