revid: added input flag for webcam input and added func to handle webcam input using ffmpeg

cmd/revid-cli/main.go

@@ -95,7 +95,7 @@ func handleFlags() revid.Config {
 	var (
 		cpuprofile = flag.String("cpuprofile", "", "write cpu profile to `file`")
 
-		inputPtr              = flag.String("Input", "", "The input type: Raspivid, File")
+		inputPtr              = flag.String("Input", "", "The input type: Raspivid, File, Webcam")
 		inputCodecPtr         = flag.String("InputCodec", "", "The codec of the input: H264, Mjpeg")
 		output1Ptr            = flag.String("Output1", "", "The first output type: Http, Rtmp, File, Udp, Rtp")
 		output2Ptr            = flag.String("Output2", "", "The second output type: Http, Rtmp, File, Udp, Rtp")
@@ -143,6 +143,8 @@ func handleFlags() revid.Config {
 	}
 
 	switch *inputPtr {
+	case "webcam":
+		cfg.Input = revid.Webcam
 	case "Raspivid":
 		cfg.Input = revid.Raspivid
 	case "File":

revid/config.go

@@ -91,6 +91,7 @@ const (
 	Udp
 	MpegtsRtp
 	Rtp
+	Webcam
 )
 
 // Default config settings

revid/revid.go

@@ -259,6 +259,8 @@ func (r *Revid) reset(config Config) error {
 	}
 
 	switch r.config.Input {
+	case Webcam:
+		r.setupInput = r.startWebcam
 	case Raspivid:
 		r.setupInput = r.startRaspivid
 	case File:
@@ -496,6 +498,37 @@ func (r *Revid) startRaspivid() error {
 	return err
 }
 
+func (r *Revid) startWebcam() error {
+	r.config.Logger.Log(smartlogger.Info, pkg+"starting webcam")
+	r.cmd = exec.Command("ffmpeg", []string{
+		"-i", "/dev/video0",
+		"-r", "25",
+		"-f", "h264", "-",
+	}...)
+
+	d, err := strconv.Atoi(r.config.FrameRate)
+	if err != nil {
+		return err
+	}
+
+	delay := time.Second / time.Duration(d)
+	stdout, err := r.cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+
+	err = r.cmd.Start()
+	if err != nil {
+		r.config.Logger.Log(smartlogger.Fatal, pkg+"cannot start webcam", "error", err.Error())
+		return err
+	}
+
+	r.config.Logger.Log(smartlogger.Info, pkg+"reading camera data")
+	err = r.lexTo(r.encoder, stdout, delay)
+	r.config.Logger.Log(smartlogger.Info, pkg+"finished reading camera data")
+	return err
+}
+
 // setupInputForFile sets things up for getting input from a file
 func (r *Revid) setupInputForFile() error {
 	fps, err := strconv.Atoi(r.config.FrameRate)