tools/testhost/ is a standalone CLI executable, not a JaySynth-specific
tool: it drives any VST2 plugin offline (no audio device, no GUI event
loop) via JUCE's own format-agnostic AudioPluginFormatManager /
AudioPluginInstance hosting API, so adding another format later (VST3,
LADSPA, eventually LV2) is just another addFormat() call - none of the
host logic changes.
- PluginHost: format-agnostic load/prepare/process/release, parameter
get/set, and patch/bank state I/O, all delegating straight to
AudioProcessor. Always queries the plugin's real input/output channel
counts rather than assuming "0 in" (instrument) or a fixed channel
layout - the same code path drives JaySynth (0 in/2 out, MIDI-driven)
and a stereo/mono effect identically.
- AudioInputSource: fills the plugin's input channels with silence
(default, correct no-op for instruments), a sine tone, white/pink
noise, or an impulse - what makes the host equally useful for
effect plugins, which need a real input signal to do anything.
- WavRecorder: records the plugin's actual output channel count to a
WAV file via WavAudioFormat/AudioFormatWriter.
- main.cpp: CLI (--plugin/--patch/--param/--note/--input/--duration/
--wav/--sampleRate/--blockSize), with basic NaN/Inf output detection.
Has its own JuceLibraryCode-equivalent package that compiles only the
module amalgams needed for hosting (not juce_audio_plugin_client,
which is the plugin-side VST entry point and would collide with this
executable's own main()), reusing the already-vendored
sdk/juce/JUCE-3.1.1 rather than a second JUCE copy - the host and any
plugin it loads are decoupled at the VST2 ABI, not the JUCE source
level, so this doesn't need to track JaySynth's own future JUCE
version bump.
Verified: builds clean (no new warnings) via
`MAKE_HOME=... make -C tools/testhost`. Smoke-tested against two very
different real plugins:
- build/linux/release/JaySynth.so (0 in/2 out, MIDI-driven): --note
60 100 --duration 2 --wav produces correct-length, non-silent,
NaN-free stereo audio.
- /usr/lib/vst/ZamDelay-vst.so (1 in/1 out, real third-party VST2
effect, no MIDI): --input pink --duration 2 --wav correctly sizes
input/output to mono and produces non-silent, NaN-free audio -
proof the host is generic, not JaySynth-shaped.
- /usr/lib/vst/ZamEQ2-vst.so: the host's own NaN/Inf detection caught
a real NaN in this plugin's default state on first render - exactly
the kind of regression this tool exists to catch without a GUI.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011dhtwRLARk4eiPngcQykLJ
