Documented the transcription bitrate decisions and hardened its fallback

app/MindWork AI Studio/Settings/DataModel/DataApp.cs

@@ -115,6 +115,13 @@ public sealed class DataApp(Expression<Func<Data, DataApp>>? configSelection = n
     /// <summary>
     /// The Opus bitrate used when normalizing uploaded audio/video for transcription.
     /// </summary>
+    /// <remarks>
+    /// Every recording is re-encoded to mono Opus before it goes to the transcription provider. That
+    /// encoding used to be fixed at 32 kbps, which cost the transcription models entire quiet passages:
+    /// a greeting spoken softly at the start of a recording was simply missing from the transcript. The
+    /// same recording compared at 64 and 128 kbps came back complete, which is why 128 kbps is the
+    /// default here. Users trading accuracy for a smaller upload can still pick a lower bitrate.
+    /// </remarks>
     public TranscriptionOpusBitrate OpusBitrate { get; set; } = ManagedConfiguration.Register(configSelection, n => n.OpusBitrate, TranscriptionOpusBitrate.KBPS_128);
 
     /// <summary>

app/MindWork AI Studio/Settings/DataModel/TranscriptionOpusBitrate.cs

@@ -2,8 +2,13 @@ namespace AIStudio.Settings.DataModel;
 
 public enum TranscriptionOpusBitrate
 {
+    // The recommended bitrate is deliberately the member with the underlying value 0: when the
+    // settings file holds a value TolerantEnumConverter cannot read, it falls back to that member.
+    // Landing on the lowest bitrate there would silently reintroduce the very defect this setting
+    // exists to prevent -- transcripts losing what was said quietly.
+    KBPS_128 = 0,
+
     KBPS_32,
     KBPS_64,
-    KBPS_128,
     KBPS_256,
-}
+}

app/MindWork AI Studio/Settings/DataModel/TranscriptionOpusBitrateExtensions.cs

@@ -21,6 +21,9 @@ public static class TranscriptionOpusBitrateExtensions
         TranscriptionOpusBitrate.KBPS_64 => 64_000,
         TranscriptionOpusBitrate.KBPS_128 => 128_000,
         TranscriptionOpusBitrate.KBPS_256 => 256_000,
-        _ => 32_000,
+
+        // A value we do not know must never mean the lowest quality: that is how quiet passages
+        // went missing from transcripts in the first place. Fall back to the recommended bitrate.
+        _ => 128_000,
     };
-}
+}