feat(studio,core)!: remove solo and the group meter (#3454)

* feat(studio,core)!: remove solo and the group meter

* docs(audio): keep removal rationale current

* refactor(core): retire studio solo bridge

packages/core/src/audioGroups.ts

@@ -232,24 +232,3 @@ export function ensureAudioGroupInertStyle(doc: Document): void {
   style.textContent = `${HF_AUDIO_GROUP_TAG}{display:none!important}`;
   doc.head.appendChild(style);
 }
-
-/** Compatibility bridge until the Studio solo controls are removed later in the stack. */
-export function isAudibleUnderSolo(
-  soloed: ReadonlySet<string>,
-  id: string,
-  groupId?: string | null,
-): boolean {
-  if (soloed.size === 0) return true;
-  if (soloed.has(id)) return true;
-  return Boolean(groupId && soloed.has(groupId));
-}
-
-/** Compatibility bridge until the Studio solo controls are removed later in the stack. */
-export function isGroupHalfLitUnderSolo(
-  soloed: ReadonlySet<string>,
-  groupId: string,
-  memberIds: readonly string[],
-): boolean {
-  if (soloed.size === 0 || soloed.has(groupId)) return false;
-  return memberIds.some((id) => soloed.has(id));
-}

packages/core/src/runtime/init.ts

@@ -43,10 +43,8 @@ import { createColorGradingRuntime, type RuntimeColorGradingApi } from "./colorG
 import { TransportClock } from "./clock";
 import { WebAudioTransport } from "./webAudioTransport";
 import {
-  audioGroupOf,
   ensureAudioGroupInertStyle,
   HF_AUDIO_GROUP_TAG,
-  isAudibleUnderSolo,
   isMemberGroupHidden,
 } from "../audioGroups";
 import { clampNativeMediaVolume } from "../audioGain";
@@ -189,15 +187,7 @@ export function initSandboxRuntimeModular(): void {
   void webAudio.init().then((ok) => {
     webAudioReady = ok;
   });
-  // Keep Studio's session-only "Hear only this" bridge alive until the solo
-  // controls are removed later in the stack. It must not be serialized into
-  // the composition because solo is preview state, not authored state.
-  let soloedIds: ReadonlySet<string> = new Set();
   window.__hf = window.__hf || {};
-  window.__hf.setAudioSolo = (ids) => {
-    soloedIds = new Set(ids);
-    webAudio.setSolo(soloedIds);
-  };
   /** Hidden by an ancestor, or by the BUS this clip belongs to. The bus is
    *  never an ancestor — membership is on the member's `data-audio-group` — so
    *  `closest()` alone could not see a muted group, which the render drops. */
@@ -2122,7 +2112,6 @@ export function initSandboxRuntimeModular(): void {
           webAudio.setElementVolume(el, authorVolume),
         isWebAudioOwned: (el) => webAudio.ownsElement(el),
         isWebAudioRouted: (el) => webAudio.routesElement(el),
-        isAudibleUnderSolo: (el) => isAudibleUnderSolo(soloedIds, el.id, audioGroupOf(el)),
         onAutoplayBlocked: () => {
           if (state.mediaAutoplayBlockedPosted) return;
           state.mediaAutoplayBlockedPosted = true;

packages/core/src/runtime/media.ts

@@ -224,9 +224,6 @@ export function syncRuntimeMedia(params: {
   /** Native media routed through WebAudio keeps its upstream element volume at
    * unity; do not mistake that transport write for an authored volume edit. */
   isWebAudioRouted?: (el: HTMLMediaElement) => boolean;
-  /** "Hear only this" gate for the HTMLMedia fallback path. WebAudio-owned
-   * sources apply the same predicate on their dedicated solo gain. */
-  isAudibleUnderSolo?: (el: HTMLMediaElement) => boolean;
   forceSync?: boolean;
 }): void {
   const forceMuteAll = !!(params.outputMuted || params.userMuted);
@@ -343,9 +340,7 @@ export function syncRuntimeMedia(params: {
       // fallback played at full level.
       const silencedByHidden =
         el.closest("[data-hidden]") !== null || isMemberGroupHidden(el.ownerDocument, el);
-      const silencedBySolo = params.isAudibleUnderSolo ? !params.isAudibleUnderSolo(el) : false;
-      const effectiveVolume =
-        silencedByHidden || silencedBySolo ? 0 : clampVolume(authorVolume * userVol);
+      const effectiveVolume = silencedByHidden ? 0 : clampVolume(authorVolume * userVol);
       el.volume = effectiveVolume;
       lastRuntimeAppliedVolume.set(el, effectiveVolume);
       params.onElementVolume?.(el, effectiveVolume, authorVolume);

packages/core/src/runtime/webAudioTransport.test.ts

@@ -18,20 +18,11 @@ function createMockAudioContext(currentTime = 100) {
     }),
     _fireEnded: () => endedListeners.forEach((cb) => cb()),
   };
-  // Every createGain call returns a distinct node. Sharing one hides graph
-  // errors because the solo stage can overwrite the authored-volume stage.
-  const gainNodes: Array<{
-    gain: { value: number };
-    connect: ReturnType<typeof vi.fn>;
-    disconnect: ReturnType<typeof vi.fn>;
-  }> = [];
-  const makeGain = () => {
-    const node = { gain: { value: 1 }, connect: vi.fn(), disconnect: vi.fn() };
-    gainNodes.push(node);
-    return node;
+  const gainNode = {
+    gain: { value: 1 },
+    connect: vi.fn(),
+    disconnect: vi.fn(),
   };
-  const gainNode = makeGain();
-  let served = 0;
   const mediaElementSourceNode = {
     connect: vi.fn(),
     disconnect: vi.fn(),
@@ -46,11 +37,11 @@ function createMockAudioContext(currentTime = 100) {
     resume: vi.fn(),
     createBufferSource: vi.fn(() => sourceNode),
     createMediaElementSource: vi.fn(() => mediaElementSourceNode),
-    createGain: vi.fn(() => (served++ === 0 ? gainNode : makeGain())),
+    createGain: vi.fn(() => gainNode),
     destination: {},
     close: vi.fn(),
   };
-  return { ctx, sourceNode, mediaElementSourceNode, gainNode, gainNodes, masterGain, startFn };
+  return { ctx, sourceNode, mediaElementSourceNode, gainNode, masterGain, startFn };
 }
 
 function setupTransport(currentTime = 100) {
@@ -121,9 +112,7 @@ describe("WebAudioTransport", () => {
       expect(mock.ctx.createMediaElementSource).toHaveBeenCalledWith(mockEl);
       expect(mock.ctx.createBufferSource).not.toHaveBeenCalled();
       expect(mock.mediaElementSourceNode.connect).toHaveBeenCalled();
-      const [volumeGain, soloGain] = mock.gainNodes;
-      expect(volumeGain?.connect).toHaveBeenCalledWith(soloGain);
-      expect(soloGain?.connect).toHaveBeenCalledWith(mock.masterGain);
+      expect(mock.gainNode.connect).toHaveBeenCalledWith(mock.masterGain);
       expect(mockEl.muted).toBe(false);
       expect(mockEl.volume).toBe(1);
       expect(mock.gainNode.gain.value).toBe(0.8);
@@ -748,15 +737,15 @@ describe("WebAudioTransport", () => {
       document.body.innerHTML = "";
     });
 
-    it("routes an ungrouped clip to master through its own solo stage", async () => {
+    it("routes an ungrouped clip straight to master through its own gain", async () => {
       const { transport, mock, gen } = setupGroupTransport();
 
       await scheduleGrouped(transport, gen, "lone");
 
-      expect(mock.gainNodes).toHaveLength(2);
-      const [clipGain, soloGain] = mock.gainNodes;
-      expect(clipGain!.connect).toHaveBeenCalledWith(soloGain);
-      expect(soloGain!.connect).toHaveBeenCalledWith(mock.masterGain);
+      // One gain per clip now that solo is gone — it goes straight to master.
+      expect(mock.gainNodes).toHaveLength(1);
+      const [clipGain] = mock.gainNodes;
+      expect(clipGain!.connect).toHaveBeenCalledWith(mock.masterGain);
     });
 
     // The media-element transport is the PRIMARY path for audio — the runtime
@@ -801,9 +790,7 @@ describe("WebAudioTransport", () => {
       await transport.scheduleMediaElementPlayback(el, 0, 0, 0, 1, gen, 1);
 
       const clipGain = mock.gainNodes[0]!;
-      const soloGain = mock.gainNodes[5]!;
-      expect(clipGain.connect).toHaveBeenCalledWith(soloGain);
-      expect(soloGain.connect).toHaveBeenCalledWith(firstGroupInput(mock));
+      expect(clipGain.connect).toHaveBeenCalledWith(firstGroupInput(mock));
       expect(clipGain.connect).not.toHaveBeenCalledWith(mock.masterGain);
     });
 
@@ -813,9 +800,8 @@ describe("WebAudioTransport", () => {
 
       await transport.scheduleMediaElementPlayback(el, 0, 0, 0, 1, gen, 1);
 
-      expect(mock.gainNodes).toHaveLength(2);
-      expect(mock.gainNodes[0]!.connect).toHaveBeenCalledWith(mock.gainNodes[1]);
-      expect(mock.gainNodes[1]!.connect).toHaveBeenCalledWith(mock.masterGain);
+      expect(mock.gainNodes).toHaveLength(1);
+      expect(mock.gainNodes[0]!.connect).toHaveBeenCalledWith(mock.masterGain);
     });
 
     it("two members of the same group land on ONE shared group gain, not master directly", async () => {
@@ -824,23 +810,20 @@ describe("WebAudioTransport", () => {
       await scheduleGrouped(transport, gen, "a", "vo");
       await scheduleGrouped(transport, gen, "b", "vo");
 
-      // Creation order for a: gain(0), group bus(1–4), solo(5). Then b uses
-      // gain(6), solo(7); both solo stages feed the one shared group input.
-      expect(mock.gainNodes.length).toBeGreaterThanOrEqual(8);
+      // Creation order for a: a-gain(0), groupInput(1), groupOutput(2),
+      // muteGain(3), fader(4) — the group bus is built lazily inside a's
+      // schedule call. Then b: b-gain(5).
+      expect(mock.gainNodes.length).toBeGreaterThanOrEqual(6);
       const aGain = mock.gainNodes[0]!;
-      const aSolo = mock.gainNodes[5]!;
       const groupInput = firstGroupInput(mock);
       const groupOutput = mock.gainNodes[2]!;
       const muteGain = mock.gainNodes[3]!;
       const fader = mock.gainNodes[4]!;
-      const bGain = mock.gainNodes[6]!;
-      const bSolo = mock.gainNodes[7]!;
+      const bGain = mock.gainNodes[5]!;
 
-      // Both members feed their own solo stage, then the shared bus.
-      expect(aGain.connect).toHaveBeenCalledWith(aSolo);
-      expect(bGain.connect).toHaveBeenCalledWith(bSolo);
-      expect(aSolo.connect).toHaveBeenCalledWith(groupInput);
-      expect(bSolo.connect).toHaveBeenCalledWith(groupInput);
+      // Both members feed the shared bus — neither connects straight to master.
+      expect(aGain.connect).toHaveBeenCalledWith(groupInput);
+      expect(bGain.connect).toHaveBeenCalledWith(groupInput);
       expect(aGain.connect).not.toHaveBeenCalledWith(mock.masterGain);
       expect(bGain.connect).not.toHaveBeenCalledWith(mock.masterGain);
 
@@ -860,11 +843,11 @@ describe("WebAudioTransport", () => {
       const { transport, mock, gen } = setupGroupTransport();
 
       await scheduleGrouped(transport, gen, "a", "vo");
-      const gainCountAfterFirst = mock.gainNodes.length;
+      const gainCountAfterFirst = mock.gainNodes.length; // a-gain + group input/output/mute/fader
       await scheduleGrouped(transport, gen, "b", "vo");
 
-      // Only b's volume and solo gains are new — no second group bus minted.
-      expect(mock.gainNodes.length).toBe(gainCountAfterFirst + 2);
+      // Only b's own gain is new — no second group bus minted.
+      expect(mock.gainNodes.length).toBe(gainCountAfterFirst + 1);
     });
 
     it("a group id with no matching <hf-audio-group> element still gets a flat bus", async () => {
@@ -930,45 +913,6 @@ describe("WebAudioTransport", () => {
       expect(mock.gainNodes.filter((n) => n === groupInput)).toHaveLength(1);
     });
 
-    describe('solo — "Hear only this" compatibility bridge', () => {
-      it("silences non-soloed members without attenuating their shared group bus", async () => {
-        const { transport, mock, gen } = setupGroupTransport();
-        await scheduleGrouped(transport, gen, "a", "vo");
-        await scheduleGrouped(transport, gen, "b", "vo");
-
-        transport.setSolo(new Set(["a"]));
-
-        expect(mock.gainNodes[5]!.gain.value).toBe(1);
-        expect(mock.gainNodes[7]!.gain.value).toBe(0);
-        expect(firstGroupInput(mock).gain.value).toBe(1);
-      });
-
-      it("soloing a group keeps every member of that group audible", async () => {
-        const { transport, mock, gen } = setupGroupTransport();
-        await scheduleGrouped(transport, gen, "a", "vo");
-        await scheduleGrouped(transport, gen, "b", "vo");
-
-        transport.setSolo(new Set(["vo"]));
-
-        expect(mock.gainNodes[5]!.gain.value).toBe(1);
-        expect(mock.gainNodes[7]!.gain.value).toBe(1);
-      });
-
-      it("applies an existing solo to newly scheduled clips and restores them when cleared", async () => {
-        const { transport, mock, gen } = setupGroupTransport();
-        transport.setSolo(new Set(["a"]));
-        await scheduleGrouped(transport, gen, "a");
-        await scheduleGrouped(transport, gen, "b");
-
-        expect(mock.gainNodes[1]!.gain.value).toBe(1);
-        expect(mock.gainNodes[3]!.gain.value).toBe(0);
-
-        transport.setSolo(new Set());
-        expect(mock.gainNodes[1]!.gain.value).toBe(1);
-        expect(mock.gainNodes[3]!.gain.value).toBe(1);
-      });
-    });
-
     // Surviving stopAll() is the point of the bus — and the trap. Its envelopes
     // were booked against the FIRST pass's absolute context times, so a replay
     // or a seek left the fader holding that pass's last value: 0 after a

packages/core/src/runtime/webAudioTransport.ts

@@ -6,12 +6,7 @@ import {
   type AutomationTiming,
 } from "../audio/audioFxAutomation.js";
 import { VOLUME_RANGE } from "../audioAutomation.js";
-import {
-  audioGroupOf,
-  isAudibleUnderSolo,
-  readAudioGroupVolume,
-  resolveGroupElement,
-} from "../audioGroups.js";
+import { audioGroupOf, readAudioGroupVolume, resolveGroupElement } from "../audioGroups.js";
 import { swallow } from "./diagnostics";
 import { clampAudioGain } from "../audioGain.js";
 import { getDebugSurface } from "./globals.js";
@@ -111,8 +106,6 @@ function scheduleVolumeLane(
 type ScheduledSourceBase = {
   el: HTMLMediaElement;
   gainNode: GainNode;
-  /** Dedicated solo stage so toggles never overwrite authored volume ramps. */
-  soloGain: GainNode;
   /** FX chain spliced between source and gain, when the element carries one. */
   fx?: ElementFxHandle | null;
   compositionStart: number;
@@ -176,8 +169,6 @@ export class WebAudioTransport {
   private _rate = 1;
   private _paused = true;
   private _playGeneration = 0;
-  // Session-only preview state pushed by Studio. Never serialized.
-  private _soloed: ReadonlySet<string> = new Set();
 
   async init(): Promise<boolean> {
     try {
@@ -251,26 +242,6 @@ export class WebAudioTransport {
     return this._playGeneration;
   }
 
-  /** Connect one source through its own solo stage and then into its group bus
-   * (or master for an ungrouped clip). Resolving the group first preserves one
-   * shared bus while solo remains strictly per member. */
-  private connectThroughSolo(
-    ctx: AudioContext,
-    masterGain: GainNode,
-    el: HTMLMediaElement,
-    gainNode: GainNode,
-    timing: { scheduledAt: number; compositionTime: number; rate: number },
-  ): GainNode {
-    const destination =
-      this.resolveDestination(el, timing.scheduledAt, timing.compositionTime, timing.rate) ??
-      masterGain;
-    const soloGain = ctx.createGain();
-    soloGain.gain.value = isAudibleUnderSolo(this._soloed, el.id, audioGroupOf(el)) ? 1 : 0;
-    gainNode.connect(soloGain);
-    soloGain.connect(destination);
-    return soloGain;
-  }
-
   /**
    * Route the browser's pitch-preserving HTMLMediaElement transport through the
    * same FX, automation, element-gain, and master graph used by final audio.
@@ -311,11 +282,9 @@ export class WebAudioTransport {
       // its fallback), so routing it at master would have left every grouped
       // track bypassing the bus whose whole premise is that a group is one
       // signal.
-      const soloGain = this.connectThroughSolo(this._ctx, this._masterGain, el, gainNode, {
-        scheduledAt,
-        compositionTime,
-        rate: safeRate,
-      });
+      gainNode.connect(
+        this.resolveDestination(el, scheduledAt, compositionTime, safeRate) ?? this._masterGain,
+      );
       scheduleVolumeLane(el, gainNode, timing);
 
       this._rate = safeRate;
@@ -328,7 +297,6 @@ export class WebAudioTransport {
         sourceNode,
         sourceKind: "media-element",
         gainNode,
-        soloGain,
         compositionStart,
         mediaStart: _mediaStart,
         scheduledAt,
@@ -515,7 +483,6 @@ export class WebAudioTransport {
       sourceNode.disconnect();
       scheduled.fx?.dispose();
       scheduled.gainNode.disconnect();
-      scheduled.soloGain.disconnect();
     } catch {
       // Already torn down.
     }
@@ -568,11 +535,9 @@ export class WebAudioTransport {
       // output — the same order the offline render uses. Preview and render run
       // the identical graph builders, so what is heard here is what is written.
       const fx = attachElementFxChain(this._ctx, el, sourceNode, gainNode, timing);
-      const soloGain = this.connectThroughSolo(this._ctx, this._masterGain, el, gainNode, {
-        scheduledAt,
-        compositionTime,
-        rate: safeRate,
-      });
+      gainNode.connect(
+        this.resolveDestination(el, scheduledAt, compositionTime, safeRate) ?? this._masterGain,
+      );
 
       scheduleVolumeLane(el, gainNode, timing);
 
@@ -594,7 +559,6 @@ export class WebAudioTransport {
         sourceNode.disconnect();
         fx?.dispose();
         gainNode.disconnect();
-        soloGain.disconnect();
         return null;
       }
 
@@ -608,7 +572,6 @@ export class WebAudioTransport {
         sourceNode,
         sourceKind: "buffer",
         gainNode,
-        soloGain,
         compositionStart,
         mediaStart,
         scheduledAt,
@@ -690,7 +653,6 @@ export class WebAudioTransport {
         source.sourceNode.disconnect();
         source.fx?.dispose();
         source.gainNode.disconnect();
-        source.soloGain.disconnect();
       } catch {
         // already stopped
       }
@@ -735,25 +697,6 @@ export class WebAudioTransport {
     this.applyMasterGain();
   }
 
-  /** Update every active source without rebuilding the graph. Group ids solo
-   * all members through the shared audibility predicate. */
-  setSolo(soloed: ReadonlySet<string>): void {
-    this._soloed = soloed;
-    for (const source of this._activeSources) {
-      try {
-        source.soloGain.gain.value = isAudibleUnderSolo(
-          this._soloed,
-          source.el.id,
-          audioGroupOf(source.el),
-        )
-          ? 1
-          : 0;
-      } catch (err) {
-        swallow("webAudioTransport.setSolo", err);
-      }
-    }
-  }
-
   private applyMasterGain(): void {
     if (this._masterGain) this._masterGain.gain.value = this._masterMuted ? 0 : this._masterVolume;
   }

packages/core/src/runtime/window.d.ts

@@ -37,12 +37,6 @@ declare global {
       onSwallowed?: (label: string, err: unknown) => void;
       seek?: (timeSeconds: number, options?: RuntimeSeekOptions) => void;
       duration?: number;
-      /**
-       * Studio's "Hear only this" push: the full set of soloed clip/group ids,
-       * replaced wholesale on every change. Session-only by design — never
-       * read from or written to any document attribute.
-       */
-      setAudioSolo?: (ids: readonly string[]) => void;
     };
     __playerReady?: boolean;
     __renderReady?: boolean;

packages/studio/src/hooks/useGroupLevel.ts

@@ -1,36 +0,0 @@
-/**
- * A group's live meter reading (0..1 RMS-ish level, whether it just clipped),
- * or null when the group is idle/unknown — never zero for "not playing yet".
- *
- * Mirrors useLivePlayheadTime's shape: the runtime posts readings at its own
- * cadence (only while playing — see `postGroupLevels` in init.ts), this just
- * throttles the re-render, it does not add its own polling loop.
- */
-import { useEffect, useRef, useState } from "react";
-import { groupLevels, type GroupLevelReading } from "../player/store/groupLevels";
-
-const THROTTLE_MS = 33;
-
-export function useGroupLevel(groupId: string): GroupLevelReading | null {
-  const latestRef = useRef<GroupLevelReading | null>(groupLevels.get().get(groupId) ?? null);
-  const [, forceRender] = useState(0);
-
-  useEffect(() => {
-    let timerId: ReturnType<typeof setTimeout> | 0 = 0;
-    const unsubscribe = groupLevels.subscribe((levels) => {
-      latestRef.current = levels.get(groupId) ?? null;
-      if (!timerId) {
-        timerId = setTimeout(() => {
-          timerId = 0;
-          forceRender((v) => v + 1);
-        }, THROTTLE_MS);
-      }
-    });
-    return () => {
-      unsubscribe();
-      if (timerId) clearTimeout(timerId);
-    };
-  }, [groupId]);
-
-  return latestRef.current;
-}

packages/studio/src/player/components/TimelineGroupBusStrip.test.tsx

@@ -1,146 +0,0 @@
-// @vitest-environment happy-dom
-
-import React, { act } from "react";
-import { createRoot, type Root } from "react-dom/client";
-import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-import { TimelineGroupBusStrip } from "./TimelineGroupBusStrip";
-import { defaultTimelineTheme } from "./timelineTheme";
-import { groupLevels } from "../store/groupLevels";
-
-(globalThis as unknown as { IS_REACT_ACT_ENVIRONMENT: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
-
-let container: HTMLDivElement;
-let root: Root;
-
-beforeEach(() => {
-  container = document.createElement("div");
-  document.body.appendChild(container);
-  root = createRoot(container);
-  groupLevels.notify(new Map());
-});
-
-afterEach(() => {
-  act(() => root.unmount());
-  container.remove();
-  vi.useRealTimers();
-});
-
-function renderStrip(overrides: Partial<React.ComponentProps<typeof TimelineGroupBusStrip>> = {}) {
-  const onVolumeChange = vi.fn();
-  const onVolumeCommit = vi.fn();
-  act(() => {
-    root.render(
-      <TimelineGroupBusStrip
-        groupId="vo"
-        volume={1}
-        memberLabels={["vo-1", "vo-2"]}
-        onVolumeChange={onVolumeChange}
-        onVolumeCommit={onVolumeCommit}
-        theme={defaultTimelineTheme}
-        {...overrides}
-      />,
-    );
-  });
-  return { onVolumeChange, onVolumeCommit };
-}
-
-function slider(): HTMLInputElement {
-  return container.querySelector('input[type="range"]') as HTMLInputElement;
-}
-
-const nativeInputValueSetter = Object.getOwnPropertyDescriptor(
-  window.HTMLInputElement.prototype,
-  "value",
-)?.set;
-
-/** React tracks the DOM's own value setter to detect real changes — a plain
- *  `input.value = ...` assignment is invisible to it, so onChange never
- *  fires. Go through the native setter, same as this codebase's other
- *  range/text input tests (e.g. propertyPanelFlatStyleSections.test.tsx). */
-function setSliderValue(input: HTMLInputElement, value: string) {
-  nativeInputValueSetter?.call(input, value);
-  input.dispatchEvent(new Event("input", { bubbles: true }));
-}
-
-describe("TimelineGroupBusStrip", () => {
-  it('renders "Holds …" from the member labels, comma-joined', () => {
-    renderStrip({ memberLabels: ["vo-1", "vo-2"] });
-    expect(container.textContent).toContain("Holds vo-1, vo-2");
-  });
-
-  it("falls back to a neutral line when a group has no members yet", () => {
-    renderStrip({ memberLabels: [] });
-    expect(container.textContent).toContain("Holds nothing yet");
-  });
-
-  it("live-writes on every drag tick, but only commits once on release", () => {
-    const { onVolumeChange, onVolumeCommit } = renderStrip({ volume: 1 });
-    const input = slider();
-
-    act(() => setSliderValue(input, "1.2"));
-    act(() => setSliderValue(input, "1.5"));
-    expect(onVolumeChange).toHaveBeenCalledTimes(2);
-    expect(onVolumeChange).toHaveBeenLastCalledWith(1.5);
-    expect(onVolumeCommit).not.toHaveBeenCalled();
-
-    act(() => {
-      input.value = "1.5";
-      input.dispatchEvent(new PointerEvent("pointerup", { bubbles: true }));
-    });
-    expect(onVolumeCommit).toHaveBeenCalledTimes(1);
-    expect(onVolumeCommit).toHaveBeenCalledWith(1.5);
-  });
-
-  it("clamps the volume slider to the 0..2 range", () => {
-    const { onVolumeChange } = renderStrip();
-    const input = slider();
-    expect(input.min).toBe("0");
-    expect(input.max).toBe("2");
-
-    act(() => setSliderValue(input, "2"));
-    expect(onVolumeChange).toHaveBeenLastCalledWith(2);
-  });
-
-  it("the level bar tracks a live reading and shows nothing extra when it isn't clipping", () => {
-    vi.useFakeTimers();
-    renderStrip();
-    act(() => {
-      groupLevels.notify(new Map([["vo", { level: 0.4, clipped: false }]]));
-      vi.advanceTimersByTime(40); // past useGroupLevel's 33ms throttle
-    });
-    expect(container.textContent).not.toContain("Too loud");
-  });
-
-  it('shows "Too loud" while clipped and holds it for ~2s after clipping stops', () => {
-    vi.useFakeTimers();
-    renderStrip();
-
-    act(() => {
-      groupLevels.notify(new Map([["vo", { level: 0.9, clipped: true }]]));
-      vi.advanceTimersByTime(40);
-    });
-    expect(container.textContent).toContain("Too loud");
-
-    // Clipping stops — the warning must still hold for a couple seconds.
-    act(() => {
-      groupLevels.notify(new Map([["vo", { level: 0.2, clipped: false }]]));
-      vi.advanceTimersByTime(40);
-    });
-    expect(container.textContent).toContain("Too loud");
-
-    act(() => {
-      vi.advanceTimersByTime(2001);
-    });
-    expect(container.textContent).not.toContain("Too loud");
-  });
-
-  it("never renders a dB number anywhere in the strip (design constraint: no dB, no peak-hold readout)", () => {
-    vi.useFakeTimers();
-    renderStrip({ volume: 1.5 });
-    act(() => {
-      groupLevels.notify(new Map([["vo", { level: 0.9, clipped: true }]]));
-      vi.advanceTimersByTime(40);
-    });
-    expect(container.textContent ?? "").not.toMatch(/dB/i);
-  });
-});

packages/studio/src/player/components/TimelineGroupBusStrip.tsx

@@ -1,103 +0,0 @@
-/**
- * B7: the group's own volume slider + a living level bar + "Holds …" — the
- * bus, not the mechanism. No dB numbers, no peak-hold readout, no routing
- * row (groups doc §5, casual-user section) — a slider, a bar that moves with
- * the sound, and the words "Too loud" when it clips.
- */
-import { useEffect, useRef, useState } from "react";
-import { useGroupLevel } from "../../hooks/useGroupLevel";
-import { STRIP_H, TRACK_H } from "./timelineLayout";
-import type { TimelineTheme } from "./timelineTheme";
-
-/** How long "Too loud" stays lit after the last clipped block. */
-const CLIP_HOLD_MS = 2000;
-
-function clampVolume(value: number): number {
-  return Math.min(2, Math.max(0, value));
-}
-
-interface TimelineGroupBusStripProps {
-  groupId: string;
-  volume: number;
-  memberLabels: readonly string[];
-  onVolumeChange: (value: number) => void;
-  onVolumeCommit: (value: number) => void;
-  theme: TimelineTheme;
-}
-
-export function TimelineGroupBusStrip({
-  groupId,
-  volume,
-  memberLabels,
-  onVolumeChange,
-  onVolumeCommit,
-  theme,
-}: TimelineGroupBusStripProps) {
-  const [dragValue, setDragValue] = useState<number | null>(null);
-  const reading = useGroupLevel(groupId);
-  const [clipped, setClipped] = useState(false);
-  const clipTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
-
-  useEffect(() => {
-    if (!reading?.clipped) return;
-    setClipped(true);
-    if (clipTimerRef.current) clearTimeout(clipTimerRef.current);
-    clipTimerRef.current = setTimeout(() => setClipped(false), CLIP_HOLD_MS);
-  }, [reading?.clipped]);
-
-  useEffect(
-    () => () => {
-      if (clipTimerRef.current) clearTimeout(clipTimerRef.current);
-    },
-    [],
-  );
-
-  const shownVolume = dragValue ?? volume;
-  const level = Math.min(1, reading?.level ?? 0);
-  const holdsText =
-    memberLabels.length > 0 ? `Holds ${memberLabels.join(", ")}` : "Holds nothing yet";
-
-  return (
-    <div
-      className="absolute left-0 right-0 flex items-center gap-2 px-2 text-[10px] text-white/70"
-      style={{ top: TRACK_H, height: STRIP_H }}
-    >
-      <input
-        type="range"
-        aria-label="Group volume"
-        min={0}
-        max={2}
-        step={0.01}
-        value={shownVolume}
-        className="h-1 w-20 shrink-0 accent-[#3CE6AC]"
-        onChange={(event) => {
-          const next = clampVolume(Number(event.currentTarget.value));
-          setDragValue(next);
-          onVolumeChange(next);
-        }}
-        onPointerUp={(event) => {
-          const next = clampVolume(Number(event.currentTarget.value));
-          setDragValue(null);
-          onVolumeCommit(next);
-        }}
-      />
-      <div
-        className="relative h-1.5 w-16 shrink-0 overflow-hidden rounded-full"
-        style={{ background: theme.gutterBorder }}
-        aria-hidden="true"
-      >
-        <div
-          className="absolute inset-y-0 left-0 rounded-full"
-          style={{
-            width: `${level * 100}%`,
-            background: clipped ? "#ff5c5c" : "#3CE6AC",
-          }}
-        />
-      </div>
-      {clipped && <span className="shrink-0 font-medium text-[#ff5c5c]">Too loud</span>}
-      <span className="min-w-0 flex-1 truncate" title={holdsText}>
-        {holdsText}
-      </span>
-    </div>
-  );
-}

packages/studio/src/player/components/TimelineSoloButton.tsx

@@ -1,32 +0,0 @@
-/**
- * "Hear only this" — the `⌗` toggle beside a track's mute control. Session
- * state only (see `audioSoloSlice`): a plain click is exclusive, ⌘/Ctrl-click
- * toggles membership without disturbing the rest of the set.
- */
-export function TimelineSoloButton({
-  isSoloed,
-  onToggle,
-}: {
-  isSoloed: boolean;
-  onToggle: (options?: { add?: boolean }) => void;
-}) {
-  return (
-    <button
-      type="button"
-      tabIndex={-1}
-      aria-pressed={isSoloed}
-      aria-label="Hear only this"
-      title="Hear only this"
-      className={`flex h-6 w-6 shrink-0 items-center justify-center rounded border-0 bg-transparent p-0 text-[13px] font-semibold transition-colors focus-visible:outline focus-visible:outline-1 focus-visible:outline-offset-[-1px] focus-visible:outline-[#3CE6AC] ${
-        isSoloed ? "text-[#F5C542] hover:text-white" : "text-white/35 hover:text-white/75"
-      }`}
-      onPointerDown={(event) => event.stopPropagation()}
-      onClick={(event) => {
-        event.stopPropagation();
-        onToggle({ add: event.metaKey || event.ctrlKey });
-      }}
-    >
-      <span aria-hidden="true">⌗</span>
-    </button>
-  );
-}

packages/studio/src/player/components/TimelineTrackHeader.test.tsx

@@ -769,9 +769,6 @@ describe("TimelineTrackHeader", () => {
       domId: "voice-2",
     };
 
-    // The set is pushed straight into the runtime, which compares it against
-    // `el.id`. A store key here matches nothing, `isAudibleUnderSolo` returns
-    // false for every element, and soloing silences the whole preview.
     // A member row is `aria-level="2"`, and without this it looked identical to
     // every top-level row — the nesting existed for a screen reader and not for
     // an eye. B2's design called for the accent rail; only the semantics shipped.

packages/studio/src/player/components/timelineLayout.ts

@@ -7,7 +7,6 @@ export const GUTTER = 32;
 export const LABEL_COL_W = 232;
 export const TRACK_H = 48;
 export const LANE_H = 28;
-export const STRIP_H = 40; // compatibility bridge; removed later in the stack
 export const RULER_H = 24;
 export const CLIP_Y = 3;
 export const CLIP_HANDLE_W = 18;

packages/studio/src/player/store/audioSoloSlice.test.ts

@@ -1,113 +0,0 @@
-// @vitest-environment happy-dom
-
-import { describe, expect, it, vi } from "vitest";
-import { usePlayerStore } from "./playerStore";
-import { isAudibleUnderSolo, isGroupHalfLitUnderSolo } from "./audioSoloSlice";
-import * as studioFileHistory from "../../utils/studioFileHistory";
-
-describe("audioSoloSlice", () => {
-  it("is exclusive by default, and clicking the only soloed element again clears it", () => {
-    usePlayerStore.getState().toggleSolo("a");
-    expect(usePlayerStore.getState().soloed).toEqual(new Set(["a"]));
-    usePlayerStore.getState().toggleSolo("b");
-    expect(usePlayerStore.getState().soloed).toEqual(new Set(["b"]));
-    usePlayerStore.getState().toggleSolo("b");
-    expect(usePlayerStore.getState().soloed).toEqual(new Set());
-  });
-
-  it("⌘/Ctrl-click adds and removes membership without disturbing the rest", () => {
-    usePlayerStore.getState().toggleSolo("a");
-    usePlayerStore.getState().toggleSolo("b", { add: true });
-    expect(usePlayerStore.getState().soloed).toEqual(new Set(["a", "b"]));
-    usePlayerStore.getState().toggleSolo("a", { add: true });
-    expect(usePlayerStore.getState().soloed).toEqual(new Set(["b"]));
-  });
-
-  it("clearSolo empties the set", () => {
-    usePlayerStore.getState().toggleSolo("a");
-    usePlayerStore.getState().clearSolo();
-    expect(usePlayerStore.getState().soloed).toEqual(new Set());
-  });
-});
-
-describe("export-safety: solo never touches an attribute or the save path", () => {
-  it("toggling, ⌘-adding, and clearing solo never calls setAttribute/removeAttribute on any element", () => {
-    usePlayerStore.getState().clearSolo();
-    const setAttributeSpy = vi.spyOn(Element.prototype, "setAttribute");
-    const removeAttributeSpy = vi.spyOn(Element.prototype, "removeAttribute");
-
-    usePlayerStore.getState().toggleSolo("a");
-    usePlayerStore.getState().toggleSolo("b", { add: true });
-    usePlayerStore.getState().toggleSolo("a", { add: true });
-    usePlayerStore.getState().clearSolo();
-
-    expect(setAttributeSpy).not.toHaveBeenCalled();
-    expect(removeAttributeSpy).not.toHaveBeenCalled();
-    setAttributeSpy.mockRestore();
-    removeAttributeSpy.mockRestore();
-  });
-
-  it("toggling, ⌘-adding, and clearing solo never invokes the project save path (setElementsHidden's own write function)", () => {
-    usePlayerStore.getState().clearSolo();
-    const saveSpy = vi.spyOn(studioFileHistory, "saveProjectFilesWithHistory");
-
-    usePlayerStore.getState().toggleSolo("a");
-    usePlayerStore.getState().toggleSolo("b", { add: true });
-    usePlayerStore.getState().clearSolo();
-
-    expect(saveSpy).not.toHaveBeenCalled();
-    saveSpy.mockRestore();
-  });
-});
-
-describe("isAudibleUnderSolo — the three-bullet rule", () => {
-  it("everything is audible when no solo is active", () => {
-    expect(isAudibleUnderSolo(new Set(), "clip-a")).toBe(true);
-    expect(isAudibleUnderSolo(new Set(), "clip-a", "group-1")).toBe(true);
-  });
-
-  it("a soloed element is audible", () => {
-    expect(isAudibleUnderSolo(new Set(["clip-a"]), "clip-a")).toBe(true);
-  });
-
-  it("a sibling of a soloed element is silent", () => {
-    expect(isAudibleUnderSolo(new Set(["clip-a"]), "clip-b")).toBe(false);
-  });
-
-  it("a member of a soloed group is audible (group solo = members solo)", () => {
-    expect(isAudibleUnderSolo(new Set(["group-1"]), "clip-a", "group-1")).toBe(true);
-  });
-
-  it("a member of an UNsoloed group, while a sibling group is soloed, is silent", () => {
-    expect(isAudibleUnderSolo(new Set(["group-2"]), "clip-a", "group-1")).toBe(false);
-  });
-
-  it("soloing one member of a group does not un-attenuate its siblings in the same group", () => {
-    // clip-a is soloed directly; clip-b shares its group but is not itself
-    // soloed and the group itself is not soloed — clip-b stays silent.
-    expect(isAudibleUnderSolo(new Set(["clip-a"]), "clip-b", "group-1")).toBe(false);
-  });
-
-  it("the group itself, monitored as a bus, is audible only when it or a member is soloed", () => {
-    expect(isAudibleUnderSolo(new Set(["clip-a"]), "group-1", null)).toBe(false);
-    expect(isAudibleUnderSolo(new Set(["group-1"]), "group-1", null)).toBe(true);
-  });
-});
-
-describe("isGroupHalfLitUnderSolo", () => {
-  it("is false when no solo is active", () => {
-    expect(isGroupHalfLitUnderSolo(new Set(), "group-1", ["a", "b"])).toBe(false);
-  });
-
-  it("is false when the group itself is soloed (fully lit, not half)", () => {
-    expect(isGroupHalfLitUnderSolo(new Set(["group-1"]), "group-1", ["a", "b"])).toBe(false);
-  });
-
-  it("is true when a member is soloed but the group is not", () => {
-    expect(isGroupHalfLitUnderSolo(new Set(["a"]), "group-1", ["a", "b"])).toBe(true);
-  });
-
-  it("is false when an unrelated element is soloed", () => {
-    expect(isGroupHalfLitUnderSolo(new Set(["other"]), "group-1", ["a", "b"])).toBe(false);
-  });
-});

packages/studio/src/player/store/audioSoloSlice.ts

@@ -1,43 +0,0 @@
-/**
- * "Hear only this" — session-only monitoring override, never persisted.
- *
- * Holds clip ids and group ids (never track numbers, per the design doc: solo
- * is a per-element/per-group concept, not a row-position one). Exclusive by
- * default (a plain toggle replaces the set); ⌘/Ctrl-click adds/removes one
- * member without disturbing the rest. Never written to any attribute or
- * document — the export-safety guarantee this slice exists to hold.
- */
-import type { StoreApi } from "zustand";
-import { isAudibleUnderSolo, isGroupHalfLitUnderSolo } from "@hyperframes/core/audio-groups";
-
-export { isAudibleUnderSolo, isGroupHalfLitUnderSolo };
-
-export interface AudioSoloSlice {
-  soloed: ReadonlySet<string>;
-  toggleSolo: (id: string, options?: { add?: boolean }) => void;
-  clearSolo: () => void;
-}
-
-export function createAudioSoloSlice(
-  set: StoreApi<AudioSoloSlice>["setState"],
-  get: StoreApi<AudioSoloSlice>["getState"],
-): AudioSoloSlice {
-  return {
-    soloed: new Set(),
-    toggleSolo: (id, options) => {
-      const current = get().soloed;
-      if (options?.add) {
-        const next = new Set(current);
-        if (next.has(id)) next.delete(id);
-        else next.add(id);
-        set({ soloed: next });
-        return;
-      }
-      // Exclusive click: soloing the only-soloed element again clears it;
-      // otherwise it replaces the set.
-      const isOnlyMember = current.size === 1 && current.has(id);
-      set({ soloed: isOnlyMember ? new Set() : new Set([id]) });
-    },
-    clearSolo: () => set({ soloed: new Set() }),
-  };
-}

packages/studio/src/player/store/groupLevels.ts

@@ -1,33 +0,0 @@
-// ponytail: mirrors liveTime.ts's plain pub-sub — same throttle-at-the-edge shape.
-/** A group's live meter reading, or absent when idle/unknown (never zero). */
-export type GroupLevelReading = { level: number; clipped: boolean };
-
-type Listener = (levels: ReadonlyMap<string, GroupLevelReading>) => void;
-const listeners = new Set<Listener>();
-let latest: ReadonlyMap<string, GroupLevelReading> = new Map();
-
-export const groupLevels = {
-  notify: (levels: ReadonlyMap<string, GroupLevelReading>) => {
-    latest = levels;
-    listeners.forEach((listener) => listener(levels));
-  },
-  subscribe: (listener: Listener) => {
-    listeners.add(listener);
-    return () => listeners.delete(listener);
-  },
-  get: () => latest,
-};
-
-/** Turns the runtime's `group-levels` postMessage payload into the map `groupLevels.notify` wants. */
-export function parseGroupLevelsMessage(
-  data: unknown,
-): ReadonlyMap<string, GroupLevelReading> | null {
-  const levels = (data as { levels?: unknown } | null)?.levels;
-  if (!Array.isArray(levels)) return null;
-  return new Map(
-    (levels as Array<{ groupId: string; level: number; clipped: boolean }>).map((entry) => [
-      entry.groupId,
-      { level: entry.level, clipped: entry.clipped },
-    ]),
-  );
-}

packages/studio/src/player/store/playerStore.ts

@@ -19,7 +19,6 @@ import {
 import { createEditingModeSlice, type EditingModeSlice } from "./editingModeSlice";
 import { createTimelineFocusRequest, type TimelineFocusRequest } from "./timelineFocusState";
 import { createThumbnailSlice, type ThumbnailSlice } from "./thumbnailSlice";
-import { createAudioSoloSlice, type AudioSoloSlice } from "./audioSoloSlice";
 
 export type { KeyframeCacheEntry } from "./keyframeSlice";
 export { liveTime } from "./liveTime";
@@ -52,12 +51,7 @@ function resolveElementSelection(
 }
 
 interface PlayerState
-  extends
-    KeyframeSlice,
-    AutomationSelectionSlice,
-    ThumbnailSlice,
-    AudioSoloSlice,
-    EditingModeSlice {
+  extends KeyframeSlice, AutomationSelectionSlice, ThumbnailSlice, EditingModeSlice {
   isPlaying: boolean;
   currentTime: number;
   duration: number;
@@ -325,7 +319,6 @@ export const usePlayerStore = create<PlayerState>((set, get) => ({
   ...createThumbnailSlice(set),
 
   ...createAutomationSelectionSlice(set),
-  ...createAudioSoloSlice(set, get),
   ...createEditingModeSlice(set),
 
   activeKeyframePct: null,

scripts/check-no-main-deletions.mjs

@@ -125,6 +125,34 @@ export const ALLOWED_DELETIONS = new Map([
     "packages/studio/src/hooks/useAudioSoloBridge.ts",
     "#3453 removes the obsolete solo bridge after its last consumer leaves",
   ],
+  [
+    "packages/studio/src/hooks/useGroupLevel.ts",
+    "#3454 deliberately removes the group level meter with the group volume strip",
+  ],
+  [
+    "packages/studio/src/player/components/TimelineGroupBusStrip.test.tsx",
+    "#3454 deliberately removes the group volume and level-meter strip and its tests",
+  ],
+  [
+    "packages/studio/src/player/components/TimelineGroupBusStrip.tsx",
+    "#3454 deliberately removes the group volume and level-meter strip",
+  ],
+  [
+    "packages/studio/src/player/components/TimelineSoloButton.tsx",
+    "#3454 deliberately removes track and group solo controls",
+  ],
+  [
+    "packages/studio/src/player/store/audioSoloSlice.test.ts",
+    "#3454 deliberately removes session solo state and its tests",
+  ],
+  [
+    "packages/studio/src/player/store/audioSoloSlice.ts",
+    "#3454 deliberately removes session solo state",
+  ],
+  [
+    "packages/studio/src/player/store/groupLevels.ts",
+    "#3454 deliberately removes group level-meter state",
+  ],
 ]);
 
 export function parseBase(argv, fallback = "origin/main") {