janus: reserve 50 bytes for RTP extensions

Author: mdevaev

janus/src/rtp.h

@@ -25,8 +25,10 @@
 #include "uslibs/types.h"
 
 
-// https://stackoverflow.com/questions/47635545/why-webrtc-chose-rtp-max-packet-size-to-1200-bytes
-#define US_RTP_TOTAL_SIZE		1200
+// Max RTP size for WebRTC is 1200 bytes:
+//   - https://stackoverflow.com/questions/47635545/why-webrtc-chose-rtp-max-packet-size-to-1200-bytes
+// We take this and substract 50 bytes for possible RTP extensions, see sdp.c
+#define US_RTP_TOTAL_SIZE		(1200 - 50)
 #define US_RTP_HEADER_SIZE		12
 #define US_RTP_PAYLOAD_SIZE		(US_RTP_TOTAL_SIZE - US_RTP_HEADER_SIZE)