A plugin to add an alpha channel to I420 video. Can optionally do chroma keying.

Original commit message from CVS:
* configure.ac:
* gst/alpha/Makefile.am:
* gst/alpha/gstalpha.c: (gst_alpha_method_get_type),
(gst_alpha_get_type), (gst_alpha_base_init),
(gst_alpha_class_init), (gst_alpha_init), (gst_alpha_set_property),
(gst_alpha_get_property), (gst_alpha_sink_link), (gst_alpha_add),
(gst_alpha_chroma_key), (gst_alpha_chain),
(gst_alpha_change_state), (plugin_init):
A plugin to add an alpha channel to I420 video. Can optionally do
chroma keying.
* gst/multipart/Makefile.am:
* gst/multipart/multipart.c: (plugin_init):
* gst/multipart/multipartdemux.c: (gst_multipart_demux_base_init),
(gst_multipart_demux_class_init), (gst_multipart_demux_init),
(gst_multipart_demux_finalize), (gst_multipart_demux_handle_event),
(gst_multipart_find_pad_by_mime), (gst_multipart_demux_chain),
(gst_multipart_demux_change_state),
(gst_multipart_demux_plugin_init):
* gst/multipart/multipartmux.c: (gst_multipart_mux_get_type),
(gst_multipart_mux_base_init), (gst_multipart_mux_class_init),
(gst_multipart_mux_get_sink_event_masks), (gst_multipart_mux_init),
(gst_multipart_mux_sinkconnect), (gst_multipart_mux_pad_link),
(gst_multipart_mux_pad_unlink),
(gst_multipart_mux_request_new_pad),
(gst_multipart_mux_handle_src_event),
(gst_multipart_mux_next_buffer), (gst_multipart_mux_compare_pads),
(gst_multipart_mux_queue_pads), (gst_multipart_mux_loop),
(gst_multipart_mux_get_property), (gst_multipart_mux_set_property),
(gst_multipart_mux_change_state), (gst_multipart_mux_plugin_init):
A Multipart demuxer/muxer. Not sure if it violates specs. Used to
send multipart jpeg images to a browser.
* gst/videobox/Makefile.am:
* gst/videobox/README:
* gst/videobox/gstvideobox.c: (gst_video_box_fill_get_type),
(gst_video_box_get_type), (gst_video_box_base_init),
(gst_video_box_class_init), (gst_video_box_init),
(gst_video_box_set_property), (gst_video_box_get_property),
(gst_video_box_sink_link), (gst_video_box_i420),
(gst_video_box_ayuv), (gst_video_box_chain),
(gst_video_box_change_state), (plugin_init):
Crops or adds borders around an image. can do alpha channel
borders as well.
* gst/videomixer/Makefile.am:
* gst/videomixer/README:
* gst/videomixer/videomixer.c: (gst_videomixer_pad_get_type),
(gst_videomixer_pad_base_init), (gst_videomixer_pad_class_init),
(gst_videomixer_pad_get_sink_event_masks),
(gst_videomixer_pad_get_property),
(gst_videomixer_pad_set_property),
(gst_videomixer_pad_sinkconnect), (gst_videomixer_pad_link),
(gst_videomixer_pad_unlink), (gst_videomixer_pad_init),
(gst_video_mixer_background_get_type), (gst_videomixer_get_type),
(gst_videomixer_base_init), (gst_videomixer_class_init),
(gst_videomixer_init), (gst_videomixer_request_new_pad),
(gst_videomixer_handle_src_event),
(gst_videomixer_blend_ayuv_i420), (gst_videomixer_fill_checker),
(gst_videomixer_fill_color), (gst_videomixer_fill_queues),
(gst_videomixer_blend_buffers), (gst_videomixer_update_queues),
(gst_videomixer_loop), (gst_videomixer_get_property),
(gst_videomixer_set_property), (gst_videomixer_change_state),
(plugin_init):
Generic video mixer plugin, can handle multiple inputs all with
different framerates and video sizes. Is fully alpha channel
aware.

2 files changed, 567 insertions, 0 deletions

diff --git a/gst/alpha/Makefile.am b/gst/alpha/Makefile.am
new file mode 100644
index 00000000..cd908f9d
--- /dev/null
+++ b/gst/alpha/Makefile.am
@@ -0,0 +1,9 @@
+
+plugin_LTLIBRARIES = libgstalpha.la
+
+libgstalpha_la_SOURCES = gstalpha.c
+libgstalpha_la_CFLAGS = $(GST_CFLAGS)
+libgstalpha_la_LIBADD =
+libgstalpha_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
+
+noinst_HEADERS = 
diff --git a/gst/alpha/gstalpha.c b/gst/alpha/gstalpha.c
new file mode 100644
index 00000000..ece724e9
--- /dev/null
+++ b/gst/alpha/gstalpha.c
@@ -0,0 +1,558 @@
+/* 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 <gst/gst.h>
+#include <gst/video/video.h>
+
+#include <string.h>
+
+#define GST_TYPE_ALPHA \
+  (gst_alpha_get_type())
+#define GST_ALPHA(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_ALPHA,GstAlpha))
+#define GST_ALPHA_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_ALPHA,GstAlphaClass))
+#define GST_IS_ALPHA(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_ALPHA))
+#define GST_IS_ALPHA_CLASS(obj) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_ALPHA))
+
+typedef struct _GstAlpha GstAlpha;
+typedef struct _GstAlphaClass GstAlphaClass;
+
+typedef enum
+{
+  ALPHA_METHOD_ADD,
+  ALPHA_METHOD_GREEN,
+  ALPHA_METHOD_BLUE,
+}
+GstAlphaMethod;
+
+#define DEFAULT_METHOD ALPHA_METHOD_ADD
+#define DEFAULT_ALPHA 1.0
+#define DEFAULT_TARGET_CR 116
+#define DEFAULT_TARGET_CB 116
+
+struct _GstAlpha
+{
+  GstElement element;
+
+  /* pads */
+  GstPad *sinkpad;
+  GstPad *srcpad;
+
+  /* caps */
+  gint in_width, in_height;
+  gint out_width, out_height;
+
+  gdouble alpha;
+
+  guint target_cr, target_cb;
+
+  GstAlphaMethod method;
+};
+
+struct _GstAlphaClass
+{
+  GstElementClass parent_class;
+};
+
+/* elementfactory information */
+static GstElementDetails gst_alpha_details =
+GST_ELEMENT_DETAILS ("alpha filter",
+    "Filter/Effect/Video",
+    "Adds an alpha channel to video",
+    "Wim Taymans <wim@fluendo.com>");
+
+
+/* Alpha signals and args */
+enum
+{
+  /* FILL ME */
+  LAST_SIGNAL
+};
+
+enum
+{
+  ARG_0,
+  ARG_METHOD,
+  ARG_ALPHA,
+  ARG_TARGET_CR,
+  ARG_TARGET_CB,
+  /* FILL ME */
+};
+
+static GstStaticPadTemplate gst_alpha_src_template =
+GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("AYUV"))
+    );
+
+static GstStaticPadTemplate gst_alpha_sink_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("I420"))
+    );
+
+
+static void gst_alpha_base_init (gpointer g_class);
+static void gst_alpha_class_init (GstAlphaClass * klass);
+static void gst_alpha_init (GstAlpha * alpha);
+
+static void gst_alpha_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_alpha_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+
+static GstPadLinkReturn
+gst_alpha_sink_link (GstPad * pad, const GstCaps * caps);
+static void gst_alpha_chain (GstPad * pad, GstData * _data);
+
+static GstElementStateReturn gst_alpha_change_state (GstElement * element);
+
+
+static GstElementClass *parent_class = NULL;
+
+#define GST_TYPE_ALPHA_METHOD (gst_alpha_method_get_type())
+static GType
+gst_alpha_method_get_type (void)
+{
+  static GType alpha_method_type = 0;
+  static GEnumValue alpha_method[] = {
+    {ALPHA_METHOD_ADD, "0", "Add alpha channel"},
+    {ALPHA_METHOD_GREEN, "1", "Chroma Key green"},
+    {ALPHA_METHOD_BLUE, "2", "Chroma Key blue"},
+    {0, NULL, NULL},
+  };
+
+  if (!alpha_method_type) {
+    alpha_method_type = g_enum_register_static ("GstAlphaMethod", alpha_method);
+  }
+  return alpha_method_type;
+}
+
+/* static guint gst_alpha_signals[LAST_SIGNAL] = { 0 }; */
+
+GType
+gst_alpha_get_type (void)
+{
+  static GType alpha_type = 0;
+
+  if (!alpha_type) {
+    static const GTypeInfo alpha_info = {
+      sizeof (GstAlphaClass),
+      gst_alpha_base_init,
+      NULL,
+      (GClassInitFunc) gst_alpha_class_init,
+      NULL,
+      NULL,
+      sizeof (GstAlpha),
+      0,
+      (GInstanceInitFunc) gst_alpha_init,
+    };
+
+    alpha_type =
+        g_type_register_static (GST_TYPE_ELEMENT, "GstAlpha", &alpha_info, 0);
+  }
+  return alpha_type;
+}
+
+static void
+gst_alpha_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details (element_class, &gst_alpha_details);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_alpha_sink_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_alpha_src_template));
+}
+static void
+gst_alpha_class_init (GstAlphaClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+
+  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
+
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_METHOD,
+      g_param_spec_enum ("method", "Method",
+          "How the alpha channels should be created", GST_TYPE_ALPHA_METHOD,
+          DEFAULT_METHOD, (GParamFlags) G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_ALPHA,
+      g_param_spec_double ("alpha", "Alpha", "The value for the alpha channel",
+          0.0, 1.0, DEFAULT_ALPHA, (GParamFlags) G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TARGET_CR,
+      g_param_spec_uint ("target_cr", "Target Red", "The Red Chroma target", 0,
+          255, 116, (GParamFlags) G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TARGET_CB,
+      g_param_spec_uint ("target_cb", "Target Blue", "The Blue Chroma target",
+          0, 255, 116, (GParamFlags) G_PARAM_READWRITE));
+
+  gobject_class->set_property = gst_alpha_set_property;
+  gobject_class->get_property = gst_alpha_get_property;
+
+  gstelement_class->change_state = gst_alpha_change_state;
+}
+
+static void
+gst_alpha_init (GstAlpha * alpha)
+{
+  /* create the sink and src pads */
+  alpha->sinkpad =
+      gst_pad_new_from_template (gst_static_pad_template_get
+      (&gst_alpha_sink_template), "sink");
+  gst_element_add_pad (GST_ELEMENT (alpha), alpha->sinkpad);
+  gst_pad_set_chain_function (alpha->sinkpad, gst_alpha_chain);
+  gst_pad_set_link_function (alpha->sinkpad, gst_alpha_sink_link);
+
+  alpha->srcpad =
+      gst_pad_new_from_template (gst_static_pad_template_get
+      (&gst_alpha_src_template), "src");
+  gst_element_add_pad (GST_ELEMENT (alpha), alpha->srcpad);
+
+  alpha->alpha = DEFAULT_ALPHA;
+  alpha->method = DEFAULT_METHOD;
+  alpha->target_cr = DEFAULT_TARGET_CR;
+  alpha->target_cb = DEFAULT_TARGET_CB;
+
+  GST_FLAG_SET (alpha, GST_ELEMENT_EVENT_AWARE);
+}
+
+/* do we need this function? */
+static void
+gst_alpha_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstAlpha *alpha;
+
+  /* it's not null if we got it, but it might not be ours */
+  g_return_if_fail (GST_IS_ALPHA (object));
+
+  alpha = GST_ALPHA (object);
+
+  switch (prop_id) {
+    case ARG_METHOD:
+      alpha->method = g_value_get_enum (value);
+      break;
+    case ARG_ALPHA:
+      alpha->alpha = g_value_get_double (value);
+      break;
+    case ARG_TARGET_CB:
+      alpha->target_cb = g_value_get_uint (value);
+      break;
+    case ARG_TARGET_CR:
+      alpha->target_cr = g_value_get_uint (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+static void
+gst_alpha_get_property (GObject * object, guint prop_id, GValue * value,
+    GParamSpec * pspec)
+{
+  GstAlpha *alpha;
+
+  /* it's not null if we got it, but it might not be ours */
+  g_return_if_fail (GST_IS_ALPHA (object));
+
+  alpha = GST_ALPHA (object);
+
+  switch (prop_id) {
+    case ARG_METHOD:
+      g_value_set_enum (value, alpha->method);
+      break;
+    case ARG_ALPHA:
+      g_value_set_double (value, alpha->alpha);
+      break;
+    case ARG_TARGET_CR:
+      g_value_set_uint (value, alpha->target_cr);
+      break;
+    case ARG_TARGET_CB:
+      g_value_set_uint (value, alpha->target_cb);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static GstPadLinkReturn
+gst_alpha_sink_link (GstPad * pad, const GstCaps * caps)
+{
+  GstAlpha *alpha;
+  GstStructure *structure;
+  gboolean ret;
+
+  alpha = GST_ALPHA (gst_pad_get_parent (pad));
+  structure = gst_caps_get_structure (caps, 0);
+
+  ret = gst_structure_get_int (structure, "width", &alpha->in_width);
+  ret &= gst_structure_get_int (structure, "height", &alpha->in_height);
+
+  return GST_PAD_LINK_OK;
+}
+
+/*
+static int yuv_colors_Y[] = {  16, 150,  29 };
+static int yuv_colors_U[] = { 128,  46, 255 };
+static int yuv_colors_V[] = { 128,  21, 107 };
+*/
+
+static void
+gst_alpha_add (guint8 * src, guint8 * dest, gint width, gint height,
+    gdouble alpha)
+{
+  gint b_alpha = (gint) (alpha * 255);
+  guint8 *srcY;
+  guint8 *srcU;
+  guint8 *srcV;
+  gint size;
+  gint half_width = width / 2;
+  gint i, j;
+
+  size = width * height;
+
+  srcY = src;
+  srcU = srcY + size;
+  srcV = srcU + size / 4;
+
+  for (i = 0; i < height; i++) {
+    for (j = 0; j < width / 2; j++) {
+      *dest++ = b_alpha;
+      *dest++ = *srcY++;
+      *dest++ = *srcU;
+      *dest++ = *srcV;
+      *dest++ = b_alpha;
+      *dest++ = *srcY++;
+      *dest++ = *srcU++;
+      *dest++ = *srcV++;
+    }
+    if (i % 2 == 0) {
+      srcU -= half_width;
+      srcV -= half_width;
+    }
+  }
+}
+
+static void
+gst_alpha_chroma_key (gchar * src, gchar * dest, gint width, gint height,
+    gboolean soft, gint target_u, gint target_v, gfloat edge_factor,
+    gdouble alpha)
+{
+  gint b_alpha;
+  gint f_alpha = (gint) (alpha * 255);
+  guint8 *srcY1, *srcY2, *srcU, *srcV;
+  guint8 *dest1, *dest2;
+  gint i, j;
+  gint x, z, u, v;
+  gint size;
+
+  size = width * height;
+
+  srcY1 = src;
+  srcY2 = src + width;
+  srcU = srcY1 + size;
+  srcV = srcU + size / 4;
+
+  dest1 = dest;
+  dest2 = dest + width * 4;
+
+  for (i = 0; i < height / 2; i++) {
+    for (j = 0; j < width / 2; j++) {
+      u = *srcU++;
+      v = *srcV++;
+
+      x = target_u - u;
+      z = target_v - v;
+
+      // only filter if in top left square
+      if ((x > 0) && (z > 0)) {
+        // only calculate lot of stuff if we'll use soft edges
+        if (soft) {
+          gint ds = (x > z) ? z : x;
+
+          gfloat df = (gfloat) (ds) / edge_factor;
+
+          if (df > 1.0)
+            df = 1.0;
+
+          // suppress foreground
+          if (x > z) {
+            u += z;
+            v += z;
+          } else {
+            u += x;
+            v += x;
+          }
+          b_alpha = (int) (f_alpha * (1.0 - df));
+        } else {
+          // kill color and alpha
+          b_alpha = 0;
+        }
+      } else {
+        // do nothing;
+        b_alpha = f_alpha;
+      }
+
+      *dest1++ = b_alpha;
+      *dest1++ = *srcY1++;
+      *dest1++ = u;
+      *dest1++ = v;
+      *dest1++ = b_alpha;
+      *dest1++ = *srcY1++;
+      *dest1++ = u;
+      *dest1++ = v;
+      *dest2++ = b_alpha;
+      *dest2++ = *srcY2++;
+      *dest2++ = u;
+      *dest2++ = v;
+      *dest2++ = b_alpha;
+      *dest2++ = *srcY2++;
+      *dest2++ = u;
+      *dest2++ = v;
+    }
+    dest1 += width * 4;
+    dest2 += width * 4;
+    srcY1 += width;
+    srcY2 += width;
+  }
+}
+
+static void
+gst_alpha_chain (GstPad * pad, GstData * _data)
+{
+  GstBuffer *buffer;
+  GstAlpha *alpha;
+  GstBuffer *outbuf;
+  gint new_width, new_height;
+
+  alpha = GST_ALPHA (gst_pad_get_parent (pad));
+
+  if (GST_IS_EVENT (_data)) {
+    GstEvent *event = GST_EVENT (_data);
+
+    switch (GST_EVENT_TYPE (event)) {
+      default:
+        gst_pad_event_default (pad, event);
+        break;
+    }
+    return;
+  }
+
+  buffer = GST_BUFFER (_data);
+
+  new_width = alpha->in_width;
+  new_height = alpha->in_height;
+
+  if (new_width != alpha->out_width ||
+      new_height != alpha->out_height || !GST_PAD_CAPS (alpha->srcpad)) {
+    GstCaps *newcaps;
+
+    newcaps = gst_caps_copy (gst_pad_get_negotiated_caps (alpha->sinkpad));
+    gst_caps_set_simple (newcaps,
+        "format", GST_TYPE_FOURCC, GST_STR_FOURCC ("AYUV"),
+        "width", G_TYPE_INT, new_width, "height", G_TYPE_INT, new_height, NULL);
+
+    if (!gst_pad_try_set_caps (alpha->srcpad, newcaps)) {
+      GST_ELEMENT_ERROR (alpha, CORE, NEGOTIATION, (NULL), (NULL));
+      return;
+    }
+
+    alpha->out_width = new_width;
+    alpha->out_height = new_height;
+  }
+
+  outbuf = gst_buffer_new_and_alloc (new_width * new_height * 4);
+  GST_BUFFER_TIMESTAMP (outbuf) = GST_BUFFER_TIMESTAMP (buffer);
+  GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (buffer);
+
+  switch (alpha->method) {
+    case ALPHA_METHOD_ADD:
+      gst_alpha_add (GST_BUFFER_DATA (buffer),
+          GST_BUFFER_DATA (outbuf), new_width, new_height, alpha->alpha);
+      break;
+    case ALPHA_METHOD_GREEN:
+      gst_alpha_chroma_key (GST_BUFFER_DATA (buffer),
+          GST_BUFFER_DATA (outbuf),
+          new_width, new_height,
+          TRUE, alpha->target_cr, alpha->target_cb, 1.0, alpha->alpha);
+      break;
+    case ALPHA_METHOD_BLUE:
+      gst_alpha_chroma_key (GST_BUFFER_DATA (buffer),
+          GST_BUFFER_DATA (outbuf),
+          new_width, new_height, TRUE, 100, 100, 1.0, alpha->alpha);
+      break;
+  }
+
+  gst_buffer_unref (buffer);
+
+  gst_pad_push (alpha->srcpad, GST_DATA (outbuf));
+}
+
+static GstElementStateReturn
+gst_alpha_change_state (GstElement * element)
+{
+  GstAlpha *alpha;
+
+  alpha = GST_ALPHA (element);
+
+  switch (GST_STATE_TRANSITION (element)) {
+    case GST_STATE_NULL_TO_READY:
+      break;
+    case GST_STATE_READY_TO_PAUSED:
+      break;
+    case GST_STATE_PAUSED_TO_PLAYING:
+      break;
+    case GST_STATE_PLAYING_TO_PAUSED:
+      break;
+    case GST_STATE_PAUSED_TO_READY:
+      break;
+    case GST_STATE_READY_TO_NULL:
+      break;
+  }
+
+  parent_class->change_state (element);
+
+  return GST_STATE_SUCCESS;
+}
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  return gst_element_register (plugin, "alpha", GST_RANK_NONE, GST_TYPE_ALPHA);
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "alpha",
+    "resizes a video by adding borders or cropping",
+    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE, GST_ORIGIN)