diff --git a/mobile/mobile.go b/mobile/mobile.go
index f37750c..d4aa958 100644
--- a/mobile/mobile.go
+++ b/mobile/mobile.go
@@ -47,6 +47,7 @@ const (
 	dataTransport    = "datachannel"
 	defaultDNSServer = "1.1.1.1:53"
 	carrierWBStream  = "wbstream"
+	carrierJazz      = "jazz"
 )
 
 //nolint:gochecknoglobals // Mobile bindings expose a singleton runtime controlled by the embedding app.
@@ -124,8 +125,8 @@ func SetVP8Options(fps, batchSize int) {
 	mu.Lock()
 	defer mu.Unlock()
 	ensureDefaultConfigLocked()
-	defaults.vp8FPS = clamp(fps, 1, 120)
-	defaults.vp8BatchSize = clamp(batchSize, 1, 64)
+	defaults.vp8FPS = clamp(fps, 120)
+	defaults.vp8BatchSize = clamp(batchSize, 64)
 }
 
 // SetDebug enables or disables verbose logging.
@@ -182,16 +183,8 @@ func Check(
 	registerDefaults()
 	carrierName = normalizeCarrier(carrierName)
 	transportName = normalizeTransport(transportName)
-
-	switch {
-	case carrierName == "":
-		return 0, errCarrierRequired
-	case roomID == "" && carrierName != "jazz":
-		return 0, errRoomIDRequired
-	case clientID == "":
-		return 0, errClientIDRequired
-	case keyHex == "":
-		return 0, errKeyHexRequired
+	if err := validateStartArgs(carrierName, roomID, clientID, keyHex); err != nil {
+		return 0, err
 	}
 
 	if timeoutMillis <= 0 {
@@ -234,8 +227,8 @@ func Check(
 			"",
 			0,
 			0,
-			clamp(vp8FPS, 1, 120),
-			clamp(vp8BatchSize, 1, 64),
+			clamp(vp8FPS, 120),
+			clamp(vp8BatchSize, 64),
 		)
 	}()
 
@@ -275,17 +268,11 @@ func startWithConfig(
 		cfg.transport = normalizeTransport(transportName)
 	}
 
-	switch {
-	case cancel != nil:
+	if cancel != nil {
 		return errAlreadyRunning
-	case carrierName == "":
-		return errCarrierRequired
-	case roomID == "" && carrierName != "jazz":
-		return errRoomIDRequired
-	case clientID == "":
-		return errClientIDRequired
-	case keyHex == "":
-		return errKeyHexRequired
+	}
+	if err := validateStartArgs(carrierName, roomID, clientID, keyHex); err != nil {
+		return err
 	}
 
 	roomURL := buildRoomURL(carrierName, roomID)
@@ -461,11 +448,26 @@ func normalizeCarrier(carrierName string) string {
 	return carrierName
 }
 
+func validateStartArgs(carrierName, roomID, clientID, keyHex string) error {
+	switch {
+	case carrierName == "":
+		return errCarrierRequired
+	case roomID == "" && carrierName != carrierJazz:
+		return errRoomIDRequired
+	case clientID == "":
+		return errClientIDRequired
+	case keyHex == "":
+		return errKeyHexRequired
+	default:
+		return nil
+	}
+}
+
 func buildRoomURL(carrierName, roomID string) string {
 	switch carrierName {
 	case "telemost":
 		return "https://telemost.yandex.ru/j/" + roomID
-	case "jazz":
+	case carrierJazz:
 		if roomID == "" {
 			return "any"
 		}
@@ -477,9 +479,9 @@ func buildRoomURL(carrierName, roomID string) string {
 	}
 }
 
-func clamp(value, minValue, maxValue int) int {
-	if value < minValue {
-		return minValue
+func clamp(value, maxValue int) int {
+	if value < 1 {
+		return 1
 	}
 	if value > maxValue {
 		return maxValue