feat: AudioLevel helper and AudioRecorder.onLevel

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
2026-10-01 15:00:40 +02:00
parent 2c4b096850
commit c8e16145e1
4 changed files with 78 additions and 3 deletions
@@ -0,0 +1,31 @@
+import Testing
+@testable import SstCore
+
+struct AudioLevelTests {
+    @Test func constantTenthIsMinusTwentyDbfs() {
+        let level = AudioLevel.rmsDbfs([Float](repeating: 0.1, count: 1_000))
+        #expect(abs(level - (-20)) < 0.01)
+    }
+
+    @Test func fullScaleIsZeroDbfs() {
+        let level = AudioLevel.rmsDbfs([Float](repeating: 1.0, count: 100))
+        #expect(abs(level) < 0.01)
+    }
+
+    @Test func negativeSamplesCountLikePositiveOnes() {
+        let level = AudioLevel.rmsDbfs([Float](repeating: -0.1, count: 1_000))
+        #expect(abs(level - (-20)) < 0.01)
+    }
+
+    @Test func emptyAndSilentBuffersHitTheFloor() {
+        #expect(AudioLevel.rmsDbfs([]) == AudioLevel.silenceFloorDbfs)
+        #expect(AudioLevel.rmsDbfs([Float](repeating: 0, count: 64)) == AudioLevel.silenceFloorDbfs)
+    }
+
+    @Test func vuIsRelativeToTheReference() {
+        #expect(AudioLevel.vu(fromDbfs: -20) == 0)
+        #expect(AudioLevel.vu(fromDbfs: -40) == -20)
+        #expect(AudioLevel.vu(fromDbfs: -17) == 3)
+        #expect(AudioLevel.vu(fromDbfs: -30, referenceDbfs: -18) == -12)
+    }
+}