diff --git a/libavcodec/opt.c b/libavcodec/opt.c
index 0bdef5c984aeabffa248e483e1215e855f3b6e68..84ea19117d0641eee98430b062afcb0e855c2bb4 100644
--- a/libavcodec/opt.c
+++ b/libavcodec/opt.c
@@ -299,3 +299,40 @@ int av_opt_show(void *obj, void *av_log_obj){
     }
     return 0;
 }
+
+void av_opt_set_defaults(void *s)
+{
+    AVOption *opt = NULL;
+    while ((opt = av_next_option(s, opt)) != NULL) {
+        switch(opt->type) {
+            case FF_OPT_TYPE_CONST:
+                /* Nothing to be done here */
+            break;
+            case FF_OPT_TYPE_FLAGS:
+            case FF_OPT_TYPE_INT: {
+                int val;
+                val = opt->default_val;
+                av_set_int(s, opt->name, val);
+            }
+            break;
+            case FF_OPT_TYPE_FLOAT: {
+                double val;
+                val = opt->default_val;
+                av_set_double(s, opt->name, val);
+            }
+            break;
+            case FF_OPT_TYPE_RATIONAL: {
+                AVRational val;
+                val = av_d2q(opt->default_val, INT_MAX);
+                av_set_q(s, opt->name, val);
+            }
+            break;
+            case FF_OPT_TYPE_STRING:
+                /* Cannot set default for string as default_val is of type * double */
+            break;
+            default:
+                av_log(s, AV_LOG_DEBUG, "AVOption type %d of option %s not implemented yet\n", opt->type, opt->name);
+        }
+    }
+}
+
diff --git a/libavcodec/opt.h b/libavcodec/opt.h
index 92a4535ecf08dafa7c61589a3f63e8dae5edca29..e7be7b54f41e292e1334ab08c3e3cf5220be5602 100644
--- a/libavcodec/opt.h
+++ b/libavcodec/opt.h
@@ -76,5 +76,6 @@ int64_t av_get_int(void *obj, const char *name, AVOption **o_out);
 const char *av_get_string(void *obj, const char *name, AVOption **o_out, char *buf, int buf_len);
 AVOption *av_next_option(void *obj, AVOption *last);
 int av_opt_show(void *obj, void *av_log_obj);
+void av_opt_set_defaults(void *s);
 
 #endif
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 0e59852eaefb530feb662bc6c1fdb007b74c4945..5aba3dac8a2be789c70686b92cf930fabda1cdfd 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -765,6 +765,9 @@ void avcodec_get_context_defaults(AVCodecContext *s){
     memset(s, 0, sizeof(AVCodecContext));
 
     s->av_class= &av_codec_context_class;
+
+    av_opt_set_defaults(s);
+
     s->bit_rate= 800*1000;
     s->bit_rate_tolerance= s->bit_rate*10;
     s->qmin= 2;
diff --git a/libavformat/utils.c b/libavformat/utils.c
index d9b57897dc83e5ca5189c18696bc2ceac06a6c8f..a9adb2b3f466f38396256649eaa7e0c661911836 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -486,6 +486,10 @@ static
 void avformat_get_context_defaults(AVFormatContext *s){
     memset(s, 0, sizeof(AVFormatContext));
 
+    s->av_class = &av_format_context_class;
+
+    av_opt_set_defaults(s);
+
     /* from mpegts.c: 1.0 second at 24Mbit/s */
     s->probesize=32000;
 }