Even if the output is SDR, setting the encoder to 10-bit (if using x265) can help prevent color banding in the final video.
Some HDR videos have very high peak brightness. You might need to use a specialized tool like ffmpeg for better tone mapping if Handbrake's output is too dark, or adjust the gamma settings in the "Video" tab slightly. convert hdr to sdr handbrake
Launch HandBrake and click on the button. Navigate to your HDR video file and select it. Once loaded, you'll be on the "Summary" tab. Even if the output is SDR, setting the
Challenges in HDR→SDR Conversion