Keep capture stream running between PTT utterances

CMakeLists.txt

@@ -100,6 +100,10 @@ if(BUILD_TESTING AND NOT CMAKE_CROSSCOMPILING)
     "-DEXPECTED_VERSION=${FRAMEYAP_VERSION}" -P "${CMAKE_CURRENT_SOURCE_DIR}/tests/cli.cmake")
   add_test(NAME frameyap.install_preflight COMMAND sh "${CMAKE_CURRENT_SOURCE_DIR}/tests/install-preflight.sh"
     "${CMAKE_CURRENT_SOURCE_DIR}/scripts/install-preflight.sh")
+  add_executable(frameyap_audio_test tests/audio_test.cpp src/audio.cpp)
+  target_include_directories(frameyap_audio_test PRIVATE src tests/fake_sdl)
+  target_compile_options(frameyap_audio_test PRIVATE -UNDEBUG)
+  add_test(NAME frameyap.audio_lifecycle COMMAND frameyap_audio_test)
   add_executable(frameyap_core_test tests/core_test.cpp)
   target_link_libraries(frameyap_core_test PRIVATE frameyap_core)
   add_test(NAME frameyap.core COMMAND frameyap_core_test)

README.md

@@ -36,7 +36,9 @@ See [third-party notes](docs/third-party.md). No GitHub release is published yet
   backs it up before repairs. See [overlay configuration](docs/overlay.md#user-theme-and-controller-configuration).
 - **Review-first:** focus your destination, then press Insert. No automatic insertion
   or submission. Maximum clip 20 seconds; accidental taps under 200 ms are discarded.
-- Other apps may still hear/transmit your voice. FrameYap does not mute them.
+- While the native app is Ready, it keeps the mic device open and discards idle
+  audio instead of opening/closing on every PTT. Quit releases the device. Other
+  apps may still hear/transmit your voice; FrameYap does not mute them.
 
 Physical gesture timing, global bindings during games, mic capture, target-app
 compatibility and headset comfort still need coordinated validation. Successful

docs/poc.md

@@ -18,14 +18,19 @@ initialize OpenVR, open a microphone, run ASR, download files or inject input.
   after first release.
   Activity/tracking loss cancels a held recording and requires neutral rearm.
 - SDL3 default recording device, mono float32 conversion at 16 kHz, 200 ms minimum,
-  20 second maximum. Microphone is closed outside actual capture. Other apps may
-  still transmit your voice: this app does **not** mute VRChat or any other app.
+  20 second maximum. In the native app the microphone stream opens after model
+  warm-up, stays running between utterances, and discards idle samples; PTT does
+  not open/pause/close the device. Quit, worker restart, device failure or capture
+  failure closes it. This avoids repeated capture-device transitions but does not
+  promise glitch-free playback on every audio stack. Other apps may still
+  transmit your voice: this app does **not** mute VRChat or any other app.
 - Persistent local Redux worker, correlated bounded pipes, private tmpfs clips,
   cancellation/reaping and deadlines; exact pinned model SHA-256 verification.
   Model imports are lazy and loading is offline. Normal repeats, request-local
   transcription failures and microphone failures retain the loaded model;
-  microphone device streams close outside capture. A cancelled in-flight request
-  or broken worker protocol may require reloading. No cloud/desktop fallback.
+  microphone device failure releases the stream for explicit retry. A cancelled
+  in-flight request or broken worker protocol may require reloading. No
+  cloud/desktop fallback.
 - Gamescope IME v2 generated bindings, per-action short-lived lease, unavailable
   handling, UTF-8/control validation and explicit separate Submit action for Enter.
 - Idempotent user-local release-archive installer: SHA-256, safe extraction,

src/audio.cpp

@@ -9,37 +9,48 @@
 namespace frameyap {
 namespace { void check(bool result) { if (!result) throw std::runtime_error(std::string("Microphone: ") + SDL_GetError()); } }
 Audio::~Audio() {
-    cancel();
+    close();
     if (initialized_) SDL_QuitSubSystem(SDL_INIT_AUDIO);
 }
-void Audio::start() {
-    if (stream_) throw std::runtime_error("Already recording");
-    // Keep SDL's audio backend initialized across utterances, but own the
-    // recording device only while actually capturing. Reinitializing PipeWire
-    // after every clip can fail even though the local model remains healthy.
+void Audio::prepare() {
+    if (stream_) return;
     if (!initialized_) { check(SDL_InitSubSystem(SDL_INIT_AUDIO)); initialized_ = true; }
     SDL_AudioSpec spec{SDL_AUDIO_F32, 1, 16000};
     stream_ = SDL_OpenAudioDeviceStream(SDL_AUDIO_DEVICE_DEFAULT_RECORDING, &spec, nullptr, nullptr);
     if (!stream_) throw std::runtime_error(std::string("Microphone: ") + SDL_GetError());
-    pcm_.clear(); pcm_.reserve(320000);
-    started_ = last_data_ = std::chrono::steady_clock::now();
     try { check(SDL_ResumeAudioStreamDevice(stream_)); }
-    catch (...) { cancel(); throw; }
+    catch (...) { close(); throw; }
+    last_data_ = std::chrono::steady_clock::now();
+}
+void Audio::start() {
+    if (recording_) throw std::runtime_error("Already recording");
+    if (!stream_) throw std::runtime_error("Microphone unavailable; retry capture");
+    // Clear queued idle data at the PTT boundary; the device never pauses or
+    // reopens. Polling also discards idle samples so the queue stays small.
+    check(SDL_ClearAudioStream(stream_));
+    std::fill(pcm_.begin(), pcm_.end(), 0.0f); pcm_.clear(); pcm_.reserve(320000);
+    started_ = last_data_ = std::chrono::steady_clock::now();
+    recording_ = true;
 }
 void Audio::drain() {
     std::array<float, 4096> chunk{};
-    while (pcm_.size() < 320000) {
+    // During idle and after the 20s bound, consume and discard device samples.
+    // Never let idle audio accumulate for the next utterance.
+    while (true) {
         int available = SDL_GetAudioStreamAvailable(stream_);
         check(available >= 0);
         if (available < int(sizeof(float))) break;
-        const int count = static_cast<int>(std::min({chunk.size(), std::size_t(available) / sizeof(float), 320000 - pcm_.size()}));
+        const int count = static_cast<int>(std::min(chunk.size(), std::size_t(available) / sizeof(float)));
         int bytes = SDL_GetAudioStreamData(stream_, chunk.data(), count * sizeof(float));
         check(bytes >= 0);
         if (bytes == 0) break;
         if (bytes % sizeof(float)) throw std::runtime_error("Misaligned microphone samples");
-        for (int i = 0; i < bytes / int(sizeof(float)); ++i)
-            if (!std::isfinite(chunk[i])) throw std::runtime_error("Invalid microphone samples");
-        pcm_.insert(pcm_.end(), chunk.begin(), chunk.begin() + bytes / sizeof(float));
+        if (recording_) {
+            const auto retain = std::min(std::size_t(bytes) / sizeof(float), 320000 - pcm_.size());
+            for (std::size_t i = 0; i < retain; ++i)
+                if (!std::isfinite(chunk[i])) throw std::runtime_error("Invalid microphone samples");
+            pcm_.insert(pcm_.end(), chunk.begin(), chunk.begin() + retain);
+        }
         last_data_ = std::chrono::steady_clock::now();
     }
 }
@@ -47,32 +58,38 @@ bool Audio::poll() {
     if (!stream_) return false;
     SDL_Event event;
     while (SDL_PollEvent(&event)) {
-        if (event.type == SDL_EVENT_AUDIO_DEVICE_REMOVED && event.adevice.recording)
+        if (event.type == SDL_EVENT_AUDIO_DEVICE_REMOVED && event.adevice.recording &&
+            event.adevice.which == SDL_GetAudioStreamDevice(stream_))
             throw std::runtime_error("Recording device removed; clip discarded");
     }
     drain();
     if (std::chrono::steady_clock::now() - last_data_ > std::chrono::seconds(2))
         throw std::runtime_error("Microphone stalled; clip discarded");
-    return pcm_.size() == 320000 || seconds() >= 20;
+    return recording_ && (pcm_.size() == 320000 || seconds() >= 20);
 }
 std::vector<float> Audio::finish() {
-    if (!stream_) return {};
+    if (!recording_) return {};
     try {
-        check(SDL_PauseAudioStreamDevice(stream_));
-        check(SDL_FlushAudioStream(stream_));
         drain();
+        recording_ = false;
         auto result = std::move(pcm_);
-        cancel();
+        pcm_.clear();
+        // Discard any resampler remainder and never pause the capture device.
+        check(SDL_ClearAudioStream(stream_));
         return result;
     } catch (...) { cancel(); throw; }
 }
 void Audio::cancel() {
+    recording_ = false;
+    std::fill(pcm_.begin(), pcm_.end(), 0.0f); pcm_.clear();
+    if (stream_) SDL_ClearAudioStream(stream_); // best effort on cancellation
+}
+void Audio::close() {
+    cancel();
     if (stream_) SDL_DestroyAudioStream(stream_);
     stream_ = nullptr;
-    // Best effort clearing of the owned buffer; no persistent recording/logging.
-    std::fill(pcm_.begin(), pcm_.end(), 0.0f); pcm_.clear();
 }
 int Audio::seconds() const {
-    return stream_ ? int(std::chrono::duration_cast<std::chrono::seconds>(std::chrono::steady_clock::now() - started_).count()) : 0;
+    return recording_ ? int(std::chrono::duration_cast<std::chrono::seconds>(std::chrono::steady_clock::now() - started_).count()) : 0;
 }
 }

src/audio.hpp

@@ -7,16 +7,20 @@ class Audio {
 public:
     Audio() = default;
     ~Audio();
-    void start();
-    bool poll(); // true at 20s limit; throws if capture was lost/stalled
+    void prepare(); // open/resume once, while app is ready; never retain idle samples
+    void start(); // arm the already-running stream without touching the device
+    bool poll(); // drain even while idle; true at 20s limit; throws on loss/stall
     std::vector<float> finish();
-    void cancel();
-    bool recording() const { return stream_ != nullptr; }
+    void cancel(); // discard current clip, leave the device running
+    void close(); // release device on shutdown or capture failure
+    bool recording() const { return recording_; }
+    bool open() const { return stream_ != nullptr; }
     int seconds() const;
 private:
     void drain();
     SDL_AudioStream* stream_ = nullptr;
     bool initialized_ = false;
+    bool recording_ = false;
     std::vector<float> pcm_;
     std::chrono::steady_clock::time_point started_, last_data_;
 };

src/runtime.cpp

@@ -47,7 +47,7 @@ int run(const Options& options) {
     std::string detail = "Review mode. Other apps may also hear your mic. Enter is separate.";
     bool quit = false;
     auto warm = [&] {
-        worker.stop(); session = Session{};
+        audio.close(); worker.stop(); session = Session{};
         worker.start(options.python, options.worker, options.model, options.threads);
         detail = "Loading local model; microphone closed. Record again when Ready.";
     };
@@ -63,6 +63,7 @@ int run(const Options& options) {
     auto start_record = [&] {
         if (session.state() == State::Review || session.state() == State::Transcribing || session.state() == State::Warming) return;
         if (!worker.ready()) { warm(); return; }
+        if (!audio.open()) audio.prepare(); // recovery only; normal PTT never opens the device
         if (session.state() == State::Error) session.cancel();
         if (!session.record()) return;
         audio.start();
@@ -86,16 +87,19 @@ int run(const Options& options) {
             }
             if (worker.ready()) session.ready();
         } catch (const std::exception& e) {
-            audio.cancel(); worker.stop();
+            audio.close(); worker.stop();
             if (session.state() != State::Review && session.state() != State::Queued) session.fail();
             detail = e.what(); // Preserve an already-correlated preview if the worker dies.
         }
         try {
-            if (audio.recording() && audio.poll()) stop_record();
+            // Prepare after model warm-up, not on PTT. Keep draining/discarding
+            // idle samples so neither a device transition nor old speech reaches
+            // the next clip. A capture failure still requires an explicit retry.
+            if (session.state() == State::Ready && !audio.open() && worker.ready()) audio.prepare();
+            if (audio.open() && audio.poll()) stop_record();
         } catch (const std::exception& e) {
-            // A microphone failure is not a model failure. Release the device,
-            // retain the loaded worker, and allow Record to retry capture.
-            audio.cancel(); session.fail(); detail = e.what();
+            // A microphone failure is not a model failure.
+            audio.close(); session.fail(); detail = e.what();
         }
         // Drawing precedes input polling: Enter is disabled until Ready is visible.
         const auto status = session.state() == State::Error && worker.ready()
@@ -118,10 +122,11 @@ int run(const Options& options) {
                 case UiAction::EndRecord: stop_record(); break;
                 case UiAction::Cancel: {
                     auto state = session.state();
-                    audio.cancel(); session.cancel(); detail = "Discarded. Microphone closed.";
+                    audio.cancel(); session.cancel(); detail = "Discarded. Idle microphone samples are discarded.";
                     if (state == State::Warming || state == State::Transcribing) {
-                        worker.stop(); session.fail(); detail = "Cancelled. Record to reload local worker.";
+                        audio.close(); worker.stop(); session.fail(); detail = "Cancelled. Record to reload local worker.";
                     } else if (state == State::Error && !worker.ready()) {
+                        audio.close();
                         session.fail(); detail = "Worker unavailable. Record to reload local worker.";
                     }
                     break;
@@ -150,7 +155,7 @@ int run(const Options& options) {
                 // only the microphone; submit failures stop their own child if
                 // the IPC stream was partially written.
                 if (session.state() == State::Recording || session.state() == State::Transcribing) {
-                    audio.cancel(); session.fail();
+                    audio.close(); session.fail();
                 }
                 detail = e.what();
             }
@@ -158,7 +163,7 @@ int run(const Options& options) {
         }
         std::this_thread::sleep_for(std::chrono::milliseconds(10));
     }
-    audio.cancel(); session.cancel(); worker.stop();
+    audio.close(); session.cancel(); worker.stop();
     return 0;
 }
 }

tests/audio_test.cpp

@@ -0,0 +1,64 @@
+#include "audio.hpp"
+#include <SDL3/SDL.h>
+#include <algorithm>
+#include <cassert>
+#include <cstring>
+#include <iostream>
+#include <stdexcept>
+
+namespace {
+SDL_AudioStream* current = nullptr;
+int opens = 0, resumes = 0, closes = 0;
+bool removed = false;
+void feed(float value, int count) { assert(current); current->queued.insert(current->queued.end(), count, value); }
+}
+const char* SDL_GetError() { return "fake failure"; }
+bool SDL_InitSubSystem(int) { return true; }
+void SDL_QuitSubSystem(int) {}
+SDL_AudioStream* SDL_OpenAudioDeviceStream(SDL_AudioDeviceID, const SDL_AudioSpec*, void*, void*) {
+    ++opens; return current = new SDL_AudioStream;
+}
+bool SDL_ResumeAudioStreamDevice(SDL_AudioStream*) { ++resumes; return true; }
+SDL_AudioDeviceID SDL_GetAudioStreamDevice(SDL_AudioStream*) { return 42; }
+int SDL_GetAudioStreamAvailable(SDL_AudioStream* stream) { return int(stream->queued.size() * sizeof(float)); }
+int SDL_GetAudioStreamData(SDL_AudioStream* stream, void* data, int size) {
+    int count = std::min(int(stream->queued.size()), size / int(sizeof(float)));
+    std::memcpy(data, stream->queued.data(), count * sizeof(float));
+    stream->queued.erase(stream->queued.begin(), stream->queued.begin() + count);
+    return count * sizeof(float);
+}
+bool SDL_ClearAudioStream(SDL_AudioStream* stream) { stream->queued.clear(); return true; }
+void SDL_DestroyAudioStream(SDL_AudioStream* stream) { ++closes; current = nullptr; delete stream; }
+bool SDL_PollEvent(SDL_Event* event) {
+    if (!removed) return false;
+    removed = false; *event = SDL_Event{SDL_EVENT_AUDIO_DEVICE_REMOVED, {true, 42}}; return true;
+}
+int main() {
+    using frameyap::Audio;
+    {
+        Audio audio;
+        audio.prepare(); audio.prepare();
+        assert(opens == 1 && resumes == 1 && audio.open() && !audio.recording());
+        feed(0.7f, 10000); audio.poll();
+        assert(current->queued.empty());
+        feed(0.8f, 200); audio.start(); // queued idle speech cannot leak
+        feed(0.1f, 3200); audio.poll();
+        feed(0.2f, 3200);
+        auto clip = audio.finish();
+        assert(clip.size() == 6400 && clip.front() == 0.1f && clip.back() == 0.2f);
+        assert(audio.open() && !audio.recording() && opens == 1 && closes == 0 && resumes == 1);
+        feed(0.5f, 200); audio.start(); feed(0.3f, 4000);
+        audio.cancel(); assert(current->queued.empty());
+        feed(0.9f, 100); audio.start(); feed(0.4f, 3200);
+        clip = audio.finish(); assert(clip.size() == 3200 && clip.front() == 0.4f);
+        assert(opens == 1 && closes == 0 && resumes == 1);
+        removed = true;
+        bool failed = false;
+        try { audio.poll(); } catch (const std::runtime_error&) { failed = true; }
+        assert(failed);
+        audio.close(); assert(closes == 1 && !audio.open());
+        audio.prepare(); assert(opens == 2 && resumes == 2);
+    }
+    assert(closes == 2);
+    std::cout << "audio lifecycle checks passed (fake device only)\n";
+}

tests/fake_sdl/SDL3/SDL.h

@@ -0,0 +1,22 @@
+#pragma once
+#include <cstdint>
+#include <vector>
+#define SDL_INIT_AUDIO 1
+#define SDL_AUDIO_F32 2
+#define SDL_AUDIO_DEVICE_DEFAULT_RECORDING 3
+#define SDL_EVENT_AUDIO_DEVICE_REMOVED 4
+using SDL_AudioDeviceID = unsigned;
+struct SDL_AudioSpec { int format, channels, freq; };
+struct SDL_AudioStream { std::vector<float> queued; };
+struct SDL_Event { int type; struct { bool recording; SDL_AudioDeviceID which; } adevice; };
+const char* SDL_GetError();
+bool SDL_InitSubSystem(int);
+void SDL_QuitSubSystem(int);
+SDL_AudioStream* SDL_OpenAudioDeviceStream(SDL_AudioDeviceID, const SDL_AudioSpec*, void*, void*);
+bool SDL_ResumeAudioStreamDevice(SDL_AudioStream*);
+SDL_AudioDeviceID SDL_GetAudioStreamDevice(SDL_AudioStream*);
+int SDL_GetAudioStreamAvailable(SDL_AudioStream*);
+int SDL_GetAudioStreamData(SDL_AudioStream*, void*, int);
+bool SDL_ClearAudioStream(SDL_AudioStream*);
+void SDL_DestroyAudioStream(SDL_AudioStream*);
+bool SDL_PollEvent(SDL_Event*);