Add new element: frame dropper. This element inserts/drops frames to go from a certain input framerate to a certain o...

Original commit message from CVS:
Add new element: frame dropper. This element inserts/drops frames to go from a certain input framerate to a certain output framerate. It's extremely simple and that's why it's so cute.

configure.ac

@@ -268,8 +268,8 @@ GST_PLUGINS_ALL="\
         monoscope oneton overlay passthrough playondemand qtdemux \
 	realmedia rtp rtjpeg silence sine smooth smpte \
 	spectrum speed stereo synaesthesia tcp udp vbidec \
-	videocrop videofilter videoflip videoscale videotestsrc \
-	volenv volume wavenc wavparse y4m"
+	videocrop videodrop videofilter videoflip videoscale \
+	videotestsrc volenv volume wavenc wavparse y4m"
 
 dnl see if we can build C++ plug-ins
 if test "x$HAVE_CXX" = "xyes"; then
@@ -1216,6 +1216,7 @@ gst/tcp/Makefile
 gst/udp/Makefile
 gst/vbidec/Makefile
 gst/videocrop/Makefile
+gst/videodrop/Makefile
 gst/videofilter/Makefile
 gst/videoflip/Makefile
 gst/videoscale/Makefile

gst/videodrop/Makefile.am

@@ -0,0 +1,10 @@
+
+plugin_LTLIBRARIES = libgstvideodrop.la
+
+libgstvideodrop_la_SOURCES = \
+			gstvideodrop.c
+libgstvideodrop_la_CFLAGS = $(GST_CFLAGS)
+libgstvideodrop_la_LIBADD =
+libgstvideodrop_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
+
+noinst_HEADERS = gstvideodrop.h

gst/videodrop/gstvideodrop.c

@@ -0,0 +1,255 @@
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * 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 <gstvideodrop.h>
+
+/* elementfactory information */
+static GstElementDetails videodrop_details = {
+  "Video frame dropper",
+  "Filter/Video",
+  "LGPL",
+  "Re-FPS'es video",
+  VERSION,
+  "Ronald Bultje <rbultje@ronald.bitfreak.net>",
+  "(C) 2003",
+};
+
+/* GstVideodrop signals and args */
+enum {
+  /* FILL ME */
+  LAST_SIGNAL
+};
+
+enum {
+  ARG_0,
+  /* FILL ME */
+};
+
+GST_PAD_TEMPLATE_FACTORY(src_template,
+  "src",
+  GST_PAD_SRC,
+  GST_PAD_ALWAYS,
+  GST_CAPS_NEW(
+    "framedropper_yuv",
+    "video/x-raw-yuv",
+      "framerate", GST_PROPS_FLOAT_RANGE (0, G_MAXFLOAT),
+      "width",     GST_PROPS_INT_RANGE (0, G_MAXINT),
+      "height",    GST_PROPS_INT_RANGE (0, G_MAXINT),
+      "format",    GST_PROPS_LIST (
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('Y','U','Y','2')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('I','4','2','0')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('Y','V','1','2')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('Y','U','Y','V')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('U','Y','V','Y'))
+                   )
+  )
+)
+
+GST_PAD_TEMPLATE_FACTORY(sink_template,
+  "sink",
+  GST_PAD_SINK,
+  GST_PAD_ALWAYS,
+  GST_CAPS_NEW(
+    "framedropper_yuv",
+    "video/x-raw-yuv",
+      "framerate", GST_PROPS_FLOAT_RANGE (0, G_MAXFLOAT),
+      "width",     GST_PROPS_INT_RANGE (0, G_MAXINT),
+      "height",    GST_PROPS_INT_RANGE (0, G_MAXINT),
+      "format",    GST_PROPS_LIST (
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('Y','U','Y','2')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('I','4','2','0')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('Y','V','1','2')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('Y','U','Y','V')),
+                     GST_PROPS_FOURCC (GST_MAKE_FOURCC ('U','Y','V','Y'))
+                   )
+  )
+)
+
+static void	gst_videodrop_class_init	(GstVideodropClass *klass);
+static void	gst_videodrop_init		(GstVideodrop *videodrop);
+static void	gst_videodrop_chain		(GstPad *pad, GstBuffer *buf);
+
+static GstElementClass *parent_class = NULL;
+/*static guint gst_videodrop_signals[LAST_SIGNAL] = { 0 }; */
+
+GType
+gst_videodrop_get_type (void)
+{
+  static GType videodrop_type = 0;
+
+  if (!videodrop_type) {
+    static const GTypeInfo videodrop_info = {
+      sizeof (GstVideodropClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) gst_videodrop_class_init,
+      NULL,
+      NULL,
+      sizeof (GstVideodrop),
+      0,
+      (GInstanceInitFunc) gst_videodrop_init,
+    };
+
+    videodrop_type = g_type_register_static (GST_TYPE_ELEMENT,
+					     "GstVideodrop",
+					     &videodrop_info, 0);
+  }
+
+  return videodrop_type;
+}
+
+static void
+gst_videodrop_class_init (GstVideodropClass *klass)
+{
+  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
+}
+
+#define gst_caps_get_float_range(caps, name, min, max) \
+  gst_props_entry_get_float_range(gst_props_get_entry((caps)->properties, \
+                                                    name), \
+                                  min, max)
+
+static GstPadLinkReturn
+gst_videodrop_link (GstPad *pad, GstCaps *caps)
+{
+  GstVideodrop *videodrop;
+  GstPadLinkReturn ret;
+  GstCaps *peercaps;
+
+  videodrop = GST_VIDEODROP (gst_pad_get_parent (pad));
+
+  videodrop->inited = FALSE;
+
+  if (!GST_CAPS_IS_FIXED (caps)) {
+    return GST_PAD_LINK_DELAYED;
+  }
+
+  gst_caps_get_float (caps, "framerate", &videodrop->from_fps);
+
+  /* calc output fps */
+  peercaps = gst_pad_get_allowed_caps (videodrop->srcpad);
+  if (gst_caps_has_fixed_property (peercaps, "framerate")) {
+    gst_caps_get_float (peercaps, "framerate", &videodrop->to_fps);
+  } else {
+    gfloat min, max;
+    gst_caps_get_float_range (peercaps, "framerate", &min, &max);
+    if (videodrop->from_fps >= min &&
+        videodrop->from_fps <= max) {
+      videodrop->to_fps = videodrop->from_fps;
+    } else {
+      videodrop->to_fps = max;
+    }
+  }
+  gst_caps_unref (peercaps);
+
+  GST_DEBUG ("%f -> %f fps",
+	     videodrop->from_fps, videodrop->to_fps);
+
+  peercaps = gst_caps_copy (caps);
+
+  peercaps->properties = gst_caps_set (peercaps, "framerate",
+				       GST_PROPS_FLOAT (videodrop->to_fps));
+
+  if ((ret = gst_pad_try_set_caps (videodrop->srcpad, peercaps)) > 0) {
+    videodrop->inited = TRUE;
+    videodrop->total = videodrop->pass = 0;
+  }
+
+  return ret;
+}
+
+static void
+gst_videodrop_init (GstVideodrop *videodrop)
+{
+  GST_DEBUG ("gst_videodrop_init");
+  videodrop->sinkpad = gst_pad_new_from_template (
+		  GST_PAD_TEMPLATE_GET (sink_template),
+		  "sink");
+  gst_element_add_pad (GST_ELEMENT (videodrop), videodrop->sinkpad);
+  gst_pad_set_chain_function (videodrop->sinkpad, gst_videodrop_chain);
+  gst_pad_set_link_function (videodrop->sinkpad, gst_videodrop_link);
+
+  videodrop->srcpad = gst_pad_new_from_template (
+		  GST_PAD_TEMPLATE_GET (src_template),
+		  "src");
+  gst_element_add_pad (GST_ELEMENT(videodrop), videodrop->srcpad);
+
+  videodrop->inited = FALSE;
+  videodrop->total = videodrop->pass = 0;
+}
+
+static void
+gst_videodrop_chain (GstPad *pad, GstBuffer *buf)
+{
+  GstVideodrop *videodrop;
+
+  GST_DEBUG ("gst_videodrop_chain");
+
+  g_return_if_fail (pad != NULL);
+  g_return_if_fail (GST_IS_PAD (pad));
+  g_return_if_fail (buf != NULL);
+
+  videodrop = GST_VIDEODROP (gst_pad_get_parent (pad));
+
+  if (GST_IS_EVENT (buf)) {
+    gst_pad_push (videodrop->srcpad, buf);
+    return;
+  }
+
+  videodrop->total++;
+  while (videodrop->to_fps / videodrop->from_fps >
+	 (gfloat) videodrop->pass / videodrop->total) {
+    videodrop->pass++;
+    gst_buffer_ref (buf);
+    gst_pad_push (videodrop->srcpad, buf);
+  }
+
+  gst_buffer_unref (buf);
+}
+
+static gboolean
+plugin_init (GModule *module, GstPlugin *plugin)
+{
+  GstElementFactory *factory;
+
+  /* create an elementfactory for the videodrop element */
+  factory = gst_element_factory_new ("videodrop", GST_TYPE_VIDEODROP,
+                                     &videodrop_details);
+  g_return_val_if_fail (factory != NULL, FALSE);
+
+  gst_element_factory_add_pad_template (factory,
+	GST_PAD_TEMPLATE_GET (sink_template));
+  gst_element_factory_add_pad_template (factory,
+	GST_PAD_TEMPLATE_GET (src_template));
+
+  gst_plugin_add_feature (plugin, GST_PLUGIN_FEATURE (factory));
+
+  return TRUE;
+}
+
+GstPluginDesc plugin_desc = {
+  GST_VERSION_MAJOR,
+  GST_VERSION_MINOR,
+  "videodrop",
+  plugin_init
+};

gst/videodrop/gstvideodrop.h

@@ -0,0 +1,62 @@
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * 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_VIDEODROP_H__
+#define __GST_VIDEODROP_H__
+
+#include <config.h>
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_VIDEODROP \
+  (gst_videodrop_get_type())
+#define GST_VIDEODROP(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_VIDEODROP,GstVideodrop))
+#define GST_VIDEODROP_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_VIDEODROP,GstVideodrop))
+#define GST_IS_VIDEODROP(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_VIDEODROP))
+#define GST_IS_VIDEODROP_CLASS(obj) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_VIDEODROP))
+
+typedef struct _GstVideodrop GstVideodrop;
+typedef struct _GstVideodropClass GstVideodropClass;
+
+struct _GstVideodrop {
+  GstElement element;
+
+  GstPad *sinkpad, *srcpad;
+
+  /* video state */
+  gboolean inited;
+  float from_fps,
+	to_fps;
+  guint64 pass, total;
+};
+
+struct _GstVideodropClass {
+  GstElementClass parent_class;
+};
+
+GType gst_videodrop_get_type(void);
+
+G_END_DECLS
+
+#endif /* __GST_VIDEODROP_H__ */