diff --git a/libavformat/rtpdec.c b/libavformat/rtpdec.c
index d0b25bcbf1..a80463b98b 100644
--- a/libavformat/rtpdec.c
+++ b/libavformat/rtpdec.c
@@ -844,7 +844,7 @@ int ff_parse_fmtp(AVFormatContext *s,
                   int (*parse_fmtp)(AVFormatContext *s,
                                     AVStream *stream,
                                     PayloadContext *data,
-                                    char *attr, char *value))
+                                    const char *attr, const char *value))
 {
     char attr[256];
     char *value;
diff --git a/libavformat/rtpdec.h b/libavformat/rtpdec.h
index 9d867321be..94f2f0cbfb 100644
--- a/libavformat/rtpdec.h
+++ b/libavformat/rtpdec.h
@@ -207,7 +207,7 @@ int ff_parse_fmtp(AVFormatContext *s,
                   int (*parse_fmtp)(AVFormatContext *s,
                                     AVStream *stream,
                                     PayloadContext *data,
-                                    char *attr, char *value));
+                                    const char *attr, const char *value));
 
 void ff_register_rtp_dynamic_payload_handlers(void);
 
diff --git a/libavformat/rtpdec_amr.c b/libavformat/rtpdec_amr.c
index 897873b63f..8216a5b911 100644
--- a/libavformat/rtpdec_amr.c
+++ b/libavformat/rtpdec_amr.c
@@ -137,7 +137,7 @@ static int amr_handle_packet(AVFormatContext *ctx, PayloadContext *data,
 
 static int amr_parse_fmtp(AVFormatContext *s,
                           AVStream *stream, PayloadContext *data,
-                          char *attr, char *value)
+                          const char *attr, const char *value)
 {
     /* Some AMR SDP configurations contain "octet-align", without
      * the trailing =1. Therefore, if the value is empty,
@@ -146,7 +146,7 @@ static int amr_parse_fmtp(AVFormatContext *s,
     if (!strcmp(value, "")) {
         av_log(s, AV_LOG_WARNING, "AMR fmtp attribute %s had "
                                   "nonstandard empty value\n", attr);
-        strcpy(value, "1");
+        value = "1";
     }
     if (!strcmp(attr, "octet-align"))
         data->octet_align = atoi(value);
diff --git a/libavformat/rtpdec_dv.c b/libavformat/rtpdec_dv.c
index 79a721817b..ce2d22de12 100644
--- a/libavformat/rtpdec_dv.c
+++ b/libavformat/rtpdec_dv.c
@@ -48,7 +48,7 @@ static av_cold void dv_free_context(PayloadContext *data)
 static av_cold int dv_sdp_parse_fmtp_config(AVFormatContext *s,
                                             AVStream *stream,
                                             PayloadContext *dv_data,
-                                            char *attr, char *value)
+                                            const char *attr, const char *value)
 {
     /* does the DV stream include audio? */
     if (!strcmp(attr, "audio") && !strcmp(value, "bundled"))
diff --git a/libavformat/rtpdec_h264.c b/libavformat/rtpdec_h264.c
index e79ac40189..a74be1fc05 100644
--- a/libavformat/rtpdec_h264.c
+++ b/libavformat/rtpdec_h264.c
@@ -144,7 +144,7 @@ int ff_h264_parse_sprop_parameter_sets(AVFormatContext *s,
 static int sdp_parse_fmtp_config_h264(AVFormatContext *s,
                                       AVStream *stream,
                                       PayloadContext *h264_data,
-                                      char *attr, char *value)
+                                      const char *attr, const char *value)
 {
     AVCodecContext *codec = stream->codec;
 
diff --git a/libavformat/rtpdec_hevc.c b/libavformat/rtpdec_hevc.c
index 44cf1d218f..4ec9767b46 100644
--- a/libavformat/rtpdec_hevc.c
+++ b/libavformat/rtpdec_hevc.c
@@ -46,7 +46,7 @@ static const uint8_t start_sequence[] = { 0x00, 0x00, 0x00, 0x01 };
 static av_cold int hevc_sdp_parse_fmtp_config(AVFormatContext *s,
                                               AVStream *stream,
                                               PayloadContext *hevc_data,
-                                              char *attr, char *value)
+                                              const char *attr, const char *value)
 {
     /* profile-space: 0-3 */
     /* profile-id: 0-31 */
diff --git a/libavformat/rtpdec_ilbc.c b/libavformat/rtpdec_ilbc.c
index bff47c7ac2..f47abc1f96 100644
--- a/libavformat/rtpdec_ilbc.c
+++ b/libavformat/rtpdec_ilbc.c
@@ -25,7 +25,7 @@
 
 static int ilbc_parse_fmtp(AVFormatContext *s,
                            AVStream *stream, PayloadContext *data,
-                           char *attr, char *value)
+                           const char *attr, const char *value)
 {
     if (!strcmp(attr, "mode")) {
         int mode = atoi(value);
diff --git a/libavformat/rtpdec_latm.c b/libavformat/rtpdec_latm.c
index 813f41b2a2..6d5b46a726 100644
--- a/libavformat/rtpdec_latm.c
+++ b/libavformat/rtpdec_latm.c
@@ -140,7 +140,7 @@ end:
 
 static int parse_fmtp(AVFormatContext *s,
                       AVStream *stream, PayloadContext *data,
-                      char *attr, char *value)
+                      const char *attr, const char *value)
 {
     int res;
 
diff --git a/libavformat/rtpdec_mpeg4.c b/libavformat/rtpdec_mpeg4.c
index fe6b440011..3fb89372ae 100644
--- a/libavformat/rtpdec_mpeg4.c
+++ b/libavformat/rtpdec_mpeg4.c
@@ -274,7 +274,7 @@ static int aac_parse_packet(AVFormatContext *ctx, PayloadContext *data,
 
 static int parse_fmtp(AVFormatContext *s,
                       AVStream *stream, PayloadContext *data,
-                      char *attr, char *value)
+                      const char *attr, const char *value)
 {
     AVCodecContext *codec = stream->codec;
     int res, i;
diff --git a/libavformat/rtpdec_xiph.c b/libavformat/rtpdec_xiph.c
index d7a08bca4d..d52de82435 100644
--- a/libavformat/rtpdec_xiph.c
+++ b/libavformat/rtpdec_xiph.c
@@ -295,7 +295,7 @@ parse_packed_headers(const uint8_t * packed_headers,
 static int xiph_parse_fmtp_pair(AVFormatContext *s,
                                 AVStream* stream,
                                 PayloadContext *xiph_data,
-                                char *attr, char *value)
+                                const char *attr, const char *value)
 {
     AVCodecContext *codec = stream->codec;
     int result = 0;