dynamically change bitrate

src/dll.cpp

@@ -127,6 +127,9 @@ RaiseEvent(VideoPipeline *pipeline,
 	case POINTER_VISIBLE: // IDR FRAME
 		pipeline->mail->event<bool>(mail::toggle_cursor)->raise(value != 0);
 		break;
+	case CHANGE_BITRATE: // IDR FRAME
+		pipeline->mail->event<int>(mail::bitrate)->raise(value);
+		break;
 	default:
 		break;
 	}

src/main.h

@@ -43,6 +43,7 @@ namespace mail {
   MAIL(switch_display);
   MAIL(toggle_cursor);
   MAIL(idr);
+  MAIL(bitrate);
   MAIL(hdr);
   MAIL(invalidate_ref_frames);
 

src/nvenc/nvenc_base.cpp

@@ -111,7 +111,7 @@ namespace nvenc {
       return false;
     }
 
-    NV_ENC_INITIALIZE_PARAMS init_params = { NV_ENC_INITIALIZE_PARAMS_VER };
+    init_params = { NV_ENC_INITIALIZE_PARAMS_VER };
 
     switch (client_config.videoFormat) {
       case 0:
@@ -406,6 +406,18 @@ namespace nvenc {
     encoder_params = {};
   }
 
+
+  void
+  nvenc_base::update_bitrate(int bitrate) {
+    NV_ENC_RECONFIGURE_PARAMS reconfigure_params = { NV_ENC_RECONFIGURE_PARAMS_VER };
+    /* reset rate control state and start from IDR */
+    init_params.encodeConfig->rcParams.averageBitRate = bitrate;
+    reconfigure_params.reInitEncodeParams = init_params;
+    reconfigure_params.resetEncoder = TRUE;
+    reconfigure_params.forceIDR = TRUE;
+    nvenc->nvEncReconfigureEncoder(encoder, &reconfigure_params);
+  }
+
   nvenc_encoded_frame
   nvenc_base::encode_frame(uint64_t frame_index, bool force_idr) {
     if (!encoder) {

src/nvenc/nvenc_base.h

@@ -25,6 +25,9 @@ namespace nvenc {
     void
     destroy_encoder();
 
+    void
+    update_bitrate(int bitrate);
+
     nvenc_encoded_frame
     encode_frame(uint64_t frame_index, bool force_idr);
 
@@ -50,6 +53,7 @@ namespace nvenc {
     std::unique_ptr<NV_ENCODE_API_FUNCTION_LIST> nvenc;
 
     void *encoder = nullptr;
+    NV_ENC_INITIALIZE_PARAMS init_params;
 
     struct {
       uint32_t width = 0;

src/video.cpp

@@ -392,6 +392,9 @@ namespace video {
     virtual void
     request_idr_frame() = 0;
 
+    virtual void
+    update_bitrate (int bitrate) = 0;
+
     virtual void
     request_normal_frame() = 0;
 
@@ -441,6 +444,13 @@ namespace video {
       }
     }
 
+    void
+    update_bitrate(int bitrate) override {
+      // bitrate = bitrate * 1000;
+      // avcodec_ctx->rc_max_rate = bitrate;
+      // avcodec_ctx->bit_rate = bitrate;
+    }
+
     void
     request_normal_frame() override {
       if (device && device->frame) {
@@ -490,6 +500,14 @@ namespace video {
       force_idr = false;
     }
 
+    void
+    update_bitrate(int bitrate) override {
+      if (!device || !device->nvenc) return;
+
+      device->nvenc->update_bitrate(bitrate);
+    }
+
+
     void
     invalidate_ref_frames(int64_t first_frame, int64_t last_frame) override {
       if (!device || !device->nvenc) return;
@@ -518,6 +536,7 @@ namespace video {
     safe::mail_raw_t::event_t<bool> shutdown_event;
     safe::mail_raw_t::queue_t<packet_t> packets;
     safe::mail_raw_t::event_t<bool> idr_events;
+    safe::mail_raw_t::event_t<int> bitrate_events;
     safe::mail_raw_t::event_t<std::string> switch_display;
     safe::mail_raw_t::event_t<bool> toggle_cursor;
     safe::mail_raw_t::event_t<hdr_info_t> hdr_events;
@@ -1763,6 +1782,7 @@ namespace video {
 
     auto packets         = mail->queue<packet_t>(mail::video_packets);
     auto idr_events      = mail->event<bool>(mail::idr);
+    auto bitrate_events  = mail->event<int>(mail::bitrate);
     auto invalidate_ref_frames_events = mail->event<std::pair<int64_t, int64_t>>(mail::invalidate_ref_frames);
 
     {
@@ -1797,7 +1817,14 @@ namespace video {
         idr_events->pop();
       }
 
+      if (bitrate_events->peek()) {
+        auto bitrate = bitrate_events->pop().value();
+        BOOST_LOG(info) << "bitrate changed"sv;
+        session->update_bitrate(bitrate);
+      }
+
       if (requested_idr_frame) {
+        BOOST_LOG(info) << "IDR frame generated"sv;
         session->request_idr_frame();
       }
 
@@ -1982,6 +2009,11 @@ namespace video {
               BOOST_LOG(info) << "cursor set to " << display_cursor;
           }
 
+          if (ctx->bitrate_events->peek()) {
+            auto bitrate = ctx->bitrate_events->pop().value();
+            BOOST_LOG(info) << "bitrate changed"sv;
+            pos->session->update_bitrate(bitrate);
+          }
           if (ctx->idr_events->peek()) {
             BOOST_LOG(info) << "IDR frame generated"sv;
             pos->session->request_idr_frame();
@@ -2160,6 +2192,7 @@ namespace video {
     // CAREFULL
     auto ptr_events = mail->event<bool>(mail::toggle_cursor);
     auto idr_events = mail->event<bool>(mail::idr);
+    auto bitrate_events = mail->event<int>(mail::bitrate);
     auto display_events = mail->event<std::string>(mail::switch_display);
     auto shutdown_event = mail->event<bool>(mail::shutdown);
     auto packets    = mail->queue<packet_t>(mail::video_packets);
@@ -2180,6 +2213,7 @@ namespace video {
         std::move(shutdown_event),
         std::move(packets),
         std::move(idr_events),
+        std::move(bitrate_events),
         std::move(display_events),
         std::move(ptr_events),
         mail->event<hdr_info_t>(mail::hdr),