Adding RadioLanewayCrossfade transition

src/analyzer/analyzersilence.cpp

@@ -10,14 +10,36 @@ namespace {
 // verify that the track samples have not changed since the last analysis
 constexpr CSAMPLE kSilenceThreshold = 0.001f; // -60 dB
 // TODO: Change the above line to:
-//constexpr CSAMPLE kSilenceThreshold = db2ratio(-60.0f);
+// constexpr CSAMPLE kSilenceThreshold = db2ratio(-60.0f);
+
+// These are in dBV expressed as Volts RMS (which seems, sensibly,
+// the way Mixxx works).
+// Don't change these to const as they are used only to feed the
+// fade thresholds which are consts below themselves while we work
+// out which one is best, and you'll just be adding to exe size.
+#define N_10DB_FADEOUT_THRESHOLD 0.3162f
+#define N_12DB_FADEOUT_THRESHOLD 0.2511f
+#define N_15DB_FADEOUT_THRESHOLD 0.1778f
+#define N_18DB_FADEOUT_THRESHOLD 0.1259f
+#define N_20DB_FADEOUT_THRESHOLD 0.1f
+#define N_24DB_FADEOUT_THRESHOLD 0.0631f
+#define N_25DB_FADEOUT_THRESHOLD 0.0562f
+#define N_27DB_FADEOUT_THRESHOLD 0.0447f
+#define N_30DB_FADEOUT_THRESHOLD 0.0316f
+#define N_40DB_FADEOUT_THRESHOLD 0.01f
+
+constexpr CSAMPLE kFadeInThreshold = N_27DB_FADEOUT_THRESHOLD;
+constexpr CSAMPLE kFadeOutThreshold = N_12DB_FADEOUT_THRESHOLD;
 
 bool shouldAnalyze(TrackPointer pTrack) {
     CuePointer pIntroCue = pTrack->findCueByType(mixxx::CueType::Intro);
     CuePointer pOutroCue = pTrack->findCueByType(mixxx::CueType::Outro);
     CuePointer pN60dBSound = pTrack->findCueByType(mixxx::CueType::N60dBSound);
+    CuePointer pFadeIn = pTrack->findCueByType(mixxx::CueType::FadeIn);
+    CuePointer pFadeOut = pTrack->findCueByType(mixxx::CueType::FadeOut);
 
-    if (!pIntroCue || !pOutroCue || !pN60dBSound || pN60dBSound->getLengthFrames() <= 0) {
+    if (!pFadeIn || !pFadeOut || !pIntroCue || !pOutroCue || !pN60dBSound ||
+            pN60dBSound->getLengthFrames() <= 0) {
         return true;
     }
     return false;
@@ -30,13 +52,29 @@ Iterator first_sound(Iterator begin, Iterator end) {
     });
 }
 
+template<typename ForwardIterator>
+ForwardIterator last_fade_in_sound(ForwardIterator begin, ForwardIterator end) {
+    return std::find_if(begin, end, [](const auto elem) {
+        return fabs(elem) >= kFadeInThreshold;
+    });
+}
+
+template<typename Iterator>
+Iterator first_fade_out_sound(Iterator begin, Iterator end) {
+    return std::find_if(begin, end, [](const auto elem) {
+        return fabs(elem) >= kFadeOutThreshold;
+    });
+}
+
 } // anonymous namespace
 
 AnalyzerSilence::AnalyzerSilence(UserSettingsPointer pConfig)
         : m_pConfig(pConfig),
           m_framesProcessed(0),
           m_signalStart(-1),
-          m_signalEnd(-1) {
+          m_signalEnd(-1),
+          m_fadeThresholdFadeInEnd(-1),
+          m_fadeThresholdFadeOutStart(-1) {
 }
 
 bool AnalyzerSilence::initialize(const AnalyzerTrack& track,
@@ -53,6 +91,8 @@ bool AnalyzerSilence::initialize(const AnalyzerTrack& track,
     m_framesProcessed = 0;
     m_signalStart = -1;
     m_signalEnd = -1;
+    m_fadeThresholdFadeInEnd = -1;
+    m_fadeThresholdFadeOutStart = -1;
     m_channelCount = channelCount;
 
     return true;
@@ -70,6 +110,28 @@ SINT AnalyzerSilence::findLastSoundInChunk(std::span<const CSAMPLE> samples) {
     return ret;
 }
 
+// static
+SINT AnalyzerSilence::findFirstFadeOutChunk(std::span<const CSAMPLE> samples) {
+    // -1 is required, because the distance from the fist sample index (0) to crend() is 1,
+    SINT ret = std::distance(
+                       first_fade_out_sound(samples.rbegin(), samples.rend()),
+                       samples.rend()) -
+            1;
+    if (ret == -1) {
+        ret = samples.size();
+    }
+    return ret;
+}
+
+// static
+SINT AnalyzerSilence::findLastFadeInChunk(std::span<const CSAMPLE> samples) {
+    SINT ret = std::distance(samples.begin(), last_fade_in_sound(samples.begin(), samples.end()));
+    //    if (ret == samples.size()) {
+    //        ret = 0;
+    //    }
+    return ret;
+}
+
 // static
 bool AnalyzerSilence::verifyFirstSound(
         std::span<const CSAMPLE> samples,
@@ -93,10 +155,24 @@ bool AnalyzerSilence::processSamples(const CSAMPLE* pIn, SINT count) {
             m_signalStart = m_framesProcessed + firstSoundSample / m_channelCount;
         }
     }
-    if (m_signalStart >= 0) {
+
+    if (m_fadeThresholdFadeInEnd < 0) {
+        const SINT lastSampleOfFadeIn = findLastFadeInChunk(samples);
+        if (lastSampleOfFadeIn < count) {
+            m_fadeThresholdFadeInEnd = m_framesProcessed + (lastSampleOfFadeIn / m_channelCount);
+        }
+    }
+    if (m_fadeThresholdFadeInEnd >= 0) {
+        const SINT lasttSampleBeforeFadeOut = findFirstFadeOutChunk(samples);
+        if (lasttSampleBeforeFadeOut < (count - 1)) {
+            m_fadeThresholdFadeOutStart = m_framesProcessed +
+                    (lasttSampleBeforeFadeOut / m_channelCount) + 1;
+        }
+    }
+    if (m_fadeThresholdFadeOutStart >= 0) {
         const SINT lastSoundSample = findLastSoundInChunk(samples);
-        if (lastSoundSample >= 0) {
-            m_signalEnd = m_framesProcessed + lastSoundSample / m_channelCount + 1;
+        if (lastSoundSample < (count - 1)) { // not only sound or silence
+            m_signalEnd = m_framesProcessed + (lastSoundSample / m_channelCount) + 1;
         }
     }
 
@@ -136,6 +212,36 @@ void AnalyzerSilence::storeResults(TrackPointer pTrack) {
 
     setupMainAndIntroCue(pTrack.get(), firstSoundPosition, m_pConfig.data());
     setupOutroCue(pTrack.get(), lastSoundPosition);
+
+    if (m_fadeThresholdFadeInEnd < 0) {
+        m_fadeThresholdFadeInEnd = 0;
+    }
+    if (m_fadeThresholdFadeOutStart < 0) {
+        m_fadeThresholdFadeOutStart = m_framesProcessed;
+    }
+    const auto fadeInEndPosition = mixxx::audio::FramePos(m_fadeThresholdFadeInEnd);
+    CuePointer pFadeIn = pTrack->findCueByType(mixxx::CueType::FadeIn);
+    if (pFadeIn == nullptr) {
+        pFadeIn = pTrack->createAndAddCue(
+                mixxx::CueType::FadeIn,
+                Cue::kNoHotCue,
+                firstSoundPosition,
+                fadeInEndPosition);
+    } else {
+        pFadeIn->setStartAndEndPosition(firstSoundPosition, fadeInEndPosition);
+    }
+
+    const auto fadeOutStartPosition = mixxx::audio::FramePos(m_fadeThresholdFadeOutStart);
+    CuePointer pFadeOut = pTrack->findCueByType(mixxx::CueType::FadeOut);
+    if (pFadeOut == nullptr) {
+        pFadeOut = pTrack->createAndAddCue(
+                mixxx::CueType::FadeOut,
+                Cue::kNoHotCue,
+                fadeOutStartPosition,
+                lastSoundPosition);
+    } else {
+        pFadeOut->setStartAndEndPosition(fadeOutStartPosition, lastSoundPosition);
+    }
 }
 
 // static

src/analyzer/analyzersilence.h

@@ -34,6 +34,16 @@ class AnalyzerSilence : public Analyzer {
             UserSettings* pConfig);
     static void setupOutroCue(Track* pTrack, mixxx::audio::FramePos lastSoundPosition);
 
+    /// returns the index of the first sample in the buffer that is above the
+    /// fade out threshold (e.g. -20 dB) or samples.size() if no sample is found
+    /// TODO CHeck if 'samples.size()' is actually meaningful in this context.
+    static SINT findLastFadeInChunk(std::span<const CSAMPLE> samples);
+
+    /// returns the index of the last sample in the buffer that is above that is
+    /// above the fade out threshold (e.g. -20 dB) or samples.size() if no
+    /// sample is found
+    static SINT findFirstFadeOutChunk(std::span<const CSAMPLE> samples);
+
     /// returns the index of the first sample in the buffer that is above -60 dB
     /// or samples.size() if no sample is found
     static SINT findFirstSoundInChunk(std::span<const CSAMPLE> samples);
@@ -56,4 +66,6 @@ class AnalyzerSilence : public Analyzer {
     SINT m_framesProcessed;
     SINT m_signalStart;
     SINT m_signalEnd;
+    SINT m_fadeThresholdFadeInEnd;
+    SINT m_fadeThresholdFadeOutStart;
 };