3 files changed, 27 insertions, 1 deletions
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 09eea74ad9..002b015255 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -953,6 +953,13 @@ typedef struct AVChapter {
 
 
 /**
+ * Callback used by devices to communicate with application.
+ */
+typedef int (*av_format_control_message)(struct AVFormatContext *s, int type,
+                                         void *data, size_t data_size);
+
+
+/**
  * The duration of a video can be estimated through various ways, and this enum can be used
  * to know how the duration was estimated.
  */
@@ -1360,6 +1367,19 @@ typedef struct AVFormatContext {
      * Muxing: Set by user via av_format_set_metadata_header_padding.
      */
     int metadata_header_padding;
+
+    /**
+     * User data.
+     * This is a place for some private data of the user.
+     * Mostly usable with control_message_cb or any future callbacks in device's context.
+     */
+    void *opaque;
+
+    /**
+     * Callback used by devices to communicate with application.
+     */
+    av_format_control_message control_message_cb;
+
 } AVFormatContext;
 
 int av_format_get_probe_score(const AVFormatContext *s);
@@ -1371,6 +1391,10 @@ AVCodec * av_format_get_subtitle_codec(const AVFormatContext *s);
 void      av_format_set_subtitle_codec(AVFormatContext *s, AVCodec *c);
 int       av_format_get_metadata_header_padding(const AVFormatContext *s);
 void      av_format_set_metadata_header_padding(AVFormatContext *s, int c);
+void *    av_format_get_opaque(const AVFormatContext *s);
+void      av_format_set_opaque(AVFormatContext *s, void *opaque);
+av_format_control_message av_format_get_control_message_cb(const AVFormatContext *s);
+void      av_format_set_control_message_cb(AVFormatContext *s, av_format_control_message callback);
 
 /**
  * Returns the method used to set ctx->duration.
diff --git a/libavformat/utils.c b/libavformat/utils.c
index d425b5bc61..ac9236b18f 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -107,6 +107,8 @@ MAKE_ACCESSORS(AVFormatContext, format, AVCodec *, video_codec)
 MAKE_ACCESSORS(AVFormatContext, format, AVCodec *, audio_codec)
 MAKE_ACCESSORS(AVFormatContext, format, AVCodec *, subtitle_codec)
 MAKE_ACCESSORS(AVFormatContext, format, int, metadata_header_padding)
+MAKE_ACCESSORS(AVFormatContext, format, void *, opaque)
+MAKE_ACCESSORS(AVFormatContext, format, av_format_control_message, control_message_cb)
 
 static AVCodec *find_decoder(AVFormatContext *s, AVStream *st, enum AVCodecID codec_id)
 {
diff --git a/libavformat/version.h b/libavformat/version.h
index 51f6d598d9..92f81a93b1 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 55
-#define LIBAVFORMAT_VERSION_MINOR 27
+#define LIBAVFORMAT_VERSION_MINOR 28
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \