Creator was recording on the Release build and hit "Couldn't start the audio — another copy of
LlamaCasty is already using the audio pipe" when going live on Debug. The guard did its job (no
crash), but the collision should not have been possible: the pipe name only suffixed when
`YTLIVE_INSTANCE` was set, and a Debug launched straight from the IDE has no id — so it asked for
the same `ytllive_audio` the Release build was serving.
DEBUG now always suffixes: the claimed instance id when there is one, otherwise the process id. Any
number of dev builds can run beside the Release app, and each Debug process is distinct from every
other. Release is unchanged — it resolves to the plain name, and the whole mechanism disappears in
`#if DEBUG` as before.
`TryStartAudioPipe` now logs the resolved name (`Audio pipe: …`), so the next report of this kind is
one grep instead of a code hunt.
Tests: AudioPipeInstanceTests pins that an id-less DEBUG process never resolves to the bare name;
572 green, 0 warnings.
Reported 2026-11-06: a Release instance crashed when clicking Go Live in test mode, while a Debug
instance was recording its window. The Windows event log gave the cause:
System.IO.IOException: All pipe instances are busy.
at System.IO.Pipes.NamedPipeServerStream.Create(...)
at ytLive.Services.Audio.NamedPipeAudioWriter.Start(...)
at ytLive.Services.Audio.AudioMixer.StartLive(...)
at MainViewModel.StartStreamingSession(...)
at MainViewModel.BeginTestStream(...)
at MainViewModel.StartFromPrimaryButton(...)
at System.Windows.Controls.Button.OnClick()
Two defects, both fixed:
1. **A button click could end the process.** `StartLive` throws when the pipe name is taken, and nothing
on the go-live path caught it. `TryStartAudioPipe` now catches, logs, toasts ("Another copy of
LlamaCasty is already using the audio pipe") and rolls the session back. Recording-only takes the same
path.
2. **The pipe name was a shared constant**, so a second instance could never go live on the same machine.
`InstanceProfile.AudioPipeName` appends the dev instance id (DEBUG only); Release keeps the plain name
so the normal single-instance case is unchanged. The encoder reads the same derived name, so mixer and
ffmpeg cannot disagree.
Tests: `AudioPipeInstanceTests` — a second server on one name throws (the collision is real), dev names
derive per instance, and a writer on a taken name throws rather than silently reusing the pipe.
Debug and Release both build clean.
gramps