gst/playback/: Add screenshot conversion code from totem.

Original commit message from CVS:
* gst/playback/Makefile.am:
* gst/playback/gstscreenshot.c: (feed_fakesrc), (save_result),
(create_element), (gst_play_frame_conv_convert):
* gst/playback/gstscreenshot.h:
Add screenshot conversion code from totem.
* gst/playback/gstplay-marshal.list:
* gst/playback/gstplaybin2.c: (gst_play_marshal_BUFFER__BOXED),
(gst_play_bin_class_init), (gst_play_bin_convert_frame),
(gst_play_bin_get_property), (no_more_pads_cb), (activate_group):
Implement frame property to get a color-unconverted snapshot.
Implement convert-frame action signal to get a converted snapshot image.
Configure connection speed in uridecodebin.
Document some more properties.
* gst/playback/gstplaysink.c: (gst_play_sink_class_init),
(gen_video_chain), (gen_audio_chain), (gst_play_sink_reconfigure),
(gst_play_sink_get_last_frame):
* gst/playback/gstplaysink.h:
Use last-buffer property of the video sink to get a video snapshot.
* tests/examples/seek/seek.c: (shot_cb), (main):
Add snapshot button for playbin2 and use the frame property to save the
frame as a png in the current directory.

ChangeLog

@@ -1,3 +1,30 @@
+2008-02-19  Wim Taymans  <wim.taymans@collabora.co.uk>
+
+	* gst/playback/Makefile.am:
+	* gst/playback/gstscreenshot.c: (feed_fakesrc), (save_result),
+	(create_element), (gst_play_frame_conv_convert):
+	* gst/playback/gstscreenshot.h:
+	Add screenshot conversion code from totem.
+
+	* gst/playback/gstplay-marshal.list:
+	* gst/playback/gstplaybin2.c: (gst_play_marshal_BUFFER__BOXED),
+	(gst_play_bin_class_init), (gst_play_bin_convert_frame),
+	(gst_play_bin_get_property), (no_more_pads_cb), (activate_group):
+	Implement frame property to get a color-unconverted snapshot.
+	Implement convert-frame action signal to get a converted snapshot image.
+	Configure connection speed in uridecodebin.
+	Document some more properties.
+
+	* gst/playback/gstplaysink.c: (gst_play_sink_class_init),
+	(gen_video_chain), (gen_audio_chain), (gst_play_sink_reconfigure),
+	(gst_play_sink_get_last_frame):
+	* gst/playback/gstplaysink.h:
+	Use last-buffer property of the video sink to get a video snapshot.
+
+	* tests/examples/seek/seek.c: (shot_cb), (main):
+	Add snapshot button for playbin2 and use the frame property to save the
+	frame as a png in the current directory.
+
 2008-02-19  Sebastian Dröge  <slomo@circular-chaos.org>
 
 	Patch by: Josep Torra Valles <josep at fluendo dot com>

gst/playback/Makefile.am

@@ -17,6 +17,7 @@ libgstplaybin_la_SOURCES = \
 	gstplaybasebin.c \
 	gstplay-enum.c \
 	gstfactorylists.c \
+	gstscreenshot.c \
 	gststreaminfo.c \
 	gststreamselector.c
 
@@ -55,6 +56,7 @@ noinst_HEADERS = \
 	gststreaminfo.h \
 	gstfactorylists.h \
 	gstplay-enum.h \
+	gstscreenshot.h \
 	gststreamselector.h
 
 noinst_PROGRAMS = test decodetest test2 test3 test4 test5 test6 test7

gst/playback/gstplay-marshal.list

@@ -6,3 +6,4 @@ ENUM:OBJECT,OBJECT,BOXED
 ENUM:OBJECT,OBJECT,OBJECT
 BOXED:OBJECT,OBJECT,BOXED
 BOXED:INT
+OBJECT:BOXED

gst/playback/gstplaybin2.c

@@ -252,6 +252,7 @@
 #include "gstplay-marshal.h"
 #include "gstplaysink.h"
 #include "gstfactorylists.h"
+#include "gstscreenshot.h"
 #include "gststreaminfo.h"
 #include "gststreamselector.h"
 
@@ -338,15 +339,22 @@ struct _GstPlayBinClass
 {
   GstPipelineClass parent_class;
 
+  /* notify app that the current uri finished decoding and it is possible to
+   * queue a new one for gapless playback */
   void (*about_to_finish) (GstPlayBin * playbin);
 
+  /* notify app that number of audio/video/text streams changed */
   void (*video_changed) (GstPlayBin * playbin);
   void (*audio_changed) (GstPlayBin * playbin);
   void (*text_changed) (GstPlayBin * playbin);
 
+  /* get audio/video/text tags for a stream */
   GstTagList *(*get_video_tags) (GstPlayBin * playbin, gint stream);
   GstTagList *(*get_audio_tags) (GstPlayBin * playbin, gint stream);
   GstTagList *(*get_text_tags) (GstPlayBin * playbin, gint stream);
+
+  /* get the last video frame and convert it to the given caps */
+  GstBuffer *(*convert_frame) (GstPlayBin * playbin, GstCaps * caps);
 };
 
 /* props */
@@ -429,6 +437,9 @@ static GstStructure *gst_play_bin_get_audio_tags (GstPlayBin * playbin,
 static GstStructure *gst_play_bin_get_text_tags (GstPlayBin * playbin,
     gint stream);
 
+static GstBuffer *gst_play_bin_convert_frame (GstPlayBin * playbin,
+    GstCaps * caps);
+
 static gboolean setup_next_source (GstPlayBin * playbin);
 
 static GstElementClass *parent_class;
@@ -441,6 +452,38 @@ GST_ELEMENT_DETAILS ("Player Bin 2",
     "Autoplug and play media from an uri",
     "Wim Taymans <wim.taymans@gmail.com>");
 
+static void
+gst_play_marshal_BUFFER__BOXED (GClosure * closure,
+    GValue * return_value G_GNUC_UNUSED,
+    guint n_param_values,
+    const GValue * param_values,
+    gpointer invocation_hint G_GNUC_UNUSED, gpointer marshal_data)
+{
+  typedef GstBuffer *(*GMarshalFunc_OBJECT__BOXED) (gpointer data1,
+      gpointer arg_1, gpointer data2);
+  register GMarshalFunc_OBJECT__BOXED callback;
+  register GCClosure *cc = (GCClosure *) closure;
+  register gpointer data1, data2;
+  GstBuffer *v_return;
+
+  g_return_if_fail (return_value != NULL);
+  g_return_if_fail (n_param_values == 2);
+
+  if (G_CCLOSURE_SWAP_DATA (closure)) {
+    data1 = closure->data;
+    data2 = g_value_peek_pointer (param_values + 0);
+  } else {
+    data1 = g_value_peek_pointer (param_values + 0);
+    data2 = closure->data;
+  }
+  callback =
+      (GMarshalFunc_OBJECT__BOXED) (marshal_data ? marshal_data : cc->callback);
+
+  v_return = callback (data1, g_value_get_boxed (param_values + 1), data2);
+
+  gst_value_take_buffer (return_value, v_return);
+}
+
 static GType
 gst_play_bin_get_type (void)
 {
@@ -509,6 +552,12 @@ gst_play_bin_class_init (GstPlayBinClass * klass)
       g_param_spec_object ("source", "Source", "Source element",
           GST_TYPE_ELEMENT, G_PARAM_READABLE));
 
+
+  /**
+   * GstPlayBin:flags
+   *
+   * Control the behaviour of playbin.
+   */
   g_object_class_install_property (gobject_klass, PROP_FLAGS,
       g_param_spec_flags ("flags", "Flags", "Flags to control behaviour",
           GST_TYPE_PLAY_FLAGS, DEFAULT_FLAGS, G_PARAM_READWRITE));
@@ -596,6 +645,13 @@ gst_play_bin_class_init (GstPlayBinClass * klass)
           "Mute the audio channel without changing the volume", FALSE,
           G_PARAM_READWRITE));
 
+  /**
+   * GstPlayBin::frame
+   * @playbin: a #GstPlayBin
+   *
+   * Get the currently rendered or prerolled frame in the sink.
+   * The #GstCaps on the buffer will describe the format of the buffer.
+   */
   g_object_class_install_property (gobject_klass, PROP_FRAME,
       gst_param_spec_mini_object ("frame", "Frame",
           "The last frame (NULL = no video available)",
@@ -711,11 +767,33 @@ gst_play_bin_class_init (GstPlayBinClass * klass)
       G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
       G_STRUCT_OFFSET (GstPlayBinClass, get_text_tags), NULL, NULL,
       gst_play_marshal_BOXED__INT, GST_TYPE_TAG_LIST, 1, G_TYPE_INT);
+  /**
+   * GstPlayBin::convert-frame
+   * @playbin: a #GstPlayBin
+   * @caps: the target format of the frame
+   *
+   * Action signal to retrieve the currently playing video frame in the format
+   * specified by @caps.
+   * If @caps is %NULL, no conversion will be performed and this function is
+   * equivalent to the #GstPlayBin::frame property.
+   *
+   * Returns: a #GstBuffer of the current video frame converted to #caps. 
+   * The caps on the buffer will describe the final layout of the buffer data.
+   * %NULL is returned when no current buffer can be retrieved or when the
+   * conversion failed.
+   */
+  gst_play_bin_signals[SIGNAL_GET_TEXT_TAGS] =
+      g_signal_new ("convert-frame", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+      G_STRUCT_OFFSET (GstPlayBinClass, convert_frame), NULL, NULL,
+      gst_play_marshal_BUFFER__BOXED, GST_TYPE_BUFFER, 1, GST_TYPE_CAPS);
 
   klass->get_video_tags = gst_play_bin_get_video_tags;
   klass->get_audio_tags = gst_play_bin_get_audio_tags;
   klass->get_text_tags = gst_play_bin_get_text_tags;
 
+  klass->convert_frame = gst_play_bin_convert_frame;
+
   gst_element_class_set_details (gstelement_klass, &gst_play_bin_details);
 
   gstelement_klass->change_state =
@@ -903,6 +981,22 @@ gst_play_bin_get_text_tags (GstPlayBin * playbin, gint stream)
   return result;
 }
 
+static GstBuffer *
+gst_play_bin_convert_frame (GstPlayBin * playbin, GstCaps * caps)
+{
+  GstBuffer *result;
+
+  result = gst_play_sink_get_last_frame (playbin->playsink);
+  if (result != NULL && caps != NULL) {
+    GstBuffer *temp;
+
+    temp = gst_play_frame_conv_convert (result, caps);
+    gst_buffer_unref (result);
+    result = temp;
+  }
+  return result;
+}
+
 static gboolean
 gst_play_bin_set_current_video_stream (GstPlayBin * playbin, gint stream)
 {
@@ -1183,6 +1277,7 @@ gst_play_bin_get_property (GObject * object, guint prop_id, GValue * value,
       g_value_set_boolean (value, gst_play_sink_get_mute (playbin->playsink));
       break;
     case PROP_FRAME:
+      gst_value_take_buffer (value, gst_play_bin_convert_frame (playbin, NULL));
       break;
     case PROP_FONT_DESC:
       break;
@@ -1568,6 +1663,9 @@ activate_group (GstPlayBin * playbin, GstSourceGroup * group)
   if (!uridecodebin)
     goto no_decodebin;
 
+  /* configure connection speed */
+  g_object_set (uridecodebin, "connection-speed", playbin->connection_speed,
+      NULL);
   /* configure uri */
   g_object_set (uridecodebin, "uri", group->uri, NULL);
 

gst/playback/gstplaysink.c

@@ -232,7 +232,7 @@ gst_play_sink_class_init (GstPlaySinkClass * klass)
           0.0, VOLUME_MAX_DOUBLE, 1.0, G_PARAM_READWRITE));
   g_object_class_install_property (gobject_klass, PROP_FRAME,
       gst_param_spec_mini_object ("frame", "Frame",
-          "The last frame (NULL = no video available)",
+          "The last video frame (NULL = no video available)",
           GST_TYPE_BUFFER, G_PARAM_READABLE));
   g_object_class_install_property (gobject_klass, PROP_FONT_DESC,
       g_param_spec_string ("subtitle-font-desc",
@@ -1358,6 +1358,32 @@ gst_play_sink_get_flags (GstPlaySink * playsink)
   return res;
 }
 
+GstBuffer *
+gst_play_sink_get_last_frame (GstPlaySink * playsink)
+{
+  GstBuffer *result = NULL;
+  GstPlayVideoChain *chain;
+
+  GST_PLAY_SINK_LOCK (playsink);
+  GST_DEBUG_OBJECT (playsink, "taking last frame");
+  /* get the video chain if we can */
+  if ((chain = (GstPlayVideoChain *) playsink->videochain)) {
+    GST_DEBUG_OBJECT (playsink, "found video chain");
+    /* see if the chain is active */
+    if (chain->chain.activated && chain->sink) {
+      GST_DEBUG_OBJECT (playsink, "video chain active and has a sink");
+      /* get the frame property if we can */
+      if (g_object_class_find_property (G_OBJECT_GET_CLASS (chain->sink),
+              "last-buffer")) {
+        GST_DEBUG_OBJECT (playsink, "getting last-buffer property");
+        g_object_get (chain->sink, "last-buffer", &result, NULL);
+      }
+    }
+  }
+  GST_PLAY_SINK_UNLOCK (playsink);
+
+  return result;
+}
 
 GstPad *
 gst_play_sink_request_pad (GstPlaySink * playsink, GstPlaySinkType type)

gst/playback/gstplaysink.h

@@ -78,6 +78,8 @@ gboolean         gst_play_sink_get_mute       (GstPlaySink *playsink);
 gboolean         gst_play_sink_set_flags      (GstPlaySink * playsink, GstPlayFlags flags);
 GstPlayFlags     gst_play_sink_get_flags      (GstPlaySink * playsink);
 
+GstBuffer *      gst_play_sink_get_last_frame (GstPlaySink * playsink);
+
 gboolean         gst_play_sink_reconfigure    (GstPlaySink * playsink);
 
 G_END_DECLS

gst/playback/gstscreenshot.c

@@ -0,0 +1,202 @@
+/* Small helper element for format conversion
+ * (c) 2004 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <string.h>
+
+#include "gstscreenshot.h"
+
+static void
+feed_fakesrc (GstElement * src, GstBuffer * buf, GstPad * pad, gpointer data)
+{
+  GstBuffer *in_buf = GST_BUFFER (data);
+
+  gst_buffer_set_caps (buf, GST_BUFFER_CAPS (in_buf));
+
+  memcpy (GST_BUFFER_DATA (buf), GST_BUFFER_DATA (in_buf),
+      GST_BUFFER_SIZE (in_buf));
+
+  GST_BUFFER_SIZE (buf) = GST_BUFFER_SIZE (in_buf);
+
+  GST_DEBUG ("feeding buffer %p, size %u, caps %" GST_PTR_FORMAT,
+      buf, GST_BUFFER_SIZE (buf), GST_BUFFER_CAPS (buf));
+}
+
+static void
+save_result (GstElement * sink, GstBuffer * buf, GstPad * pad, gpointer data)
+{
+  GstBuffer **p_buf = (GstBuffer **) data;
+
+  *p_buf = gst_buffer_ref (buf);
+
+  GST_DEBUG ("received converted buffer %p with caps %" GST_PTR_FORMAT,
+      *p_buf, GST_BUFFER_CAPS (*p_buf));
+}
+
+static gboolean
+create_element (const gchar * factory_name, GstElement ** element,
+    GError ** err)
+{
+  *element = gst_element_factory_make (factory_name, NULL);
+  if (*element)
+    return TRUE;
+
+  if (err && *err == NULL) {
+    *err = g_error_new (GST_CORE_ERROR, GST_CORE_ERROR_MISSING_PLUGIN,
+        "cannot create element '%s' - please check your GStreamer installation",
+        factory_name);
+  }
+
+  return FALSE;
+}
+
+/* takes ownership of the input buffer */
+GstBuffer *
+gst_play_frame_conv_convert (GstBuffer * buf, GstCaps * to_caps)
+{
+  GstElement *src, *csp, *filter1, *vscale, *filter2, *sink, *pipeline;
+  GstMessage *msg;
+  GstBuffer *result = NULL;
+  GError *error = NULL;
+  GstBus *bus;
+  GstCaps *to_caps_no_par;
+
+  g_return_val_if_fail (GST_BUFFER_CAPS (buf) != NULL, NULL);
+
+  /* videoscale is here to correct for the pixel-aspect-ratio for us */
+  GST_DEBUG ("creating elements");
+  if (!create_element ("fakesrc", &src, &error) ||
+      !create_element ("ffmpegcolorspace", &csp, &error) ||
+      !create_element ("videoscale", &vscale, &error) ||
+      !create_element ("capsfilter", &filter1, &error) ||
+      !create_element ("capsfilter", &filter2, &error) ||
+      !create_element ("fakesink", &sink, &error))
+    goto no_elements;
+
+  pipeline = gst_pipeline_new ("screenshot-pipeline");
+  if (pipeline == NULL)
+    goto no_pipeline;
+
+  GST_DEBUG ("adding elements");
+  gst_bin_add_many (GST_BIN (pipeline), src, csp, filter1, vscale, filter2,
+      sink, NULL);
+
+  g_signal_connect (src, "handoff", G_CALLBACK (feed_fakesrc), buf);
+
+  /* set to 'fixed' sizetype */
+  g_object_set (src, "sizemax", GST_BUFFER_SIZE (buf), "sizetype", 2,
+      "num-buffers", 1, "signal-handoffs", TRUE, NULL);
+
+  /* adding this superfluous capsfilter makes linking cheaper */
+  to_caps_no_par = gst_caps_copy (to_caps);
+  gst_structure_remove_field (gst_caps_get_structure (to_caps_no_par, 0),
+      "pixel-aspect-ratio");
+  g_object_set (filter1, "caps", to_caps_no_par, NULL);
+  gst_caps_unref (to_caps_no_par);
+
+  g_object_set (filter2, "caps", to_caps, NULL);
+
+  g_signal_connect (sink, "handoff", G_CALLBACK (save_result), &result);
+
+  g_object_set (sink, "preroll-queue-len", 1, "signal-handoffs", TRUE, NULL);
+
+  /* FIXME: linking is still way too expensive, profile this properly */
+  GST_DEBUG ("linking src->csp");
+  if (!gst_element_link_pads (src, "src", csp, "sink"))
+    return NULL;
+
+  GST_DEBUG ("linking csp->filter1");
+  if (!gst_element_link_pads (csp, "src", filter1, "sink"))
+    return NULL;
+
+  GST_DEBUG ("linking filter1->vscale");
+  if (!gst_element_link_pads (filter1, "src", vscale, "sink"))
+    return NULL;
+
+  GST_DEBUG ("linking vscale->capsfilter");
+  if (!gst_element_link_pads (vscale, "src", filter2, "sink"))
+    return NULL;
+
+  GST_DEBUG ("linking capsfilter->sink");
+  if (!gst_element_link_pads (filter2, "src", sink, "sink"))
+    return NULL;
+
+  GST_DEBUG ("running conversion pipeline");
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+  bus = gst_element_get_bus (pipeline);
+  msg =
+      gst_bus_poll (bus, GST_MESSAGE_ERROR | GST_MESSAGE_EOS, 25 * GST_SECOND);
+
+  if (msg) {
+    switch (GST_MESSAGE_TYPE (msg)) {
+      case GST_MESSAGE_EOS:{
+        if (result) {
+          GST_DEBUG ("conversion successful: result = %p", result);
+        } else {
+          GST_WARNING ("EOS but no result frame?!");
+        }
+        break;
+      }
+      case GST_MESSAGE_ERROR:{
+        gchar *dbg = NULL;
+
+        gst_message_parse_error (msg, &error, &dbg);
+        if (error) {
+          g_warning ("Could not take screenshot: %s", error->message);
+          GST_DEBUG ("%s [debug: %s]", error->message, GST_STR_NULL (dbg));
+          g_error_free (error);
+        } else {
+          g_warning ("Could not take screenshot (and NULL error!)");
+        }
+        g_free (dbg);
+        result = NULL;
+        break;
+      }
+      default:{
+        g_return_val_if_reached (NULL);
+      }
+    }
+  } else {
+    g_warning ("Could not take screenshot: %s", "timeout during conversion");
+    result = NULL;
+  }
+
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (pipeline);
+
+  return result;
+
+  /* ERRORS */
+no_elements:
+  {
+    g_warning ("Could not take screenshot: %s", error->message);
+    g_error_free (error);
+    return NULL;
+  }
+no_pipeline:
+  {
+    g_warning ("Could not take screenshot: %s", "no pipeline (unknown error)");
+    return NULL;
+  }
+}

gst/playback/gstscreenshot.h

@@ -0,0 +1,31 @@
+/* Small helper element for format conversion
+ * (c) 2004 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_PLAY_FRAME_CONV_H__
+#define __GST_PLAY_FRAME_CONV_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+GstBuffer *     gst_play_frame_conv_convert  (GstBuffer *buf, GstCaps   *to);
+
+G_END_DECLS
+
+#endif /* __GST_PLAY_FRAME_CONV_H__ */

tests/examples/seek/seek.c

@@ -1625,6 +1625,68 @@ volume_spinbutton_changed_cb (GtkSpinButton * button, GstPipeline * pipeline)
   g_object_set (pipeline, "volume", volume, NULL);
 }
 
+static void
+shot_cb (GtkButton * button, gpointer data)
+{
+  GstBuffer *buffer;
+  GstCaps *caps;
+
+  /* convert to our desired format (RGB24) */
+  caps = gst_caps_new_simple ("video/x-raw-rgb",
+      "bpp", G_TYPE_INT, 24, "depth", G_TYPE_INT, 24,
+      /* Note: we don't ask for a specific width/height here, so that
+       * videoscale can adjust dimensions from a non-1/1 pixel aspect
+       * ratio to a 1/1 pixel-aspect-ratio */
+      "pixel-aspect-ratio", GST_TYPE_FRACTION, 1, 1,
+      "endianness", G_TYPE_INT, G_BIG_ENDIAN,
+      "red_mask", G_TYPE_INT, 0xff0000,
+      "green_mask", G_TYPE_INT, 0x00ff00,
+      "blue_mask", G_TYPE_INT, 0x0000ff, NULL);
+
+  g_signal_emit_by_name (pipeline, "convert-frame", caps, &buffer);
+  gst_caps_unref (caps);
+
+  if (buffer) {
+    GstCaps *caps;
+    GstStructure *s;
+    gboolean res;
+    gint width, height;
+    GdkPixbuf *pixbuf;
+    GError *error = NULL;
+
+    /* get the snapshot buffer format now. We set the caps on the appsink so
+     * that it can only be an rgb buffer. The only thing we have not specified
+     * on the caps is the height, which is dependant on the pixel-aspect-ratio
+     * of the source material */
+    caps = GST_BUFFER_CAPS (buffer);
+    if (!caps) {
+      g_warning ("could not get snapshot format\n");
+      goto done;
+    }
+    s = gst_caps_get_structure (caps, 0);
+
+    /* we need to get the final caps on the buffer to get the size */
+    res = gst_structure_get_int (s, "width", &width);
+    res |= gst_structure_get_int (s, "height", &height);
+    if (!res) {
+      g_warning ("could not get snapshot dimension\n");
+      goto done;
+    }
+
+    /* create pixmap from buffer and save, gstreamer video buffers have a stride
+     * that is rounded up to the nearest multiple of 4 */
+    pixbuf = gdk_pixbuf_new_from_data (GST_BUFFER_DATA (buffer),
+        GDK_COLORSPACE_RGB, FALSE, 8, width, height,
+        GST_ROUND_UP_4 (width * 3), NULL, NULL);
+
+    /* save the pixbuf */
+    gdk_pixbuf_save (pixbuf, "snapshot.png", "png", &error, NULL);
+
+  done:
+    gst_buffer_unref (buffer);
+  }
+}
+
 static void
 message_received (GstBus * bus, GstMessage * message, GstPipeline * pipeline)
 {
@@ -1757,8 +1819,8 @@ print_usage (int argc, char **argv)
 int
 main (int argc, char **argv)
 {
-  GtkWidget *window, *hbox, *vbox, *panel, *boxes, *flagtable;
+  GtkWidget *window, *hbox, *vbox, *panel, *boxes, *flagtable, *boxes2;
-  GtkWidget *play_button, *pause_button, *stop_button;
+  GtkWidget *play_button, *pause_button, *stop_button, *shot_button;
   GtkWidget *accurate_checkbox, *key_checkbox, *loop_checkbox, *flush_checkbox;
   GtkWidget *scrub_checkbox, *play_scrub_checkbox, *rate_spinbutton;
   GtkWidget *rate_label;
@@ -1874,7 +1936,6 @@ main (int argc, char **argv)
   if (pipeline_type == 16) {
     /* the playbin2 panel controls for the video/audio/subtitle tracks */
     panel = gtk_hbox_new (FALSE, 0);
-    boxes = gtk_hbox_new (FALSE, 0);
     video_combo = gtk_combo_box_new_text ();
     audio_combo = gtk_combo_box_new_text ();
     text_combo = gtk_combo_box_new_text ();
@@ -1890,12 +1951,14 @@ main (int argc, char **argv)
         G_CALLBACK (audio_combo_cb), pipeline);
     g_signal_connect (G_OBJECT (text_combo), "changed",
         G_CALLBACK (text_combo_cb), pipeline);
+    /* playbin2 panel for flag checkboxes and volume/mute */
+    boxes = gtk_hbox_new (FALSE, 0);
     vis_checkbox = gtk_check_button_new_with_label ("Vis");
     video_checkbox = gtk_check_button_new_with_label ("Video");
     audio_checkbox = gtk_check_button_new_with_label ("Audio");
     text_checkbox = gtk_check_button_new_with_label ("Text");
     mute_checkbox = gtk_check_button_new_with_label ("Mute");
-    volume_spinbutton = gtk_spin_button_new_with_range (0, 5.0, 0.1);
+    volume_spinbutton = gtk_spin_button_new_with_range (0, 10.0, 0.1);
     gtk_spin_button_set_value (GTK_SPIN_BUTTON (volume_spinbutton), 1.0);
     gtk_box_pack_start (GTK_BOX (boxes), vis_checkbox, TRUE, TRUE, 2);
     gtk_box_pack_start (GTK_BOX (boxes), audio_checkbox, TRUE, TRUE, 2);
@@ -1920,8 +1983,17 @@ main (int argc, char **argv)
         G_CALLBACK (mute_toggle_cb), pipeline);
     g_signal_connect (G_OBJECT (volume_spinbutton), "value_changed",
         G_CALLBACK (volume_spinbutton_changed_cb), pipeline);
+    /* playbin2 panel for snapshot */
+    boxes2 = gtk_hbox_new (FALSE, 0);
+    shot_button = gtk_button_new_from_stock (GTK_STOCK_SAVE);
+    gtk_tooltips_set_tip (tips, shot_button,
+        "save a screenshot .png in the current directory", NULL);
+    gtk_box_pack_start (GTK_BOX (boxes2), shot_button, TRUE, TRUE, 2);
+    g_signal_connect (G_OBJECT (shot_button), "clicked", G_CALLBACK (shot_cb),
+        pipeline);
+
   } else {
-    panel = boxes = NULL;
+    panel = boxes = boxes2 = NULL;
   }
 
   /* do the packing stuff ... */
@@ -1943,9 +2015,10 @@ main (int argc, char **argv)
   gtk_table_attach_defaults (GTK_TABLE (flagtable), rate_label, 3, 4, 0, 1);
   gtk_table_attach_defaults (GTK_TABLE (flagtable), rate_spinbutton, 3, 4, 1,
       2);
-  if (panel && boxes) {
+  if (panel && boxes && boxes2) {
     gtk_box_pack_start (GTK_BOX (vbox), panel, TRUE, TRUE, 2);
     gtk_box_pack_start (GTK_BOX (vbox), boxes, TRUE, TRUE, 2);
+    gtk_box_pack_start (GTK_BOX (vbox), boxes2, TRUE, TRUE, 2);
   }
   gtk_box_pack_start (GTK_BOX (vbox), hscale, TRUE, TRUE, 2);