Three things about the dshow backend, all of them found by reading rather
than by running, so all three want checking on a real Windows machine.
The device listing is parsed in both of the shapes ffmpeg has printed it in:
newer builds mark every device `(audio)` or `(video)`, older ones print a
heading and no marks, and only the first was read. Each pattern is anchored at
both ends now, so the error lines the command ends with, which quote the device
name it was told to look for, are no longer read as a device of that name.
What is stored for a device is the alternative name under it rather than the
friendly one. A laptop with a headset plugged in has two microphones called the
same thing, and `audio=Microphone` reaches the first of them whichever one was
picked; the alternative name is unique. The friendly name stays what is shown,
which is what the (id, description) pair in these lists has always been for.
An unset microphone meant "the first one listed", and the listing costs an
ffmpeg of its own, so every press of the key paid for a process before the
recording started. The last listing is remembered instead, and opening Settings
or running `dikte devices` takes a fresh one.
And a fourth thing, which is about what the interface says rather than what it
does: whether the far side of a meeting can be captured at all is now an entry
in `audio.Sound` instead of being read off an empty device list. The two are not
the same answer. An empty list on Linux means pactl is not installed, which a
user can go and fix; False on Windows means there is no such device and no
driver that would add one. The Meeting tab says so under the empty box, and
starting a meeting says it instead of sending somebody to Settings to pick from
a list that will never have anything in it.
Three of the four collisions were the same one: master moved the directory
rule into paths.py while this branch was adding a Windows case to the copy in
config.py and the second copy in ggml.py. The case moves to paths.py with the
rest of it, and the directories test moves to tests/test_paths.py where master
put its neighbours.
The fourth is MeetingRecorder, which now starts a process per capture device.
Windows keeps its two lines there: no console window for either process, and
a stop that terminates rather than sending a signal the platform does not have.
A recording is never deleted for being disappointing. A microphone that
handed over nothing still leaves the right channel, which is everyone
else, and an hour of them is worth more than the empty channel costs; the
one thing the user cannot get back is the half that was there. So the
exact-zero check stays and stops throwing the file away: it says what the
microphone did, in a tray warning next to the recording being written up,
and the minutes are produced from what there is.
Reading the two capture pipes in turn from one thread put the failure it
was meant to fix back in a worse place. A microphone that stops delivering
leaves that read waiting forever, and the far side is not read either
until its pipe fills and its ffmpeg stops writing into it: the meeting
freezes, the levels sit still, and nothing is said for as long as nobody
looks. Each stream now has a reader of its own and a queue, so neither can
hold the other up, and a side that has said nothing for STALL_SECONDS ends
the recording the way a dead ffmpeg already did, out loud and keeping what
was captured.
Which system needs how many processes belongs in the table with everything
else that differs, so meeting() returns the list of commands it takes:
one on PulseAudio, one per device on a Mac. meeting_commands() is the
chooser again rather than a function with a Mac inside it, and the empty
entry in COREAUDIO is gone. The two AVFoundation targets are resolved
against a single device listing, which costs one ffmpeg run instead of two
and cannot see the indexes renumber between the microphone and the far
side.
yusufipek