diff --git a/doc/APIchanges b/doc/APIchanges
index 7545fa51dce7dacf3a46a43055946d9ba1053473..87de464ebbc15bb023e533b5604bf0c127016ddd 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -13,6 +13,9 @@ libavutil:   2011-04-18
 
 API changes, most recent first:
 
+2012-01-31 - xxxxxxx - lavc 54.01.0
+  Add avcodec_is_open() function.
+
 2012-01-30 - xxxxxxx - lavu 51.22.0 - intfloat.h
   Add a new installed header libavutil/intfloat.h with int/float punning
   functions.
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index a6bb6863f2d4f51562d18a84595087ffca17a0f4..284c7f8cb821251437ae418576b0fe09449e5159 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -4183,4 +4183,10 @@ enum AVMediaType avcodec_get_type(enum CodecID codec_id);
  */
 const AVClass *avcodec_get_class(void);
 
+/**
+ * @return a positive value if s is open (i.e. avcodec_open2() was called on it
+ * with no corresponding avcodec_close()), 0 otherwise.
+ */
+int avcodec_is_open(AVCodecContext *s);
+
 #endif /* AVCODEC_AVCODEC_H */
diff --git a/libavcodec/options.c b/libavcodec/options.c
index c416b4aa4f18b2564a61f9fc4aa7caab56f040bf..52fc66400a1f232bb00243c5958208867213cb19 100644
--- a/libavcodec/options.c
+++ b/libavcodec/options.c
@@ -485,7 +485,7 @@ AVCodecContext *avcodec_alloc_context3(AVCodec *codec){
 
 int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src)
 {
-    if (dest->codec) { // check that the dest context is uninitialized
+    if (avcodec_is_open(dest)) { // check that the dest context is uninitialized
         av_log(dest, AV_LOG_ERROR,
                "Tried to copy AVCodecContext %p into already-initialized %p\n",
                src, dest);
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 34a4122d5d93f381e36976527e3077d9d9baa028..3ee6b09f748b76210ef1aeb4eedbd9a1aa039efc 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -627,6 +627,9 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, AVCodec *codec, AVD
     int ret = 0;
     AVDictionary *tmp = NULL;
 
+    if (avcodec_is_open(avctx))
+        return 0;
+
     if (avctx->extradata_size < 0 || avctx->extradata_size >= FF_MAX_EXTRADATA_SIZE)
         return AVERROR(EINVAL);
 
@@ -1803,3 +1806,8 @@ enum AVMediaType avcodec_get_type(enum CodecID codec_id)
 
     return AVMEDIA_TYPE_UNKNOWN;
 }
+
+int avcodec_is_open(AVCodecContext *s)
+{
+    return !!s->internal;
+}
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 9c59947fb719ab8eaae9885fdbf09516363c85f6..1b2239a068f9af787c719171d285e392437b6eb0 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2006,7 +2006,7 @@ static int try_decode_frame(AVStream *st, AVPacket *avpkt, AVDictionary **option
     AVFrame picture;
     AVPacket pkt = *avpkt;
 
-    if(!st->codec->codec){
+    if (!avcodec_is_open(st->codec)) {
         AVDictionary *thread_opt = NULL;
 
         codec = avcodec_find_decoder(st->codec->codec_id);
@@ -2354,8 +2354,7 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
     // close codecs which were opened in try_decode_frame()
     for(i=0;i<ic->nb_streams;i++) {
         st = ic->streams[i];
-        if(st->codec->codec)
-            avcodec_close(st->codec);
+        avcodec_close(st->codec);
     }
     for(i=0;i<ic->nb_streams;i++) {
         st = ic->streams[i];