NVENC HEVC CQP using higher bitrate since v30.2.0

jayzerbeam

New Member
I record with NVENC HEVC 4:4:4 @ CQP 20, and since upgrading from v30.1.2 to any v30.2.x version, the recordings are using more bitrate for the same encoder settings.

Recordings with v30.1.x are around 85 Mb/s whereas those with v31.2.x are up around 115Mb/s. Settings and drivers between the two are the same. I've checked the changelogs and don't see any relevant notes.

My settings are identical between versions, but the params passed to nvenc seem to be slightly different according to the logs

v30.1.2
Code:
22:38:24.628: [FFmpeg NVENC encoder: 'advanced_video_recording'] settings:
22:38:24.628:     encoder:      NVIDIA NVENC HEVC (FFmpeg)
22:38:24.628:     rate_control: CQP
22:38:24.628:     bitrate:      0
22:38:24.628:     cqp:          20
22:38:24.628:     keyint:       60
22:38:24.628:     preset:       p4
22:38:24.628:     tuning:       hq
22:38:24.628:     multipass:    disabled
22:38:24.628:     profile:      main
22:38:24.628:     width:        2560
22:38:24.628:     height:       1440
22:38:24.628:     b-frames:     2
22:38:24.628:     psycho-aq:    0
22:38:24.628:     GPU:          0

v30.2.3
Code:
16:17:48.224: [obs-nvenc: 'advanced_video_recording'] settings:
16:17:48.224:     codec:        HEVC
16:17:48.224:     rate_control: CQP
16:17:48.224:     bitrate:      0
16:17:48.224:     cqp:          20
16:17:48.224:     keyint:       60
16:17:48.224:     preset:       p4
16:17:48.224:     tuning:       hq
16:17:48.224:     multipass:    disabled
16:17:48.224:     profile:      main
16:17:48.224:     width:        2560
16:17:48.224:     height:       1440
16:17:48.224:     b-frames:     2
16:17:48.224:     lookahead:    false
16:17:48.224:     psycho_aq:    false
 
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