{
  "mime_type": "audio/webm;codecs=opus",
  "timeslice_ms": 250,
  "pre_speech_chunk_count": 5,
  "chunk_sizes": [
    204,
    70,
    70,
    70,
    70,
    3864,
    5796,
    4830,
    4830,
    1945
  ],
  "payload_file": "chromium-webm-opus.webm",
  "browser": "140.0.7339.16",
  "generator": "testing/probes/generate_mediarecorder_fixture.js"
}