diff --git a/libavcodec/pamenc.c b/libavcodec/pamenc.c
index 50c9fcb..143d38f 100644
--- a/libavcodec/pamenc.c
+++ b/libavcodec/pamenc.c
@@ -98,7 +98,7 @@ static int pam_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     bytestream       = pkt->data;
     bytestream_end   = pkt->data + pkt->size;
 
-    snprintf(bytestream, bytestream_end - bytestream,
+    snprintf((char *)bytestream, bytestream_end - bytestream,
              "P7\nWIDTH %d\nHEIGHT %d\nDEPTH %d\nMAXVAL %d\nTUPLTYPE %s\nENDHDR\n",
              w, h, depth, maxval, tuple_type);
     bytestream += strlen(bytestream);
diff --git a/libavcodec/pnmenc.c b/libavcodec/pnmenc.c
index ba9478d..f1bcbc6 100644
--- a/libavcodec/pnmenc.c
+++ b/libavcodec/pnmenc.c
@@ -80,12 +80,12 @@ static int pnm_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     default:
         return -1;
     }
-    snprintf(bytestream, bytestream_end - bytestream,
+    snprintf((char *)bytestream, bytestream_end - bytestream,
              "P%c\n%d %d\n", c, avctx->width, h1);
     bytestream += strlen(bytestream);
     if (avctx->pix_fmt != AV_PIX_FMT_MONOWHITE) {
         int maxdepth = (1 << av_pix_fmt_desc_get(avctx->pix_fmt)->comp[0].depth) - 1;
-        snprintf(bytestream, bytestream_end - bytestream,
+        snprintf((char *)bytestream, bytestream_end - bytestream,
                  "%d\n", maxdepth);
         bytestream += strlen(bytestream);
     }
diff --git a/libavcodec/xbmenc.c b/libavcodec/xbmenc.c
index b25615f..7f7fbc0 100644
--- a/libavcodec/xbmenc.c
+++ b/libavcodec/xbmenc.c
@@ -28,14 +28,16 @@ static int xbm_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                             const AVFrame *p, int *got_packet)
 {
     int i, j, ret, size, linesize;
-    uint8_t *ptr, *buf;
+    // buf is a char* instead of a uint8_t* to make FORTIFY on clang happy.
+    char *buf;
+    uint8_t *ptr;
 
     linesize = (avctx->width + 7) / 8;
     size     = avctx->height * (linesize * 7 + 2) + 110;
     if ((ret = ff_alloc_packet2(avctx, pkt, size, 0)) < 0)
         return ret;
 
-    buf = pkt->data;
+    buf = (char *)pkt->data;
     ptr = p->data[0];
 
     buf += snprintf(buf, 32, "#define image_width %u\n", avctx->width);
@@ -49,7 +51,7 @@ static int xbm_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     }
     buf += snprintf(buf, 5, " };\n");
 
-    pkt->size   = buf - pkt->data;
+    pkt->size   = (uint8_t *)buf - pkt->data;
     pkt->flags |= AV_PKT_FLAG_KEY;
     *got_packet = 1;
     return 0;
diff --git a/libavcodec/xsubenc.c b/libavcodec/xsubenc.c
index b3da909..a4a8221 100644
--- a/libavcodec/xsubenc.c
+++ b/libavcodec/xsubenc.c
@@ -163,7 +163,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
         return -1;
     }
 
-    snprintf(buf, 28,
+    snprintf((char *)buf, 28,
         "[%02d:%02d:%02d.%03d-%02d:%02d:%02d.%03d]",
         start_tc[3], start_tc[2], start_tc[1], start_tc[0],
         end_tc[3],   end_tc[2],   end_tc[1],   end_tc[0]);
diff --git a/libavfilter/af_astats.c b/libavfilter/af_astats.c
index e7f9675..32c6041 100644
--- a/libavfilter/af_astats.c
+++ b/libavfilter/af_astats.c
@@ -211,8 +211,8 @@ static inline void update_stat(AudioStatsContext *s, ChannelStats *p, double d,
 static void set_meta(AVDictionary **metadata, int chan, const char *key,
                      const char *fmt, double val)
 {
-    uint8_t value[128];
-    uint8_t key2[128];
+    char value[128];
+    char key2[128];
 
     snprintf(value, sizeof(value), fmt, val);
     if (chan)
diff --git a/libavfilter/avf_aphasemeter.c b/libavfilter/avf_aphasemeter.c
index 8e8b292..4afc6bb 100644
--- a/libavfilter/avf_aphasemeter.c
+++ b/libavfilter/avf_aphasemeter.c
@@ -190,7 +190,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 
     metadata = avpriv_frame_get_metadatap(out);
     if (metadata) {
-        uint8_t value[128];
+        char value[128];
 
         snprintf(value, sizeof(value), "%f", fphase);
         av_dict_set(metadata, "lavfi.aphasemeter.phase", value, 0);
diff --git a/libavformat/flacenc.c b/libavformat/flacenc.c
index 89b21e9..8ef4292 100644
--- a/libavformat/flacenc.c
+++ b/libavformat/flacenc.c
@@ -115,7 +115,7 @@ static int flac_write_header(struct AVFormatContext *s)
             av_log(s, AV_LOG_WARNING, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
                    "already present, this muxer will not overwrite it.\n");
         } else {
-            uint8_t buf[32];
+            char buf[32];
             snprintf(buf, sizeof(buf), "0x%"PRIx64, par->channel_layout);
             av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf, 0);
         }
diff --git a/libavformat/http.c b/libavformat/http.c
index adb3d92..282310b 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -1095,7 +1095,7 @@ static int http_connect(URLContext *h, const char *path, const char *local_path,
     if (s->headers)
         av_strlcpy(headers + len, s->headers, sizeof(headers) - len);
 
-    snprintf(s->buffer, sizeof(s->buffer),
+    snprintf((char *)s->buffer, sizeof(s->buffer),
              "%s %s HTTP/1.1\r\n"
              "%s"
              "%s"
@@ -1593,7 +1593,7 @@ redo:
 
     authstr = ff_http_auth_create_response(&s->proxy_auth_state, auth,
                                            path, "CONNECT");
-    snprintf(s->buffer, sizeof(s->buffer),
+    snprintf((char *)s->buffer, sizeof(s->buffer),
              "CONNECT %s HTTP/1.1\r\n"
              "Host: %s\r\n"
              "Connection: close\r\n"
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 2a2877f..2788ff7 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -576,7 +576,8 @@ static int put_flac_codecpriv(AVFormatContext *s,
         const char *vendor = (s->flags & AVFMT_FLAG_BITEXACT) ?
                              "Lavf" : LIBAVFORMAT_IDENT;
         AVDictionary *dict = NULL;
-        uint8_t buf[32], *data, *p;
+        char buf[32];
+        uint8_t *data, *p;
         int64_t len;
 
         snprintf(buf, sizeof(buf), "0x%"PRIx64, par->channel_layout);
diff --git a/libavformat/md5proto.c b/libavformat/md5proto.c
index 0e04b90..23a067a 100644
--- a/libavformat/md5proto.c
+++ b/libavformat/md5proto.c
@@ -57,7 +57,8 @@ static int md5_close(URLContext *h)
 {
     struct MD5Context *c = h->priv_data;
     const char *filename = h->filename;
-    uint8_t md5[16], buf[64];
+    uint8_t md5[16];
+    char buf[64];
     URLContext *out;
     int i, err = 0;
 
diff --git a/libavformat/nutenc.c b/libavformat/nutenc.c
index 9e422e1..d698711 100644
--- a/libavformat/nutenc.c
+++ b/libavformat/nutenc.c
@@ -533,7 +533,7 @@ static int write_streaminfo(NUTContext *nut, AVIOContext *bc, int stream_id) {
             count += add_info(dyn_bc, "Disposition", ff_nut_dispositions[i].str);
     }
     if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
-        uint8_t buf[256];
+        char buf[256];
         if (st->r_frame_rate.num>0 && st->r_frame_rate.den>0)
             snprintf(buf, sizeof(buf), "%d/%d", st->r_frame_rate.num, st->r_frame_rate.den);
         else
@@ -842,7 +842,7 @@ static int write_sm_data(AVFormatContext *s, AVIOContext *bc, AVPacket *pkt, int
     unsigned flags;
     AVIOContext *dyn_bc;
     int sm_data_count = 0;
-    uint8_t tmp[256];
+    char tmp[256];
     uint8_t *dyn_buf;
 
     ret = avio_open_dyn_buf(&dyn_bc);
diff --git a/libavformat/rtmppkt.c b/libavformat/rtmppkt.c
index 0d693c2..4856808 100644
--- a/libavformat/rtmppkt.c
+++ b/libavformat/rtmppkt.c
@@ -494,10 +494,10 @@ int ff_amf_get_field_value(const uint8_t *data, const uint8_t *data_end,
         if (size == namelen && !memcmp(data-size, name, namelen)) {
             switch (*data++) {
             case AMF_DATA_TYPE_NUMBER:
-                snprintf(dst, dst_size, "%g", av_int2double(AV_RB64(data)));
+                snprintf((char *)dst, dst_size, "%g", av_int2double(AV_RB64(data)));
                 break;
             case AMF_DATA_TYPE_BOOL:
-                snprintf(dst, dst_size, "%s", *data ? "true" : "false");
+                snprintf((char *)dst, dst_size, "%s", *data ? "true" : "false");
                 break;
             case AMF_DATA_TYPE_STRING:
                 len = bytestream_get_be16(&data);
diff --git a/libavutil/hash.c b/libavutil/hash.c
index 7037b0d..27637b7 100644
--- a/libavutil/hash.c
+++ b/libavutil/hash.c
@@ -215,7 +215,7 @@ void av_hash_final_hex(struct AVHashContext *ctx, uint8_t *dst, int size)
 
     av_hash_final(ctx, buf);
     for (i = 0; i < FFMIN(rsize, size / 2); i++)
-        snprintf(dst + i * 2, size - i * 2, "%02x", buf[i]);
+        snprintf((char *)dst + i * 2, size - i * 2, "%02x", buf[i]);
 }
 
 void av_hash_final_b64(struct AVHashContext *ctx, uint8_t *dst, int size)
diff --git a/libavutil/opt.c b/libavutil/opt.c
index cd16bd1..f7f5225 100644
--- a/libavutil/opt.c
+++ b/libavutil/opt.c
@@ -733,7 +733,8 @@ int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
 {
     void *dst, *target_obj;
     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
-    uint8_t *bin, buf[128];
+    uint8_t *bin;
+    char buf[128];
     int len, i, ret;
     int64_t i64;
 
@@ -795,7 +796,7 @@ int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
         }
         bin = *(uint8_t **)dst;
         for (i = 0; i < len; i++)
-            snprintf(*out_val + i * 2, 3, "%02X", bin[i]);
+            snprintf(*(char **)out_val + i * 2, 3, "%02X", bin[i]);
         return 0;
     case AV_OPT_TYPE_IMAGE_SIZE:
         ret = snprintf(buf, sizeof(buf), "%dx%d", ((int *)dst)[0], ((int *)dst)[1]);
