Update docs for new nvenc config

docs/source/about/advanced_usage.rst

@@ -986,14 +986,15 @@ sw_tune
 
       sw_tune    = zerolatency
 
-nv_preset
+nvenc_preset
-^^^^^^^^^
+^^^^^^^^^^^^
 
 **Description**
-   The encoder preset to use.
+   NVENC encoder performance preset.
+   Higher numbers improve compression (quality at given bitrate) at the cost of increased encoding latency.
+   Recommended to change only when limited by network or decoder, otherwise similar effect can be accomplished by increasing bitrate. 
 
-   .. Note:: This option only applies when using nvenc `encoder`_. For more information on the presets, see
+   .. Note:: This option only applies when using NVENC `encoder`_.
-      `nvenc preset migration guide <https://docs.nvidia.com/video-technologies/video-codec-sdk/nvenc-preset-migration-guide/>`__.
 
 **Choices**
 
@@ -1003,30 +1004,65 @@ nv_preset
    ========== ===========
    Value      Description
    ========== ===========
-   p1         fastest (lowest quality)
+   1          P1 (fastest)
-   p2         faster (lower quality)
+   2          P2
-   p3         fast (low quality)
+   3          P3
-   p4         medium (default)
+   4          P4
-   p5         slow (good quality)
+   5          P5
-   p6         slower (better quality)
+   6          P6
-   p7         slowest (best quality)
+   7          P7 (slowest)
    ========== ===========
 
 **Default**
-   ``p4``
+   ``1``
 
 **Example**
    .. code-block:: text
 
-      nv_preset = p4
+      nvenc_preset = 1
 
-nv_tune
+nvenc_twopass
-^^^^^^^
+^^^^^^^^^^^^^
 
 **Description**
-   The encoder tuning profile.
+   Enable two-pass mode in NVENC encoder.
+   This allows to detect more motion vectors, better distribute bitrate across the frame and more strictly adhere to bitrate limits.
+   Disabling it is not recommended since this can lead to occasional bitrate overshoot and subsequent packet loss. 
 
-   .. Note:: This option only applies when using nvenc `encoder`_.
+   .. Note:: This option only applies when using NVENC `encoder`_.
+
+**Choices**
+
+.. table::
+   :widths: auto
+
+   =========== ===========
+   Value       Description
+   =========== ===========
+   disabled    One pass (fastest)
+   quarter_res Two passes, first pass at quarter resolution (faster)
+   full_res    Two passes, first pass at full resolution (slower)
+   =========== ===========
+
+**Default**
+   ``quarter_res``
+
+**Example**
+   .. code-block:: text
+
+      nvenc_twopass = quarter_res
+
+nvenc_realtime_hags
+^^^^^^^^^^^^^^^^^^^
+
+**Description**
+   Use realtime gpu scheduling priority in NVENC when hardware accelerated gpu scheduling (HAGS) is enabled in Windows.
+   Currently NVIDIA drivers may freeze in encoder when HAGS is enabled, realtime priority is used and VRAM utilization is close to maximum.
+   Disabling this option lowers the priority to high, sidestepping the freeze at the cost of reduced capture performance when the GPU is heavily loaded. 
+
+   .. Note:: This option only applies when using NVENC `encoder`_.
+
+   .. Caution:: Applies to Windows only.
 
 **Choices**
 
@@ -1036,27 +1072,26 @@ nv_tune
    ========== ===========
    Value      Description
    ========== ===========
-   hq         high quality
+   disabled   Use high priority
-   ll         low latency
+   enabled    Use realtime priority
-   ull        ultra low latency
-   lossless   lossless
    ========== ===========
 
 **Default**
-   ``ull``
+   ``enabled``
 
 **Example**
    .. code-block:: text
 
-      nv_tune = ull
+      nvenc_realtime_hags = enabled
 
-nv_rc
+nvenc_h264_cavlc
-^^^^^
+^^^^^^^^^^^^^^^^
 
 **Description**
-   The encoder rate control.
+   Prefer CAVLC entropy coding over CABAC in H.264 when using NVENC.
+   CAVLC is outdated and needs around 10% more bitrate for same quality, but provides slightly faster decoding when using software decoder.
 
-   .. Note:: This option only applies when using nvenc `encoder`_.
+   .. Note:: This option only applies when using H.264 format with NVENC `encoder`_.
 
 **Choices**
 
@@ -1066,47 +1101,17 @@ nv_rc
    ========== ===========
    Value      Description
    ========== ===========
-   constqp    constant QP mode
+   disabled   Prefer CABAC
-   vbr        variable bitrate
+   enabled    Prefer CAVLC
-   cbr        constant bitrate
    ========== ===========
 
 **Default**
-   ``cbr``
+   ``disabled``
 
 **Example**
    .. code-block:: text
 
-      nv_rc = cbr
+      nvenc_h264_cavlc = disabled
-
-nv_coder
-^^^^^^^^
-
-**Description**
-   The entropy encoding to use.
-
-   .. Note:: This option only applies when using H264 with nvenc `encoder`_.
-
-**Choices**
-
-.. table::
-   :widths: auto
-
-   ========== ===========
-   Value      Description
-   ========== ===========
-   auto       let ffmpeg decide
-   cabac      context adaptive binary arithmetic coding - higher quality
-   cavlc      context adaptive variable-length coding - faster decode
-   ========== ===========
-
-**Default**
-   ``auto``
-
-**Example**
-   .. code-block:: text
-
-      nv_coder = auto
 
 qsv_preset
 ^^^^^^^^^^