Add codec property

Add codec property, which stores general encoding parameters,
to MediaTrackConstraints.

examples/simple/main.go

@@ -52,6 +52,7 @@ func main() {
 		Audio: func(c *mediadevices.MediaTrackConstraints) {
 			c.Codec = webrtc.Opus
 			c.Enabled = true
+			c.BitRate = 32000 // 32kbps
 		},
 		Video: func(c *mediadevices.MediaTrackConstraints) {
 			c.Codec = videoCodecName
@@ -59,6 +60,7 @@ func main() {
 			c.Enabled = true
 			c.Width = 640
 			c.Height = 480
+			c.BitRate = 100000 // 100kbps
 		},
 	})
 	if err != nil {

pkg/codec/codec.go

@@ -8,5 +8,5 @@ import (
 	"github.com/pion/mediadevices/pkg/prop"
 )
 
-type VideoEncoderBuilder func(r video.Reader, p prop.Video) (io.ReadCloser, error)
+type VideoEncoderBuilder func(r video.Reader, p prop.Media) (io.ReadCloser, error)
-type AudioEncoderBuilder func(r audio.Reader, p prop.Audio) (io.ReadCloser, error)
+type AudioEncoderBuilder func(r audio.Reader, p prop.Media) (io.ReadCloser, error)

pkg/codec/openh264/openh264.go

@@ -35,7 +35,11 @@ func init() {
 	codec.Register(webrtc.H264, codec.VideoEncoderBuilder(NewEncoder))
 }
 
-func NewEncoder(r video.Reader, p prop.Video) (io.ReadCloser, error) {
+func NewEncoder(r video.Reader, p prop.Media) (io.ReadCloser, error) {
+	if p.BitRate == 0 {
+		p.BitRate = 100000
+	}
+
 	cEncoder, err := C.enc_new(C.EncoderOptions{
 		width:          C.int(p.Width),
 		height:         C.int(p.Height),

pkg/codec/opus/opus.go

@@ -29,7 +29,7 @@ func init() {
 	codec.Register(webrtc.Opus, codec.AudioEncoderBuilder(NewEncoder))
 }
 
-func NewEncoder(r audio.Reader, p prop.Audio) (io.ReadCloser, error) {
+func NewEncoder(r audio.Reader, p prop.Media) (io.ReadCloser, error) {
 	if p.SampleRate == 0 {
 		return nil, fmt.Errorf("opus: inProp.SampleRate is required")
 	}
@@ -38,6 +38,10 @@ func NewEncoder(r audio.Reader, p prop.Audio) (io.ReadCloser, error) {
 		p.Latency = 20
 	}
 
+	if p.BitRate == 0 {
+		p.BitRate = 32000
+	}
+
 	// Select the nearest supported latency
 	var targetLatency float64
 	latencyInMS := float64(p.Latency.Milliseconds())
@@ -59,6 +63,9 @@ func NewEncoder(r audio.Reader, p prop.Audio) (io.ReadCloser, error) {
 	if err != nil {
 		return nil, err
 	}
+	if err := engine.SetBitrate(p.BitRate); err != nil {
+		return nil, err
+	}
 
 	inBuffSize := targetLatency * float64(p.SampleRate) / 1000
 	inBuff := make([][2]float32, int(inBuffSize))

pkg/codec/registrar.go

@@ -23,7 +23,7 @@ func Register(name string, builder interface{}) {
 	}
 }
 
-func BuildVideoEncoder(name string, r video.Reader, p prop.Video) (io.ReadCloser, error) {
+func BuildVideoEncoder(name string, r video.Reader, p prop.Media) (io.ReadCloser, error) {
 	b, ok := videoEncoders[name]
 	if !ok {
 		return nil, fmt.Errorf("codec: can't find %s video encoder", name)
@@ -32,7 +32,7 @@ func BuildVideoEncoder(name string, r video.Reader, p prop.Video) (io.ReadCloser
 	return b(r, p)
 }
 
-func BuildAudioEncoder(name string, r audio.Reader, p prop.Audio) (io.ReadCloser, error) {
+func BuildAudioEncoder(name string, r audio.Reader, p prop.Media) (io.ReadCloser, error) {
 	b, ok := audioEncoders[name]
 	if !ok {
 		return nil, fmt.Errorf("codec: can't find %s audio encoder", name)

pkg/codec/vpx/vpx.go

@@ -63,16 +63,24 @@ func init() {
 }
 
 // NewVP8Encoder creates new VP8 encoder
-func NewVP8Encoder(r video.Reader, p prop.Video) (io.ReadCloser, error) {
+func NewVP8Encoder(r video.Reader, p prop.Media) (io.ReadCloser, error) {
 	return newEncoder(r, p, C.ifaceVP8())
 }
 
 // NewVP9Encoder creates new VP9 encoder
-func NewVP9Encoder(r video.Reader, p prop.Video) (io.ReadCloser, error) {
+func NewVP9Encoder(r video.Reader, p prop.Media) (io.ReadCloser, error) {
 	return newEncoder(r, p, C.ifaceVP9())
 }
 
-func newEncoder(r video.Reader, p prop.Video, codecIface *C.vpx_codec_iface_t) (io.ReadCloser, error) {
+func newEncoder(r video.Reader, p prop.Media, codecIface *C.vpx_codec_iface_t) (io.ReadCloser, error) {
+	if p.BitRate == 0 {
+		p.BitRate = 100000
+	}
+
+	if p.KeyFrameInterval == 0 {
+		p.KeyFrameInterval = 60
+	}
+
 	cfg := &C.vpx_codec_enc_cfg_t{}
 	if ec := C.vpx_codec_enc_config_default(codecIface, cfg, 0); ec != 0 {
 		return nil, fmt.Errorf("vpx_codec_enc_config_default failed (%d)", ec)
@@ -101,7 +109,7 @@ func newEncoder(r video.Reader, p prop.Video, codecIface *C.vpx_codec_iface_t) (
 		r:                video.ToI420(r),
 		codec:            codec,
 		raw:              rawNoBuffer,
-		keyframeInterval: 30, // TODO: Set via prop.Video
+		keyframeInterval: p.KeyFrameInterval,
 	}, nil
 }
 

pkg/prop/prop.go

@@ -12,6 +12,7 @@ import (
 type Media struct {
 	Video
 	Audio
+	Codec
 }
 
 func (p *Media) FitnessDistance(o Media) float64 {
@@ -62,7 +63,6 @@ type Video struct {
 	Width, Height int
 	FrameRate     float32
 	FrameFormat   frame.Format
-	BitRate       int
 }
 
 // Audio represents an audio's properties
@@ -72,3 +72,17 @@ type Audio struct {
 	SampleRate   int
 	SampleSize   int
 }
+
+// Codec represents an codec's encoding properties
+type Codec struct {
+	// Target bitrate in bps.
+	BitRate int
+
+	// Quolity of the encoding [0-9].
+	// Larger value results higher quality and higher CPU usage.
+	// It depends on the selected codec.
+	Quality int
+
+	// Expected interval of the keyframes in frames.
+	KeyFrameInterval int
+}

track.go

@@ -99,9 +99,7 @@ func newVideoTrack(codecs []*webrtc.RTPCodec, d driver.Driver, constraints Media
 		return nil, err
 	}
 
-	// TODO: Remove hardcoded bitrate
+	encoder, err := codec.BuildVideoEncoder(codecName, r, constraints.Media)
-	constraints.BitRate = 100000
-	encoder, err := codec.BuildVideoEncoder(codecName, r, constraints.Video)
 	if err != nil {
 		return nil, err
 	}
@@ -172,7 +170,7 @@ func newAudioTrack(codecs []*webrtc.RTPCodec, d driver.Driver, constraints Media
 		return nil, err
 	}
 
-	encoder, err := codec.BuildAudioEncoder(codecName, reader, constraints.Audio)
+	encoder, err := codec.BuildAudioEncoder(codecName, reader, constraints.Media)
 	if err != nil {
 		return nil, err
 	}