Auto-DJ: Don't adopt first sound as intro start, when user has explic…

…it deleted it.

Use transition time instead if possible, else fall back to first sound.

src/library/autodj/autodjprocessor.cpp

@@ -1093,8 +1093,25 @@ void AutoDJProcessor::playerOutroEndChanged(DeckAttributes* pAttributes, double
 double AutoDJProcessor::getIntroStartSecond(DeckAttributes* pDeck) {
     const mixxx::audio::FramePos trackEndPosition = pDeck->trackEndPosition();
     const mixxx::audio::FramePos introStartPosition = pDeck->introStartPosition();
+    const mixxx::audio::FramePos introEndPosition = pDeck->introEndPosition();
     if (!introStartPosition.isValid() || introStartPosition > trackEndPosition) {
-        return getFirstSoundSecond(pDeck);
+        double firstSoundSecond = getFirstSoundSecond(pDeck);
+        if (!introEndPosition.isValid() || introEndPosition > trackEndPosition) {
+            // No intro start and intro end set, use First Sound.
+            return firstSoundSecond;
+        }
+        double introEndSecond = framePositionToSeconds(introEndPosition, pDeck);
+        if (m_transitionTime >= 0 && firstSoundSecond < introEndSecond) {
+            double introStartFromTime = introEndSecond - m_transitionTime;
+            if (introStartFromTime > firstSoundSecond) {
+                // The introStart is automatically placed by AnalyzerSilence at the first sound
+                // Here the user has removed it, but has placed an intro end.
+                // Use the transition time instead the dismissed first sound position.
+                return introStartFromTime;
+            }
+            return firstSoundSecond;
+        }
+        return introEndSecond;
     }
     return framePositionToSeconds(introStartPosition, pDeck);
 }