Comment by lifthrasiir

For the completeness, the omitted Uint8Array is the following 340-byte binary (here in base64):

    GkXfo59ChoEBQveBAULygQRC84EIQoKEd2VibUKHgQRChYECGFOAZwH/////////FUmpZpkq17GD
    D0JATYCGQ2hyb21lV0GGQ2hyb21lFlSua6mup9eBAXPFh89gnOoYna+DgQFV7oEBhoVWX1ZQOOCK
    sIEBuoEBU8CBAR9DtnUB/////////+eBAKDMoaKBAAAAEAIAnQEqAQABAAvHCIWFiJmEiD+CAAwN
    YAD+5WoAdaGlpqPugQGlnhACAJ0BKgEAAQALxwiFhYiZhIg/ggAMDWAA/uh4AKC7oZiBA+kAsQEA
    LxH8ABgAMD/0DAAAAP7lagB1oZumme6BAaWUsQEALxH8ABgAMD/0DAAAAP7oeAD7gQCgvKGYgQfQ
    ALEBAC8R/AAYADA/9AwAAAD+5WoAdaGbppnugQGllLEBAC8R/AAYADA/9AwAAAD+6HgA+4ID6Q==

VLC somehow refuses to play it, but its nominal length can be verified with a short JS code like:

    v = document.createElement('video');
    v.src = `data:video/webm;base64,<as above>`;
    await new Promise(resolve => v.onloadedmetadata = resolve);
    console.log(v.duration);