feat: Add Max Bitrate option (#3628)

src/config.cpp

@@ -509,7 +509,8 @@ namespace config {
       {}  // wa
     },  // display_device
 
-    1  // min_fps_factor
+    1,  // min_fps_factor
+    0  // max_bitrate
   };
 
   audio_t audio {
@@ -1138,6 +1139,7 @@ namespace config {
     bool_f(vars, "dd_wa_hdr_toggle", video.dd.wa.hdr_toggle);
 
     int_between_f(vars, "min_fps_factor", video.min_fps_factor, {1, 3});
+    int_f(vars, "max_bitrate", video.max_bitrate);
 
     path_f(vars, "pkey", nvhttp.pkey);
     path_f(vars, "cert", nvhttp.cert);

src/config.h

@@ -138,6 +138,7 @@ namespace config {
     } dd;
 
     int min_fps_factor;  // Minimum fps target, determines minimum frame time
+    int max_bitrate;  // Maximum bitrate, sets ceiling in kbps for bitrate requested from client
   };
 
   struct audio_t {

src/video.cpp

@@ -1687,7 +1687,8 @@ namespace video {
         }
       }
 
-      auto bitrate = config.bitrate * 1000;
+      auto bitrate = ((config::video.max_bitrate > 0) ? std::min(config.bitrate, config::video.max_bitrate) : config.bitrate) * 1000;
+      BOOST_LOG(info) << "Max bitrate is " << config::video.max_bitrate;
       ctx->rc_max_rate = bitrate;
       ctx->bit_rate = bitrate;