diff --git a/writer/internal/media/g711.go b/writer/internal/media/g711.go
index 0927e5c..e5472a8 100644
--- a/writer/internal/media/g711.go
+++ b/writer/internal/media/g711.go
@@ -11,7 +11,7 @@ import (
 	"log"
 )
 
-// CheckG711Format finds the H264 media and format.
+// CheckG711Format finds the G711 media and format.
 func CheckG711Format(desc *description.Session) (*format.G711, *description.Media, error) {
 	var g711Format *format.G711
 	g711Media := desc.FindFormat(&g711Format)
diff --git a/writer/internal/procRTSP/client.go b/writer/internal/procRTSP/client.go
index 88158b9..bbe344d 100644
--- a/writer/internal/procRTSP/client.go
+++ b/writer/internal/procRTSP/client.go
@@ -7,6 +7,8 @@ import (
 	"github.com/bluenviron/gortsplib/v4/pkg/base"
 	"github.com/bluenviron/gortsplib/v4/pkg/description"
 	"github.com/bluenviron/gortsplib/v4/pkg/format"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtph264"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtplpcm"
 	"github.com/pion/rtp"
 	_ "github.com/zaf/g711"
 	"log"
@@ -18,6 +20,8 @@ import (
 
 var (
 	resolutions = []string{"1280x720"}
+	h264RTPDec  *rtph264.Decoder
+	g711RTPDec  *rtplpcm.Decoder
 )
 
 // ProcRTSP process RTSP protocol and writes H264 and PCM flows into TS container.
@@ -70,15 +74,19 @@ func ProcRTSP(period int, URI string) error {
 	////////////////////////////////////////////////////////////////////////////////////////
 
 	// Create RTP -> H264 decoder.
-	h264RTPDec, err := h264Format.CreateDecoder()
-	if err != nil {
-		return fmt.Errorf("create H264 decoder error: %w", err)
+	if h264Format != nil {
+		h264RTPDec, err = h264Format.CreateDecoder()
+		if err != nil {
+			return fmt.Errorf("create H264 decoder error: %w", err)
+		}
 	}
 
 	// Create RTP -> H264 decoder.
-	g711RTPDec, err := g711Format.CreateDecoder()
-	if err != nil {
-		return fmt.Errorf("create G711 decoder error: %w", err)
+	if g711Format != nil {
+		g711RTPDec, err = g711Format.CreateDecoder()
+		if err != nil {
+			return fmt.Errorf("create G711 decoder error: %w", err)
+		}
 	}
 
 	////////////////////////////////////////////////////////////////////////////////////////