diff --git a/ietf/rtp7587.h b/ietf/rtp7587.h
new file mode 100644
index 0000000..fee9c89
--- /dev/null
+++ b/ietf/rtp7587.h
@@ -0,0 +1,9 @@
+/*
+ * RTP Payload Format for the Opus Speech and Audio Codec
+ */
+#ifndef __BITSTREAM_IETF_RTP7587_H__
+# define __BITSTREAM_IETF_RTP7587_H__
+
+#define RTP_7587_CLOCKRATE       48000
+
+#endif /* !__BITSTREAM_IETF_RTP7587_H__ */