Converting EXR file to wide-gamut H.264

[hybridherbst]

Describe the bug
I'm trying to use ffmpeg.wasm to convert EXR files (floating point) to wide-gamut H.264 files such as used on https://www.wide-gamut.com/test.

An example input file: https://dl.polyhaven.org/file/ph-assets/HDRIs/exr/1k/lonely_road_afternoon_puresky_1k.exr
An example output file: https://www.wide-gamut.com/assets/video-hdr/P3-GREEN-HDR-1000nits.mp4

To Reproduce
Drop the above input file in https://ffmpegwasm.netlify.app/playground and try to convert it to mp4. This already fails with

[exr @ 0xdea640] decode_block() failed.
strange codes is not implemented. 

so I'm not getting to the point where I can actually try converting to a HDR video.

Expected behavior
Ability to convert EXR to single-frame wide-gamut video.

Desktop (please complete the following information):

• OS: Mac OS
• Browser Chrome

Additional context
Conversion to HDR AVIF would also be interesting but I'm not sure if that is supported in ffmpeg.wasm at all.