Use access unit delimiters (default false) Set target quality level (0 to 51, 0 means automatic) for constant quality mode in VBR rate control (from 0 to 51) (default 0) AQ strength scale is from 1 (low) - 15 (aggressive) (from 1 to 15) (default 8) When Spatial AQ is enabled, this field is used to specify AQ strength. Set 1 to minimize GOP-to-GOP rate fluctuations (default false) Set this to 1 to enable automatic insertion of non-reference P-frames (default false)
Set 1 to indicate zero latency operation (no reordering delay) (default false) set to 1 to enable Temporal AQ (default false) set to 1 to enable Spatial AQ (default false) If forcing keyframes, force them as IDR frames. When lookahead is enabled, set this to 1 to disable adaptive I-frame insertion at scene cuts (default false) Delay frame output by the given amount of frames (from 0 to INT_MAX) (default INT_MAX) (from -2 to INT_MAX) (default any)Īny E.V. Number of concurrent surfaces (from 0 to 64) (default 0) Number of frames to look ahead for rate-control (from 0 to INT_MAX) (default 0) Constant bitrate low delay high quality modeĬbr_hq E.V. Multi-pass variable bitrate mode (deprecated)Ĭbr_ld_hq E.V. Multi-pass optimized for constant frame size (deprecated) Multi-pass optimized for image quality (deprecated)
Variable bitrate mode with MinQP (deprecated) Override the preset rate-control (from -1 to INT_MAX) (default -1) Set the encoding tier (from 0 to 1) (default main) Set the encoding level restriction (from 0 to 186) (default auto) Set the encoding profile (from 0 to 4) (default main) Set the encoding preset (from 0 to 11) (default medium) In the NVDEC codec documentation, I see 2 options related to CBR: -rc cbrĭoes anyone know what the difference is? Setting “-cbr 1” doesn’t seem to make any difference compared to "-rc cbr "?įor reference, the codec options available: ffmpeg -h encoder=hevc_nvencįfmpeg version n4.2-60-g3de33c6 Copyright (c) 2000-2019 the FFmpeg developers ffmpeg -hwaccel nvdec -i INPUT_MCAST -c:a aac -c:v hevc_nvenc -profile:v main10 -rc cbr -b:v 10M -minrate 10M -maxrate 10M -bufsize 512k -r 50 -g 100 -f OUTPUT_MCAST ffmpeg was never good at generating a true CBR output, one usually tries to micmic it ( Limiting the output bitrate – FFmpeg). The only thing that puzzles me is how to generate the “most CBR” output…here is an example command used, it generates an output that is mostly CBR, but it varies +/- 1Mbit around my target value.
Since a couple of days I’m playing with a Tesla P4 card and transcoding live 4k contents with ffmpeg (which works perfectly fine).
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