[thingfish]

I added an .mp4 source. Still not playing in BlueStacks Android. Does it work in a real Andriod?

[blueflow]

Pay attention to the the codecs, mp4 is a container format that may contain a codec that Android doesn't support. This is a rabbit hole.

[mdaniel]

According to ffprobe:

  Duration: 00:00:21.20, start: 0.000000, bitrate: 307 kb/s
  Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 960x672, 306 kb/s, 10 fps, 10 tbr, 10240 tbn (default)

so maybe in a comically ancient version of Android, or perhaps a "hardened" distro that eschews modern stuff?

Merely as another datum, I did URL surgery to get the prior .webm flavor and it's blank for my FF 137 on macOS so there was obviously something else going on (by blank I mean it had 21 seconds worth of black pixels, not that it didn't play)