diff --git a/packages/core/src/runtime/clock.ts b/packages/core/src/runtime/clock.ts
index 4d7deabfb3..be846c5989 100644
--- a/packages/core/src/runtime/clock.ts
+++ b/packages/core/src/runtime/clock.ts
@@ -1,5 +1,5 @@
 import { timeAtSourceTime, type RateSpec } from "../speedRamp.js";
-import { MEDIA_HARD_SYNC_SECONDS } from "./media.js";
+import { MEDIA_HARD_SYNC_SECONDS } from "./mediaSteer.js";
 import { playRangeHoldTime } from "./protocol.js";
 
 export type TransportClockSnapshot = {
diff --git a/packages/core/src/runtime/media.ts b/packages/core/src/runtime/media.ts
index 0df53bfde2..36796f080c 100644
--- a/packages/core/src/runtime/media.ts
+++ b/packages/core/src/runtime/media.ts
@@ -2,11 +2,12 @@ import { swallow } from "./diagnostics";
 import { isClipVisibleAt, isInClipWindow } from "./clipWindow";
 import { mediaElementTime } from "./mediaClock";
 import { sameInstant } from "../clipFacts";
-import { interpolateVolumeGain, type VolumeKeyframe } from "./mediaVolumeEnvelope.js";
+import { interpolateVolumeGain } from "./mediaVolumeEnvelope.js";
 import { elementVolumeLaneGain } from "./audioAutomationVolume.js";
-import { fadeGain, NO_FADES, readElementFades, type AudioFades } from "../audioFade.js";
+import { fadeGain, NO_FADES, readElementFades } from "../audioFade.js";
 import { readElementPlaybackRate, readElementRateSpec, readMediaStart } from "./playbackRate.js";
-import { rateAt, sourceTimeAt, timeAtSourceTime, type RateSpec } from "../speedRamp.js";
+import { rateAt, sourceTimeAt, timeAtSourceTime } from "../speedRamp.js";
+import type { RuntimeMediaClip } from "./types.js";
 import { clampAudioGain, clipGain, gainTimesLane } from "../audioGain.js";
 import { isMemberGroupHidden } from "../audioGroups.js";
 import { findInjectedRenderFrame } from "./renderFrameSibling.js";
@@ -16,10 +17,12 @@ import { cutToHostSlots, type HostSlot } from "../mediaTiming.js";
 import {
   forgetSteering,
   isSteering,
+  MEDIA_HARD_SYNC_SECONDS,
   MEDIA_SYNC_TOLERANCE_SECONDS,
   steerMedia,
 } from "./mediaSteer.js";
 export { MEDIA_SYNC_TOLERANCE_SECONDS } from "./mediaSteer.js";
+export type { RuntimeMediaClip } from "./types.js";
 export {
   readElementPlaybackRate,
   readElementRateSpec,
@@ -85,32 +88,6 @@ export function resolveRuntimeMediaClipDuration(params: {
   return candidates.length > 0 ? Math.min(...candidates) : null;
 }
 
-export type RuntimeMediaClip = {
-  el: HTMLVideoElement | HTMLAudioElement;
-  start: number;
-  /** The clip's own t=0 when a host's in-point cut its head; source time, lanes and fades run from it. */
-  origin?: number;
-  mediaStart: number;
-  duration: number;
-  end: number;
-  volume: number | null;
-  playbackRate: number;
-  /** The rate lane when the clip has one; otherwise `playbackRate`. */
-  rate?: RateSpec;
-  loop: boolean;
-  /** Source media duration in seconds (from el.duration). Used for loop wrapping. */
-  sourceDuration: number | null;
-  /**
-   * Probed volume keyframes from the GSAP timeline (same probe the renderer
-   * uses). When present, `syncRuntimeMedia` drives volume from the envelope
-   * rather than from `data-volume` + GSAP-change tracking, eliminating the
-   * race between the 60 Hz transport tick and GSAP's own seek.
-   */
-  volumeKeyframes?: VolumeKeyframe[];
-  /** Clip-edge fades from `data-fade-in` / `data-fade-out`; see audioFade.ts. */
-  fades?: AudioFades;
-};
-
 export function refreshRuntimeMediaCache(params?: {
   resolveStartSeconds?: (element: Element) => number;
   resolveDurationSeconds?: (element: HTMLVideoElement | HTMLAudioElement) => number | null;
@@ -273,7 +250,6 @@ export function hasMediaSyncStateForTest(el: HTMLMediaElement): boolean {
   );
 }
 
-export const MEDIA_HARD_SYNC_SECONDS = 0.5;
 export const MEDIA_PRESEEK_SECONDS = 1.5;
 
 export function mediaSourceTimeAt(clip: RuntimeMediaClip, timeSeconds: number): number {
diff --git a/packages/core/src/runtime/mediaSteer.ts b/packages/core/src/runtime/mediaSteer.ts
index ef72d9ab1e..c47fa910b3 100644
--- a/packages/core/src/runtime/mediaSteer.ts
+++ b/packages/core/src/runtime/mediaSteer.ts
@@ -1,5 +1,6 @@
 /** Drift a playing element may carry before sync pulls it back onto the playhead. */
 export const MEDIA_SYNC_TOLERANCE_SECONDS = 0.04;
+export const MEDIA_HARD_SYNC_SECONDS = 0.5;
 
 // Steered by rate, not seeked (a seek resets a video's decoder and clicks in audio); steps keep rate writes rare.
 const MEDIA_STEER = 0.03;
diff --git a/packages/core/src/runtime/state.ts b/packages/core/src/runtime/state.ts
index 469766657d..ccdaef7512 100644
--- a/packages/core/src/runtime/state.ts
+++ b/packages/core/src/runtime/state.ts
@@ -1,5 +1,4 @@
-import type { RuntimeDeterministicAdapter, RuntimeTimelineLike } from "./types";
-import type { RuntimeMediaClip } from "./media";
+import type { RuntimeDeterministicAdapter, RuntimeMediaClip, RuntimeTimelineLike } from "./types";
 import type { TransportClock } from "./clock";
 
 export type RuntimeState = {
diff --git a/packages/core/src/runtime/timeline.ts b/packages/core/src/runtime/timeline.ts
index cf5ec0b976..80c0cea1c1 100644
--- a/packages/core/src/runtime/timeline.ts
+++ b/packages/core/src/runtime/timeline.ts
@@ -13,7 +13,7 @@ import {
 } from "./authoredTiming";
 import { swallow } from "./diagnostics";
 import { readTimelineDurationSeconds } from "./timelineDuration";
-import { readElementPlaybackRate, readElementPlaybackStart } from "./media";
+import { readElementPlaybackRate, readMediaStart } from "./playbackRate";
 import {
   parseStrictFiniteTimingNumber,
   resolveMediaElementDurationSeconds,
@@ -499,7 +499,7 @@ export function collectRuntimeTimelinePayload(params: {
       parentCompositionId: compositionContext.parentCompositionId,
       nodePath: null,
       compositionSrc: toAbsoluteAssetUrl(node.getAttribute("data-composition-src")),
-      playbackStart: readElementPlaybackStart(node),
+      playbackStart: readMediaStart(node),
       playbackRate: readElementPlaybackRate(node),
       assetUrl: resolveNodeAssetUrl(node),
       timelineRole: node.getAttribute("data-timeline-role"),
@@ -629,7 +629,7 @@ export function collectRuntimeTimelinePayload(params: {
             parentCompositionId: rootCompositionIdForGsap,
             nodePath: null,
             compositionSrc: null,
-            playbackStart: readElementPlaybackStart(el),
+            playbackStart: readMediaStart(el),
             playbackRate: readElementPlaybackRate(el),
             assetUrl: null,
             timelineRole: el.getAttribute("data-timeline-role"),
@@ -686,7 +686,7 @@ export function collectRuntimeTimelinePayload(params: {
         parentCompositionId: rootCompositionIdForGsap,
         nodePath: null,
         compositionSrc: null,
-        playbackStart: readElementPlaybackStart(el),
+        playbackStart: readMediaStart(el),
         playbackRate: readElementPlaybackRate(el),
         assetUrl: null,
         timelineRole,
diff --git a/packages/core/src/runtime/types.ts b/packages/core/src/runtime/types.ts
index 09aba58f1c..4e942aa203 100644
--- a/packages/core/src/runtime/types.ts
+++ b/packages/core/src/runtime/types.ts
@@ -1,5 +1,8 @@
 import type { HfColorGradingTarget } from "../colorGrading";
 import type { RuntimeAnalyticsEvent } from "./analytics";
+import type { AudioFades } from "../audioFade";
+import type { RateSpec } from "../speedRamp";
+import type { VolumeKeyframe } from "./mediaVolumeEnvelope";
 
 export type RuntimeJson =
   | string
@@ -456,3 +459,22 @@ type RuntimeBridgeControlAction =
 
 export type RuntimeBridgeControlMessage = RuntimeBridgeControlMessageBase &
   RuntimeDataControlFields;
+
+export type RuntimeMediaClip = {
+  el: HTMLVideoElement | HTMLAudioElement;
+  start: number;
+  /** The clip's own t=0 when a host's in-point cut its head; source time, lanes and fades run from it. */
+  origin?: number;
+  mediaStart: number;
+  duration: number;
+  end: number;
+  volume: number | null;
+  playbackRate: number;
+  /** The rate lane when the clip has one; otherwise `playbackRate`. */
+  rate?: RateSpec;
+  loop: boolean;
+  sourceDuration: number | null;
+  /** Probed from the GSAP timeline as the renderer does; when set they drive volume, not `data-volume`. */
+  volumeKeyframes?: VolumeKeyframe[];
+  fades?: AudioFades;
+};
diff --git a/packages/core/tsconfig.json b/packages/core/tsconfig.json
index 306f5fbc58..a73319e714 100644
--- a/packages/core/tsconfig.json
+++ b/packages/core/tsconfig.json
@@ -17,6 +17,7 @@
     "src/runtime/compositionLength.ts",
     "src/runtime/customEase.ts",
     "src/runtime/mediaVolumeEnvelope.ts",
+    "src/runtime/mediaSteer.ts",
     "src/runtime/positionEdits.ts",
     "src/runtime/protocol.ts",
     "src/runtime/stackingContext.ts",