diff --git a/common/av_common.c b/common/av_common.c
index 89a647593f..5d07349af0 100644
--- a/common/av_common.c
+++ b/common/av_common.c
@@ -40,20 +40,6 @@
 #include "av_common.h"
 #include "codecs.h"
 
-int mp_lavc_set_extradata(AVCodecContext *avctx, void *ptr, int size)
-{
-    if (size) {
-        av_free(avctx->extradata);
-        avctx->extradata_size = 0;
-        avctx->extradata = av_mallocz(size + AV_INPUT_BUFFER_PADDING_SIZE);
-        if (!avctx->extradata)
-            return -1;
-        avctx->extradata_size = size;
-        memcpy(avctx->extradata, ptr, size);
-    }
-    return 0;
-}
-
 enum AVMediaType mp_to_av_stream_type(int type)
 {
     switch (type) {
diff --git a/common/av_common.h b/common/av_common.h
index 2c97ad19cc..1f05e14fab 100644
--- a/common/av_common.h
+++ b/common/av_common.h
@@ -31,7 +31,6 @@ struct mp_codec_params;
 struct AVDictionary;
 struct mp_log;
 
-int mp_lavc_set_extradata(AVCodecContext *avctx, void *ptr, int size);
 enum AVMediaType mp_to_av_stream_type(int type);
 AVCodecParameters *mp_codec_params_to_av(const struct mp_codec_params *c);
 int mp_set_avctx_codec_headers(AVCodecContext *avctx, const struct mp_codec_params *c);