Handling codec errors

[itsdouges]

Hey folks, I have an error coming through where a web codec isn't available. Brave / arc browsers both have it.

What's odd is im not using a specific one, just this code:

const videoCodec = await getFirstEncodableVideoCodec(output.format.getSupportedVideoCodecs(), {
width: node.width * targetScale,
height: node.height * targetScale,
});

Should I be doing something else to get a usable codec?

[Vanilagy]

Your dimensions are odd (1921x1080), and AVC only supports even dimensions (width and height divisible by 2). This also should cause getFirstEncodableVideoCodec not to return AVC. Are you calling it with different dimensions?

[itsdouges]

This seems like an arc bug perhaps? I'm setting the h/w to 1920x1080, canvas to 960x540 as it's 2dpi, but then get this error from mediabunny:

Error: This specific encoder configuration (avc1.640032, 12888000 bps, 2871x1615, hardware acceleration: no-preference) is not supported by this browser. Consider using another codec or changing your video parameters.

Where the dimensions in the error seem to be the browser viewport size

[itsdouges]

this is the encoderConfig I get in arc (throws an exception when generating video)

{
    "codec": "avc1.640032",
    "width": 2266,
    "height": 1275,
    "bitrate": 8223000,
    "framerate": 60,
    "avc": {
        "format": "avc"
    }
}

this is the config I get in chrome (works fine)

{
    "codec": "avc1.640028",
    "width": 1920,
    "height": 1080,
    "bitrate": 6000000,
    "framerate": 60,
    "avc": {
        "format": "avc"
    }
}

the width and height are unexpectedly different 🤔

going back further it's the sample video reporting the wrong dimensions in arc... which are just reporting what the canvas size is, so it's probably on my end. thanks will dig into why this is the case!

[Vanilagy]

Are you getting your video frames from a fixed-size source like a canvas or do they come from a live source like webcam or screen recording or something? Sometimes, these can change resolution mid-video. There's this flag in Mediabunny to control that: https://mediabunny.dev/api/VideoEncodingConfig#sizechangebehavior

Might be relevant, might not, not sure.

Oh no, but the default is 'deny', so it should throw if that's the case.

Yeah keep digging and see if you find anything.

[itsdouges]

Hi! Just following up, this was a combination of a bug in paper shaders and being able to set arbitrary sizes on the canvas. Thanks for the help!

[Vanilagy]

Oh that's very interesting, you went deep. Awesome!