From 67b120d73c39723dddb37e806d7468f243830f88 Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Tue, 30 Jun 2020 08:36:41 +0200
Subject: Fix RTP sequence number overflow check

---
 src/AVTInput.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/AVTInput.cpp b/src/AVTInput.cpp
index 32f6518..0d6f229 100644
--- a/src/AVTInput.cpp
+++ b/src/AVTInput.cpp
@@ -218,7 +218,11 @@ const uint8_t* AVTInput::_findDABFrameFromUDP(const uint8_t* buf, size_t size,
             if (version == 2 && payloadType == 34) {
                 const uint16_t seqnr = (buf[index+2] << 8) | buf[index+3];
                 if ((_previousRtpIndex != -1) and
-                        (((_previousRtpIndex + 1) % 0xFFFF) != seqnr)) {
+                        (((_previousRtpIndex + 1) % 5000) != seqnr)) {
+                    /* the sequence number apparently overflows at 5000, even though
+                     * RFC 3550 (RTP protocol) suggests that it should overflow at 0xFFFF.
+                     * Maybe the AVT uses DLFC as RTP sequence number.
+                     */
                     fprintf(stderr, "RTP sequence number jump from %d to %d\n",
                             _previousRtpIndex, seqnr);
                 }
-- 
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