Repository: flutter
Issue: iOS release crash : `figTimebaseCopyTargetTimebase` :  `pthread_mutex_lock$VARIANT$mp`
Labels: c: crash,platform-ios,waiting for customer response,engine,a: production,needs repro info,team-engine,fyi-ios

### Steps to reproduce

The crash has happened in release mode on my live user. I have no way to reproduce it as i don't know what is it and never encountered it during development. 
Unfortunately i have no way to contact this user either.

I am guessing according to the [StackTrace](https://github.com/user-attachments/files/18507520/trace.txt) that this is a crash from the `video_player` but i am defintely not sure. 

I only see `AVFCore` and `CoreMedia`  so i am guessing..

### Expected results

The app should not crash

### Actual results

The app is crashing

### Code sample

<details open><summary>Code sample</summary>

```dart
[Paste your code here]
```

</details>


### Screenshots or Video

<details open>
<summary>Screenshots / Video demonstration</summary>

[Upload media here]

</details>


### Logs

<details open><summary>Logs</summary>

```console
Crashed: com.apple.root.default-qos
0  libsystem_pthread.dylib        0xae18 pthread_mutex_lock$VARIANT$mp + 8
1  CoreMedia                      0x2b8ac figTimebaseCopyTargetTimebase + 48
2  CoreMedia                      0x2bec8 FigTimebaseCopyUltimateMasterClockAndHeight + 28
3  CoreMedia                      0x2cd58 CMTimebaseGetTimeClampedAboveAnchorTime + 84
4  AVFCore                        0x3d614 AVTimebaseObserver_figTimebaseGetTime + 44
5  AVFCore                        0xb048 -[AVPeriodicTimebaseObserver _handleTimeDiscontinuity] + 76
6  AVFCore                        0xac5c __AVTimebaseObserver_timebaseNotificationCallback_block_invoke + 112
7  libdispatch.dylib              0x63094 _dispatch_call_block_and_release + 24
8  libdispatch.dylib              0x64094 _dispatch_client_callout + 16
9  libdispatch.dylib              0x6858 _dispatch_queue_override_invoke + 720
10 libdispatch.dylib              0x13b94 _dispatch_root_queue_drain + 340
11 libdispatch.dylib              0x1439c _dispatch_worker_thread2 + 172
12 libsystem_pthread.dylib        0x1dc4 _pthread_wqthread + 224
13 libsystem_pthread.dylib        0x192c start_wqthread + 8
```

</details>


### Flutter Doctor output

<details open><summary>Doctor output</summary>

```console
[✓] Flutter (Channel stable, 3.27.2, on macOS 15.2 24C101 darwin-x64, locale fr-FR)
    • Flutter version 3.27.2 on channel stable at /Users/foxtom/Desktop/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 68415ad1d9 (9 days ago), 2025-01-13 10:22:03 -0800
    • Engine revision e672b006cb
    • Dart version 3.6.1
    • DevTools version 2.40.2

[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
    • Android SDK at /Users/foxtom/Library/Android/sdk
    • Platform android-35, build-tools 35.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 21.0.4+-12422083-b607.1)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 16.2)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 16C5032a
    • CocoaPods version 1.16.2

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2024.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 21.0.4+-12422083-b607.1)

[✓] VS Code (version 1.96.4)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension can be installed from:
      🔨 https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[✓] Connected device (5 available)
    • moto g 8 power (mobile)   • adb-ZY22BNDW2C-yyjDO7._adb-tls-connect._tcp • android-arm64  • Android 11 (API 30)
    • Now You See Me (mobile)   • 00008020-001204401E78002E                   • ios            • iOS 18.2.1 22C161
    • macOS (desktop)           • macos                                       • darwin-x64     • macOS 15.2 24C101 darwin-x64
    • Chrome (web)              • chrome                                      • web-javascript • Google Chrome 131.0.6778.265

[✓] Network resources
    • All expected network resources are available.

• No issues found!
```

</details>