[Bug]: Video recording is not creating a valid webm file for Firefox, works fine with other browsers

[sandy-tpp]

Version

1.49.1

Steps to reproduce

Added param - video: 'retain-on-failure', in playwright.config.js
On test failure view file with .webm extension is created file.
Open the .webm file in any browser or supported video player

Expected behavior

The video should play in browser

Actual behavior

The videos are opening file when test is run with all browsers except Firefox. I have the latest browsers too ff 132.0. The webm file from firefox test is not opening / playing in any browser or player. The size is also just 110 bytes.

Sample webm file attached
https://github.com/user-attachments/assets/07d50ca5-86d6-4e75-abab-08c732bd1949

Additional context

No response

Environment

System:
    OS: macOS 15.1
    CPU: (8) arm64 Apple M1 Pro
    Memory: 105.13 MB / 16.00 GB
  Binaries:
    Node: 20.10.0 - ~/.nvm/versions/node/v20.10.0/bin/node
    Yarn: 1.22.19 - /opt/homebrew/bin/yarn
    npm: 10.2.3 - ~/.nvm/versions/node/v20.10.0/bin/npm
  IDEs:
    VSCode: 1.95.2 - /usr/local/bin/code
  Languages:
    Bash: 3.2.57 - /bin/bash

[pavelfeldman]

We need a minimal repro to act on this issue.