diff --git a/src/dvr/dvr_rec.c b/src/dvr/dvr_rec.c
index 3b61430c..4929a738 100644
--- a/src/dvr/dvr_rec.c
+++ b/src/dvr/dvr_rec.c
@@ -253,7 +253,7 @@ dvr_rec_start(dvr_entry_t *de, htsmsg_t *m)
   enum CodecType codec_type;
   const char *codec_name;
   char urlname[512];
-  int err;
+  int err, r;
   htsmsg_field_t *f;
   htsmsg_t *sub, *streams;
   const char *type, *lang;
@@ -356,7 +356,11 @@ dvr_rec_start(dvr_entry_t *de, htsmsg_t *m)
     ctx->codec_id   = codec_id;
     ctx->codec_type = codec_type;
 
-    if(avcodec_open(ctx, codec) < 0) {
+    pthread_mutex_lock(&ffmpeg_lock);
+    r = avcodec_open(ctx, codec);
+    pthread_mutex_unlock(&ffmpeg_lock);
+
+    if(r < 0) {
       tvhlog(LOG_ERR, "dvr",
 	     "%s - Cannot open codec for %s, ignoring stream", 
 	     de->de_ititle, codec_name);
@@ -703,7 +707,9 @@ dvr_thread_epilog(dvr_entry_t *de)
   
   for(i = 0; i < fctx->nb_streams; i++) {
     st = fctx->streams[i];
+    pthread_mutex_lock(&ffmpeg_lock);
     avcodec_close(st->codec);
+    pthread_mutex_unlock(&ffmpeg_lock);
     free(st->codec);
     free(st);
   }
diff --git a/src/main.c b/src/main.c
index 3ab2347b..f4e03916 100644
--- a/src/main.c
+++ b/src/main.c
@@ -60,6 +60,7 @@ extern const char *htsversion_full;
 time_t dispatch_clock;
 static LIST_HEAD(, gtimer) gtimers;
 pthread_mutex_t global_lock;
+pthread_mutex_t ffmpeg_lock;
 
 static void
 handle_sigpipe(int x)
@@ -290,6 +291,8 @@ main(int argc, char **argv)
 
   hts_settings_init("tvheadend", homedir);
 
+  pthread_mutex_init(&ffmpeg_lock, NULL);
+
   pthread_mutex_init(&global_lock, NULL);
 
   pthread_mutex_lock(&global_lock);
diff --git a/src/transports.c b/src/transports.c
index 7f8fcd1f..fd86e163 100644
--- a/src/transports.c
+++ b/src/transports.c
@@ -86,8 +86,11 @@ transport_stop(th_transport_t *t)
     if(st->st_parser != NULL)
       av_parser_close(st->st_parser);
     
-    if(st->st_ctx != NULL)
+    if(st->st_ctx != NULL) {
+      pthread_mutex_lock(&ffmpeg_lock);
       avcodec_close(st->st_ctx);
+      pthread_mutex_unlock(&ffmpeg_lock);
+    }
 
     av_free(st->st_ctx);
 
@@ -244,8 +247,10 @@ transport_start(th_transport_t *t, unsigned int weight, int force_start)
       c = avcodec_find_decoder(id);
       if(c != NULL) {
 	st->st_ctx = avcodec_alloc_context();
+	pthread_mutex_lock(&ffmpeg_lock);
 	avcodec_open(st->st_ctx, c);
-	st->st_parser = av_parser_init(id);
+	pthread_mutex_unlock(&ffmpeg_lock);
+      st->st_parser = av_parser_init(id);
       } else {
 	abort();
       }
diff --git a/src/tvhead.h b/src/tvhead.h
index dfe3dc5f..597252ec 100644
--- a/src/tvhead.h
+++ b/src/tvhead.h
@@ -37,6 +37,7 @@
 #include "redblack.h"
 
 extern pthread_mutex_t global_lock;
+extern pthread_mutex_t ffmpeg_lock;
 
 static inline void
 lock_assert0(pthread_mutex_t *l, const char *file, int line)