diff --git a/libavformat/aiffenc.c b/libavformat/aiffenc.c
index 24bc17400e..1f8e0dd670 100644
--- a/libavformat/aiffenc.c
+++ b/libavformat/aiffenc.c
@@ -82,7 +82,7 @@ static int put_id3v2_tags(AVFormatContext *s, AIFFOutputContext *aiff)
 
 static void put_meta(AVFormatContext *s, const char *key, uint32_t id)
 {
-    AVDictionaryEntry *tag;
+    const AVDictionaryEntry *tag;
     AVIOContext *pb = s->pb;
 
     if (tag = av_dict_get(s->metadata, key, NULL, 0)) {
diff --git a/libavformat/apetag.c b/libavformat/apetag.c
index 6f82fbe202..d94356f5a0 100644
--- a/libavformat/apetag.c
+++ b/libavformat/apetag.c
@@ -174,7 +174,7 @@ static int string_is_ascii(const uint8_t *str)
 
 int ff_ape_write_tag(AVFormatContext *s)
 {
-    AVDictionaryEntry *e = NULL;
+    const AVDictionaryEntry *e = NULL;
     int size, ret, count = 0;
     AVIOContext *dyn_bc;
     uint8_t *dyn_buf;
diff --git a/libavformat/asfenc.c b/libavformat/asfenc.c
index a0510df7dc..8632877117 100644
--- a/libavformat/asfenc.c
+++ b/libavformat/asfenc.c
@@ -355,7 +355,7 @@ static int asf_write_markers(AVFormatContext *s)
 
     for (unsigned i = 0; i < s->nb_chapters; i++) {
         AVChapter *c = s->chapters[i];
-        AVDictionaryEntry *t = av_dict_get(c->metadata, "title", NULL, 0);
+        const AVDictionaryEntry *t = av_dict_get(c->metadata, "title", NULL, 0);
         int64_t pres_time = av_rescale_q(c->start, c->time_base, scale);
         uint64_t offset;
         int32_t send_time = get_send_time(asf, pres_time, &offset);
@@ -389,7 +389,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
 {
     ASFContext *asf = s->priv_data;
     AVIOContext *pb = s->pb;
-    AVDictionaryEntry *tags[5];
+    const AVDictionaryEntry *tags[5];
     int header_size, extra_size, extra_size2, wav_extra_size;
     int has_title, has_aspect_ratio = 0;
     int metadata_count;
@@ -420,7 +420,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
     for (unsigned n = 0; n < s->nb_streams; n++) {
         AVStream *const st = s->streams[n];
         AVCodecParameters *const par = st->codecpar;
-        AVDictionaryEntry *entry;
+        const AVDictionaryEntry *entry;
 
         avpriv_set_pts_info(s->streams[n], 32, 1, 1000); /* 32 bit pts in ms */
 
@@ -599,7 +599,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
         end_header(pb, hpos);
     }
     if (metadata_count) {
-        AVDictionaryEntry *tag = NULL;
+        const AVDictionaryEntry *tag = NULL;
         hpos = put_header(pb, &ff_asf_extended_content_header);
         avio_wl16(pb, metadata_count);
         while ((tag = av_dict_get(s->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
diff --git a/libavformat/au.c b/libavformat/au.c
index 9bd408f65c..a408e55e36 100644
--- a/libavformat/au.c
+++ b/libavformat/au.c
@@ -258,7 +258,7 @@ static int au_get_annotations(AVFormatContext *s, AVBPrint *annotations)
     };
     int cnt = 0;
     AVDictionary *m = s->metadata;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
 
     for (int i = 0; i < FF_ARRAY_ELEMS(keys); i++) {
         t = av_dict_get(m, keys[i], NULL, 0);
diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index b09a715d86..8bf0d3a1fe 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -491,7 +491,7 @@ static int avi_read_header(AVFormatContext *s)
     uint64_t list_end   = 0;
     int64_t pos;
     int ret;
-    AVDictionaryEntry *dict_entry;
+    const AVDictionaryEntry *dict_entry;
 
     avi->stream_index = -1;
 
diff --git a/libavformat/avienc.c b/libavformat/avienc.c
index 3b11841cd3..0d01a45d0a 100644
--- a/libavformat/avienc.c
+++ b/libavformat/avienc.c
@@ -263,7 +263,7 @@ static int avi_write_header(AVFormatContext *s)
     AVCodecParameters *video_par;
     AVStream *video_st = NULL;
     int64_t list1, list2, strh, strf;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     int padding;
 
     if (s->nb_streams > AVI_MAX_STREAM_COUNT) {
diff --git a/libavformat/avio.c b/libavformat/avio.c
index 4846bbd8c6..2e45c5b5d1 100644
--- a/libavformat/avio.c
+++ b/libavformat/avio.c
@@ -167,7 +167,7 @@ int ffurl_connect(URLContext *uc, AVDictionary **options)
 {
     int err;
     AVDictionary *tmp_opts = NULL;
-    AVDictionaryEntry *e;
+    const AVDictionaryEntry *e;
 
     if (!options)
         options = &tmp_opts;
@@ -309,7 +309,7 @@ int ffurl_open_whitelist(URLContext **puc, const char *filename, int flags,
                          URLContext *parent)
 {
     AVDictionary *tmp_opts = NULL;
-    AVDictionaryEntry *e;
+    const AVDictionaryEntry *e;
     int ret = ffurl_alloc(puc, filename, flags, int_cb);
     if (ret < 0)
         return ret;
diff --git a/libavformat/cafenc.c b/libavformat/cafenc.c
index 412b3230e3..8a06e5a46b 100644
--- a/libavformat/cafenc.c
+++ b/libavformat/cafenc.c
@@ -106,7 +106,7 @@ static int caf_write_header(AVFormatContext *s)
     AVIOContext *pb = s->pb;
     AVCodecParameters *par = s->streams[0]->codecpar;
     CAFContext *caf = s->priv_data;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     unsigned int codec_tag = ff_codec_get_tag(ff_codec_caf_tags, par->codec_id);
     int64_t chunk_size = 0;
     int frame_size = par->frame_size;
diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
index 06bbf36c95..a8ba8ec2ac 100644
--- a/libavformat/dashenc.c
+++ b/libavformat/dashenc.c
@@ -794,7 +794,7 @@ static int write_adaptation_set(AVFormatContext *s, AVIOContext *out, int as_ind
 {
     DASHContext *c = s->priv_data;
     AdaptationSet *as = &c->as[as_index];
-    AVDictionaryEntry *lang, *role;
+    const AVDictionaryEntry *lang, *role;
     int i;
 
     avio_printf(out, "\t\t<AdaptationSet id=\"%d\" contentType=\"%s\" startWithSAP=\"1\" segmentAlignment=\"true\" bitstreamSwitching=\"true\"",
@@ -1138,7 +1138,7 @@ static int write_manifest(AVFormatContext *s, int final)
     const char *proto = avio_find_protocol_name(s->url);
     int use_rename = proto && !strcmp(proto, "file");
     static unsigned int warned_non_file = 0;
-    AVDictionaryEntry *title = av_dict_get(s->metadata, "title", NULL, 0);
+    const AVDictionaryEntry *title = av_dict_get(s->metadata, "title", NULL, 0);
     AVDictionary *opts = NULL;
 
     if (!use_rename && !warned_non_file++)
@@ -1366,7 +1366,7 @@ static int write_manifest(AVFormatContext *s, int final)
 
 static int dict_copy_entry(AVDictionary **dst, const AVDictionary *src, const char *key)
 {
-    AVDictionaryEntry *entry = av_dict_get(src, key, NULL, 0);
+    const AVDictionaryEntry *entry = av_dict_get(src, key, NULL, 0);
     if (entry)
         av_dict_set(dst, key, entry->value, AV_DICT_DONT_OVERWRITE);
     return 0;
diff --git a/libavformat/dvenc.c b/libavformat/dvenc.c
index 9a853ba7ce..7061be656d 100644
--- a/libavformat/dvenc.c
+++ b/libavformat/dvenc.c
@@ -384,7 +384,7 @@ static int dv_write_header(AVFormatContext *s)
 {
     AVRational rate;
     DVMuxContext *dvc = s->priv_data;
-    AVDictionaryEntry *tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
+    const AVDictionaryEntry *tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
 
     if (!dv_init_mux(s)) {
         av_log(s, AV_LOG_ERROR, "Can't initialize DV format!\n"
diff --git a/libavformat/ffmetaenc.c b/libavformat/ffmetaenc.c
index edd66e1a04..1d72b43b86 100644
--- a/libavformat/ffmetaenc.c
+++ b/libavformat/ffmetaenc.c
@@ -40,7 +40,7 @@ static void write_escape_str(AVIOContext *s, const uint8_t *str)
 
 static void write_tags(AVIOContext *s, AVDictionary *m)
 {
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     while ((t = av_dict_get(m, "", t, AV_DICT_IGNORE_SUFFIX))) {
         write_escape_str(s, t->key);
         avio_w8(s, '=');
diff --git a/libavformat/fifo.c b/libavformat/fifo.c
index 51d7fa5b94..e9d73cb4d4 100644
--- a/libavformat/fifo.c
+++ b/libavformat/fifo.c
@@ -147,7 +147,7 @@ static int fifo_thread_write_header(FifoThreadContext *ctx)
 
     // Check for options unrecognized by underlying muxer
     if (format_options) {
-        AVDictionaryEntry *entry = NULL;
+        const AVDictionaryEntry *entry = NULL;
         while ((entry = av_dict_get(format_options, "", entry, AV_DICT_IGNORE_SUFFIX)))
             av_log(avf2, AV_LOG_ERROR, "Unknown option '%s'\n", entry->key);
         ret = AVERROR(EINVAL);
diff --git a/libavformat/flacdec.c b/libavformat/flacdec.c
index 04d3cadf1c..826ccbe303 100644
--- a/libavformat/flacdec.c
+++ b/libavformat/flacdec.c
@@ -173,7 +173,7 @@ static int flac_read_header(AVFormatContext *s)
             }
             /* process supported blocks other than STREAMINFO */
             if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
-                AVDictionaryEntry *chmask;
+                const AVDictionaryEntry *chmask;
 
                 ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);
                 if (ret < 0) {
diff --git a/libavformat/flacenc.c b/libavformat/flacenc.c
index 44c9341493..70e120e291 100644
--- a/libavformat/flacenc.c
+++ b/libavformat/flacenc.c
@@ -83,7 +83,7 @@ static int flac_write_picture(struct AVFormatContext *s, AVPacket *pkt)
     AVIOContext *pb = s->pb;
     const AVPixFmtDescriptor *pixdesc;
     const CodecMime *mime = ff_id3v2_mime_tags;
-    AVDictionaryEntry *e;
+    const AVDictionaryEntry *e;
     const char *mimetype = NULL, *desc = "";
     const AVStream *st = s->streams[pkt->stream_index];
     int i, mimelen, desclen, type = 0, blocklen;
@@ -241,7 +241,7 @@ static int flac_init(struct AVFormatContext *s)
     if (par->channel_layout &&
         !(par->channel_layout & ~0x3ffffULL) &&
         !ff_flac_is_native_layout(par->channel_layout)) {
-        AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
+        const AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
                                                 NULL, 0);
 
         if (chmask) {
diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index 44a7e5f93c..d9567f4e21 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -1267,7 +1267,7 @@ retry_duration:
         }
         if (type == 0 && (!st->codecpar->extradata || st->codecpar->codec_id == AV_CODEC_ID_AAC ||
             st->codecpar->codec_id == AV_CODEC_ID_H264)) {
-            AVDictionaryEntry *t;
+            const AVDictionaryEntry *t;
 
             if (st->codecpar->extradata) {
                 if ((ret = flv_queue_extradata(flv, s->pb, stream_type, size)) < 0)
diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
index 3f24c7e192..78f4433ee9 100644
--- a/libavformat/flvenc.c
+++ b/libavformat/flvenc.c
@@ -278,7 +278,7 @@ static void write_metadata(AVFormatContext *s, unsigned int ts)
     int write_duration_filesize = !(flv->flags & FLV_NO_DURATION_FILESIZE);
     int metadata_count = 0;
     int64_t metadata_count_pos;
-    AVDictionaryEntry *tag = NULL;
+    const AVDictionaryEntry *tag = NULL;
 
     /* write meta_tag */
     avio_w8(pb, FLV_TAG_TYPE_META);            // tag type META
diff --git a/libavformat/gxfenc.c b/libavformat/gxfenc.c
index 8cc3bd456e..1053126b32 100644
--- a/libavformat/gxfenc.c
+++ b/libavformat/gxfenc.c
@@ -689,7 +689,7 @@ static int gxf_write_header(AVFormatContext *s)
     uint8_t tracks[255] = {0};
     int i, media_info = 0;
     int ret;
-    AVDictionaryEntry *tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
+    const AVDictionaryEntry *tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
 
     if (!(pb->seekable & AVIO_SEEKABLE_NORMAL)) {
         av_log(s, AV_LOG_ERROR, "gxf muxer does not support streamed output, patch welcome\n");
diff --git a/libavformat/hls.c b/libavformat/hls.c
index 9fd4ad9f32..4a9fc55fa8 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -1063,8 +1063,8 @@ static void parse_id3(AVFormatContext *s, AVIOContext *pb,
 static int id3_has_changed_values(struct playlist *pls, AVDictionary *metadata,
                                   ID3v2ExtraMetaAPIC *apic)
 {
-    AVDictionaryEntry *entry = NULL;
-    AVDictionaryEntry *oldentry;
+    const AVDictionaryEntry *entry = NULL;
+    const AVDictionaryEntry *oldentry;
     /* check that no keys have changed values */
     while ((entry = av_dict_get(metadata, "", entry, AV_DICT_IGNORE_SUFFIX))) {
         oldentry = av_dict_get(pls->id3_initial, entry->key, NULL, AV_DICT_MATCH_CASE);
diff --git a/libavformat/http.c b/libavformat/http.c
index 476b9a8456..a1372b585a 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -883,7 +883,7 @@ static int parse_set_cookie(const char *set_cookie, AVDictionary **dict)
 static int parse_cookie(HTTPContext *s, const char *p, AVDictionary **cookies)
 {
     AVDictionary *new_params = NULL;
-    AVDictionaryEntry *e, *cookie_entry;
+    const AVDictionaryEntry *e, *cookie_entry;
     char *eql, *name;
 
     // ensure the cookie is parsable
@@ -901,7 +901,7 @@ static int parse_cookie(HTTPContext *s, const char *p, AVDictionary **cookies)
     if ((e = av_dict_get(new_params, "expires", NULL, 0)) && e->value) {
         struct tm new_tm = {0};
         if (!parse_set_cookie_expiry_time(e->value, &new_tm)) {
-            AVDictionaryEntry *e2;
+            const AVDictionaryEntry *e2;
 
             // if the cookie has already expired ignore it
             if (av_timegm(&new_tm) < av_gettime() / 1000000) {
@@ -944,7 +944,7 @@ static int parse_cookie(HTTPContext *s, const char *p, AVDictionary **cookies)
 
 static int cookie_string(AVDictionary *dict, char **cookies)
 {
-    AVDictionaryEntry *e = NULL;
+    const AVDictionaryEntry *e = NULL;
     int len = 1;
 
     // determine how much memory is needed for the cookies string
@@ -1141,7 +1141,7 @@ static int get_cookies(HTTPContext *s, char **cookies, const char *path,
     *cookies = NULL;
     while ((cookie = av_strtok(next, "\n", &saveptr)) && !ret) {
         AVDictionary *cookie_params = NULL;
-        AVDictionaryEntry *cookie_entry, *e;
+        const AVDictionaryEntry *cookie_entry, *e;
 
         next = NULL;
         // store the cookie in a dict in case it is updated in the response
diff --git a/libavformat/id3v2.c b/libavformat/id3v2.c
index ff27c062e5..cc4f103614 100644
--- a/libavformat/id3v2.c
+++ b/libavformat/id3v2.c
@@ -535,9 +535,9 @@ static int is_number(const char *str)
     return !*str;
 }
 
-static AVDictionaryEntry *get_date_tag(AVDictionary *m, const char *tag)
+static const AVDictionaryEntry *get_date_tag(AVDictionary *m, const char *tag)
 {
-    AVDictionaryEntry *t;
+    const AVDictionaryEntry *t;
     if ((t = av_dict_get(m, tag, NULL, AV_DICT_MATCH_CASE)) &&
         strlen(t->value) == 4 && is_number(t->value))
         return t;
@@ -546,7 +546,7 @@ static AVDictionaryEntry *get_date_tag(AVDictionary *m, const char *tag)
 
 static void merge_date(AVDictionary **m)
 {
-    AVDictionaryEntry *t;
+    const AVDictionaryEntry *t;
     char date[17] = { 0 };      // YYYY-MM-DD hh:mm
 
     if (!(t = get_date_tag(*m, "TYER")) &&
diff --git a/libavformat/id3v2enc.c b/libavformat/id3v2enc.c
index 5d821ea4db..fbfc5ff82b 100644
--- a/libavformat/id3v2enc.c
+++ b/libavformat/id3v2enc.c
@@ -149,7 +149,7 @@ static int id3v2_put_priv(ID3v2EncContext *id3, AVIOContext *avioc, const char *
     return len + ID3v2_HEADER_SIZE;
 }
 
-static int id3v2_check_write_tag(ID3v2EncContext *id3, AVIOContext *pb, AVDictionaryEntry *t,
+static int id3v2_check_write_tag(ID3v2EncContext *id3, AVIOContext *pb, const AVDictionaryEntry *t,
                                  const char table[][4], enum ID3v2Encoding enc)
 {
     uint32_t tag;
@@ -166,7 +166,7 @@ static int id3v2_check_write_tag(ID3v2EncContext *id3, AVIOContext *pb, AVDictio
 
 static void id3v2_3_metadata_split_date(AVDictionary **pm)
 {
-    AVDictionaryEntry *mtag = NULL;
+    const AVDictionaryEntry *mtag = NULL;
     AVDictionary *dst = NULL;
     const char *key, *value;
     char year[5] = {0}, day_month[5] = {0};
@@ -219,7 +219,7 @@ void ff_id3v2_start(ID3v2EncContext *id3, AVIOContext *pb, int id3v2_version,
 static int write_metadata(AVIOContext *pb, AVDictionary **metadata,
                           ID3v2EncContext *id3, int enc)
 {
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     int ret;
 
     ff_metadata_conv(metadata, ff_id3v2_34_metadata_conv, NULL);
@@ -351,7 +351,7 @@ int ff_id3v2_write_metadata(AVFormatContext *s, ID3v2EncContext *id3)
 int ff_id3v2_write_apic(AVFormatContext *s, ID3v2EncContext *id3, AVPacket *pkt)
 {
     AVStream *st = s->streams[pkt->stream_index];
-    AVDictionaryEntry *e;
+    const AVDictionaryEntry *e;
 
     AVIOContext *dyn_buf;
     uint8_t     *buf;
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 500c83ac3a..8979d10973 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2051,7 +2051,7 @@ static int matroska_parse_flac(AVFormatContext *s,
         /* check for the channel mask */
         if (block_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
             AVDictionary *dict = NULL;
-            AVDictionaryEntry *chmask;
+            const AVDictionaryEntry *chmask;
 
             ff_vorbis_comment(s, &dict, p, block_size, 0);
             chmask = av_dict_get(dict, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
diff --git a/libavformat/metadata.c b/libavformat/metadata.c
index b9b6de7972..e2fe4332b1 100644
--- a/libavformat/metadata.c
+++ b/libavformat/metadata.c
@@ -29,7 +29,7 @@ void ff_metadata_conv(AVDictionary **pm, const AVMetadataConv *d_conv,
     /* TODO: use binary search to look up the two conversion tables
        if the tables are getting big enough that it would matter speed wise */
     const AVMetadataConv *sc, *dc;
-    AVDictionaryEntry *mtag = NULL;
+    const AVDictionaryEntry *mtag = NULL;
     AVDictionary *dst = NULL;
     const char *key;
 
diff --git a/libavformat/mov.c b/libavformat/mov.c
index d0b8b2595b..22168f0f4e 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -2155,7 +2155,7 @@ static void mov_parse_stsd_audio(MOVContext *c, AVIOContext *pb,
     int bits_per_sample, flags;
     uint16_t version = avio_rb16(pb);
     uint32_t id = 0;
-    AVDictionaryEntry *compatible_brands = av_dict_get(c->fc->metadata, "compatible_brands", NULL, AV_DICT_MATCH_CASE);
+    const AVDictionaryEntry *compatible_brands = av_dict_get(c->fc->metadata, "compatible_brands", NULL, AV_DICT_MATCH_CASE);
 
     avio_rb16(pb); /* revision level */
     id = avio_rl32(pb); /* vendor */
@@ -7451,7 +7451,7 @@ static void export_orphan_timecode(AVFormatContext *s)
 
         if (st->codecpar->codec_tag  == MKTAG('t','m','c','d') &&
             !tmcd_is_referenced(s, i + 1)) {
-            AVDictionaryEntry *tcr = av_dict_get(st->metadata, "timecode", NULL, 0);
+            const AVDictionaryEntry *tcr = av_dict_get(st->metadata, "timecode", NULL, 0);
             if (tcr) {
                 av_dict_set(&s->metadata, "timecode", tcr->value, 0);
                 break;
@@ -7614,7 +7614,7 @@ static int mov_read_header(AVFormatContext *s)
         AVStream *st = s->streams[i];
         MOVStreamContext *sc = st->priv_data;
         if (sc->timecode_track > 0) {
-            AVDictionaryEntry *tcr;
+            const AVDictionaryEntry *tcr;
             int tmcd_st_id = -1;
 
             for (j = 0; j < s->nb_streams; j++)
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 1a2f24c410..bc9e77a44c 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -2088,7 +2088,7 @@ static int mov_write_mdcv_tag(AVIOContext *pb, MOVTrack *track)
 
 static void find_compressor(char * compressor_name, int len, MOVTrack *track)
 {
-    AVDictionaryEntry *encoder;
+    const AVDictionaryEntry *encoder;
     int xdcam_res =  (track->par->width == 1280 && track->par->height == 720)
                   || (track->par->width == 1440 && track->par->height == 1080)
                   || (track->par->width == 1920 && track->par->height == 1080);
@@ -2347,7 +2347,7 @@ static int mov_write_tmcd_tag(AVIOContext *pb, MOVTrack *track)
 #if 1
     int frame_duration;
     int nb_frames;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
 
     if (!track->st->avg_frame_rate.num || !track->st->avg_frame_rate.den) {
         av_log(NULL, AV_LOG_ERROR, "avg_frame_rate not set for tmcd track.\n");
@@ -2840,7 +2840,7 @@ static int mov_write_hdlr_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra
             // hdlr.name is used by some players to identify the content title
             // of the track. So if an alternate handler description is
             // specified, use it.
-            AVDictionaryEntry *t;
+            const AVDictionaryEntry *t;
             t = av_dict_get(track->st->metadata, "handler_name", NULL, 0);
             if (t && utf8len(t->value))
                 descr = t->value;
@@ -3312,7 +3312,7 @@ static int mov_write_track_metadata(AVIOContext *pb, AVStream *st,
                                     const char *tag, const char *str)
 {
     int64_t pos = avio_tell(pb);
-    AVDictionaryEntry *t = av_dict_get(st->metadata, str, NULL, 0);
+    const AVDictionaryEntry *t = av_dict_get(st->metadata, str, NULL, 0);
     if (!t || !utf8len(t->value))
         return 0;
 
@@ -3565,11 +3565,11 @@ static int mov_write_string_tag(AVIOContext *pb, const char *name,
     return size;
 }
 
-static AVDictionaryEntry *get_metadata_lang(AVFormatContext *s,
+static const AVDictionaryEntry *get_metadata_lang(AVFormatContext *s,
                                             const char *tag, int *lang)
 {
     int l, len, len2;
-    AVDictionaryEntry *t, *t2 = NULL;
+    const AVDictionaryEntry *t, *t2 = NULL;
     char tag2[16];
 
     *lang = 0;
@@ -3595,7 +3595,7 @@ static int mov_write_string_metadata(AVFormatContext *s, AVIOContext *pb,
                                      int long_style)
 {
     int lang;
-    AVDictionaryEntry *t = get_metadata_lang(s, tag, &lang);
+    const AVDictionaryEntry *t = get_metadata_lang(s, tag, &lang);
     if (!t)
         return 0;
     return mov_write_string_tag(pb, name, t->value, lang, long_style);
@@ -3604,7 +3604,7 @@ static int mov_write_string_metadata(AVFormatContext *s, AVIOContext *pb,
 /* iTunes bpm number */
 static int mov_write_tmpo_tag(AVIOContext *pb, AVFormatContext *s)
 {
-    AVDictionaryEntry *t = av_dict_get(s->metadata, "tmpo", NULL, 0);
+    const AVDictionaryEntry *t = av_dict_get(s->metadata, "tmpo", NULL, 0);
     int size = 0, tmpo = t ? atoi(t->value) : 0;
     if (tmpo) {
         size = 26;
@@ -3626,7 +3626,7 @@ static int mov_write_loci_tag(AVFormatContext *s, AVIOContext *pb)
     int64_t pos = avio_tell(pb);
     double latitude, longitude, altitude;
     int32_t latitude_fix, longitude_fix, altitude_fix;
-    AVDictionaryEntry *t = get_metadata_lang(s, "location", &lang);
+    const AVDictionaryEntry *t = get_metadata_lang(s, "location", &lang);
     const char *ptr, *place = "";
     char *end;
     static const char *astronomical_body = "earth";
@@ -3674,7 +3674,7 @@ static int mov_write_loci_tag(AVFormatContext *s, AVIOContext *pb)
 static int mov_write_trkn_tag(AVIOContext *pb, MOVMuxContext *mov,
                               AVFormatContext *s, int disc)
 {
-    AVDictionaryEntry *t = av_dict_get(s->metadata,
+    const AVDictionaryEntry *t = av_dict_get(s->metadata,
                                        disc ? "disc" : "track",
                                        NULL, 0);
     int size = 0, track = t ? atoi(t->value) : 0;
@@ -3702,7 +3702,7 @@ static int mov_write_int8_metadata(AVFormatContext *s, AVIOContext *pb,
                                    const char *name, const char *tag,
                                    int len)
 {
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     uint8_t num;
     int size = 24 + len;
 
@@ -3811,7 +3811,7 @@ static int mov_write_mdta_hdlr_tag(AVIOContext *pb, MOVMuxContext *mov,
 static int mov_write_mdta_keys_tag(AVIOContext *pb, MOVMuxContext *mov,
                                    AVFormatContext *s)
 {
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     int64_t pos = avio_tell(pb);
     int64_t curpos, entry_pos;
     int count = 0;
@@ -3840,7 +3840,7 @@ static int mov_write_mdta_keys_tag(AVIOContext *pb, MOVMuxContext *mov,
 static int mov_write_mdta_ilst_tag(AVIOContext *pb, MOVMuxContext *mov,
                                    AVFormatContext *s)
 {
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     int64_t pos = avio_tell(pb);
     int count = 1; /* keys are 1-index based */
 
@@ -3885,7 +3885,7 @@ static int mov_write_raw_metadata_tag(AVFormatContext *s, AVIOContext *pb,
                                       const char *name, const char *key)
 {
     int len;
-    AVDictionaryEntry *t;
+    const AVDictionaryEntry *t;
 
     if (!(t = av_dict_get(s->metadata, key, NULL, 0)))
         return 0;
@@ -3923,7 +3923,7 @@ static int mov_write_3gp_udta_tag(AVIOContext *pb, AVFormatContext *s,
                                   const char *tag, const char *str)
 {
     int64_t pos = avio_tell(pb);
-    AVDictionaryEntry *t = av_dict_get(s->metadata, str, NULL, 0);
+    const AVDictionaryEntry *t = av_dict_get(s->metadata, str, NULL, 0);
     if (!t || !utf8len(t->value))
         return 0;
     avio_wb32(pb, 0);   /* size */
@@ -3954,7 +3954,7 @@ static int mov_write_chpl_tag(AVIOContext *pb, AVFormatContext *s)
 
     for (i = 0; i < nb_chapters; i++) {
         AVChapter *c = s->chapters[i];
-        AVDictionaryEntry *t;
+        const AVDictionaryEntry *t;
         avio_wb64(pb, av_rescale_q(c->start, c->time_base, (AVRational){1,10000000}));
 
         if ((t = av_dict_get(c->metadata, "title", NULL, 0))) {
@@ -4040,7 +4040,7 @@ static void mov_write_psp_udta_tag(AVIOContext *pb,
 
 static int mov_write_uuidusmt_tag(AVIOContext *pb, AVFormatContext *s)
 {
-    AVDictionaryEntry *title = av_dict_get(s->metadata, "title", NULL, 0);
+    const AVDictionaryEntry *title = av_dict_get(s->metadata, "title", NULL, 0);
     int64_t pos, pos2;
 
     if (title) {
@@ -4277,7 +4277,7 @@ static int mov_write_isml_manifest(AVIOContext *pb, MOVMuxContext *mov, AVFormat
         char track_name_buf[32] = { 0 };
 
         AVStream *st = track->st;
-        AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,0);
+        const AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,0);
 
         if (track->par->codec_type == AVMEDIA_TYPE_VIDEO && !is_cover_image(st)) {
             type = "video";
@@ -6266,7 +6266,7 @@ static int mov_create_chapter_track(AVFormatContext *s, int tracknum)
 
     for (i = 0; i < s->nb_chapters; i++) {
         AVChapter *c = s->chapters[i];
-        AVDictionaryEntry *t;
+        const AVDictionaryEntry *t;
 
         int64_t end = av_rescale_q(c->end, c->time_base, (AVRational){1,mov->movie_timescale});
         pkt->pts = pkt->dts = av_rescale_q(c->start, c->time_base, (AVRational){1,mov->movie_timescale});
@@ -6630,13 +6630,13 @@ static int mov_init(AVFormatContext *s)
 
     if (   mov->write_tmcd == -1 && (mov->mode == MODE_MOV || mov->mode == MODE_MP4)
         || mov->write_tmcd == 1) {
-        AVDictionaryEntry *global_tcr = av_dict_get(s->metadata, "timecode",
+        const AVDictionaryEntry *global_tcr = av_dict_get(s->metadata, "timecode",
                                                     NULL, 0);
 
         /* +1 tmcd track for each video stream with a timecode */
         for (i = 0; i < s->nb_streams; i++) {
             AVStream *st = s->streams[i];
-            AVDictionaryEntry *t = global_tcr;
+            const AVDictionaryEntry *t = global_tcr;
             if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
                 (t || (t=av_dict_get(st->metadata, "timecode", NULL, 0)))) {
                 AVTimecode tc;
@@ -6696,7 +6696,7 @@ static int mov_init(AVFormatContext *s)
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st= s->streams[i];
         MOVTrack *track= &mov->tracks[i];
-        AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,0);
+        const AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,0);
 
         track->st  = st;
         track->par = st->codecpar;
diff --git a/libavformat/mp3enc.c b/libavformat/mp3enc.c
index c8328b8b9d..79c4b8ef9e 100644
--- a/libavformat/mp3enc.c
+++ b/libavformat/mp3enc.c
@@ -40,7 +40,7 @@
 static int id3v1_set_string(AVFormatContext *s, const char *key,
                             uint8_t *buf, int buf_size)
 {
-    AVDictionaryEntry *tag;
+    const AVDictionaryEntry *tag;
     if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
         av_strlcpy(buf, tag->value, buf_size);
     return !!tag;
@@ -49,7 +49,7 @@ static int id3v1_set_string(AVFormatContext *s, const char *key,
 // refer to: http://id3.org/ID3v1
 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
 {
-    AVDictionaryEntry *tag;
+    const AVDictionaryEntry *tag;
     int i, count = 0;
 
     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
@@ -144,7 +144,7 @@ static int mp3_write_xing(AVFormatContext *s)
 {
     MP3Context       *mp3 = s->priv_data;
     AVCodecParameters *par = s->streams[mp3->audio_stream_idx]->codecpar;
-    AVDictionaryEntry *enc = av_dict_get(s->streams[mp3->audio_stream_idx]->metadata, "encoder", NULL, 0);
+    const AVDictionaryEntry *enc = av_dict_get(s->streams[mp3->audio_stream_idx]->metadata, "encoder", NULL, 0);
     AVIOContext *dyn_ctx;
     int32_t        header;
     MPADecodeHeader  mpah;
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index 98dac17994..b9d34d1584 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -515,7 +515,7 @@ static int mpegts_write_pmt(AVFormatContext *s, MpegTSService *service)
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];
         MpegTSWriteStream *ts_st = st->priv_data;
-        AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL, 0);
+        const AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL, 0);
         const char default_language[] = "und";
         const char *language = lang && strlen(lang->value) >= 3 ? lang->value : default_language;
         enum AVCodecID codec_id = st->codecpar->codec_id;
@@ -965,7 +965,7 @@ static MpegTSService *mpegts_add_service(AVFormatContext *s, int sid,
 {
     MpegTSWrite *ts = s->priv_data;
     MpegTSService *service;
-    AVDictionaryEntry *title, *provider;
+    const AVDictionaryEntry *title, *provider;
     char default_service_name[32];
     const char *service_name;
     const char *provider_name;
@@ -1067,7 +1067,7 @@ static void select_pcr_streams(AVFormatContext *s)
 static int mpegts_init(AVFormatContext *s)
 {
     MpegTSWrite *ts = s->priv_data;
-    AVDictionaryEntry *provider;
+    const AVDictionaryEntry *provider;
     const char *provider_name;
     int i, j;
     int ret;
diff --git a/libavformat/mux.c b/libavformat/mux.c
index 2053a5636e..28e0f5639a 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -227,7 +227,7 @@ static int init_muxer(AVFormatContext *s, AVDictionary **options)
     FFFormatContext *const si = ffformatcontext(s);
     AVDictionary *tmp = NULL;
     const AVOutputFormat *of = s->oformat;
-    AVDictionaryEntry *e;
+    const AVDictionaryEntry *e;
     int ret = 0;
 
     if (options)
diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index 56facbe4b7..846956142f 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -759,9 +759,9 @@ static void mxf_write_identification(AVFormatContext *s)
 {
     MXFContext *mxf = s->priv_data;
     AVIOContext *pb = s->pb;
-    AVDictionaryEntry *com_entry = av_dict_get(s->metadata, "company_name", NULL, 0);
-    AVDictionaryEntry *product_entry = av_dict_get(s->metadata, "product_name", NULL, 0);
-    AVDictionaryEntry *version_entry = av_dict_get(s->metadata, "product_version", NULL, 0);
+    const AVDictionaryEntry *com_entry = av_dict_get(s->metadata, "company_name", NULL, 0);
+    const AVDictionaryEntry *product_entry = av_dict_get(s->metadata, "product_name", NULL, 0);
+    const AVDictionaryEntry *version_entry = av_dict_get(s->metadata, "product_version", NULL, 0);
     const char *company = com_entry ? com_entry->value : "FFmpeg";
     const char *product = product_entry ? product_entry->value : s->oformat != &ff_mxf_opatom_muxer ? "OP1a Muxer" : "OPAtom Muxer";
     const char *platform = s->flags & AVFMT_FLAG_BITEXACT ? "Lavf" : PLATFORM_IDENT;
@@ -1540,7 +1540,7 @@ static int mxf_write_tagged_value(AVFormatContext *s, const char* name, const ch
 static int mxf_write_user_comments(AVFormatContext *s, const AVDictionary *m)
 {
     MXFContext *mxf = s->priv_data;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     int count = 0;
 
     while ((t = av_dict_get(m, "comment_", t, AV_DICT_IGNORE_SUFFIX))) {
@@ -1680,7 +1680,7 @@ static int mxf_write_essence_container_data(AVFormatContext *s)
 static int mxf_write_header_metadata_sets(AVFormatContext *s)
 {
     MXFContext *mxf = s->priv_data;
-    AVDictionaryEntry *entry = NULL;
+    const AVDictionaryEntry *entry = NULL;
     AVStream *st = NULL;
     int i;
     MXFPackage packages[3] = {{0}};
@@ -2479,7 +2479,7 @@ static void mxf_gen_umid(AVFormatContext *s)
 static int mxf_init_timecode(AVFormatContext *s, AVStream *st, AVRational tbc)
 {
     MXFContext *mxf = s->priv_data;
-    AVDictionaryEntry *tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
+    const AVDictionaryEntry *tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
 
     if (!ff_mxf_get_content_package_rate(tbc)) {
         if (s->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL) {
@@ -2655,7 +2655,7 @@ static int mxf_write_header(AVFormatContext *s)
             if (ret < 0)
                 return ret;
         } else if (st->codecpar->codec_type == AVMEDIA_TYPE_DATA) {
-            AVDictionaryEntry *e = av_dict_get(st->metadata, "data_type", NULL, 0);
+            const AVDictionaryEntry *e = av_dict_get(st->metadata, "data_type", NULL, 0);
             if (e && !strcmp(e->value, "vbi_vanc_smpte_436M")) {
                 sc->index = INDEX_S436M;
             } else {
diff --git a/libavformat/nutenc.c b/libavformat/nutenc.c
index 7977980935..54727f21bc 100644
--- a/libavformat/nutenc.c
+++ b/libavformat/nutenc.c
@@ -494,7 +494,7 @@ static int add_info(AVIOContext *bc, const char *type, const char *value)
 static int write_globalinfo(NUTContext *nut, AVIOContext *bc)
 {
     AVFormatContext *s   = nut->avf;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     AVIOContext *dyn_bc;
     uint8_t *dyn_buf = NULL;
     int count        = 0, dyn_size;
@@ -522,7 +522,7 @@ static int write_globalinfo(NUTContext *nut, AVIOContext *bc)
 static int write_streaminfo(NUTContext *nut, AVIOContext *bc, int stream_id) {
     AVFormatContext *s= nut->avf;
     AVStream* st = s->streams[stream_id];
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     AVIOContext *dyn_bc;
     uint8_t *dyn_buf=NULL;
     int count=0, dyn_size, i;
@@ -565,7 +565,7 @@ static int write_chapter(NUTContext *nut, AVIOContext *bc, int id)
 {
     AVIOContext *dyn_bc;
     uint8_t *dyn_buf     = NULL;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     AVChapter *ch        = nut->avf->chapters[id];
     int ret, dyn_size, count = 0;
 
diff --git a/libavformat/riffenc.c b/libavformat/riffenc.c
index ffccfa3d48..be66c7bdce 100644
--- a/libavformat/riffenc.c
+++ b/libavformat/riffenc.c
@@ -337,7 +337,7 @@ void ff_riff_write_info(AVFormatContext *s)
     AVIOContext *pb = s->pb;
     int i;
     int64_t list_pos;
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
 
     ff_metadata_conv(&s->metadata, ff_riff_info_conv, NULL);
 
diff --git a/libavformat/rmenc.c b/libavformat/rmenc.c
index 1b2b0ecf38..d0b76b7a54 100644
--- a/libavformat/rmenc.c
+++ b/libavformat/rmenc.c
@@ -76,7 +76,7 @@ static int rv10_write_header(AVFormatContext *ctx,
     int nb_packets, packet_total_size, packet_max_size, size, packet_avg_size, i;
     int bit_rate, v, duration, flags;
     int data_offset;
-    AVDictionaryEntry *tag;
+    const AVDictionaryEntry *tag;
 
     ffio_wfourcc(s, ".RMF");
     avio_wb32(s,18); /* header size */
diff --git a/libavformat/sapenc.c b/libavformat/sapenc.c
index 9319ee6f80..0c0e17d986 100644
--- a/libavformat/sapenc.c
+++ b/libavformat/sapenc.c
@@ -76,7 +76,7 @@ static int sap_write_header(AVFormatContext *s)
     struct sockaddr_storage localaddr;
     socklen_t addrlen = sizeof(localaddr);
     int udp_fd;
-    AVDictionaryEntry* title = av_dict_get(s->metadata, "title", NULL, 0);
+    const AVDictionaryEntry* title = av_dict_get(s->metadata, "title", NULL, 0);
 
     if (!ff_network_init())
         return AVERROR(EIO);
diff --git a/libavformat/sdp.c b/libavformat/sdp.c
index 1200e553f9..2d8f61f9b8 100644
--- a/libavformat/sdp.c
+++ b/libavformat/sdp.c
@@ -757,7 +757,7 @@ void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
 
 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
 {
-    AVDictionaryEntry *title = av_dict_get(ac[0]->metadata, "title", NULL, 0);
+    const AVDictionaryEntry *title = av_dict_get(ac[0]->metadata, "title", NULL, 0);
     struct sdp_session_level s = { 0 };
     int i, j, port, ttl, is_multicast, index = 0;
     char dst[32], dst_type[5];
diff --git a/libavformat/segment.c b/libavformat/segment.c
index 2b024fd373..b11a183322 100644
--- a/libavformat/segment.c
+++ b/libavformat/segment.c
@@ -349,7 +349,7 @@ static int segment_end(AVFormatContext *s, int write_trailer, int is_last)
     int ret = 0;
     AVTimecode tc;
     AVRational rate;
-    AVDictionaryEntry *tcr;
+    const AVDictionaryEntry *tcr;
     char buf[AV_TIMECODE_STR_SIZE];
     int i;
     int err;
@@ -435,7 +435,7 @@ static int segment_end(AVFormatContext *s, int write_trailer, int is_last)
                 char st_buf[AV_TIMECODE_STR_SIZE];
                 AVTimecode st_tc;
                 AVRational st_rate = s->streams[i]->avg_frame_rate;
-                AVDictionaryEntry *st_tcr = av_dict_get(s->streams[i]->metadata, "timecode", NULL, 0);
+                const AVDictionaryEntry *st_tcr = av_dict_get(s->streams[i]->metadata, "timecode", NULL, 0);
                 if (st_tcr) {
                     if ((av_timecode_init_from_string(&st_tc, st_rate, st_tcr->value, s) < 0)) {
                         av_log(s, AV_LOG_WARNING, "Could not increment stream %d timecode, error occurred during timecode creation.\n", i);
diff --git a/libavformat/smjpegenc.c b/libavformat/smjpegenc.c
index ac5576fa76..56d00c1d1b 100644
--- a/libavformat/smjpegenc.c
+++ b/libavformat/smjpegenc.c
@@ -34,7 +34,7 @@ typedef struct SMJPEGMuxContext {
 
 static int smjpeg_write_header(AVFormatContext *s)
 {
-    AVDictionaryEntry *t = NULL;
+    const AVDictionaryEntry *t = NULL;
     AVIOContext *pb = s->pb;
     int n, tag;
 
diff --git a/libavformat/soxenc.c b/libavformat/soxenc.c
index e24501bacd..9b934f9f6e 100644
--- a/libavformat/soxenc.c
+++ b/libavformat/soxenc.c
@@ -46,7 +46,7 @@ static int sox_write_header(AVFormatContext *s)
     SoXContext *sox = s->priv_data;
     AVIOContext *pb = s->pb;
     AVCodecParameters *par = s->streams[0]->codecpar;
-    AVDictionaryEntry *comment;
+    const AVDictionaryEntry *comment;
     size_t comment_len = 0, comment_size;
 
     comment = av_dict_get(s->metadata, "comment", NULL, 0);
diff --git a/libavformat/ttmlenc.c b/libavformat/ttmlenc.c
index 896fc81958..21aa8e4ed5 100644
--- a/libavformat/ttmlenc.c
+++ b/libavformat/ttmlenc.c
@@ -135,7 +135,7 @@ static int ttml_write_header(AVFormatContext *ctx)
         AVStream    *st = ctx->streams[0];
         AVIOContext *pb = ctx->pb;
 
-        AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,
+        const AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,
                                               0);
         const char *printed_lang = (lang && lang->value) ? lang->value : "";
 
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 509c0ecdce..5aaee9abb0 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -1434,7 +1434,7 @@ static int match_stream_specifier(AVFormatContext *s, AVStream *st,
                 return AVERROR(EINVAL);
             return match && (stream_id == st->id);
         } else if (*spec == 'm' && *(spec + 1) == ':') {
-            AVDictionaryEntry *tag;
+            const AVDictionaryEntry *tag;
             char *key, *val;
             int ret;
 
@@ -1809,7 +1809,7 @@ int ff_is_http_proto(const char *filename) {
 
 int ff_parse_creation_time_metadata(AVFormatContext *s, int64_t *timestamp, int return_seconds)
 {
-    AVDictionaryEntry *entry;
+    const AVDictionaryEntry *entry;
     int64_t parsed_timestamp;
     int ret;
     if ((entry = av_dict_get(s->metadata, "creation_time", NULL, 0))) {
diff --git a/libavformat/vorbiscomment.c b/libavformat/vorbiscomment.c
index 13ee065a44..0340465f57 100644
--- a/libavformat/vorbiscomment.c
+++ b/libavformat/vorbiscomment.c
@@ -45,7 +45,7 @@ int64_t ff_vorbiscomment_length(const AVDictionary *m, const char *vendor_string
     len += strlen(vendor_string);
     if (chapters && nb_chapters) {
         for (int i = 0; i < nb_chapters; i++) {
-            AVDictionaryEntry *tag = NULL;
+            const AVDictionaryEntry *tag = NULL;
             len += 4 + 12 + 1 + 10;
             while ((tag = av_dict_get(chapters[i]->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
                 int64_t len1 = !strcmp(tag->key, "title") ? 4 : strlen(tag->key);
@@ -54,7 +54,7 @@ int64_t ff_vorbiscomment_length(const AVDictionary *m, const char *vendor_string
         }
     }
     if (m) {
-        AVDictionaryEntry *tag = NULL;
+        const AVDictionaryEntry *tag = NULL;
         while ((tag = av_dict_get(m, "", tag, AV_DICT_IGNORE_SUFFIX))) {
             len += 4 +strlen(tag->key) + 1 + strlen(tag->value);
         }
@@ -77,7 +77,7 @@ int ff_vorbiscomment_write(AVIOContext *pb, const AVDictionary *m,
     }
     if (m) {
         int count = av_dict_count(m) + cm_count;
-        AVDictionaryEntry *tag = NULL;
+        const AVDictionaryEntry *tag = NULL;
         avio_wl32(pb, count);
         while ((tag = av_dict_get(m, "", tag, AV_DICT_IGNORE_SUFFIX))) {
             int64_t len1 = strlen(tag->key);
diff --git a/libavformat/wavenc.c b/libavformat/wavenc.c
index 2317700be1..c1189aa3ac 100644
--- a/libavformat/wavenc.c
+++ b/libavformat/wavenc.c
@@ -88,7 +88,7 @@ typedef struct WAVMuxContext {
 #if CONFIG_WAV_MUXER
 static inline void bwf_write_bext_string(AVFormatContext *s, const char *key, int maxlen)
 {
-    AVDictionaryEntry *tag;
+    const AVDictionaryEntry *tag;
     size_t len = 0;
 
     if (tag = av_dict_get(s->metadata, key, NULL, 0)) {
@@ -102,7 +102,7 @@ static inline void bwf_write_bext_string(AVFormatContext *s, const char *key, in
 
 static void bwf_write_bext_chunk(AVFormatContext *s)
 {
-    AVDictionaryEntry *tmp_tag;
+    const AVDictionaryEntry *tmp_tag;
     uint64_t time_reference = 0;
     int64_t bext = ff_start_tag(s->pb, "bext");
 
diff --git a/libavformat/webmdashenc.c b/libavformat/webmdashenc.c
index cf69bd35b1..0dfc75c33d 100644
--- a/libavformat/webmdashenc.c
+++ b/libavformat/webmdashenc.c
@@ -68,7 +68,7 @@ static double get_duration(AVFormatContext *s)
     int i = 0;
     double max = 0.0;
     for (i = 0; i < s->nb_streams; i++) {
-        AVDictionaryEntry *duration = av_dict_get(s->streams[i]->metadata,
+        const AVDictionaryEntry *duration = av_dict_get(s->streams[i]->metadata,
                                                   DURATION, NULL, 0);
         if (!duration || atof(duration->value) < 0) continue;
         if (atof(duration->value) > max) max = atof(duration->value);
@@ -127,11 +127,11 @@ static void write_footer(AVFormatContext *s)
 static int subsegment_alignment(AVFormatContext *s, const AdaptationSet *as)
 {
     int i;
-    AVDictionaryEntry *gold = av_dict_get(s->streams[as->streams[0]]->metadata,
+    const AVDictionaryEntry *gold = av_dict_get(s->streams[as->streams[0]]->metadata,
                                           CUE_TIMESTAMPS, NULL, 0);
     if (!gold) return 0;
     for (i = 1; i < as->nb_streams; i++) {
-        AVDictionaryEntry *ts = av_dict_get(s->streams[as->streams[i]]->metadata,
+        const AVDictionaryEntry *ts = av_dict_get(s->streams[as->streams[i]]->metadata,
                                             CUE_TIMESTAMPS, NULL, 0);
         if (!ts || !av_strstart(ts->value, gold->value, NULL)) return 0;
     }
@@ -142,13 +142,13 @@ static int bitstream_switching(AVFormatContext *s, const AdaptationSet *as)
 {
     int i;
     const AVStream *gold_st = s->streams[as->streams[0]];
-    AVDictionaryEntry *gold_track_num = av_dict_get(gold_st->metadata,
+    const AVDictionaryEntry *gold_track_num = av_dict_get(gold_st->metadata,
                                                     TRACK_NUMBER, NULL, 0);
     AVCodecParameters *gold_par = gold_st->codecpar;
     if (!gold_track_num) return 0;
     for (i = 1; i < as->nb_streams; i++) {
         const AVStream *st = s->streams[as->streams[i]];
-        AVDictionaryEntry *track_num = av_dict_get(st->metadata,
+        const AVDictionaryEntry *track_num = av_dict_get(st->metadata,
                                                    TRACK_NUMBER, NULL, 0);
         AVCodecParameters *par = st->codecpar;
         if (!track_num ||
@@ -174,7 +174,7 @@ static int write_representation(AVFormatContext *s, AVStream *st, char *id,
     WebMDashMuxContext *w = s->priv_data;
     AVIOContext *pb = s->pb;
     const AVCodecParameters *par = st->codecpar;
-    AVDictionaryEntry *bandwidth = av_dict_get(st->metadata, BANDWIDTH, NULL, 0);
+    const AVDictionaryEntry *bandwidth = av_dict_get(st->metadata, BANDWIDTH, NULL, 0);
     const char *bandwidth_str;
     avio_printf(pb, "<Representation id=\"%s\"", id);
     if (bandwidth) {
@@ -202,10 +202,10 @@ static int write_representation(AVFormatContext *s, AVStream *st, char *id,
         avio_printf(pb, " startsWithSAP=\"1\"");
         avio_printf(pb, ">");
     } else {
-        AVDictionaryEntry *irange = av_dict_get(st->metadata, INITIALIZATION_RANGE, NULL, 0);
-        AVDictionaryEntry *cues_start = av_dict_get(st->metadata, CUES_START, NULL, 0);
-        AVDictionaryEntry *cues_end = av_dict_get(st->metadata, CUES_END, NULL, 0);
-        AVDictionaryEntry *filename = av_dict_get(st->metadata, FILENAME, NULL, 0);
+        const AVDictionaryEntry *irange = av_dict_get(st->metadata, INITIALIZATION_RANGE, NULL, 0);
+        const AVDictionaryEntry *cues_start = av_dict_get(st->metadata, CUES_START, NULL, 0);
+        const AVDictionaryEntry *cues_end = av_dict_get(st->metadata, CUES_END, NULL, 0);
+        const AVDictionaryEntry *filename = av_dict_get(st->metadata, FILENAME, NULL, 0);
         if (!irange || !cues_start || !cues_end || !filename)
             return AVERROR(EINVAL);
 
@@ -304,7 +304,7 @@ static int write_adaptation_set(AVFormatContext *s, int as_index)
     AdaptationSet *as = &w->as[as_index];
     const AVStream *st = s->streams[as->streams[0]];
     AVCodecParameters *par = st->codecpar;
-    AVDictionaryEntry *lang;
+    const AVDictionaryEntry *lang;
     AVIOContext *pb = s->pb;
     int i;
     static const char boolean[2][6] = { "false", "true" };
@@ -344,7 +344,7 @@ static int write_adaptation_set(AVFormatContext *s, int as_index)
                 boolean[w->is_live || subsegment_alignment(s, as)]);
 
     for (i = 0; i < as->nb_streams; i++) {
-        AVDictionaryEntry *kf = av_dict_get(s->streams[as->streams[i]]->metadata,
+        const AVDictionaryEntry *kf = av_dict_get(s->streams[as->streams[i]]->metadata,
                                             CLUSTER_KEYFRAME, NULL, 0);
         if (!w->is_live && (!kf || !strncmp(kf->value, "0", 1))) subsegmentStartsWithSAP = 0;
     }
@@ -352,7 +352,7 @@ static int write_adaptation_set(AVFormatContext *s, int as_index)
     avio_printf(pb, ">\n");
 
     if (w->is_live) {
-        AVDictionaryEntry *filename =
+        const AVDictionaryEntry *filename =
             av_dict_get(st->metadata, FILENAME, NULL, 0);
         char *underscore_pos, *period_pos;
         int ret;
@@ -380,7 +380,7 @@ static int write_adaptation_set(AVFormatContext *s, int as_index)
         AVStream *st = s->streams[as->streams[i]];
         int ret;
         if (w->is_live) {
-            AVDictionaryEntry *filename =
+            const AVDictionaryEntry *filename =
                 av_dict_get(st->metadata, FILENAME, NULL, 0);
             if (!filename)
                 return AVERROR(EINVAL);
diff --git a/libavformat/wtvenc.c b/libavformat/wtvenc.c
index 9c67a6d3e8..e35c9909c0 100644
--- a/libavformat/wtvenc.c
+++ b/libavformat/wtvenc.c
@@ -670,7 +670,7 @@ static void write_table_entries_attrib(AVFormatContext *s)
 {
     WtvContext *wctx = s->priv_data;
     AVIOContext *pb = s->pb;
-    AVDictionaryEntry *tag = 0;
+    const AVDictionaryEntry *tag = 0;
 
     ff_standardize_creation_time(s);
     //FIXME: translate special tags (e.g. WM/Bitrate) to binary representation
@@ -698,7 +698,7 @@ static void write_table_redirector_legacy_attrib(AVFormatContext *s)
 {
     WtvContext *wctx = s->priv_data;
     AVIOContext *pb = s->pb;
-    AVDictionaryEntry *tag = 0;
+    const AVDictionaryEntry *tag = 0;
     int64_t pos = 0;
 
     //FIXME: translate special tags to binary representation
