fix: capture system audio as mono

2026-08-26 11:56:27 +02:00
parent 4e8fdc7603
commit 9f3805733b
2 changed files with 9 additions and 9 deletions
@@ -138,11 +138,11 @@ final class ProcessTap {
            tapDescription = CATapDescription(stereoMixdownOfProcesses: [process.objectID])
            logger.debug("Configuring tap for single process objectID: \(process.objectID)")
        case .systemAudio:
-            // Keep the HAL tap's buffer layout consistent with the default
-            // output stream. AudioManager performs the stereo-to-mono mix when
-            // it converts the captured audio to the 16 kHz transcription file.
-            tapDescription = CATapDescription(stereoGlobalTapButExcludeProcesses: [])
-            logger.debug("Configuring a stereo global system audio tap.")
+            // The transcription file is mono, so ask Core Audio for a mono
+            // mixdown at the source. This avoids interpreting a stereo HAL
+            // buffer as half as many frames before the 16 kHz conversion.
+            tapDescription = CATapDescription(monoGlobalTapButExcludeProcesses: [])
+            logger.info("Configuring a mono global system audio tap.")
        }
        
        tapDescription.uuid = UUID()