Bring back x11 adapter for Linux build only

Original x11 adapter uses ~40% less CPU usage than kbinani/screenshot.
Ideally, we should migrate 100% to kbinani/screenshot. But, the CPU
usage difference is substantial. In the future, we should look deeper
into kbinani/screenshot and try to improve it.

README.md

@@ -85,7 +85,7 @@ func main() {
 | :--------: | :---: | :-: | :-----: |
 |   Camera   |  ✔️   | ✔️  |   ✔️    |
 | Microphone |  ✔️   | ✔️  |   ✔️    |
-|   Screen   |  ✔️   | ✖️  |   ✖️    |
+|   Screen   |  ✔️   | ✔️  |   ✔️    |
 
 By default, there's no media input registered. This decision was made to allow you to pay what you need. Therefore, you need to import the associated packages for the media inputs. For example, if you want to use a camera, you need to import the camera package as a side effect:
 
@@ -144,8 +144,7 @@ A free software library and application for encoding video streams into the H.26
 A framework to enable H264 hardware encoding for Raspberry Pi or boards that use VideoCore GPUs.
 
 * Package: [github.com/pion/mediadevices/pkg/codec/mmal](https://pkg.go.dev/github.com/pion/mediadevices/pkg/codec/mmal)
-* Installation:
-  * Raspbian: `export PKG_CONFIG_PATH=/opt/vc/lib/pkgconfig`
+* Installation: no installation needed, mmal should come built in Raspberry Pi devices
 
 #### openh264
 A codec library which supports H.264 encoding and decoding. It is suitable for use in real time applications.

go.mod

@@ -3,9 +3,13 @@ module github.com/pion/mediadevices
 go 1.13
 
 require (
+	github.com/BurntSushi/xgb v0.0.0-20201008132610-5f9e7b3c49cd // indirect
 	github.com/blackjack/webcam v0.0.0-20200313125108-10ed912a8539
-	github.com/gen2brain/malgo v0.10.24
+	github.com/gen2brain/malgo v0.10.25
+	github.com/gen2brain/shm v0.0.0-20200228170931-49f9650110c5 // indirect
+	github.com/kbinani/screenshot v0.0.0-20191211154542-3a185f1ce18f
 	github.com/lherman-cs/opus v0.0.2
+	github.com/lxn/win v0.0.0-20201111105847-2a20daff6a55 // indirect
 	github.com/pion/logging v0.2.2
 	github.com/pion/rtp v1.6.1
 	github.com/pion/webrtc/v2 v2.2.26

go.sum

@@ -1,3 +1,5 @@
+github.com/BurntSushi/xgb v0.0.0-20201008132610-5f9e7b3c49cd h1:u7K2oMFMd8APDV3fM1j2rO3U/XJf1g1qC3DDTKou8iM=
+github.com/BurntSushi/xgb v0.0.0-20201008132610-5f9e7b3c49cd/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/blackjack/webcam v0.0.0-20200313125108-10ed912a8539 h1:1aIqYfg9s9RETAJHGfVKZW4ok0b22p4QTwk8MsdRtPs=
 github.com/blackjack/webcam v0.0.0-20200313125108-10ed912a8539/go.mod h1:G0X+rEqYPWSq0dG8OMf8M446MtKytzpPjgS3HbdOJZ4=
 github.com/cheekybits/genny v1.0.0 h1:uGGa4nei+j20rOSeDeP5Of12XVm7TGUd4dJA9RDitfE=
@@ -7,8 +9,10 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
-github.com/gen2brain/malgo v0.10.24 h1:q9TFP4lRYpK8UbH3XSa/SNnMwMLUZraRyZt2u+qKYxg=
-github.com/gen2brain/malgo v0.10.24/go.mod h1:zHSUNZAXfCeNsZou0RtQ6Zk7gDYLIcKOrUWtAdksnEs=
+github.com/gen2brain/malgo v0.10.25 h1:VRiYTBmBeHTCXD0wCg7XyLi6lJJBqND/XVmSEyrGkGc=
+github.com/gen2brain/malgo v0.10.25/go.mod h1:zHSUNZAXfCeNsZou0RtQ6Zk7gDYLIcKOrUWtAdksnEs=
+github.com/gen2brain/shm v0.0.0-20200228170931-49f9650110c5 h1:Y5Q2mEwfzjMt5+3u70Gtw93ZOu2UuPeeeTBDntF7FoY=
+github.com/gen2brain/shm v0.0.0-20200228170931-49f9650110c5/go.mod h1:uF6rMu/1nvu+5DpiRLwusA6xB8zlkNoGzKn8lmYONUo=
 github.com/golang/mock v1.2.0 h1:28o5sBqPkBsMGnC6b4MvE2TzSr5/AT4c/1fLqVGIwlk=
 github.com/golang/mock v1.2.0/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
@@ -17,6 +21,8 @@ github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
+github.com/kbinani/screenshot v0.0.0-20191211154542-3a185f1ce18f h1:5hWo+DzJQSOBl6X+TDac0SPWffRonuRJ2///OYtYRT8=
+github.com/kbinani/screenshot v0.0.0-20191211154542-3a185f1ce18f/go.mod h1:f8GY5V3lRzakvEyr49P7hHRYoHtPr8zvj/7JodCoRzw=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
@@ -26,6 +32,8 @@ github.com/lherman-cs/opus v0.0.2 h1:fE9Du3NKXDBztqvoTd6P2y9eJ9vgIHahGK8yQostnhA
 github.com/lherman-cs/opus v0.0.2/go.mod h1:v9KQvlDYMuvlwniumBVMlrB0VHQvyTgxNvaXjPmTmps=
 github.com/lucas-clemente/quic-go v0.7.1-0.20190401152353-907071221cf9 h1:tbuodUh2vuhOVZAdW3NEUvosFHUMJwUNl7jk/VSEiwc=
 github.com/lucas-clemente/quic-go v0.7.1-0.20190401152353-907071221cf9/go.mod h1:PpMmPfPKO9nKJ/psF49ESTAGQSdfXxlg1otPbEB2nOw=
+github.com/lxn/win v0.0.0-20201111105847-2a20daff6a55 h1:4BxFx5XCtXc+nFtXDGDW+Uu5sPtsAbvPh6RObj3fG9o=
+github.com/lxn/win v0.0.0-20201111105847-2a20daff6a55/go.mod h1:KxxjdtRkfNoYDCUP5ryK7XJJNTnpC8atvtmTheChOtk=
 github.com/marten-seemann/qtls v0.2.3 h1:0yWJ43C62LsZt08vuQJDK1uC1czUc3FJeCLPoNAI4vA=
 github.com/marten-seemann/qtls v0.2.3/go.mod h1:xzjG7avBwGGbdZ8dTGxlBnLArsVKLvwmjgmPuiQEcYk=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
@@ -111,6 +119,7 @@ golang.org/x/sys v0.0.0-20190228124157-a34e9553db1e/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201018230417-eeed37f84f13/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201029080932-201ba4db2418 h1:HlFl4V6pEMziuLXyRkm5BIYq1y1GAbb02pRlWvI54OM=
 golang.org/x/sys v0.0.0-20201029080932-201ba4db2418/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=

pkg/codec/mmal/mmal.go

@@ -3,7 +3,8 @@
 // Reference: https://github.com/raspberrypi/userland/tree/master/interface/mmal
 package mmal
 
-// #cgo pkg-config: mmal
+// #cgo CFLAGS: -I/opt/vc/include
+// #cgo LDFLAGS: -L/opt/vc/lib -lmmal -lmmal_core -lmmal_util -lmmal_vc_client -lbcm_host -lvcsm -lvcos
 // #include "bridge.h"
 import "C"
 import (

pkg/driver/camera/camera_linux.go

@@ -21,6 +21,7 @@ import (
 
 const (
 	maxEmptyFrameCount = 5
+	prioritizedDevice  = "video0"
 )
 
 var (
@@ -94,9 +95,14 @@ func init() {
 
 			discovered[reallink] = struct{}{}
 			cam := newCamera(device)
+			priority := driver.PriorityNormal
+			if label == prioritizedDevice {
+				priority = driver.PriorityHigh
+			}
 			driver.GetManager().Register(cam, driver.Info{
 				Label:      label,
 				DeviceType: driver.Camera,
+				Priority:   priority,
 			})
 		}
 	}

pkg/driver/microphone/microphone.go

@@ -37,12 +37,6 @@ type microphone struct {
 
 func init() {
 	var err error
-	/*
-		backends := []malgo.Backend{
-			malgo.BackendPulseaudio,
-			malgo.BackendAlsa,
-		}
-	*/
 	ctx, err = malgo.InitContext(nil, malgo.ContextConfig{}, func(message string) {
 		logger.Debugf("%v\n", message)
 	})
@@ -56,11 +50,18 @@ func init() {
 	}
 
 	for _, device := range devices {
-		// TODO: Detect default device and prioritize it
-		driver.GetManager().Register(newMicrophone(device), driver.Info{
-			Label:      device.ID.String(),
-			DeviceType: driver.Microphone,
-		})
+		info, err := ctx.DeviceInfo(malgo.Capture, device.ID, malgo.Shared)
+		if err == nil {
+			priority := driver.PriorityNormal
+			if info.IsDefault > 0 {
+				priority = driver.PriorityHigh
+			}
+			driver.GetManager().Register(newMicrophone(info), driver.Info{
+				Label:      device.ID.String(),
+				DeviceType: driver.Microphone,
+				Priority:   priority,
+			})
+		}
 	}
 
 	// Decide which endian
@@ -133,7 +134,7 @@ func (m *microphone) AudioRecord(inputProp prop.Media) (audio.Reader, error) {
 		return nil, err
 	}
 
-	return audio.ReaderFunc(func() (wave.Audio, func(), error) {
+	var reader audio.Reader = audio.ReaderFunc(func() (wave.Audio, func(), error) {
 		chunk, ok := <-m.chunkChan
 		if !ok {
 			device.Stop()
@@ -145,7 +146,12 @@ func (m *microphone) AudioRecord(inputProp prop.Media) (audio.Reader, error) {
 		// FIXME: the decoder should also fill this information
 		decodedChunk.(*wave.Float32Interleaved).Size.SamplingRate = inputProp.SampleRate
 		return decodedChunk, func() {}, err
-	}), nil
+	})
+
+	// FIXME: The current audio detection and audio encoder can only work with a static latency. Since the latency from the driver
+	//        can fluctuate, we need to stabilize it. Maybe there's a better way for doing this?
+	reader = audio.NewBuffer(int(inputProp.Latency.Seconds() * float64(inputProp.SampleRate)))(reader)
+	return reader, nil
 }
 
 func (m *microphone) Properties() []prop.Media {
@@ -159,46 +165,36 @@ func (m *microphone) Properties() []prop.Media {
 	}
 
 	for ch := m.MinChannels; ch <= m.MaxChannels; ch++ {
-		for sampleRate := m.MinSampleRate; sampleRate <= m.MaxSampleRate; sampleRate += sampleRateStep {
-			for i := 0; i < int(m.FormatCount); i++ {
-				format := m.Formats[i]
+		// FIXME: Currently support 48kHz only. We need to implement a resampler first.
+		// for sampleRate := m.MinSampleRate; sampleRate <= m.MaxSampleRate; sampleRate += sampleRateStep {
+		sampleRate := 48000
+		for i := 0; i < int(m.FormatCount); i++ {
+			format := m.Formats[i]
 
-				supportedProp := prop.Media{
-					Audio: prop.Audio{
-						ChannelCount: int(ch),
-						SampleRate:   int(sampleRate),
-						IsBigEndian:  isBigEndian,
-						// miniaudio only supports interleaved at the moment
-						IsInterleaved: true,
-					},
-				}
-
-				switch malgo.FormatType(format) {
-				case malgo.FormatF32:
-					supportedProp.SampleSize = 4
-					supportedProp.IsFloat = true
-				case malgo.FormatS16:
-					supportedProp.SampleSize = 2
-					supportedProp.IsFloat = false
-				}
-
-				supportedProps = append(supportedProps, supportedProp)
+			supportedProp := prop.Media{
+				Audio: prop.Audio{
+					ChannelCount: int(ch),
+					SampleRate:   int(sampleRate),
+					IsBigEndian:  isBigEndian,
+					// miniaudio only supports interleaved at the moment
+					IsInterleaved: true,
+					// FIXME: should change this to a less discrete value
+					Latency: time.Millisecond * 20,
+				},
 			}
-		}
-	}
 
-	// FIXME: remove this hardcoded value. Malgo doesn't support "ma_context_get_device_info" API yet. The above iterations
-	//        will always return nothing as of now
-	supportedProps = append(supportedProps, prop.Media{
-		Audio: prop.Audio{
-			Latency:       time.Millisecond * 20,
-			ChannelCount:  1,
-			SampleRate:    48000,
-			SampleSize:    4,
-			IsFloat:       true,
-			IsBigEndian:   isBigEndian,
-			IsInterleaved: true,
-		},
-	})
+			switch malgo.FormatType(format) {
+			case malgo.FormatF32:
+				supportedProp.SampleSize = 4
+				supportedProp.IsFloat = true
+			case malgo.FormatS16:
+				supportedProp.SampleSize = 2
+				supportedProp.IsFloat = false
+			}
+
+			supportedProps = append(supportedProps, supportedProp)
+		}
+		// }
+	}
 	return supportedProps
 }

pkg/driver/screen/screen.go

@@ -1 +1,81 @@
+// +build !linux
+
 package screen
+
+import (
+	"fmt"
+	"image"
+	"io"
+
+	"github.com/kbinani/screenshot"
+	"github.com/pion/mediadevices/pkg/driver"
+	"github.com/pion/mediadevices/pkg/frame"
+	"github.com/pion/mediadevices/pkg/io/video"
+	"github.com/pion/mediadevices/pkg/prop"
+)
+
+type screen struct {
+	displayIndex int
+	doneCh       chan struct{}
+}
+
+func init() {
+	activeDisplays := screenshot.NumActiveDisplays()
+	for i := 0; i < activeDisplays; i++ {
+		priority := driver.PriorityNormal
+		if i == 0 {
+			priority = driver.PriorityHigh
+		}
+
+		s := newScreen(i)
+		driver.GetManager().Register(s, driver.Info{
+			Label:      fmt.Sprint(i),
+			DeviceType: driver.Screen,
+			Priority:   priority,
+		})
+	}
+}
+
+func newScreen(displayIndex int) *screen {
+	s := screen{
+		displayIndex: displayIndex,
+	}
+	return &s
+}
+
+func (s *screen) Open() error {
+	s.doneCh = make(chan struct{})
+	return nil
+}
+
+func (s *screen) Close() error {
+	close(s.doneCh)
+	return nil
+}
+
+func (s *screen) VideoRecord(selectedProp prop.Media) (video.Reader, error) {
+	r := video.ReaderFunc(func() (img image.Image, release func(), err error) {
+		select {
+		case <-s.doneCh:
+			return nil, nil, io.EOF
+		default:
+		}
+
+		img, err = screenshot.CaptureDisplay(s.displayIndex)
+		release = func() {}
+		return
+	})
+	return r, nil
+}
+
+func (s *screen) Properties() []prop.Media {
+	resolution := screenshot.GetDisplayBounds(s.displayIndex)
+	supportedProp := prop.Media{
+		Video: prop.Video{
+			Width:       resolution.Dx(),
+			Height:      resolution.Dy(),
+			FrameFormat: frame.FormatRGBA,
+		},
+	}
+	return []prop.Media{supportedProp}
+}

track.go

@@ -379,9 +379,6 @@ func newAudioTrackFromDriver(d driver.Driver, recorder driver.AudioRecorder, con
 		return nil, err
 	}
 
-	// FIXME: The current audio detection and audio encoder can only work with a static latency. Since the latency from the driver
-	//        can fluctuate, we need to stabilize it. Maybe there's a better way for doing this?
-	reader = audio.NewBuffer(int(constraints.selectedMedia.Latency.Seconds() * float64(constraints.selectedMedia.SampleRate)))(reader)
 	return newAudioTrackFromReader(d, reader, selector), nil
 }