Code refactoring for ffmpeg device and virtual

internal/ffmpeg/virtual/virtual.go

@@ -4,56 +4,59 @@ import (
 	"net/url"
 )
 
-func GetInput(src string) (string, error) {
+func GetInput(src string) string {
 	query, err := url.ParseQuery(src)
 	if err != nil {
-		return "", err
+		return ""
 	}
 
-	// set defaults (using Add instead of Set)
-	query.Add("video", "testsrc")
-	query.Add("size", "1920x1080")
-	query.Add("decimals", "2")
+	input := "-re"
 
-	// https://ffmpeg.org/ffmpeg-filters.html
-	video := query.Get("video")
-	input := "-re -f lavfi -i " + video
+	for _, video := range query["video"] {
+		// https://ffmpeg.org/ffmpeg-filters.html
+		sep := "=" // first separator
 
-	sep := "=" // first separator
-	for key, values := range query {
-		value := values[0]
-
-		// https://ffmpeg.org/ffmpeg-utils.html#video-size-syntax
-		switch key {
-		case "color", "rate", "duration", "sar":
-		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/
-			}
-		case "decimals":
-			if video != "testsrc" {
-				continue
-			}
-		default:
-			continue
+		if video == "" {
+			video = "testsrc=decimals=2" // default video
+			sep = ":"
 		}
 
-		input += sep + key + "=" + value
-		sep = ":" // next separator
+		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
+		}
 	}
 
-	if s := query.Get("format"); s != "" {
-		input += ",format=" + s
-	}
-
-	return input, nil
+	return input
 }