From ede59e17d8f85d35840505d9345668b345a53369 Mon Sep 17 00:00:00 2001
From: ns6089 <61738816+ns6089@users.noreply.github.com>
Date: Sat, 28 Oct 2023 12:26:32 +0300
Subject: [PATCH] Expose more nvenc options

1. Spatial AQ, for some reason NVENC have problems recovering details on
   flat regions of static images over multiple frames, official docs
   recommend to enable it for "game-streaming"
2. Percentage increase of default single-frame VBV/HRD, can act as
   low latency variable bitrate substitute
---
 src/config.cpp           | 2 ++
 src/nvenc/nvenc_base.cpp | 6 +++++-
 src/nvenc/nvenc_config.h | 3 +++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/config.cpp b/src/config.cpp
index 1489786b..b1948638 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -939,6 +939,8 @@ namespace config {
     string_f(vars, "sw_tune", video.sw.sw_tune);
 
     int_between_f(vars, "nvenc_preset", video.nv.quality_preset, { 1, 7 });
+    int_between_f(vars, "nvenc_vbv_increase", video.nv.vbv_percentage_increase, { 0, 400 });
+    bool_f(vars, "nvenc_spatial_aq", video.nv.adaptive_quantization);
     generic_f(vars, "nvenc_twopass", video.nv.two_pass, nv::twopass_from_view);
     bool_f(vars, "nvenc_h264_cavlc", video.nv.h264_cavlc);
     bool_f(vars, "nvenc_realtime_hags", video.nv_realtime_hags);
diff --git a/src/nvenc/nvenc_base.cpp b/src/nvenc/nvenc_base.cpp
index f305f768..205a163d 100644
--- a/src/nvenc/nvenc_base.cpp
+++ b/src/nvenc/nvenc_base.cpp
@@ -222,6 +222,9 @@ namespace nvenc {
 
     if (get_encoder_cap(NV_ENC_CAPS_SUPPORT_CUSTOM_VBV_BUF_SIZE)) {
       enc_config.rcParams.vbvBufferSize = client_config.bitrate * 1000 / client_config.framerate;
+      if (config.vbv_percentage_increase > 0) {
+        enc_config.rcParams.vbvBufferSize += enc_config.rcParams.vbvBufferSize * config.vbv_percentage_increase / 100;
+      }
     }
 
     auto set_h264_hevc_common_format_config = [&](auto &format_config) {
@@ -369,9 +372,10 @@ namespace nvenc {
       if (init_params.enableEncodeAsync) extra += " async";
       if (buffer_is_10bit()) extra += " 10-bit";
       if (enc_config.rcParams.multiPass != NV_ENC_MULTI_PASS_DISABLED) extra += " two-pass";
+      if (config.vbv_percentage_increase > 0 && get_encoder_cap(NV_ENC_CAPS_SUPPORT_CUSTOM_VBV_BUF_SIZE)) extra += " vbv+" + std::to_string(config.vbv_percentage_increase);
       if (encoder_params.rfi) extra += " rfi";
       if (init_params.enableWeightedPrediction) extra += " weighted-prediction";
-      if (enc_config.rcParams.enableAQ) extra += " adaptive-quantization";
+      if (enc_config.rcParams.enableAQ) extra += " spatial-aq";
       if (enc_config.rcParams.enableMinQP) extra += " qpmin=" + std::to_string(enc_config.rcParams.minQP.qpInterP);
       if (config.insert_filler_data) extra += " filler-data";
       BOOST_LOG(info) << "NvEnc: created encoder " << quality_preset_string_from_guid(init_params.presetGUID) << extra;
diff --git a/src/nvenc/nvenc_config.h b/src/nvenc/nvenc_config.h
index 632146b7..c4aae12a 100644
--- a/src/nvenc/nvenc_config.h
+++ b/src/nvenc/nvenc_config.h
@@ -20,6 +20,9 @@ namespace nvenc {
     // Use optional preliminary pass for better motion vectors, bitrate distribution and stricter VBV(HRD), uses CUDA cores
     nvenc_two_pass two_pass = nvenc_two_pass::quarter_resolution;
 
+    // Percentage increase of VBV/HRD from the default single frame, allows low-latency variable bitrate
+    int vbv_percentage_increase = 0;
+
     // Improves fades compression, uses CUDA cores
     bool weighted_prediction = false;