Mute audio across all client apps — default muted, settable from every config path

[jonathaneoliver]

Motivation

When testing streaming we rarely want to hear the audio. Every client app should have a mute option that defaults to muted, lives in Settings → Advanced, and is settable from every way we configure the app (Settings UI, cold-launch flags, Appium capabilities / config-on-connect, harness per-play app-config, and the characterization matrix knobs).

In scope: iOS/tvOS (apple/) + Android (android/), plus the dashboard/proxy/harness config plumbing.
Out of scope: Roku.

Current state (verified 2026-06-23)

• iOS — mostly built. isMuted + a "Mute audio" toggle in Settings/Advanced, the is.flag.muted launch flag, UserDefaults persistence, and always-muted preview tiles all already exist. Pointers: apple/InfiniteStreamPlayer/InfiniteStreamPlayer/PlayerViewModel.swift:103,485,732,1337,2274,2308,2372,2445; SettingsOverlay.swift:375. Gaps below.
• Android — not built. android/ exists but has no app-level mute (no FLAG_MUTED / setVolume / muted). Tiles silence via a no-audio renderer factory (LivePreviewTile.kt). Full feature needed.
• Harness — no muted. tools/harness-cli/cmd/harness/appconfig.go covers segment/protocol/live-offset/peak-bitrate only.

Requirements

1. Mute toggle in Settings → Advanced on iOS and Android.
2. Default = muted (true) on both platforms.
3. Live toggle (no relaunch) updates the player immediately.
4. Settable from all config paths, all converging on the same state:
   • Settings UI (persisted)
   • Cold-launch flag -is.flag.muted true|false (NSArgumentDomain / intent extra)
   • Appium capability / config-on-connect (isAudioMuted / app.muted)
   • Harness per-play harness app-config <target> --muted true|false
   • Characterization matrix per-arm + sweep knobs

Scope checklist

iOS (apple/InfiniteStreamPlayer/InfiniteStreamPlayer/)

• Flip default to muted — PlayerViewModel.swift:103 isMuted = false → true.
• Add muted: Bool? to ServerAppConfig (struct ~:1073); parse it in fetchServerAppConfig(); overlay in applyServerAppConfig() so harness/config-on-connect per-play push works.
• Confirm the isAudioMuted → is.flag.muted capability mapping (PlayerViewModel.swift:3912) is complete end to end.

Android (android/InfiniteStreamPlayer/) — build the whole thing, copy the allow4K toggle pattern

• UiState.muted: Boolean = true (state/PlayerState.kt).
• FLAG_MUTED = "advanced_muted" + setMuted() setter that writes SharedPreferences and applies player.volume = if (muted) 0f else 1f (state/PlayerViewModel.kt).
• Load order: LaunchConfig.muted ?: prefs.getBoolean(FLAG_MUTED, true) in loadAdvancedFlags().
• LaunchConfig.muted holder + intent-extra capture for is.flag.muted (MainActivity.kt).
• "Mute audio" PickerItem in the Advanced section (ui/screen/SettingsOverlay.kt).
• Add muted: Boolean? to Android ServerAppConfig; parse from /api/sessions; overlay in applyServerAppConfig().

Harness + characterization plumbing (tools/harness-cli/, tests/characterization/)

• appconfig.go: add --muted flag → ac["muted"] in buildAppConfigBody (+ usage text + appconfig_test.go case).
• runner/probe.go: ProbeConfig.Muted + emit -is.flag.muted in ProbeLaunchArgs (+ probe_test.go case).
• Char matrix: Muted on the Arm spec (internal/charmatrix/spec.go); CHAR_ARM_<i>_MUTED + CHAR_SWEEP_MUTED in cmd/harness/char.go; read them in modes/char_matrix_fleet_test.go.
• Decide whether characterization should force a baseline (runner/appium.go baselineTestFlags / modes/runconfig.go) — default-muted may make a forced baseline unnecessary; document the choice.
• Config-on-connect parser (go-proxy/cmd/server/configconnect.go) is generic (app.muted=true routes automatically) — no change expected; verify.

Acceptance criteria

• iOS and Android both launch muted by default, with a working Settings → Advanced toggle that takes effect live.
• -is.flag.muted false at launch, harness app-config --muted false, and a char-matrix arm muted: false each produce audible playback on a real run; the inverse mutes.
• Verify from data, not just the UI: confirm on a real play that audio is/ isn't flowing (per the project's "don't trust a screenshot" rule).

[jonathaneoliver]

Points: 8 (Fibonacci)
Effort: ~3–4 days calendar

Priority: P2 — next sprint
Developer-ergonomics / testing quality-of-life; no user-facing production impact, no blocker on current sprint work. Worth queuing soon because the missing default-muted means every characterization run currently needs manual intervention or a harness override to suppress audio during automated runs.

Value: medium
Meaningfully improves internal test quality and operator experience (silent automated runs, reliable harness control, char-matrix config parity), but the feature only affects developers running characterization — no end-user flow is touched.

Rationale:
iOS is ~80% done (one-line default flip + ServerAppConfig.muted wiring ≈ 2 hrs), but Android is a full build-from-scratch that copies the allow4K pattern across 5 files (UiState, ViewModel, LaunchConfig, MainActivity, SettingsOverlay, ServerAppConfig) — verified the pattern exists but none of the mute wiring does. The harness side is well-bounded: appconfig.go + appconfig_test.go, probe.go + probe_test.go, spec.go, char.go, and char_matrix_fleet_test.go — ~6 files, each change is mechanical and follows an existing slot in the CHAR_ARM/CHAR_SWEEP env pipeline. The config-on-connect parser (go-proxy/configconnect.go) is noted as generic and requires only verification, not a code change. Total surface: 2 platforms + ~8 files, no novel architecture, some Android real-device verification time. 8 points is right; 5 would undercount the Android build + cross-platform verification leg.