Support for Nvidia GPU Accelerated Transcoding
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**Is your feature request related to a problem? Please describe:**
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My Homebridge server has a powerful Nvidia GPU (GeForce 3090). Currently the Unifi Protect plugin appears to only be using CPU-based transcoding.

**Describe the solution you'd like:**
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I would love to be able to set a feature flag to enable "Nvidia GPU Accelerated Transcoding" in the Unifi Protect Plugin. This option would then pass in the proper flags to the ffmpeg transcoder, easing the burden on my CPU.

**Describe alternatives you've considered:**
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N/A

**Additional context:**
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https://stackoverflow.com/questions/44510765/gpu-accelerated-video-processing-with-ffmpeg

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