From 3faa8920cef0a920f01dd316b0e4bf79c9232806 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Mon, 16 Dec 2013 10:24:28 +0100
Subject: [PATCH] pngparse: Post VIDEO_CODEC tag

---
 gst/videoparsers/gstpngparse.c | 36 +++++++++++++++++++++++++++++++++++-
 gst/videoparsers/gstpngparse.h |  2 ++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/gst/videoparsers/gstpngparse.c b/gst/videoparsers/gstpngparse.c
index 72aadb1..efd62a6 100644
--- a/gst/videoparsers/gstpngparse.c
+++ b/gst/videoparsers/gstpngparse.c
@@ -24,7 +24,8 @@
 
 #include "gstpngparse.h"
 
-#include <gst/base/gstbytereader.h>
+#include <gst/base/base.h>
+#include <gst/pbutils/pbutils.h>
 
 #define PNG_SIGNATURE G_GUINT64_CONSTANT (0x89504E470D0A1A0A)
 
@@ -50,6 +51,8 @@ G_DEFINE_TYPE (GstPngParse, gst_png_parse, GST_TYPE_BASE_PARSE);
 static gboolean gst_png_parse_start (GstBaseParse * parse);
 static GstFlowReturn gst_png_parse_handle_frame (GstBaseParse * parse,
     GstBaseParseFrame * frame, gint * skipsize);
+static GstFlowReturn gst_png_parse_pre_push_frame (GstBaseParse * parse,
+    GstBaseParseFrame * frame);
 
 static void
 gst_png_parse_class_init (GstPngParseClass * klass)
@@ -70,6 +73,8 @@ gst_png_parse_class_init (GstPngParseClass * klass)
   /* Override BaseParse vfuncs */
   parse_class->start = GST_DEBUG_FUNCPTR (gst_png_parse_start);
   parse_class->handle_frame = GST_DEBUG_FUNCPTR (gst_png_parse_handle_frame);
+  parse_class->pre_push_frame =
+      GST_DEBUG_FUNCPTR (gst_png_parse_pre_push_frame);
 }
 
 static void
@@ -90,6 +95,8 @@ gst_png_parse_start (GstBaseParse * parse)
   pngparse->width = 0;
   pngparse->height = 0;
 
+  pngparse->sent_codec_tag = FALSE;
+
   return TRUE;
 }
 
@@ -209,3 +216,30 @@ beach:
 
   return ret;
 }
+
+static GstFlowReturn
+gst_png_parse_pre_push_frame (GstBaseParse * parse, GstBaseParseFrame * frame)
+{
+  GstPngParse *pngparse = GST_PNG_PARSE (parse);
+
+  if (!pngparse->sent_codec_tag) {
+    GstTagList *taglist;
+    GstCaps *caps;
+
+    taglist = gst_tag_list_new_empty ();
+
+    /* codec tag */
+    caps = gst_pad_get_current_caps (GST_BASE_PARSE_SRC_PAD (parse));
+    gst_pb_utils_add_codec_description_to_tag_list (taglist,
+        GST_TAG_VIDEO_CODEC, caps);
+    gst_caps_unref (caps);
+
+    gst_pad_push_event (GST_BASE_PARSE_SRC_PAD (pngparse),
+        gst_event_new_tag (taglist));
+
+    /* also signals the end of first-frame processing */
+    pngparse->sent_codec_tag = TRUE;
+  }
+
+  return GST_FLOW_OK;
+}
diff --git a/gst/videoparsers/gstpngparse.h b/gst/videoparsers/gstpngparse.h
index 5fccdf5..3574481 100644
--- a/gst/videoparsers/gstpngparse.h
+++ b/gst/videoparsers/gstpngparse.h
@@ -49,6 +49,8 @@ struct _GstPngParse
 
   guint width;
   guint height;
+  
+  gboolean sent_codec_tag;
 };
 
 struct _GstPngParseClass
-- 
2.7.4