diff --git a/codec/pcm/pcm.go b/codec/pcm/pcm.go
index 99877eb9..9e8393f9 100644
--- a/codec/pcm/pcm.go
+++ b/codec/pcm/pcm.go
@@ -293,6 +293,6 @@ func SFFromString(s string) (SampleFormat, error) {
 	case "FLOAT64_BE":
 		return FLOAT64_BE, nil
 	default:
-		return Unknown, errors.Errorf("Unknown FormatType (%d)", s)
+		return Unknown, errors.Errorf("Unknown FormatType (%s)", s)
 	}
 }