config: add min_fps setting

docs/source/about/advanced_usage.rst

@@ -378,6 +378,23 @@ dwmflush
 
       dwmflush = enabled
 
+fps_min
+^^^^^^^
+
+**Description**
+   The minimum framerate Sunshine will attempt to maintain. Increasing this value slightly may help when streaming
+   mostly static content.
+
+   .. Warning:: Higher values will consume more bandwidth.
+
+**Default**
+   ``10``
+
+**Example**
+   .. code-block:: text
+
+      fps_min = 10
+
 Audio
 -----
 

src/config.cpp

@@ -314,7 +314,8 @@ video_t video {
 
   0, // hevc_mode
 
-  1, // min_threads
+  10, // min_fps
+  1,  // min_threads
   {
     "superfast"s,   // preset
     "zerolatency"s, // tune

src/config.h

@@ -15,6 +15,7 @@ struct video_t {
 
   int hevc_mode;
 
+  int min_fps;     // Minimum framerate
   int min_threads; // Minimum number of threads/slices for CPU encoding
   struct {
     std::string sw_preset;

src/video.cpp

@@ -1281,6 +1281,26 @@ void encode_run(
   const encoder_t &encoder,
   void *channel_data) {
 
+  // get minimum fps from config
+  auto min_fps = config::video.min_fps;
+  auto minimum_frame_time = std::chrono::milliseconds(1000 / 10); // default value
+
+  // check if min_fps is an integer
+  if(min_fps != (int)min_fps) {
+    BOOST_LOG(warning) << "Minimum FPS must be an integer, update your config. Falling back to 10 FPS."sv;
+  }
+  else {
+    minimum_frame_time = std::chrono::milliseconds(1000 / config::video.min_fps); // use config value if it is an integer
+  }
+
+  // check if minimum frame time is between 1 and 240 fps
+  if(minimum_frame_time < std::chrono::milliseconds(1000 / 240)) {
+    minimum_frame_time = std::chrono::milliseconds(1000 / 240);
+  }
+  else if(minimum_frame_time > std::chrono::milliseconds(1000 / 1)) { // 1 fps, showing equation just for clarity... maybe should have a min fps a little higher than 1?
+    minimum_frame_time = std::chrono::milliseconds(1000 / 1);
+  }
+
   auto session = make_session(disp.get(), encoder, config, disp->width, disp->height, std::move(hwdevice));
   if(!session) {
     return;
@@ -1311,9 +1331,9 @@ void encode_run(
       idr_events->pop();
     }
 
-    // Encode at a minimum of 10 FPS to avoid image quality issues with static content
+    // Encode at a minimum of FPS to avoid image quality issues with static content
     if(!frame->key_frame || images->peek()) {
-      if(auto img = images->pop(100ms)) {
+      if(auto img = images->pop(minimum_frame_time)) {
         if(session->device->convert(*img)) {
           BOOST_LOG(error) << "Could not convert image"sv;
           return;

src_assets/common/assets/web/config.html

@@ -502,6 +502,21 @@ <h1 class="my-4">Configuration</h1>
           Disable if you encounter any VSync-related issues.
         </div>
       </div>
+      <!--fps_min-->
+      <div class="mb-3">
+        <label for="qp" class="form-label">FPS Minimum</label>
+        <input
+          type="number"
+          class="form-control"
+          id="fps_min"
+          placeholder="10"
+          v-model="config.min_fps"
+        />
+        <div class="form-text">
+          The minimum framerate Sunshine will attempt to maintain.<br />
+          Increasing this value slightly may help when streaming mostly static content.<br />
+          Higher values will consume more bandwidth.<br />
+        </div>
       <div class="mb-3" class="config-page" v-if="platform === 'linux'">
         <label for="output_name" class="form-label">Monitor number</label>
         <input
@@ -547,7 +562,7 @@ <h1 class="my-4">Configuration</h1>
           Quantization Parameter<br />
           Some devices may not support Constant Bit Rate.<br />
           For those devices, QP is used instead.<br />
-          Higher value means more compression, but less quality<br />
+          Higher value means more compression, but less quality.<br />
         </div>
       </div>
       <!-- Min Threads -->
@@ -914,6 +929,7 @@ <h1 class="my-4">Configuration</h1>
     "dwmflush": "enabled",
     "encoder": "",
     "fps": "[10,30,60,90,120]",
+    "fps_min": 10,
     "gamepad": "x360",
     "hevc_mode": 0,
     "key_rightalt_to_key_win": "disabled",