diff --git a/libav/au.c b/libav/au.c
index 5b4c84859a..8c3d62a595 100644
--- a/libav/au.c
+++ b/libav/au.c
@@ -32,7 +32,7 @@
 #define AU_UNKOWN_SIZE ((UINT32)(~0))
 
 /* The ffmpeg codecs we support, and the IDs they have in the file */
-CodecTag codec_au_tags[] = {
+static const CodecTag codec_au_tags[] = {
     { CODEC_ID_PCM_MULAW, 1 },
     { CODEC_ID_PCM_S16BE, 3 },
     { CODEC_ID_PCM_ALAW, 27 },
@@ -40,7 +40,7 @@ CodecTag codec_au_tags[] = {
 };
 
 /* AUDIO_FILE header */
-int put_au_header(ByteIOContext *pb, AVCodecContext *enc)
+static int put_au_header(ByteIOContext *pb, AVCodecContext *enc)
 {
     int tag;
 
diff --git a/libav/audio.c b/libav/audio.c
index bef3e466cc..06aad4e8e2 100644
--- a/libav/audio.c
+++ b/libav/audio.c
@@ -272,7 +272,7 @@ static int audio_read_close(AVFormatContext *s1)
     return 0;
 }
 
-AVInputFormat audio_in_format = {
+static AVInputFormat audio_in_format = {
     "audio_device",
     "audio grab and output",
     sizeof(AudioData),
@@ -283,7 +283,7 @@ AVInputFormat audio_in_format = {
     .flags = AVFMT_NOFILE,
 };
 
-AVOutputFormat audio_out_format = {
+static AVOutputFormat audio_out_format = {
     "audio_device",
     "audio grab and output",
     "",
diff --git a/libav/avformat.h b/libav/avformat.h
index 37a2a13e5a..305085dba9 100644
--- a/libav/avformat.h
+++ b/libav/avformat.h
@@ -335,7 +335,6 @@ int strstart(const char *str, const char *val, const char **ptr);
 int stristart(const char *str, const char *val, const char **ptr);
 void pstrcpy(char *buf, int buf_size, const char *str);
 char *pstrcat(char *buf, int buf_size, const char *s);
-int match_ext(const char *filename, const char *extensions);
 
 struct in_addr;
 int resolve_host(struct in_addr *sin_addr, const char *hostname);
diff --git a/libav/avi.h b/libav/avi.h
index a0acd28848..d1b5eb5789 100644
--- a/libav/avi.h
+++ b/libav/avi.h
@@ -6,7 +6,7 @@
 #define AVIF_WASCAPTUREFILE	0x00010000
 #define AVIF_COPYRIGHTED	0x00020000
 
-offset_t start_tag(ByteIOContext *pb, char *tag);
+offset_t start_tag(ByteIOContext *pb, const char *tag);
 void end_tag(ByteIOContext *pb, offset_t start);
 
 typedef struct CodecTag {
@@ -15,14 +15,14 @@ typedef struct CodecTag {
     unsigned int invalid_asf : 1;
 } CodecTag;
 
-void put_bmp_header(ByteIOContext *pb, AVCodecContext *enc, CodecTag *tags, int for_asf);
+void put_bmp_header(ByteIOContext *pb, AVCodecContext *enc, const CodecTag *tags, int for_asf);
 int put_wav_header(ByteIOContext *pb, AVCodecContext *enc);
 int wav_codec_get_id(unsigned int tag, int bps);
 void get_wav_header(ByteIOContext *pb, AVCodecContext *codec, 
                     int has_extra_data);
 
-extern CodecTag codec_bmp_tags[];
-extern CodecTag codec_wav_tags[];
+extern const CodecTag codec_bmp_tags[];
+extern const CodecTag codec_wav_tags[];
 
 unsigned int codec_get_tag(const CodecTag *tags, int id);
 int codec_get_id(const CodecTag *tags, unsigned int tag);
diff --git a/libav/crc.c b/libav/crc.c
index dddc6e7588..553ab537cb 100644
--- a/libav/crc.c
+++ b/libav/crc.c
@@ -91,7 +91,7 @@ static int crc_write_trailer(struct AVFormatContext *s)
     return 0;
 }
 
-AVOutputFormat crc_format = {
+static AVOutputFormat crc_format = {
     "crc",
     "crc testing format",
     NULL,
diff --git a/libav/dv.c b/libav/dv.c
index 44caf5b2bf..1f152a2fba 100644
--- a/libav/dv.c
+++ b/libav/dv.c
@@ -49,8 +49,7 @@ static int dv_read_header(AVFormatContext *s,
 }
 
 /* XXX: build fake audio stream when DV audio decoder will be finished */
-int dv_read_packet(AVFormatContext *s,
-                   AVPacket *pkt)
+static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, size, dsf;
     uint8_t buf[4];
@@ -77,12 +76,12 @@ int dv_read_packet(AVFormatContext *s,
     return ret;
 }
 
-int dv_read_close(AVFormatContext *s)
+static int dv_read_close(AVFormatContext *s)
 {
     return 0;
 }
 
-AVInputFormat dv_iformat = {
+static AVInputFormat dv_iformat = {
     "dv",
     "DV video format",
     sizeof(DVDemuxContext),
diff --git a/libav/ffm.c b/libav/ffm.c
index dba0886543..c21599c69f 100644
--- a/libav/ffm.c
+++ b/libav/ffm.c
@@ -651,7 +651,7 @@ static int ffm_probe(AVProbeData *p)
     return 0;
 }
 
-AVInputFormat ffm_iformat = {
+static AVInputFormat ffm_iformat = {
     "ffm",
     "ffm format",
     sizeof(FFMContext),
@@ -662,7 +662,7 @@ AVInputFormat ffm_iformat = {
     ffm_seek,
 };
 
-AVOutputFormat ffm_oformat = {
+static AVOutputFormat ffm_oformat = {
     "ffm",
     "ffm format",
     "",
diff --git a/libav/grab.c b/libav/grab.c
index c19d2c4175..60368d40b7 100644
--- a/libav/grab.c
+++ b/libav/grab.c
@@ -312,7 +312,7 @@ static int grab_read_close(AVFormatContext *s1)
     return 0;
 }
 
-AVInputFormat video_grab_device_format = {
+static AVInputFormat video_grab_device_format = {
     "video_grab_device",
     "video grab",
     sizeof(VideoData),
@@ -961,7 +961,7 @@ static int aiw_grab_read_close(AVFormatContext *s1)
     return 0;
 }
 
-AVInputFormat aiw_grab_device_format = {
+static AVInputFormat aiw_grab_device_format = {
     "aiw_grab_device",
     "All-In-Wonder (km read-based) video grab",
     sizeof(AIWVideoData),
diff --git a/libav/img.c b/libav/img.c
index 70bf2a180a..7d092d8547 100644
--- a/libav/img.c
+++ b/libav/img.c
@@ -719,7 +719,7 @@ static int img_write_trailer(AVFormatContext *s)
     return 0;
 }
 
-AVInputFormat pgm_iformat = {
+static AVInputFormat pgm_iformat = {
     "pgm",
     "pgm image format",
     sizeof(VideoData),
@@ -732,7 +732,7 @@ AVInputFormat pgm_iformat = {
     .extensions = "pgm",
 };
 
-AVOutputFormat pgm_oformat = {
+static AVOutputFormat pgm_oformat = {
     "pgm",
     "pgm image format",
     "",
@@ -746,7 +746,7 @@ AVOutputFormat pgm_oformat = {
     AVFMT_NOFILE | AVFMT_NEEDNUMBER,
 };
 
-AVInputFormat pgmyuv_iformat = {
+static AVInputFormat pgmyuv_iformat = {
     "pgmyuv",
     "pgm with YUV content image format",
     sizeof(VideoData),
@@ -758,7 +758,7 @@ AVInputFormat pgmyuv_iformat = {
     AVFMT_NOFILE | AVFMT_NEEDNUMBER,
 };
 
-AVOutputFormat pgmyuv_oformat = {
+static AVOutputFormat pgmyuv_oformat = {
     "pgmyuv",
     "pgm with YUV content image format",
     "",
@@ -772,7 +772,7 @@ AVOutputFormat pgmyuv_oformat = {
     AVFMT_NOFILE | AVFMT_NEEDNUMBER,
 };
 
-AVInputFormat ppm_iformat = {
+static AVInputFormat ppm_iformat = {
     "ppm",
     "ppm image format",
     sizeof(VideoData),
@@ -785,7 +785,7 @@ AVInputFormat ppm_iformat = {
     .extensions = "ppm",
 };
 
-AVOutputFormat ppm_oformat = {
+static AVOutputFormat ppm_oformat = {
     "ppm",
     "ppm image format",
     "",
@@ -799,7 +799,7 @@ AVOutputFormat ppm_oformat = {
     AVFMT_NOFILE | AVFMT_NEEDNUMBER | AVFMT_RGB24,
 };
 
-AVInputFormat imgyuv_iformat = {
+static AVInputFormat imgyuv_iformat = {
     ".Y.U.V",
     ".Y.U.V format",
     sizeof(VideoData),
@@ -812,7 +812,7 @@ AVInputFormat imgyuv_iformat = {
     .extensions = "Y",
 };
 
-AVOutputFormat imgyuv_oformat = {
+static AVOutputFormat imgyuv_oformat = {
     ".Y.U.V",
     ".Y.U.V format",
     "",
@@ -826,7 +826,7 @@ AVOutputFormat imgyuv_oformat = {
     AVFMT_NOFILE | AVFMT_NEEDNUMBER,
 };
 
-AVInputFormat pgmpipe_iformat = {
+static AVInputFormat pgmpipe_iformat = {
     "pgmpipe",
     "PGM pipe format",
     sizeof(VideoData),
@@ -837,7 +837,7 @@ AVInputFormat pgmpipe_iformat = {
     NULL,
 };
 
-AVOutputFormat pgmpipe_oformat = {
+static AVOutputFormat pgmpipe_oformat = {
     "pgmpipe",
     "PGM pipe format",
     "",
@@ -850,7 +850,7 @@ AVOutputFormat pgmpipe_oformat = {
     img_write_trailer,
 };
 
-AVInputFormat pgmyuvpipe_iformat = {
+static AVInputFormat pgmyuvpipe_iformat = {
     "pgmyuvpipe",
     "PGM YUV pipe format",
     sizeof(VideoData),
@@ -861,7 +861,7 @@ AVInputFormat pgmyuvpipe_iformat = {
     NULL,
 };
 
-AVOutputFormat pgmyuvpipe_oformat = {
+static AVOutputFormat pgmyuvpipe_oformat = {
     "pgmyuvpipe",
     "PGM YUV pipe format",
     "",
@@ -874,7 +874,7 @@ AVOutputFormat pgmyuvpipe_oformat = {
     img_write_trailer,
 };
 
-AVInputFormat ppmpipe_iformat = {
+static AVInputFormat ppmpipe_iformat = {
     "ppmpipe",
     "PPM pipe format",
     sizeof(VideoData),
@@ -886,7 +886,7 @@ AVInputFormat ppmpipe_iformat = {
     .flags = AVFMT_RGB24,
 };
 
-AVOutputFormat ppmpipe_oformat = {
+static AVOutputFormat ppmpipe_oformat = {
     "ppmpipe",
     "PPM pipe format",
     "",
@@ -901,7 +901,7 @@ AVOutputFormat ppmpipe_oformat = {
 };
 
 
-AVOutputFormat yuv4mpegpipe_oformat = {
+static AVOutputFormat yuv4mpegpipe_oformat = {
     "yuv4mpegpipe",
     "YUV4MPEG pipe format",
     "",
diff --git a/libav/ogg.c b/libav/ogg.c
index 61d8ebb4e5..bd2547f4f9 100644
--- a/libav/ogg.c
+++ b/libav/ogg.c
@@ -148,7 +148,7 @@ static int ogg_write_trailer(AVFormatContext *avfcontext) {
 }
 
 
-AVOutputFormat ogg_oformat = {
+static AVOutputFormat ogg_oformat = {
     "ogg",
     "Ogg Vorbis",
     "audio/x-vorbis",
diff --git a/libav/rm.c b/libav/rm.c
index e8efbe112b..be90a27c89 100644
--- a/libav/rm.c
+++ b/libav/rm.c
@@ -742,7 +742,7 @@ static int rm_probe(AVProbeData *p)
         return 0;
 }
 
-AVInputFormat rm_iformat = {
+static AVInputFormat rm_iformat = {
     "rm",
     "rm format",
     sizeof(RMContext),
@@ -752,7 +752,7 @@ AVInputFormat rm_iformat = {
     rm_read_close,
 };
 
-AVOutputFormat rm_oformat = {
+static AVOutputFormat rm_oformat = {
     "rm",
     "rm format",
     "audio/x-pn-realaudio",
diff --git a/libav/utils.c b/libav/utils.c
index 78004d699b..c810d0c512 100644
--- a/libav/utils.c
+++ b/libav/utils.c
@@ -54,7 +54,7 @@ void av_register_output_format(AVOutputFormat *format)
     format->next = NULL;
 }
 
-int match_ext(const char *filename, const char *extensions)
+static int match_ext(const char *filename, const char *extensions)
 {
     const char *ext, *p;
     char ext1[32], *q;