TASK 4 audio fixes round 2: dB-scaled meters, game bar moved into the preview, Notepad About button replaced by the logo → in-app About — AudioLevelMeter.ToDisplay maps -60..0 dBFS onto 0..1 (real speech/game RMS ~0.01..0.1 linear left the flat scale dead; both meters now scale through it before volume); the game audio bar moved OUT of the footer (back to two rows) and is now a bottom-center dark chip overlaid on the preview window — monitoring UI only, never on the live output; the top-bar About button (opened THIRD-PARTY-NOTICES.txt in the OS viewer) removed, the ytLlive wordmark now opens the in-app About overlay, and task 21 queued (real logo + creator-hub About with premium/coffee/socials links + in-app scrolling licensing panel) — 169 tests passing, 0 warnings

Services/Audio/AudioLevelMeter.cs

@@ -13,6 +13,20 @@ public sealed class AudioLevelMeter
 
     public float Level => _level;
 
+    /// <summary>
+    /// Maps a linear level (0..1) onto the meter's display scale: -60 dBFS..0 dBFS
+    /// spread linearly across 0..1. Linear RMS of real speech or game audio is
+    /// ~0.01..0.1 (-40..-20 dBFS), which leaves a flat (linear) meter looking
+    /// dead; the log scale makes typical levels occupy the bar.
+    /// </summary>
+    public static float ToDisplay(float linear)
+    {
+        if (linear <= 0.001f)
+            return 0f;
+        var db = 20f * MathF.Log10(linear);
+        return Math.Clamp(1f + db / 60f, 0f, 1f);
+    }
+
     public float Push(AudioSample sample)
     {
         if (sample.Samples.Length == 0)

Services/index.md

@@ -49,7 +49,7 @@ External-facing logic: YouTube API, persistence. See
 | `Audio/WasapiLoopbackAudioSource.cs` | Desktop/game capture: NAudio `WasapiLoopbackCapture` on the default render device — automatic at unity; the game bar's meter consumes it |
 | `Audio/WasapiMicAudioSource.cs` | Mic capture: NAudio `WasapiCapture` with the device resolved by `FriendlyName` matching `MicSourceName` (DisplayName only), default capture endpoint fallback; name provider `Func<string?>` re-read at each `Start` so a device picked mid-session takes effect immediately (the mixer restarts the mic on pick) |
 | `Audio/AudioMixer.cs` | Owns both sources; capture starts once at startup (`MainViewModel.StartMicCaptureAsync`) and stops on `Shutdown` — NOT go-live (preview monitoring). Mic samples → `AudioLevelMeter` → `MicLevelChanged`; loopback samples → the game bar's meter via `LoopbackLevelChanged`. Surfaces mic connection state: `MicConnected`/`MicFailed` (drives the status dot) + `RestartMic()` (device swap mid-session, keeps loopback). Failures log via `AppLog`; mic failure zeroes the meter, loopback failure doesn't kill the mic. Note: the meter `Push` is unconditional (the `?.` on the event would otherwise skip the argument when nothing is subscribed) |
-| `Audio/AudioLevelMeter.cs` | Pure smoothed RMS level (0..1): `Push(AudioSample)` + `Reset` — the unit-tested math behind `AudioLevel` and `GameAudioLevel` |
+| `Audio/AudioLevelMeter.cs` | Pure smoothed RMS level (0..1): `Push(AudioSample)` + `Reset` — the unit-tested math behind `AudioLevel` and `GameAudioLevel`. `ToDisplay(float)` maps the raw linear RMS onto the meter's display scale (−60..0 dBFS spread across 0..1) — real speech/game RMS (~0.01..0.1) would otherwise leave a flat scale looking dead |
 | `Audio/WaveToFloat.cs` | Pure WASAPI buffer → float conversion: IEEE float 32-bit direct, PCM 16-bit normalized, `WaveFormatExtensible` IEEE-float subformat GUID, trailing partial samples ignored |
 | `IGameAudioDetector.cs` | **TASK 4 game audio bar seam**: `IsGameAudioActive` + `IsGameAudioActiveChanged` + `Poll()` — detects "a working game with sound is up in the preview" |
 | `GameAudioHysteresis.cs` | Pure show/hide state machine for the game bar: SHOW = full-screen app holds sound ~500ms; HIDE = the app leaves fullscreen ~1s. **Silence never hides an active bar** — only the game leaving the preview does (creator's rule). No timers; `Update(isFullScreen, hasSound, now)` |