What

• part of Native video decoder via ffmpeg CLI #7607

Most replacing randomness with warnings. I haven't deep dived on which version will work but 5.1 went fine with my test data minus a bit of log spam which I fixed here.

I considered adding a check for coded availability, but this seems a bit cumbersome given that any off-the-shelf ffmpeg install comes with h264: the problem is that while we get a full string of compile options that ffmpeg was built with, we can't really infer the decoders from this since any given library may fulfill various roles. Instead we'd need to parse the output of ffmpeg -codecs. We should eventually! But doesn't seem urgent right now.

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
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  • Using examples from latest main build: rerun.io/viewer
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