install go2rtc on bob

installs_on_host/go2rtc/internal/ffmpeg/virtual/virtual.go

@@ -0,0 +1,79 @@
+package virtual
+
+import (
+	"net/url"
+)
+
+func GetInput(src string) string {
+	query, err := url.ParseQuery(src)
+	if err != nil {
+		return ""
+	}
+
+	input := "-re"
+
+	for _, video := range query["video"] {
+		// https://ffmpeg.org/ffmpeg-filters.html
+		sep := "=" // first separator
+
+		if video == "" {
+			video = "testsrc=decimals=2" // default video
+			sep = ":"
+		}
+
+		input += " -f lavfi -i " + video
+
+		// set defaults (using Add instead of Set)
+		query.Add("size", "1920x1080")
+
+		for key, values := range query {
+			value := values[0]
+
+			// https://ffmpeg.org/ffmpeg-utils.html#video-size-syntax
+			switch key {
+			case "color", "rate", "duration", "sar", "decimals":
+			case "size":
+				switch value {
+				case "720":
+					value = "1280x720" // crf=1 -> 12 Mbps
+				case "1080":
+					value = "1920x1080" // crf=1 -> 25 Mbps
+				case "2K":
+					value = "2560x1440" // crf=1 -> 43 Mbps
+				case "4K":
+					value = "3840x2160" // crf=1 -> 103 Mbps
+				case "8K":
+					value = "7680x4230" // https://reolink.com/blog/8k-resolution/
+				}
+			default:
+				continue
+			}
+
+			input += sep + key + "=" + value
+			sep = ":" // next separator
+		}
+
+		if s := query.Get("format"); s != "" {
+			input += ",format=" + s
+		}
+	}
+
+	return input
+}
+
+func GetInputTTS(src string) string {
+	query, err := url.ParseQuery(src)
+	if err != nil {
+		return ""
+	}
+
+	input := `-re -f lavfi -i "flite=text='` + query.Get("text") + `'`
+
+	// ffmpeg -f lavfi -i flite=list_voices=1
+	// awb, kal, kal16, rms, slt
+	if voice := query.Get("voice"); voice != "" {
+		input += ":voice" + voice
+	}
+
+	return input + `"`
+}