diff --git a/internal/ffmpeg/device/devices.go b/internal/ffmpeg/device/devices.go
index a51abd64..69b13444 100644
--- a/internal/ffmpeg/device/devices.go
+++ b/internal/ffmpeg/device/devices.go
@@ -1,11 +1,9 @@
 package device
 
 import (
-	"errors"
 	"net/http"
 	"net/url"
 	"strconv"
-	"strings"
 	"sync"
 
 	"github.com/AlexxIT/go2rtc/internal/api"
@@ -17,24 +15,15 @@ func Init(bin string) {
 	api.HandleFunc("api/ffmpeg/devices", apiDevices)
 }
 
-func GetInput(src string) (string, error) {
-	i := strings.IndexByte(src, '?')
-	if i < 0 {
-		return "", errors.New("empty query: " + src)
-	}
-
-	query, err := url.ParseQuery(src[i+1:])
+func GetInput(src string) string {
+	query, err := url.ParseQuery(src)
 	if err != nil {
-		return "", err
+		return ""
 	}
 
 	runonce.Do(initDevices)
 
-	if input := queryToInput(query); input != "" {
-		return input, nil
-	}
-
-	return "", errors.New("wrong query: " + src)
+	return queryToInput(query)
 }
 
 var Bin string
diff --git a/internal/ffmpeg/ffmpeg.go b/internal/ffmpeg/ffmpeg.go
index 63b4a39d..c5587e3c 100644
--- a/internal/ffmpeg/ffmpeg.go
+++ b/internal/ffmpeg/ffmpeg.go
@@ -189,21 +189,21 @@ func parseArgs(s string) *ffmpeg.Args {
 			s += "?video&audio"
 		}
 		args.Input = inputTemplate("rtsp", s, query)
-	} else if strings.HasPrefix(s, "device?") {
-		var err error
-		args.Input, err = device.GetInput(s)
-		if err != nil {
-			return nil
-		}
-	} else if strings.HasPrefix(s, "virtual?") {
-		var err error
-		if args.Input, err = virtual.GetInput(s[8:]); err != nil {
-			return nil
+	} else if i = strings.Index(s, "?"); i > 0 {
+		switch s[:i] {
+		case "device":
+			args.Input = device.GetInput(s[i+1:])
+		case "virtual":
+			args.Input = virtual.GetInput(s[i+1:])
 		}
 	} else {
 		args.Input = inputTemplate("file", s, query)
 	}
 
+	if args.Input == "" {
+		return nil
+	}
+
 	if query["async"] != nil {
 		args.Input = "-use_wallclock_as_timestamps 1 -async 1 " + args.Input
 	}
diff --git a/internal/ffmpeg/virtual/virtual.go b/internal/ffmpeg/virtual/virtual.go
index 2e1dd9bd..f738c41f 100644
--- a/internal/ffmpeg/virtual/virtual.go
+++ b/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
 }