src/audio/audio_manager.cpp

@@ -157,6 +157,40 @@ namespace radiantwave::audio
         return enabled_ ? (volume_ / 100.0f) : 0.0f;
     }
 
+    SDL_PropertiesID AudioManager::createInfiniteLoopOptions()
+    {
+        // MIX_PlayTrack()'s options default to a single pass; requesting
+        // infinite loops is what keeps a track going until it is explicitly
+        // faded out or the app shuts down.
+        SDL_PropertiesID props = SDL_CreateProperties();
+        if (props)
+        {
+            SDL_SetNumberProperty(props, MIX_PROP_PLAY_LOOPS_NUMBER, -1);
+        }
+        return props;
+    }
+
+    bool AudioManager::playTrackLooping(int slotIndex)
+    {
+        if (!initialized_ || !mixer_ || slotIndex < 0 || slotIndex >= 2 ||
+            !slots_[slotIndex].track)
+        {
+            return false;
+        }
+
+        SDL_PropertiesID props = createInfiniteLoopOptions();
+        if (!props)
+        {
+            logger::Logger::instance().error(
+                "Audio", "Failed to create playback options for " +
+                             displayNameFor(currentTrack_));
+            return false;
+        }
+        bool ok = MIX_PlayTrack(slots_[slotIndex].track, props);
+        SDL_DestroyProperties(props);
+        return ok;
+    }
+
     void AudioManager::shutdown()
     {
         std::lock_guard<std::mutex> lock(mutex_);
@@ -495,7 +529,7 @@ namespace radiantwave::audio
                 else
                 {
                     MIX_SetTrackGain(slots_[activeSlot_].track, 1.0f);
-                    MIX_PlayTrack(slots_[activeSlot_].track, 0); // Loop playback
+                    playTrackLooping(activeSlot_); // Loop playback
                 }
             }
         }
@@ -553,7 +587,7 @@ namespace radiantwave::audio
         slot.fadeInDuration = seconds;
         slot.fadeInElapsed = 0.0f;
         MIX_SetTrackGain(slot.track, 0.0f);
-        MIX_PlayTrack(slot.track, 0); // Loop playback
+        playTrackLooping(slotIndex); // Loop playback
         logger::Logger::instance().info("Audio", "Started playback of " + displayNameFor(currentTrack_) + " (fade-in)");
     }
 
@@ -567,7 +601,7 @@ namespace radiantwave::audio
             return false;
 
         MIX_SetTrackGain(slots_[activeSlot_].track, 1.0f);
-        MIX_PlayTrack(slots_[activeSlot_].track, 0); // Loop playback
+        playTrackLooping(activeSlot_); // Loop playback
 
         // Explicit user selection: persist the manual track so it survives a
         // restart and is used whenever dynamic audio is turned off. Dynamic
@@ -604,10 +638,11 @@ namespace radiantwave::audio
             slot.fadeInElapsed = 0.0f;
             slot.fadeOutRemaining = 0.0f;
             MIX_SetTrackGain(slot.track, 1.0f);
-            if (!MIX_TrackPlaying(slot.track))
-            {
-                MIX_PlayTrack(slot.track, 0); // Loop playback
-            }
+            // Always restart: MIX_PlayTrack() re-starts a playing track too, so
+            // this cancels any in-flight stop-fade inherited from a quick
+            // pop->push within the fade window. Gating on MIX_TrackPlaying()
+            // left a fading track to finish its fade and go silently stopped.
+            playTrackLooping(activeSlot_); // Loop playback
             return true;
         }
 
@@ -642,10 +677,14 @@ namespace radiantwave::audio
         if (!loadTrackInto(otherSlot, wav_filename))
             return false;
 
-        // Fade out whatever is currently playing on the active slot.
+        // Fade out whatever is currently playing on the active slot. Clear any
+        // in-flight fade-in bookkeeping first so update() stops ramping this
+        // slot's gain up while the mixer fades it down.
         TrackSlot &active = slots_[activeSlot_];
         if (active.audio)
         {
+            active.fadeInDuration = 0.0f;
+            active.fadeInElapsed = 0.0f;
             MIX_StopTrack(active.track, MIX_TrackMSToFrames(active.track, static_cast<Sint64>(fade * 1000.0)));
             active.fadeOutRemaining = fade;
         }
@@ -673,6 +712,10 @@ namespace radiantwave::audio
             {
                 continue;
             }
+            // The mixer owns the ramp now; drop any pending fade-in so the
+            // per-frame update() cannot fight the fade-out.
+            slot.fadeInDuration = 0.0f;
+            slot.fadeInElapsed = 0.0f;
             MIX_StopTrack(slot.track, MIX_TrackMSToFrames(slot.track, static_cast<Sint64>(fade * 1000.0)));
             slot.fadeOutRemaining = fade;
             faded = true;
@@ -707,7 +750,29 @@ namespace radiantwave::audio
         {
             TrackSlot &slot = slots_[i];
             if (!slot.track)
+            {
                 continue;
+            }
+
+            // A slot mid stop-fade belongs to the mixer: skip both the fade-in
+            // ramp and the active-gain pin so nothing drives its gain up while
+            // the mixer ramps it down (this also keeps a quit/pop fade clean).
+            if (slot.fadeOutRemaining > 0.0f)
+            {
+                slot.fadeOutRemaining -= dt;
+                if (slot.fadeOutRemaining <= 0.0f)
+                {
+                    slot.fadeOutRemaining = 0.0f;
+                    // Free the audio once the fade-out has finished; the track
+                    // object itself is reused.
+                    if (slot.audio)
+                    {
+                        MIX_DestroyAudio(slot.audio);
+                        slot.audio = nullptr;
+                    }
+                }
+                continue;
+            }
 
             if (slot.fadeInDuration > 0.0f)
             {
@@ -724,21 +789,12 @@ namespace radiantwave::audio
                 // Keep the active track at full per-track gain; the mixer gain
                 // carries the user's volume / mute state.
                 MIX_SetTrackGain(slot.track, 1.0f);
-            }
-
-            if (slot.fadeOutRemaining > 0.0f)
-            {
-                slot.fadeOutRemaining -= dt;
-                if (slot.fadeOutRemaining <= 0.0f)
+                // Self-heal: playback must continue indefinitely, so restart a
+                // track that stopped unexpectedly (there is no pause state and
+                // nothing else should legitimately stop the active track).
+                if (slot.audio && enabled_ && !MIX_TrackPlaying(slot.track))
                 {
-                    slot.fadeOutRemaining = 0.0f;
-                    // Free the audio once the fade-out has finished; the track
-                    // object itself is reused.
-                    if (slot.audio)
-                    {
-                        MIX_DestroyAudio(slot.audio);
-                        slot.audio = nullptr;
-                    }
+                    playTrackLooping(i);
                 }
             }
         }

src/audio/audio_manager.h

@@ -66,6 +66,12 @@ public:
     // for tests; the real lookup is through getPlaybackDevices().
     static std::string resolvePlaybackDeviceName(SDL_AudioDeviceID id);
 
+    // Builds the SDL_PropertiesID passed to MIX_PlayTrack() for tracks that
+    // loop forever (MIX_PROP_PLAY_LOOPS_NUMBER = -1). Exposed for tests; no
+    // mixer, track, or audio device is required. The caller owns the property
+    // set and must release it with SDL_DestroyProperties().
+    static SDL_PropertiesID createInfiniteLoopOptions();
+
     // Playback control
     bool playTrack(const std::string& wav_filename);
     void stopTrack();
@@ -97,6 +103,11 @@ private:
     void startFadeIn(int slotIndex, float seconds);
     std::string displayNameFor(const std::string& wav_filename) const;
 
+    // Starts the track on the given slot with infinite looping. The track must
+    // already be loaded on the slot. Calling this on a playing/stopped/fading
+    // track restarts it (cancelling any in-flight stop-fade).
+    bool playTrackLooping(int slotIndex);
+
     // Recreates the mixer on the given playback device id (0 = system default).
     // Called with mutex_ held. Preserves playback state: whichever track was
     // playing on the active slot is reloaded and resumed at full gain, an

tests/test_audio.cpp

@@ -59,3 +59,14 @@ TEST(AudioTest, AudioManagerVolumeClamping) {
     am.shutdown();
     std::filesystem::remove(temp_path);
 }
+
+TEST(AudioTest, PlayOptionsLoopInfinite) {
+    // Regression: MIX_PlayTrack() must not default to a single pass. Tracks
+    // have to loop forever so playback never runs out mid-scroll; a track that
+    // stops (rather than attenuates) also can't be revived by raising app
+    // volume. Assert the options request infinite looping (-1).
+    SDL_PropertiesID props = AudioManager::createInfiniteLoopOptions();
+    ASSERT_NE(props, 0u);
+    EXPECT_EQ(SDL_GetNumberProperty(props, MIX_PROP_PLAY_LOOPS_NUMBER, 0), -1);
+    SDL_DestroyProperties(props);
+}

tests/test_scroller_streams.cpp

@@ -94,6 +94,62 @@ TEST(ScrollerStreamsTest, InterleavesSelectedWithDefault)
     EXPECT_EQ(streams[3].audioFilename, "OriginalAudio.wav");
 }
 
+TEST(ScrollerStreamsTest, InterleavedListCyclesBackToFirstSelected)
+{
+    // Three selected proclamations: the built list must be
+    // [S1, Default, S2, Default, S3, Default]. ScrollerPage advances through
+    // this list with a modulo, so once the trailing default finishes the cycle
+    // restarts at the FIRST selected proclamation — the "always on" default
+    // must never accumulate or take over the queue.
+    ProclamationRecord b;
+    b.id = "B";
+    b.title = "B";
+    b.content = "bbbb";
+    b.selected = true;
+    b.solfeggio_frequency_id = 2;
+
+    ProclamationRecord c;
+    c.id = "C";
+    c.title = "C";
+    c.content = "cccc";
+    c.selected = true;
+    c.solfeggio_frequency_id = 3;
+
+    ProclamationRecord d;
+    d.id = "D";
+    d.title = "D";
+    d.content = "dddd";
+    d.selected = true;
+    d.solfeggio_frequency_id = 4;
+
+    ProclamationRecord def;
+    def.id = kDefaultId;
+    def.title = "Default";
+    def.content = "dddddddddd";
+    def.selected = true;
+    def.solfeggio_frequency_id = 5;
+
+    auto streams = buildStreams({b, def, c, d}, {}, palette(), {}, kDefaultId);
+
+    ASSERT_EQ(streams.size(), 6u);
+    EXPECT_EQ(streams[0].name, "B");
+    EXPECT_EQ(streams[1].name, "Default");
+    EXPECT_EQ(streams[2].name, "C");
+    EXPECT_EQ(streams[3].name, "Default");
+    EXPECT_EQ(streams[4].name, "D");
+    EXPECT_EQ(streams[5].name, "Default");
+
+    // Every default copy is independent playback state (fresh counters), so a
+    // copy finishing its passes advances to the next stream rather than
+    // restarting "the default" forever.
+    for (size_t i = 1; i < streams.size(); i += 2) {
+        EXPECT_EQ(streams[i].name, "Default");
+        EXPECT_EQ(streams[i].completed, 0) << "default copy " << i;
+        EXPECT_EQ(streams[i].wordsPlaced, 0) << "default copy " << i;
+        EXPECT_EQ(streams[i].repeat, kDefaultRepeatCount) << "default copy " << i;
+    }
+}
+
 TEST(ScrollerStreamsTest, DefaultOnlyWhenNothingSelected)
 {
     ProclamationRecord p1;