pass screen frame rate to gstreamer pipeline.

README.md

@@ -29,6 +29,7 @@ This app uses Web RTC to stream a desktop inside of a docker container. This is
 - Stereo sound (works properly only in Firefox host).
 - Added limited support for some mobile browsers with `playsinline` attribute.
 - Added `VIDEO_BITRATE` and `AUDIO_BITRATE` in kbit/s to control stream quality (in collaboration with @mbattista).
+- Added `MAX_FPS`, where you can specify max WebRTC frame rate. When set to `0`, frame rate won't be capped and you can enjoy your real `60fps` experience. Originally, it was constant at `25fps`.
 
 ### Bugs
 - Fixed minor gst pipeline bug.

server/internal/gst/gst.go

@@ -50,7 +50,7 @@ var pipelinesLock sync.Mutex
 var registry *C.GstRegistry
 
 const (
-	videoSrc = "ximagesrc display-name=%s show-pointer=true use-damage=false ! video/x-raw,framerate=30/1 ! videoconvert ! queue ! "
+	videoSrc = "ximagesrc display-name=%s show-pointer=true use-damage=false ! video/x-raw,framerate=%d/1 ! videoconvert ! queue ! "
 	audioSrc = "pulsesrc device=%s ! audio/x-raw,channels=2 ! audioconvert ! "
 )
 
@@ -61,7 +61,7 @@ func init() {
 
 // CreateRTMPPipeline creates a GStreamer Pipeline
 func CreateRTMPPipeline(pipelineDevice string, pipelineDisplay string, pipelineSrc string, pipelineRTMP string) (*Pipeline, error) {
-	video := fmt.Sprintf(videoSrc, pipelineDisplay)
+	video := fmt.Sprintf(videoSrc, pipelineDisplay, 25)
 	audio := fmt.Sprintf(audioSrc, pipelineDevice)
 
 	var pipelineStr string
@@ -75,7 +75,7 @@ func CreateRTMPPipeline(pipelineDevice string, pipelineDisplay string, pipelineS
 }
 
 // CreateAppPipeline creates a GStreamer Pipeline
-func CreateAppPipeline(codecName string, pipelineDevice string, pipelineSrc string, bitrate uint) (*Pipeline, error) {
+func CreateAppPipeline(codecName string, pipelineDevice string, pipelineSrc string, fps int, bitrate uint) (*Pipeline, error) {
 	pipelineStr := " ! appsink name=appsink"
 
 	switch codecName {
@@ -90,7 +90,7 @@ func CreateAppPipeline(codecName string, pipelineDevice string, pipelineSrc stri
 		if pipelineSrc != "" {
 			pipelineStr = fmt.Sprintf(pipelineSrc+pipelineStr, pipelineDevice)
 		} else {
-			pipelineStr = fmt.Sprintf(videoSrc+"vp8enc target-bitrate=%d cpu-used=-5 threads=4 deadline=1 error-resilient=partitions keyframe-max-dist=30 auto-alt-ref=true"+pipelineStr, pipelineDevice, bitrate*1000)
+			pipelineStr = fmt.Sprintf(videoSrc+"vp8enc target-bitrate=%d cpu-used=-5 threads=4 deadline=1 error-resilient=partitions keyframe-max-dist=30 auto-alt-ref=true"+pipelineStr, pipelineDevice, fps, bitrate*1000)
 		}
 	case "VP9":
 		// https://gstreamer.freedesktop.org/documentation/vpx/vp9enc.html?gi-language=c
@@ -104,7 +104,7 @@ func CreateAppPipeline(codecName string, pipelineDevice string, pipelineSrc stri
 		if pipelineSrc != "" {
 			pipelineStr = fmt.Sprintf(pipelineSrc+pipelineStr, pipelineDevice)
 		} else {
-			pipelineStr = fmt.Sprintf(videoSrc+"vp9enc target-bitrate=%d cpu-used=-5 threads=4 deadline=1 keyframe-max-dist=30 auto-alt-ref=true"+pipelineStr, pipelineDevice, bitrate*1000)
+			pipelineStr = fmt.Sprintf(videoSrc+"vp9enc target-bitrate=%d cpu-used=-5 threads=4 deadline=1 keyframe-max-dist=30 auto-alt-ref=true"+pipelineStr, pipelineDevice, fps, bitrate*1000)
 		}
 	case "H264":
 		if err := CheckPlugins([]string{"ximagesrc"}); err != nil {
@@ -120,7 +120,7 @@ func CreateAppPipeline(codecName string, pipelineDevice string, pipelineSrc stri
 		// gstreamer1.0-plugins-bad
 		// openh264enc multi-thread=4 complexity=high bitrate=3072000 max-bitrate=4096000
 		if err := CheckPlugins([]string{"openh264"}); err == nil {
-			pipelineStr = fmt.Sprintf(videoSrc+"openh264enc multi-thread=4 complexity=high bitrate=%d max-bitrate=%d ! video/x-h264,stream-format=byte-stream"+pipelineStr, pipelineDevice, bitrate*1000, (bitrate+1024)*1000)
+			pipelineStr = fmt.Sprintf(videoSrc+"openh264enc multi-thread=4 complexity=high bitrate=%d max-bitrate=%d ! video/x-h264,stream-format=byte-stream"+pipelineStr, pipelineDevice, fps, bitrate*1000, (bitrate+1024)*1000)
 			break
 		}
 
@@ -131,7 +131,7 @@ func CreateAppPipeline(codecName string, pipelineDevice string, pipelineSrc stri
 			return nil, err
 		}
 
-		pipelineStr = fmt.Sprintf(videoSrc+"video/x-raw,format=I420 ! x264enc threads=4 bitrate=%d byte-stream=true tune=zerolatency speed-preset=veryfast ! video/x-h264,stream-format=byte-stream"+pipelineStr, pipelineDevice, bitrate)
+		pipelineStr = fmt.Sprintf(videoSrc+"video/x-raw,format=I420 ! x264enc threads=4 bitrate=%d byte-stream=true tune=zerolatency speed-preset=veryfast ! video/x-h264,stream-format=byte-stream"+pipelineStr, pipelineDevice, fps, bitrate)
 	case "Opus":
 		// https://gstreamer.freedesktop.org/documentation/opus/opusenc.html
 		// gstreamer1.0-plugins-base

server/internal/remote/manager.go

@@ -130,11 +130,18 @@ func (manager *RemoteManager) Streaming() bool {
 }
 
 func (manager *RemoteManager) createPipelines() {
+	// handle maximum fps
+	rate := manager.config.ScreenRate
+	if manager.config.MaxFPS != 0 && manager.config.MaxFPS < manager.config.ScreenRate {
+		rate = manager.config.MaxFPS
+	}
+
 	var err error
 	manager.video, err = gst.CreateAppPipeline(
 		manager.config.VideoCodec,
 		manager.config.Display,
 		manager.config.VideoParams,
+		rate,
 		manager.config.VideoBitrate,
 	)
 	if err != nil {
@@ -145,6 +152,7 @@ func (manager *RemoteManager) createPipelines() {
 		manager.config.AudioCodec,
 		manager.config.Device,
 		manager.config.AudioParams,
+		0, // fps: n/a for audio
 		manager.config.AudioBitrate,
 	)
 	if err != nil {
@@ -171,11 +179,17 @@ func (manager *RemoteManager) ChangeResolution(width int, height int, rate int)
 		return err
 	}
 
+	// handle maximum fps
+	if manager.config.MaxFPS != 0 && manager.config.MaxFPS < rate {
+		rate = manager.config.MaxFPS
+	}
+
 	var err error
 	manager.video, err = gst.CreateAppPipeline(
 		manager.config.VideoCodec,
 		manager.config.Display,
 		manager.config.VideoParams,
+		rate,
 		manager.config.VideoBitrate,
 	)
 	if err != nil {

server/internal/types/config/remote.go

@@ -20,6 +20,7 @@ type Remote struct {
 	ScreenWidth  int
 	ScreenHeight int
 	ScreenRate   int
+	MaxFPS       int
 }
 
 func (Remote) Init(cmd *cobra.Command) error {
@@ -58,6 +59,11 @@ func (Remote) Init(cmd *cobra.Command) error {
 		return err
 	}
 
+	cmd.PersistentFlags().Int("max_fps", 25, "maximum fps delivered via WebRTC, 0 is for no maximum")
+	if err := viper.BindPFlag("max_fps", cmd.PersistentFlags().Lookup("max_fps")); err != nil {
+		return err
+	}
+
 	// video codecs
 	cmd.PersistentFlags().Bool("vp8", false, "use VP8 video codec")
 	if err := viper.BindPFlag("vp8", cmd.PersistentFlags().Lookup("vp8")); err != nil {
@@ -146,4 +152,6 @@ func (s *Remote) Set() {
 			s.ScreenRate = int(rate)
 		}
 	}
+
+	s.MaxFPS = viper.GetInt("max_fps")
 }