This uses the existing optional runtime ffmpeg dependency to add support
for m4a files (and in theory whatever other file formats ffmpeg
supports) to the import audio dialog.
The same functionality is mostly already available via Session -> Open
Video, with the "import audio only" selection (even though m4a isn't
currently included as one of the video formats, it still works). Having
this in the import audio dialog however seems much more user friendly.
Harvid daemonizes and does not write anything
to stdout/err. as opposed to select(), poll() on
macOS does not return when the child process
terminates or is killed.
However poll() on an invalid FD does throw an
error and POLLNVAL is set.
*now that you can grab "anywhere" in the region, trim edges are inferior because they are hard to hit
*modifier had to change anyway (since CTRL is used as a copy-drag on both mac and win), so that invalidates prior muscle memory
*potentially frees up modifier on the trim edge for some other purpose (anchored_trim)
Control Points should ignore x_constraint which is set in Drag::motion and potentially other places.
The only thing that should prevent CP sliding is can_slide which is false for the points at the ends of a region.
There is no need to connect signals twice, can connect them directly to the
helper UI loop and skip the surface loop. Then let the server decide if it is
necessary to call lws_cancel_service() or not.
Also rename WebsocketsServer::should_request_write() to read_blocks_event_loop()
it makes more sense for the caller now on-demand write logic is completely
implemented by the server class.
In between timespans Ardour disables freewheeling and
only later resumes freewheel. It can happen that
Session::process can summon the butler while start_audio_export()
calls Track::seek.
Just waiting for an earlier Butler::wait_until_finished() does
not prevent the butler from running again later.
This can lead to concurrent calls of DR::refill_audio from both
the butler and start_audio_export(), leading to garbled buffers.
ExportHandler::start_timespan() is also used to stop export
when there are no more timespans to be processed.
This is done because freewheeling has to be stopped from
outside the process cycle.
This is an update to the surface ArdourFeedback class that is needed to support
the new event loop integration method.
The various session event callbacks cannot be queued in the surface event loop
because that would create a delay between the time such events are fired and
the time for writing to clients arrive, due to lws_service() blocking while
it waits to read. To solve this issue a helper AbstractUI is created for
catching events as soon as possible and issuing a call to lws_cancel_service().
See WebsocketsServer::glib_idle_callback()
Some distro repositories offer versions of libwebsockets that have not been
compiled with LWS_WITH_GLIB or LWS_WITH_EXTERNAL_POLL enabled. For such cases
a different event loop integration method is needed.
True for Ubuntu 20.04 as of Jun '21
