Example using cgo; example device fmt; updating webcam example

examples/format/devfmt.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"flag"
+	"log"
+	"strings"
+
+	"github.com/vladimirvivien/go4vl/v4l2"
+)
+
+func main() {
+	devName := "/dev/video0"
+	width := 640
+	height := 480
+	format := "yuyv"
+
+	flag.StringVar(&devName, "d", devName, "device name (path)")
+	flag.IntVar(&width, "w", width, "capture width")
+	flag.IntVar(&height, "h", height, "capture height")
+	flag.StringVar(&format, "f", format, "pixel format")
+	flag.Parse()
+
+	device, err := v4l2.Open(devName)
+	if err != nil {
+		log.Fatalf("failed to open device: %s", err)
+	}
+	defer device.Close()
+
+	currFmt, err := device.GetPixFormat()
+	if err != nil {
+		log.Fatalf("unable to get format: %s", err)
+	}
+	log.Printf("Current format: %s", currFmt)
+
+	fmtEnc := v4l2.PixelFmtYUYV
+	switch strings.ToLower(format) {
+	case "mjpeg":
+		fmtEnc = v4l2.PixelFmtMJPEG
+	case "h264", "h.264":
+		fmtEnc = v4l2.PixelFmtH264
+	case "yuyv":
+		fmtEnc = v4l2.PixelFmtYUYV
+	}
+
+	if err := device.SetPixFormat(v4l2.PixFormat{
+		Width: uint32(width),
+		Height: uint32(height),
+		PixelFormat: fmtEnc,
+		Field: v4l2.FieldNone,
+	}); err != nil {
+		log.Fatalf("failed to set format: %s", err)
+	}
+
+	currFmt, err = device.GetPixFormat()
+	if err != nil {
+		log.Fatalf("unable to get format: %s", err)
+	}
+	log.Printf("Updated format: %s", currFmt)
+}