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Our workflow involves huge 8K clips(i.e., 8192x8192). The inputs are mostly very high bitrates 264/265 clips, though we are using ProRes or DNxHD for post-production within the process, we do not want to archive such huge files as the "master" copies(easily over 100GB for 1 minute).

My current approach is, using FFMPEG to compress the ProRes/DHxHD clips into H.265 clips using a very high-quality setting (crf=12, slow profile).

Another quality related setting is the pixel format config. Then my question comes up:

Targeting the same clips(5 of them), using the same compress settings, one with yuv420 8-bit, one with yuv444 10-bit, yuv444 outputs are constantly smaller than yuv420 outputs(5%-10%), i.e, lower bitrates.

If yuv444 10-bit needs to store more information, how could this be possible?

  • I can't answer your question, but may I ask which camers you are using? As not even RED's r3d codec at 8k uses so much storage. Thanks. – Timothy Lukas H. Jan 8 at 23:00
  • Yes, this is not from a single camera, they are VR content, a multiple camera setup. – Jerry Tian Jan 9 at 2:39
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From Why does 10-bit save bandwidth (even when content is 8-bit)?

When encoding with the 10-bit tool, the compression process is performed with at least 10-bit accuracy compared to only 8-bit otherwise. So there is less truncation errors, especially in the motion compensation stage, increasing the efficiency of compression tools. As a consequence, there is less need to quantize to achieve a given bit-rate.

The net result is a better quality for the same bit-rate or conversely less bit-rate for the same quality: between 5% and 20% on typical sources.

See the link for additional info.

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