diff --git a/libavformat/oggdec.c b/libavformat/oggdec.c
index 5459e1784b3a754fe748f8ad38c84106731667d3..ceec6442b41a8559869c6dff04bf16137f871faf 100644
--- a/libavformat/oggdec.c
+++ b/libavformat/oggdec.c
@@ -37,7 +37,7 @@
 #define MAX_PAGE_SIZE 65307
 #define DECODER_BUFFER_SIZE MAX_PAGE_SIZE
 
-static ogg_codec_t *ogg_codecs[] = {
+static const ogg_codec_t * const ogg_codecs[] = {
     &speex_codec,
     &vorbis_codec,
     &theora_codec,
@@ -126,7 +126,7 @@ ogg_reset (ogg_t * ogg)
     return 0;
 }
 
-static ogg_codec_t *
+static const ogg_codec_t *
 ogg_find_codec (uint8_t * buf, int size)
 {
     int i;
diff --git a/libavformat/oggdec.h b/libavformat/oggdec.h
index 4e88d0e3931659bcdb0de676164adfe12b15e5b7..1be3fc194372a49ba46c866dbc668523cb891f83 100644
--- a/libavformat/oggdec.h
+++ b/libavformat/oggdec.h
@@ -75,15 +75,15 @@ typedef struct ogg {
 #define OGG_FLAG_BOS  2
 #define OGG_FLAG_EOS  4
 
-extern ogg_codec_t flac_codec;
-extern ogg_codec_t ogm_audio_codec;
-extern ogg_codec_t ogm_old_codec;
-extern ogg_codec_t ogm_text_codec;
-extern ogg_codec_t ogm_video_codec;
-extern ogg_codec_t old_flac_codec;
-extern ogg_codec_t speex_codec;
-extern ogg_codec_t theora_codec;
-extern ogg_codec_t vorbis_codec;
+extern const ogg_codec_t flac_codec;
+extern const ogg_codec_t ogm_audio_codec;
+extern const ogg_codec_t ogm_old_codec;
+extern const ogg_codec_t ogm_text_codec;
+extern const ogg_codec_t ogm_video_codec;
+extern const ogg_codec_t old_flac_codec;
+extern const ogg_codec_t speex_codec;
+extern const ogg_codec_t theora_codec;
+extern const ogg_codec_t vorbis_codec;
 
 extern int vorbis_comment(AVFormatContext *ms, uint8_t *buf, int size);
 
diff --git a/libavformat/oggparseflac.c b/libavformat/oggparseflac.c
index 386a70ebd44cf3ff7228638604c174c718a95c81..7a0084e7fbeb17ea43da2c62bcfe9f5d342cbda2 100644
--- a/libavformat/oggparseflac.c
+++ b/libavformat/oggparseflac.c
@@ -85,13 +85,13 @@ old_flac_header (AVFormatContext * s, int idx)
     return 0;
 }
 
-ogg_codec_t flac_codec = {
+const ogg_codec_t flac_codec = {
     .magic = "\177FLAC",
     .magicsize = 5,
     .header = flac_header
 };
 
-ogg_codec_t old_flac_codec = {
+const ogg_codec_t old_flac_codec = {
     .magic = "fLaC",
     .magicsize = 4,
     .header = old_flac_header
diff --git a/libavformat/oggparseogm.c b/libavformat/oggparseogm.c
index af1e4cfaaa5dd7d303bca1241d7f679decd886ba..72a3aed98f9d2dbc745daf5023a9acb2f992cc88 100644
--- a/libavformat/oggparseogm.c
+++ b/libavformat/oggparseogm.c
@@ -149,28 +149,28 @@ ogm_packet(AVFormatContext *s, int idx)
     return 0;
 }
 
-ogg_codec_t ogm_video_codec = {
+const ogg_codec_t ogm_video_codec = {
     .magic = "\001video",
     .magicsize = 6,
     .header = ogm_header,
     .packet = ogm_packet
 };
 
-ogg_codec_t ogm_audio_codec = {
+const ogg_codec_t ogm_audio_codec = {
     .magic = "\001audio",
     .magicsize = 6,
     .header = ogm_header,
     .packet = ogm_packet
 };
 
-ogg_codec_t ogm_text_codec = {
+const ogg_codec_t ogm_text_codec = {
     .magic = "\001text",
     .magicsize = 5,
     .header = ogm_header,
     .packet = ogm_packet
 };
 
-ogg_codec_t ogm_old_codec = {
+const ogg_codec_t ogm_old_codec = {
     .magic = "\001Direct Show Samples embedded in Ogg",
     .magicsize = 35,
     .header = ogm_dshow_header,
diff --git a/libavformat/oggparsespeex.c b/libavformat/oggparsespeex.c
index ad2f0b7db44fb37f4952efbae6a9c266612ae20c..1612f2e632c7ac08ff33656ab6d12317239fb8df 100644
--- a/libavformat/oggparsespeex.c
+++ b/libavformat/oggparsespeex.c
@@ -54,7 +54,7 @@ static int speex_header(AVFormatContext *s, int idx) {
     return 0;
 }
 
-ogg_codec_t speex_codec = {
+const ogg_codec_t speex_codec = {
     .magic = "Speex   ",
     .magicsize = 8,
     .header = speex_header
diff --git a/libavformat/oggparsetheora.c b/libavformat/oggparsetheora.c
index 1a16ca501aeb42f976c37db0f232aa3ca0539e1d..d1a4fdf9984e622ab51ef1c6ff8dce9522ab930c 100644
--- a/libavformat/oggparsetheora.c
+++ b/libavformat/oggparsetheora.c
@@ -130,7 +130,7 @@ theora_gptopts(AVFormatContext *ctx, int idx, uint64_t gp)
     return iframe + pframe;
 }
 
-ogg_codec_t theora_codec = {
+const ogg_codec_t theora_codec = {
     .magic = "\200theora",
     .magicsize = 7,
     .header = theora_header,
diff --git a/libavformat/oggparsevorbis.c b/libavformat/oggparsevorbis.c
index b116273f8c21c6cdf23d8461e6bb26831b809bd1..a773847f826efc171dd2aa9c106c49d765599435 100644
--- a/libavformat/oggparsevorbis.c
+++ b/libavformat/oggparsevorbis.c
@@ -219,7 +219,7 @@ vorbis_header (AVFormatContext * s, int idx)
     return os->seq < 3;
 }
 
-ogg_codec_t vorbis_codec = {
+const ogg_codec_t vorbis_codec = {
     .magic = "\001vorbis",
     .magicsize = 7,
     .header = vorbis_header