Nvidia NVENC configuration

[bmegli]

NVENC specific configuration.

At the same time we will prefix vaapi specific configuration opetions.

This will be breaking change (config names change)

[bmegli]

Ubuntu 20.04

 ffmpeg -h encoder=h264_nvenc -hide_banner
Encoder h264_nvenc [NVIDIA NVENC H.264 encoder]:
    General capabilities: delay hardware 
    Threading capabilities: none
    Supported pixel formats: yuv420p nv12 p010le yuv444p p016le yuv444p16le bgr0 rgb0 cuda
h264_nvenc AVOptions:
  -preset            <int>        E..V..... Set the encoding preset (from 0 to 11) (default medium)
     default                      E..V..... 
     slow                         E..V..... hq 2 passes
     medium                       E..V..... hq 1 pass
     fast                         E..V..... hp 1 pass
     hp                           E..V..... 
     hq                           E..V..... 
     bd                           E..V..... 
     ll                           E..V..... low latency
     llhq                         E..V..... low latency hq
     llhp                         E..V..... low latency hp
     lossless                     E..V..... 
     losslesshp                   E..V..... 
  -profile           <int>        E..V..... Set the encoding profile (from 0 to 3) (default main)
     baseline                     E..V..... 
     main                         E..V..... 
     high                         E..V..... 
     high444p                     E..V..... 
  -level             <int>        E..V..... Set the encoding level restriction (from 0 to 51) (default auto)
     auto                         E..V..... 
     1                            E..V..... 
     1.0                          E..V..... 
     1b                           E..V..... 
     1.0b                         E..V..... 
     1.1                          E..V..... 
     1.2                          E..V..... 
     1.3                          E..V..... 
     2                            E..V..... 
     2.0                          E..V..... 
     2.1                          E..V..... 
     2.2                          E..V..... 
     3                            E..V..... 
     3.0                          E..V..... 
     3.1                          E..V..... 
     3.2                          E..V..... 
     4                            E..V..... 
     4.0                          E..V..... 
     4.1                          E..V..... 
     4.2                          E..V..... 
     5                            E..V..... 
     5.0                          E..V..... 
     5.1                          E..V..... 
  -rc                <int>        E..V..... Override the preset rate-control (from -1 to INT_MAX) (default -1)
     constqp                      E..V..... Constant QP mode
     vbr                          E..V..... Variable bitrate mode
     cbr                          E..V..... Constant bitrate mode
     vbr_minqp                    E..V..... Variable bitrate mode with MinQP (deprecated)
     ll_2pass_quality              E..V..... Multi-pass optimized for image quality (deprecated)
     ll_2pass_size                E..V..... Multi-pass optimized for constant frame size (deprecated)
     vbr_2pass                    E..V..... Multi-pass variable bitrate mode (deprecated)
     cbr_ld_hq                    E..V..... Constant bitrate low delay high quality mode
     cbr_hq                       E..V..... Constant bitrate high quality mode
     vbr_hq                       E..V..... Variable bitrate high quality mode
  -rc-lookahead      <int>        E..V..... Number of frames to look ahead for rate-control (from 0 to INT_MAX) (default 0)
  -surfaces          <int>        E..V..... Number of concurrent surfaces (from 0 to 64) (default 0)
  -cbr               <boolean>    E..V..... Use cbr encoding mode (default false)
  -2pass             <boolean>    E..V..... Use 2pass encoding mode (default auto)
  -gpu               <int>        E..V..... Selects which NVENC capable GPU to use. First GPU is 0, second is 1, and so on. (from -2 to INT_MAX) (default any)
     any                          E..V..... Pick the first device available
     list                         E..V..... List the available devices
  -delay             <int>        E..V..... Delay frame output by the given amount of frames (from 0 to INT_MAX) (default INT_MAX)
  -no-scenecut       <boolean>    E..V..... When lookahead is enabled, set this to 1 to disable adaptive I-frame insertion at scene cuts (default false)
  -forced-idr        <boolean>    E..V..... If forcing keyframes, force them as IDR frames. (default false)
  -b_adapt           <boolean>    E..V..... When lookahead is enabled, set this to 0 to disable adaptive B-frame decision (default true)
  -spatial-aq        <boolean>    E..V..... set to 1 to enable Spatial AQ (default false)
  -temporal-aq       <boolean>    E..V..... set to 1 to enable Temporal AQ (default false)
  -zerolatency       <boolean>    E..V..... Set 1 to indicate zero latency operation (no reordering delay) (default false)
  -nonref_p          <boolean>    E..V..... Set this to 1 to enable automatic insertion of non-reference P-frames (default false)
  -strict_gop        <boolean>    E..V..... Set 1 to minimize GOP-to-GOP rate fluctuations (default false)
  -aq-strength       <int>        E..V..... When Spatial AQ is enabled, this field is used to specify AQ strength. AQ strength scale is from 1 (low) - 15 (aggressive) (from 1 to 15) (default 8)
  -cq                <float>      E..V..... Set target quality level (0 to 51, 0 means automatic) for constant quality mode in VBR rate control (from 0 to 51) (default 0)
  -aud               <boolean>    E..V..... Use access unit delimiters (default false)
  -bluray-compat     <boolean>    E..V..... Bluray compatibility workarounds (default false)
  -init_qpP          <int>        E..V..... Initial QP value for P frame (from -1 to 51) (default -1)
  -init_qpB          <int>        E..V..... Initial QP value for B frame (from -1 to 51) (default -1)
  -init_qpI          <int>        E..V..... Initial QP value for I frame (from -1 to 51) (default -1)
  -qp                <int>        E..V..... Constant quantization parameter rate control method (from -1 to 51) (default -1)
  -weighted_pred     <int>        E..V..... Set 1 to enable weighted prediction (from 0 to 1) (default 0)
  -coder             <int>        E..V..... Coder type (from -1 to 2) (default default)
     default                      E..V..... 
     auto                         E..V..... 
     cabac                        E..V..... 
     cavlc                        E..V..... 
     ac                           E..V..... 
     vlc                          E..V..... 
  -b_ref_mode        <int>        E..V..... Use B frames as references (from 0 to 2) (default disabled)
     disabled                     E..V..... B frames will not be used for reference
     each                         E..V..... Each B frame will be used for reference
     middle                       E..V..... Only (number of B frames)/2 will be used for reference
  -a53cc             <boolean>    E..V..... Use A53 Closed Captions (if available) (default true)

[bmegli]

We want to be able to stream low-latency video.

There are at least 3 sources of latency under control:

• encoding time
  • typically low with hardware encoder
• encoder delay
  • not outputting encoded data immediately (push multiple frames before encoder output)
• codec structure/algorithm
  • references to forward frames, B frames, multi-pass
  • reordering of frames

All above are somewhat interconnected and speed/quality/latency/throughput trade-off.

[bmegli]

We will expose for now minimum:

• preset
• delay
• zerolatency

[bmegli]

We will name them:

• nvenc_preset (string)
• nvenc_delay (int)
• nvenc_zerolatency (int)

[bmegli]

We want to be able to:

• leave defaults (not set value)
• fail if setting is not correct

We will map:

• 0 to leave defaults (or empty string, NULL string)
• -1 to explicitly set 0

This way if user just initializes config struct with {0} he will get defaults.