diff --git a/libavformat/sapdec.c b/libavformat/sapdec.c
index ed3e8578d5..fe7bd825f2 100644
--- a/libavformat/sapdec.c
+++ b/libavformat/sapdec.c
@@ -27,6 +27,7 @@
 #include "internal.h"
 #include "avio_internal.h"
 #include "url.h"
+#include "rtpdec.h"
 #if HAVE_POLL_H
 #include <poll.h>
 #endif
@@ -63,7 +64,7 @@ static int sap_read_header(AVFormatContext *s)
 {
     struct SAPState *sap = s->priv_data;
     char host[1024], path[1024], url[1024];
-    uint8_t recvbuf[1500];
+    uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
     int port;
     int ret, i;
     AVInputFormat* infmt;
@@ -186,7 +187,7 @@ static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
     int fd = ffurl_get_file_handle(sap->ann_fd);
     int n, ret;
     struct pollfd p = {fd, POLLIN, 0};
-    uint8_t recvbuf[1500];
+    uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
 
     if (sap->eof)
         return AVERROR_EOF;
diff --git a/libavformat/srtp.c b/libavformat/srtp.c
index 65309d0763..b6e821115c 100644
--- a/libavformat/srtp.c
+++ b/libavformat/srtp.c
@@ -25,6 +25,7 @@
 #include "libavutil/intreadwrite.h"
 #include "libavutil/log.h"
 #include "rtp.h"
+#include "rtpdec.h"
 #include "srtp.h"
 
 void ff_srtp_free(struct SRTPContext *s)
@@ -419,7 +420,7 @@ static void test_encrypt(const uint8_t *data, int in_len, const char *suite,
 {
     struct SRTPContext enc = { 0 }, dec = { 0 };
     int len;
-    char buf[1500];
+    char buf[RTP_MAX_PACKET_LENGTH];
     ff_srtp_set_crypto(&enc, suite, key);
     ff_srtp_set_crypto(&dec, suite, key);
     len = ff_srtp_encrypt(&enc, data, in_len, buf, sizeof(buf));
@@ -441,7 +442,7 @@ int main(void)
     static const char *aes128_32_suite = "AES_CM_128_HMAC_SHA1_32";
     static const char *aes128_80_32_suite = "SRTP_AES128_CM_HMAC_SHA1_32";
     static const char *test_key = "abcdefghijklmnopqrstuvwxyz1234567890ABCD";
-    uint8_t buf[1500];
+    uint8_t buf[RTP_MAX_PACKET_LENGTH];
     struct SRTPContext srtp = { 0 };
     int len;
     ff_srtp_set_crypto(&srtp, aes128_80_suite, aes128_80_key);
diff --git a/libavformat/srtpproto.c b/libavformat/srtpproto.c
index f5e3d14090..f9d6b1733f 100644
--- a/libavformat/srtpproto.c
+++ b/libavformat/srtpproto.c
@@ -25,6 +25,7 @@
 #include "url.h"
 
 #include "internal.h"
+#include "rtpdec.h"
 #include "srtp.h"
 
 typedef struct SRTPProtoContext {
@@ -33,7 +34,7 @@ typedef struct SRTPProtoContext {
     const char *out_suite, *out_params;
     const char *in_suite, *in_params;
     struct SRTPContext srtp_out, srtp_in;
-    uint8_t encryptbuf[1500];
+    uint8_t encryptbuf[RTP_MAX_PACKET_LENGTH];
 } SRTPProtoContext;
 
 #define D AV_OPT_FLAG_DECODING_PARAM