2 Commits

Author	SHA1	Message	Date
Jorge Fritis	7671385ba8	Audio: song loudness normalization, in-process VSTs (perf), and stereo routing (#24) ... * audio: flush denormals in the RT path + normalize the backing track Two realtime-audio fixes (engine only — no change to amp/effect DSP): 1. Denormal flush (FTZ/DAZ). The signal path is full of IIR state (NAM, cab IRs, VST amp/EQ/comp chains); after each note that state decays toward zero and lands in the denormal range, where each float op is 10-100x slower. That produced sporadic CPU spikes -> buffer underruns heard as random "scratches" plus frame stutter (worse with larger buffers, independent of song/tone). Add a scoped juce::ScopedNoDenormals at the three RT entry points: - AudioEngine::audioDeviceIOCallbackWithContext (whole callback) - SignalChain::process (the plugin chain) - the sandbox worker's plugin processBlock in src/vst-host/main.cpp (VST3s run OUT-OF-PROCESS, so the host-side FTZ doesn't reach them) Denormals are sub -300 dBFS, so this is inaudible — CPU only, no tone change. 2. Backing-track loudness normalizer (BackingLeveler.h). Brings each song's backing to a consistent -12 LUFS so songs don't jump in level, applied in renderBackingBlockLocked BEFORE the mixer's backing-volume fader (so the fader still attenuates). Short-term BS.1770 K-weighted AGC (slow, no pumping) + a -1 dBFS brickwall limiter. RT-safe (no allocation in process()). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * audio: extend denormal flush to the split-output path + reuse chain MidiBuffer Opt-1 low-risk RT tidy-ups (no DSP/tone change): - ScopedNoDenormals in audioOutputCallback (the split-mode output clock that renders the backing track + phase-vocoder + leveler) — the primary callback's scope doesn't reach this separate output thread, leaving an IIR/decay path unprotected (a remaining source of the periodic "scratches"). - SignalChain::process reuses one juce::MidiBuffer across slots instead of copy-constructing it per slot per block (avoids RT-thread allocation). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * audio: per-slot pan + parallel branch routing (St-1 stereo, engine side) Adds pan-only stereo to the signal chain so the node editor can place one amp left and another right, pan effects, and let stereo plugins pass true L/R. ProcessorSlot gains two fields: - pan : -1..+1 constant-power, applied to that slot's output (0 = no-op) - branch : 0 = trunk (serial), >=1 = a parallel branch id SignalChain::process keeps a bit-identical serial fast path when no slot has a branch. When branches exist it runs the trunk-pre slots in place, snapshots that as the split source, processes each branch on its own pre-allocated scratch buffer, pans it, sums the branches into a merge bus, then runs any trunk-post slots on the merged signal. Scratch is sized in prepare() (never on the RT thread); falls back to serial for a non-stereo / oversized block. The dual-mono amp output + post-amp pan is what yields "amp A left, amp B right" without touching NAM or amp DSP. Preset schema emits pan/branch only when non-default (mono presets unchanged); N-API gains setPan/setBranch and getChainState/loadPreset round-trip them. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * audio: per-branch source channel (St-2) — feed a split L/R into separate branches Extends the parallel-branch model so a stereo-out gear (e.g. a stereo delay) can send its L output to one branch and its R to another. ProcessorSlot gains branchSrc (0 = both, 1 = L, 2 = R); when seeding a branch from the split source, L-only / R-only mono-izes that channel into the branch. Read from any slot in the branch. N-API setBranchSrc + getChainState/preset round-trip it. Default 0 keeps existing routing identical. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * audio-bridge: expose setPan/setBranch/setBranchSrc to the renderer The engine N-API gained the stereo routing setters (setPan/setBranch/ setBranchSrc) but the main-process IPC handlers + the preload bridge didn't forward them, so window.slopsmithDesktop.audio.setPan was undefined and the node editor's stereo controls no-op'd. Wire all three through audio:setPan / setBranch / setBranchSrc. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * audio: run scanned VSTs in-process + forward params + cut RT stalls Big CPU/latency win for chains with VST plugins, plus the missing parameter path. The out-of-process sandbox exists to crash-isolate the SCAN of unknown plugins; a plugin only reaches a chain after it scanned cleanly, so paying the per-block IPC cost (N serial round-trips, memcpy, poll waits) for every block of playback was pure overhead. - shouldSandbox(): default VST3 playback to IN-PROCESS. The runtime crash blocklist + launch sentinel still route a faulting plugin back through the sandbox on its next load, so it self-heals; only genuinely crash-prone gear keeps paying for isolation. Eliminates the IPC round-trips + the per-load subprocess spawn that caused the load-time "scratches". - SignalChain::clear(): detach slots under a brief lock, destroy them OFF the lock. Sandbox teardown is slow; doing it under `lock` starved the RT ScopedTryLock and dropped audio blocks on every chain reload. - AudioChannel::popBlock(): bounded busy-spin on the write index before the blocking poll() — a fast plugin's output lands within microseconds, so we skip the syscall + doorbell wakeup latency; a slow plugin falls through to the efficient wait (correctness + heavy-chain cost unchanged). - SandboxedProcessor::setSandboxedParameter() + SignalChain::setParameter() route param changes to a sandboxed plugin over the control pipe (kSetParameter) — the JUCE getParameters() proxy layer isn't wired, so without this a sandboxed plugin's knobs/preset never reached it and it played at defaults. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * audio: PR #24 review follow-ups — POSIX fault guard + routing/spin/leveler fixes Follow-up fixes from review of PR #24. == POSIX in-process plugin fault guard (the main one) == PR #24 makes scanned VSTs run in-process by default. invokePlugin()'s catch(...) only catches a plugin fault on Windows (where /EHa maps the SEH access violation to a C++ exception); on macOS/Linux a plugin SIGSEGV during playback took down the whole app, breaking the fail-soft-audio + cross-platform guarantees. Add a POSIX fault guard in SignalChain.cpp: install chained SIGSEGV/SIGBUS/ SIGFPE/SIGILL handlers; while a guarded plugin call is live on the current thread (thread-local, initial-exec TLS so the handler stays async-signal-safe), siglongjmp() back into invokePlugin() and take the SAME blocklist+leak+survive path as Windows. Faults outside a guarded call chain to the previously-installed handler (V8/ASan/default), so real crashes and sanitizers are never masked. The guard's armed flag is restored on EVERY exit from the guarded region — normal return, signal-fault longjmp, and a normal C++ exception from the plugin — so a thread is never left armed with a stale landing pad. Known limit: stack-overflow faults aren't reliably caught (no sigaltstack on JUCE audio threads). Comments in SandboxFactory_shared.cpp updated to match the kept in-process default (the stale 'every VST3 sandboxes' / 'diagnostic tagging only' notes). == Smaller correctness/quality fixes == - SignalChain parallel path: a branch==0 (trunk) slot interleaved inside the branch region was run by none of the loops -> silently dropped. Detect the region first and fall back to a serial chain (jassertfalse in debug) so no slot is lost if the node-editor contiguity invariant breaks. - AudioChannel pop busy-spin: add a cpuRelax() (_mm_pause / arm yield) hint. - BackingLeveler: reset AGC/limiter state on loadBackingTrack so a new song doesn't inherit the previous track's gain follower and briefly mis-level. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * test: integration test for the in-process plugin fault guard Drives deliberately-faulting in-process AudioProcessors through a real SignalChain::process() and asserts the host survives, the processor is released, and it's added to the crash blocklist (shouldSandbox() then routes it out-of-process). Covers BOTH fault kinds: a hardware SIGSEGV (POSIX guard / Windows SEH) and a normal C++ exception (the path that must leave the guard disarmed). End-to-end counterpart to the standalone mechanism check — exercises the actual invokePlugin() guard. Lives in the POSIX-only sandbox e2e harness (already links juce_audio_processors + the full sandbox set). Leak detection is disabled for the target because the guard leaks the faulting processor by design. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Jafz2001 <ignacio.fritis@mundotelecomunicaciones.cl> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Co-authored-by: Byron Gamatos <xasiklas@gmail.com>	2026-06-19 23:08:05 +02:00
Byron Gamatos	bd603184d5	Clean release snapshot	2026-06-16 18:48:12 +02:00