Move ffmpeg device to separate module

cmd/ffmpeg/device/device_linux.go

@@ -0,0 +1,50 @@
+package device
+
+import (
+	"bytes"
+	"github.com/AlexxIT/go2rtc/pkg/streamer"
+	"io/ioutil"
+	"os/exec"
+	"strings"
+)
+
+// https://trac.ffmpeg.org/wiki/Capture/Webcam
+const deviceInputPrefix = "-f v4l2"
+
+func deviceInputSuffix(videoIdx, audioIdx int) string {
+	video := findMedia(streamer.KindVideo, videoIdx)
+	return video.Title
+}
+
+func loadMedias() {
+	files, err := ioutil.ReadDir("/dev")
+	if err != nil {
+		return
+	}
+	for _, file := range files {
+		log.Trace().Msg("[ffmpeg] " + file.Name())
+		if strings.HasPrefix(file.Name(), streamer.KindVideo) {
+			media := loadMedia(streamer.KindVideo, "/dev/"+file.Name())
+			if media != nil {
+				medias = append(medias, media)
+			}
+		}
+	}
+}
+
+func loadMedia(kind, name string) *streamer.Media {
+	cmd := exec.Command(
+		Bin, "-hide_banner", "-f", "v4l2", "-list_formats", "all", "-i", name,
+	)
+	var buf bytes.Buffer
+	cmd.Stderr = &buf
+	_ = cmd.Run()
+
+	if !bytes.Contains(buf.Bytes(), []byte("Raw")) {
+		return nil
+	}
+
+	return &streamer.Media{
+		Kind: kind, Title: name,
+	}
+}