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Comment by barosl

13 hours ago

I tested the demo at https://moq.dev/publish/ and it's buttery as hell. Very impressive. Thanks for the great technology!

Watching the Big Buck Bunny demo at https://moq.dev/watch/?name=bbb on my mobile phone leaves a lot of horizontal black lines. (Strangely, it is OK on my PC despite using the same Wi-Fi network.) Is it due to buffer size? Can I increase it client-side, or should it be done server-side?

Also, thanks for not missing South Kora in your "global" CDN map!

19 comments

barosl

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nine_k  4 hours ago

The page mentions a lot of Rust code and WASM. Maybe your phone's CPU cannot run WASM fast enough?

My Samsung S20 shows no black lines.

kixelated  12 hours ago

Horizontal black lines? Dunno what that could be about, we render to a <canvas> element which is resized to match the source video and then resized again to match the window with CSS.

  • chrismorgan  6 hours ago

    What’s that like for performance and power usage? I understand normal videos can generally be entirely hardware-accelerated so that the video doesn’t even touch the CPU, and are passed straight through to the compositor. I’m guessing with this you’re stuck with only accelerating individual frames, and there’ll be more back and forth so that resource usage will probably be a fair bit higher?

    An interesting and unpleasant side-effect of rendering to canvas: it bypasses video autoplay blocking.

    • kixelated  5 hours ago

      It's all hardware accelerated, assuming the VideoDecoder has hardware support for the codec. VideoFrame is available in WebGL and WebGPU as a texture or gpu-buffer. We're only rendering after a`requestAnimationFrame` callback so decoded frames may get automatically skipped based on the display frame rate.

      I don't think the performance would be any worse than the <video> tag. The only exception would be browser bugs. It definitely sounds like the black bars are a browser rendering bug given it's fine when recorded.

      1 reply →

  • Numerlor  10 hours ago

    Doesn't show up on screen capture, but there's random rolling quickly flickering lines on my phone, kinda like from analog distortion on old tvs

stronglikedan  12 hours ago

I don't get the black lines on Android/Chrome but it doesn't respect my aspect ratio when I go full screen. Instead of adding black bars to the sides, it excludes the top and bottom of the video completely.