Rate Control - Target bitrate not achieved

[Radhakrishnan Venugopal Rajaganesan]

For ElFuente_3840x2160_5994fps.yuv video there is huge difference between given ABR and achieved target bitrate in all presets. It has 500 frames. In ultrafast preset achieved bitrate is on average ~50% more than given. In other presets achieved bitrate is on average ~40% less than given. I have attached the csv logs.

command line: --input-res 3840x2160 --fps 59.94 --bitrate 25000 --input ElFuente_3840x2160_5994fps.yuv --preset ultrafast --psnr --ssim -o elfuente.hevc

[Divya Manivannan]

This video has huge black frames and very less content so it is achieving lesser bitrate than target in all presets except ultrafast.

More bitrate in ultrafast is because of disabling scenecut threshold. Can you test with ultrafast by enabling scenecut threshold?

[Radhakrishnan Venugopal Rajaganesan]

Yes when scenecut is enabled, ultrafast is behaving like other presets in terms of achieved bitrate. In ultrafast, achieved bitrate is approximately 40% less than given just as like other presets.