How do I convert 10-bit H.265 videos to H.264 without quality loss?

Question

My laptop can't handle 10bit H.265 / HEVC videos, so I'm looking to convert them to 10bit H.264. How do I do this using, say, ffmpeg, with the least quality loss? And how can I convert 10-bit H.265 to 8-bit H.265?

Answer 1

Convert 10-bit H.265 to 10-bit H.264:

ffmpeg -i input -c:v libx264 -crf 18 -c:a copy output.mkv

• libx264 will automatically to to match the pixel format of the input, so no extra parameters are needed.

• The example uses -crf 18 which will likely appear visually lossless. If you want true lossless mode then then use -crf 0, but note this can create large files. See FFmpeg Wiki: H.264.

Convert 10-bit H.265 to 8-bit H.265:

ffmpeg -i input -c:v libx265 -vf format=yuv420p -c:a copy output.mkv

• Uses the format filter to choose the yuv420p pixel format to create 8-bit output.

• Adjust the -crf value to provide the desired level of quality. Default is -crf 28. See FFmpeg Wiki: H.265.

• If you want lossless mode then then replace -crf with -x265-params lossless=1, but note this can create large files.

Convert 10-bit H.265 to 8-bit H.264:

ffmpeg -i input -c:v libx264 -crf 18 -vf format=yuv420p -c:a copy output.mkv

• Uses the format filter to choose the yuv420p pixel format to create 8-bit output.

• The example uses -crf 18 which will likely appear visually lossless. If you want true lossless mode then then use -crf 0, but note this can create large files. See FFmpeg Wiki: H.264.

Answer 2

Handbrake can handle most anything.

The release notes mention 10-bit support.

The UI has all the options. I suggest you start there and get familiar with it.
See quick start guide.

There is also a CLI that can be downloaded here.
And the guide that has all the options laid out.