Working LV2 plugin discovery.

- Separate gstsignalprocessor into a separate library (not sure if this
  is in the right place, but it works for now anyway)
- Create LV2 element based on LADSPA element, port most discovery
  functionality

4 files changed, 1163 insertions, 0 deletions

diff --git a/gst-libs/gst/signalprocessor/.gitignore b/gst-libs/gst/signalprocessor/.gitignore
new file mode 100644
index 00000000..08f5ed37
--- /dev/null
+++ b/gst-libs/gst/signalprocessor/.gitignore
@@ -0,0 +1,7 @@
+Makefile
+Makefile.in
+*.o
+*.lo
+*.la
+.deps
+.libs
diff --git a/gst-libs/gst/signalprocessor/Makefile.am b/gst-libs/gst/signalprocessor/Makefile.am
new file mode 100644
index 00000000..a8455390
--- /dev/null
+++ b/gst-libs/gst/signalprocessor/Makefile.am
@@ -0,0 +1,8 @@
+lib_LTLIBRARIES = libgstsignalprocessor.la
+
+noinst_HEADERS = gstsignalprocessor.h
+
+libgstsignalprocessor_la_SOURCES = gstsignalprocessor.c
+libgstsignalprocessor_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS)
+libgstsignalprocessor_la_LDFLAGS = $(GST_PLUGINS_BASE_LIBS)
+
diff --git a/gst-libs/gst/signalprocessor/gstsignalprocessor.c b/gst-libs/gst/signalprocessor/gstsignalprocessor.c
new file mode 100644
index 00000000..c46ae7a8
--- /dev/null
+++ b/gst-libs/gst/signalprocessor/gstsignalprocessor.c
@@ -0,0 +1,1024 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2000 Wim Taymans <wtay@chello.be>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *
+ * gstsignalprocessor.c: 
+ *
+ * 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.
+ */
+
+/*
+ * SECTION:gstsignalprocessor
+ *
+ * This baseclass allows to write elements that need data on all pads before
+ * their processing function can run.
+ *
+ * In push mode (gst_signal_processor_chain) it operates as follows:
+ * 1. store each received buffer on the pad and decrement pending_in
+ * 2. when pending_in==0, process as much as we can and push outputs
+ *
+ * In pull mode (gst_signal_processor_getrange) is operates as follows:
+ * 1. if there is an output ready, deliver
+ * 2. otherwise pull from each sink-pad, process requested frames and deliver
+ *    the buffer
+ */
+
+#include <stdlib.h>
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <gst/audio/audio.h>
+#include "gstsignalprocessor.h"
+
+
+GST_DEBUG_CATEGORY_STATIC (gst_signal_processor_debug);
+#define GST_CAT_DEFAULT gst_signal_processor_debug
+
+/* FIXME: this is mono only */
+static GstStaticCaps template_caps =
+GST_STATIC_CAPS (GST_AUDIO_FLOAT_STANDARD_PAD_TEMPLATE_CAPS);
+
+#define GST_TYPE_SIGNAL_PROCESSOR_PAD_TEMPLATE \
+    (gst_signal_processor_pad_template_get_type ())
+#define GST_SIGNAL_PROCESSOR_PAD_TEMPLATE(obj) \
+    (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_SIGNAL_PROCESSOR_PAD_TEMPLATE,\
+    GstSignalProcessorPadTemplate))
+typedef struct _GstSignalProcessorPadTemplate GstSignalProcessorPadTemplate;
+typedef GstPadTemplateClass GstSignalProcessorPadTemplateClass;
+
+struct _GstSignalProcessorPadTemplate
+{
+  GstPadTemplate parent;
+
+  guint index;
+};
+
+static GType
+gst_signal_processor_pad_template_get_type (void)
+{
+  static GType type = 0;
+
+  if (!type) {
+    static const GTypeInfo info = {
+      sizeof (GstSignalProcessorPadTemplateClass), NULL, NULL, NULL, NULL,
+      NULL, sizeof (GstSignalProcessorPadTemplate), 0, NULL
+    };
+
+    type = g_type_register_static (GST_TYPE_PAD_TEMPLATE,
+        "GstSignalProcessorPadTemplate", &info, 0);
+  }
+  return type;
+}
+
+/*
+ * gst_signal_processor_class_add_pad_template:
+ * @klass: element class
+ * @name: pad name
+ * @direction: pad direction (src/sink)
+ * @index: index for the pad per direction (starting from 0)
+ *
+ */
+void
+gst_signal_processor_class_add_pad_template (GstSignalProcessorClass * klass,
+    const gchar * name, GstPadDirection direction, guint index)
+{
+  GstPadTemplate *new;
+  GstCaps *caps;
+
+  g_return_if_fail (GST_IS_SIGNAL_PROCESSOR_CLASS (klass));
+  g_return_if_fail (name != NULL);
+  g_return_if_fail (direction == GST_PAD_SRC || direction == GST_PAD_SINK);
+
+  /* FIXME: would be nice to have the template as a parameter, right now this can
+   * only create mono pads */
+  caps = gst_caps_copy (gst_static_caps_get (&template_caps));
+
+  new = g_object_new (gst_signal_processor_pad_template_get_type (),
+      "name", name, "name-template", name,
+      "direction", direction, "presence", GST_PAD_ALWAYS, "caps", caps, NULL);
+
+  GST_SIGNAL_PROCESSOR_PAD_TEMPLATE (new)->index = index;
+
+  gst_element_class_add_pad_template (GST_ELEMENT_CLASS (klass), new);
+}
+
+
+#define GST_TYPE_SIGNAL_PROCESSOR_PAD (gst_signal_processor_pad_get_type ())
+#define GST_SIGNAL_PROCESSOR_PAD(obj) \
+    (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_SIGNAL_PROCESSOR_PAD,\
+    GstSignalProcessorPad))
+typedef struct _GstSignalProcessorPad GstSignalProcessorPad;
+typedef GstPadClass GstSignalProcessorPadClass;
+
+struct _GstSignalProcessorPad
+{
+  GstPad parent;
+
+  GstBuffer *pen;
+
+  /* index for the pad per direction (starting from 0) */
+  guint index;
+
+  /* these are only used for sink pads */
+  guint samples_avail;          /* available mono sample frames */
+  gfloat *data;                 /* data pointer to read from / write to */
+};
+
+static GType
+gst_signal_processor_pad_get_type (void)
+{
+  static GType type = 0;
+
+  if (!type) {
+    static const GTypeInfo info = {
+      sizeof (GstSignalProcessorPadClass), NULL, NULL, NULL, NULL,
+      NULL, sizeof (GstSignalProcessorPad), 0, NULL
+    };
+
+    type = g_type_register_static (GST_TYPE_PAD,
+        "GstSignalProcessorPad", &info, 0);
+  }
+  return type;
+}
+
+
+GST_BOILERPLATE (GstSignalProcessor, gst_signal_processor, GstElement,
+    GST_TYPE_ELEMENT);
+
+
+static void gst_signal_processor_finalize (GObject * object);
+static gboolean gst_signal_processor_src_activate_pull (GstPad * pad,
+    gboolean active);
+static gboolean gst_signal_processor_sink_activate_push (GstPad * pad,
+    gboolean active);
+static GstStateChangeReturn gst_signal_processor_change_state (GstElement *
+    element, GstStateChange transition);
+
+static gboolean gst_signal_processor_event (GstPad * pad, GstEvent * event);
+static GstFlowReturn gst_signal_processor_getrange (GstPad * pad,
+    guint64 offset, guint length, GstBuffer ** buffer);
+static GstFlowReturn gst_signal_processor_chain (GstPad * pad,
+    GstBuffer * buffer);
+static gboolean gst_signal_processor_setcaps (GstPad * pad, GstCaps * caps);
+
+
+static void
+gst_signal_processor_base_init (gpointer g_class)
+{
+  GST_DEBUG_CATEGORY_INIT (gst_signal_processor_debug, "gst-dsp", 0,
+      "signalprocessor element");
+}
+
+static void
+gst_signal_processor_class_init (GstSignalProcessorClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = G_OBJECT_CLASS (klass);
+  gstelement_class = GST_ELEMENT_CLASS (klass);
+
+  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_signal_processor_finalize);
+
+  gstelement_class->change_state =
+      GST_DEBUG_FUNCPTR (gst_signal_processor_change_state);
+}
+
+static void
+gst_signal_processor_add_pad_from_template (GstSignalProcessor * self,
+    GstPadTemplate * templ)
+{
+  GstPad *new;
+
+  new = g_object_new (GST_TYPE_SIGNAL_PROCESSOR_PAD,
+      "name", GST_OBJECT_NAME (templ), "direction", templ->direction,
+      "template", templ, NULL);
+  GST_SIGNAL_PROCESSOR_PAD (new)->index =
+      GST_SIGNAL_PROCESSOR_PAD_TEMPLATE (templ)->index;
+
+  gst_pad_set_setcaps_function (new,
+      GST_DEBUG_FUNCPTR (gst_signal_processor_setcaps));
+
+  if (templ->direction == GST_PAD_SINK) {
+    GST_DEBUG ("added new sink pad");
+
+    gst_pad_set_event_function (new,
+        GST_DEBUG_FUNCPTR (gst_signal_processor_event));
+    gst_pad_set_chain_function (new,
+        GST_DEBUG_FUNCPTR (gst_signal_processor_chain));
+    gst_pad_set_activatepush_function (new,
+        GST_DEBUG_FUNCPTR (gst_signal_processor_sink_activate_push));
+  } else {
+    GST_DEBUG ("added new src pad");
+
+    gst_pad_set_getrange_function (new,
+        GST_DEBUG_FUNCPTR (gst_signal_processor_getrange));
+    gst_pad_set_activatepull_function (new,
+        GST_DEBUG_FUNCPTR (gst_signal_processor_src_activate_pull));
+  }
+
+  gst_element_add_pad (GST_ELEMENT (self), new);
+}
+
+static void
+gst_signal_processor_init (GstSignalProcessor * self,
+    GstSignalProcessorClass * klass)
+{
+  GList *templates;
+
+  templates =
+      gst_element_class_get_pad_template_list (GST_ELEMENT_CLASS (klass));
+
+  while (templates) {
+    GstPadTemplate *templ = GST_PAD_TEMPLATE (templates->data);
+
+    gst_signal_processor_add_pad_from_template (self, templ);
+    templates = templates->next;
+  }
+
+  self->state = GST_SIGNAL_PROCESSOR_STATE_NULL;
+
+  self->audio_in = g_new0 (gfloat *, klass->num_audio_in);
+  self->control_in = g_new0 (gfloat, klass->num_control_in);
+  self->audio_out = g_new0 (gfloat *, klass->num_audio_out);
+  self->control_out = g_new0 (gfloat, klass->num_control_out);
+
+  /* init */
+  self->pending_in = klass->num_audio_in;
+  self->pending_out = 0;
+
+  self->sample_rate = 0;
+}
+
+static void
+gst_signal_processor_finalize (GObject * object)
+{
+  GstSignalProcessor *self = GST_SIGNAL_PROCESSOR (object);
+
+  g_free (self->audio_in);
+  self->audio_in = NULL;
+  g_free (self->control_in);
+  self->control_in = NULL;
+  g_free (self->audio_out);
+  self->audio_out = NULL;
+  g_free (self->control_out);
+  self->control_out = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static gboolean
+gst_signal_processor_setup (GstSignalProcessor * self, guint sample_rate)
+{
+  GstSignalProcessorClass *klass;
+  gboolean ret = TRUE;
+
+  klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  GST_INFO_OBJECT (self, "setup()");
+
+  g_return_val_if_fail (self->state == GST_SIGNAL_PROCESSOR_STATE_NULL, FALSE);
+
+  if (klass->setup)
+    ret = klass->setup (self, sample_rate);
+
+  if (!ret)
+    goto setup_failed;
+
+  self->state = GST_SIGNAL_PROCESSOR_STATE_INITIALIZED;
+
+  return ret;
+
+setup_failed:
+  {
+    GST_INFO_OBJECT (self, "setup() failed at %u Hz", sample_rate);
+    return ret;
+  }
+}
+
+static gboolean
+gst_signal_processor_start (GstSignalProcessor * self)
+{
+  GstSignalProcessorClass *klass;
+  gboolean ret = TRUE;
+
+  klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  g_return_val_if_fail (self->state == GST_SIGNAL_PROCESSOR_STATE_INITIALIZED,
+      FALSE);
+
+  GST_INFO_OBJECT (self, "start()");
+
+  if (klass->start)
+    ret = klass->start (self);
+
+  if (!ret)
+    goto start_failed;
+
+  self->state = GST_SIGNAL_PROCESSOR_STATE_RUNNING;
+
+  return ret;
+
+start_failed:
+  {
+    GST_INFO_OBJECT (self, "start() failed");
+    return ret;
+  }
+}
+
+static void
+gst_signal_processor_stop (GstSignalProcessor * self)
+{
+  GstSignalProcessorClass *klass;
+  GstElement *elem;
+  GList *sinks;
+
+  klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+  elem = GST_ELEMENT (self);
+
+  GST_INFO_OBJECT (self, "stop()");
+
+  g_return_if_fail (self->state == GST_SIGNAL_PROCESSOR_STATE_RUNNING);
+
+  if (klass->stop)
+    klass->stop (self);
+
+  for (sinks = elem->sinkpads; sinks; sinks = sinks->next)
+    /* force set_caps when going to RUNNING, see note in _setcaps () */
+    gst_pad_set_caps (GST_PAD (sinks->data), NULL);
+
+  /* should also flush our buffers perhaps? */
+
+  self->state = GST_SIGNAL_PROCESSOR_STATE_INITIALIZED;
+}
+
+static void
+gst_signal_processor_cleanup (GstSignalProcessor * self)
+{
+  GstSignalProcessorClass *klass;
+
+  klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  GST_INFO_OBJECT (self, "cleanup()");
+
+  g_return_if_fail (self->state == GST_SIGNAL_PROCESSOR_STATE_INITIALIZED);
+
+  if (klass->cleanup)
+    klass->cleanup (self);
+
+  self->state = GST_SIGNAL_PROCESSOR_STATE_NULL;
+}
+
+static gboolean
+gst_signal_processor_setcaps_pull (GstSignalProcessor * self, GstPad * pad,
+    GstCaps * caps)
+{
+  if (GST_PAD_IS_SRC (pad)) {
+    GList *l;
+
+    for (l = GST_ELEMENT (self)->sinkpads; l; l = l->next)
+      if (!gst_pad_set_caps (GST_PAD (l->data), caps))
+        goto src_setcaps_failed;
+  } else {
+    GstPad *peer;
+    gboolean res;
+
+    peer = gst_pad_get_peer (pad);
+    if (!peer)
+      goto unlinked_sink;
+
+    res = gst_pad_set_caps (peer, caps);
+    gst_object_unref (peer);
+
+    if (!res)
+      goto peer_setcaps_failed;
+  }
+
+  return TRUE;
+
+src_setcaps_failed:
+  {
+    /* not logging, presumably the sink pad already logged */
+    return FALSE;
+  }
+unlinked_sink:
+  {
+    GST_WARNING_OBJECT (self, "unlinked sink pad %" GST_PTR_FORMAT ", I wonder "
+        "how we passed activate_pull()", pad);
+    return FALSE;
+  }
+peer_setcaps_failed:
+  {
+    GST_INFO_OBJECT (self, "peer of %" GST_PTR_FORMAT " did not accept caps",
+        pad);
+    return FALSE;
+  }
+}
+
+static gboolean
+gst_signal_processor_setcaps (GstPad * pad, GstCaps * caps)
+{
+  GstSignalProcessor *self;
+
+  self = GST_SIGNAL_PROCESSOR (gst_pad_get_parent (pad));
+
+  if (self->mode == GST_ACTIVATE_PULL && !gst_caps_is_equal (caps, self->caps)
+      && !gst_signal_processor_setcaps_pull (self, pad, caps))
+    goto setcaps_pull_failed;
+
+  /* the whole processor has one caps; if the sample rate changes, let subclass
+     implementations know */
+  if (!gst_caps_is_equal (caps, self->caps)) {
+    GstStructure *s;
+    gint sample_rate;
+
+    GST_DEBUG_OBJECT (pad, "got caps %" GST_PTR_FORMAT, caps);
+
+    s = gst_caps_get_structure (caps, 0);
+    if (!gst_structure_get_int (s, "rate", &sample_rate)) {
+      GST_WARNING ("got no sample-rate");
+      goto impossible;
+    }
+
+    GST_DEBUG_OBJECT (self, "Got rate=%d", sample_rate);
+
+    if (GST_SIGNAL_PROCESSOR_IS_RUNNING (self))
+      gst_signal_processor_stop (self);
+    if (GST_SIGNAL_PROCESSOR_IS_INITIALIZED (self))
+      gst_signal_processor_cleanup (self);
+
+    if (!gst_signal_processor_setup (self, sample_rate))
+      goto start_or_setup_failed;
+
+    self->sample_rate = sample_rate;
+    gst_caps_replace (&self->caps, caps);
+  } else {
+    GST_DEBUG_OBJECT (self, "skipping, have caps already");
+  }
+
+  /* we use this method to manage the processor's state, hence the caps clearing
+     in stop(). so it can be that we enter here just to manage the processor's
+     state, to take it to RUNNING from already being INITIALIZED with the right
+     sample rate (e.g., when having gone PLAYING->READY->PLAYING). make sure
+     when we leave that the processor is RUNNING. */
+  if (!GST_SIGNAL_PROCESSOR_IS_INITIALIZED (self)
+      && !gst_signal_processor_setup (self, self->sample_rate))
+    goto start_or_setup_failed;
+  if (!GST_SIGNAL_PROCESSOR_IS_RUNNING (self)
+      && !gst_signal_processor_start (self))
+    goto start_or_setup_failed;
+
+  gst_object_unref (self);
+
+  return TRUE;
+
+start_or_setup_failed:
+  {
+    gst_object_unref (self);
+    return FALSE;
+  }
+setcaps_pull_failed:
+  {
+    gst_object_unref (self);
+    return FALSE;
+  }
+impossible:
+  {
+    g_critical ("something impossible happened");
+    gst_object_unref (self);
+    return FALSE;
+  }
+}
+
+static gboolean
+gst_signal_processor_event (GstPad * pad, GstEvent * event)
+{
+  GstSignalProcessor *self;
+  GstSignalProcessorClass *bclass;
+  gboolean ret;
+
+  self = GST_SIGNAL_PROCESSOR (gst_pad_get_parent (pad));
+  bclass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  /* FIXME, this probably isn't the correct interface: what about return values,
+   * what about overriding event_default
+   * Sync with GstBaseTransform::gst_base_transform_sink_event */
+  if (bclass->event)
+    bclass->event (self, event);
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_FLUSH_START:
+      break;
+    case GST_EVENT_FLUSH_STOP:
+      /* clear errors now */
+      self->flow_state = GST_FLOW_OK;
+      break;
+    default:
+      break;
+  }
+  ret = gst_pad_event_default (pad, event);
+
+  gst_object_unref (self);
+
+  return ret;
+}
+
+static guint
+gst_signal_processor_prepare (GstSignalProcessor * self, guint nframes)
+{
+  GstElement *elem = (GstElement *) self;
+  GstSignalProcessorClass *klass;
+  GList *sinks, *srcs;
+  guint samples_avail = nframes;
+
+  klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  /* first, assign audio_in pointers, and determine the number of samples that
+   * we can process */
+  for (sinks = elem->sinkpads; sinks; sinks = sinks->next) {
+    GstSignalProcessorPad *sinkpad;
+
+    sinkpad = (GstSignalProcessorPad *) sinks->data;
+    g_assert (sinkpad->samples_avail > 0);
+    samples_avail = MIN (samples_avail, sinkpad->samples_avail);
+    self->audio_in[sinkpad->index] = sinkpad->data;
+  }
+
+  /* FIXME: return if samples_avail==0 ? */
+
+  /* now assign output buffers. we can avoid allocation by reusing input
+     buffers, but only if process() can work in place, and if the input buffer
+     is the exact size of the number of samples we are processing. */
+  sinks = elem->sinkpads;
+  srcs = elem->srcpads;
+  if (GST_SIGNAL_PROCESSOR_CLASS_CAN_PROCESS_IN_PLACE (klass)) {
+    while (sinks && srcs) {
+      GstSignalProcessorPad *sinkpad, *srcpad;
+
+      sinkpad = (GstSignalProcessorPad *) sinks->data;
+      srcpad = (GstSignalProcessorPad *) srcs->data;
+
+      if (GST_BUFFER_SIZE (sinkpad->pen) == samples_avail * sizeof (gfloat)) {
+        /* reusable, yay */
+        g_assert (sinkpad->samples_avail == samples_avail);
+        srcpad->pen = sinkpad->pen;
+        sinkpad->pen = NULL;
+        self->audio_out[srcpad->index] = sinkpad->data;
+        self->pending_out++;
+
+        srcs = srcs->next;
+      }
+
+      sinks = sinks->next;
+    }
+  }
+
+  g_return_val_if_fail (GST_SIGNAL_PROCESSOR_IS_RUNNING (self), 0);
+
+  /* now allocate for any remaining outputs */
+  while (srcs) {
+    GstSignalProcessorPad *srcpad;
+    GstFlowReturn ret;
+
+    srcpad = (GstSignalProcessorPad *) srcs->data;
+
+    ret =
+        gst_pad_alloc_buffer_and_set_caps (GST_PAD (srcpad), -1,
+        samples_avail * sizeof (gfloat), self->caps, &srcpad->pen);
+
+    if (ret != GST_FLOW_OK) {
+      self->flow_state = ret;
+      return 0;
+    } else {
+      self->audio_out[srcpad->index] = (gfloat *) GST_BUFFER_DATA (srcpad->pen);
+      self->pending_out++;
+    }
+
+    srcs = srcs->next;
+  }
+
+  return samples_avail;
+}
+
+static void
+gst_signal_processor_update_inputs (GstSignalProcessor * self, guint nprocessed)
+{
+  GstElement *elem = (GstElement *) self;
+  GList *sinks;
+
+  for (sinks = elem->sinkpads; sinks; sinks = sinks->next) {
+    GstSignalProcessorPad *sinkpad;
+
+    sinkpad = (GstSignalProcessorPad *) sinks->data;
+    g_assert (sinkpad->samples_avail >= nprocessed);
+
+    if (sinkpad->pen && sinkpad->samples_avail == nprocessed) {
+      /* used up this buffer, unpen */
+      gst_buffer_unref (sinkpad->pen);
+      sinkpad->pen = NULL;
+    }
+
+    if (!sinkpad->pen) {
+      /* this buffer was used up */
+      self->pending_in++;
+      sinkpad->data = NULL;
+      sinkpad->samples_avail = 0;
+    } else {
+      /* advance ->data pointers and decrement ->samples_avail, unreffing buffer
+         if no samples are left */
+      sinkpad->samples_avail -= nprocessed;
+      sinkpad->data += nprocessed;      /* gfloat* arithmetic */
+    }
+  }
+}
+
+static void
+gst_signal_processor_process (GstSignalProcessor * self, guint nframes)
+{
+  GstElement *elem;
+  GstSignalProcessorClass *klass;
+
+  /* check if we have buffers enqueued */
+  g_return_if_fail (self->pending_in == 0);
+  g_return_if_fail (self->pending_out == 0);
+
+  elem = GST_ELEMENT (self);
+
+  /* check how much input is available and prepare output buffers */
+  nframes = gst_signal_processor_prepare (self, nframes);
+  if (G_UNLIKELY (nframes == 0))
+    goto flow_error;
+
+  klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  GST_LOG_OBJECT (self, "process(%u)", nframes);
+
+  klass->process (self, nframes);
+
+  gst_signal_processor_update_inputs (self, nframes);
+
+  return;
+
+flow_error:
+  {
+    GST_WARNING ("gst_pad_alloc_buffer_and_set_caps() returned %d",
+        self->flow_state);
+    return;
+  }
+}
+
+static void
+gst_signal_processor_pen_buffer (GstSignalProcessor * self, GstPad * pad,
+    GstBuffer * buffer)
+{
+  GstSignalProcessorPad *spad = (GstSignalProcessorPad *) pad;
+
+  if (spad->pen)
+    goto had_buffer;
+
+  /* keep the reference */
+  spad->pen = buffer;
+  spad->data = (gfloat *) GST_BUFFER_DATA (buffer);
+  spad->samples_avail = GST_BUFFER_SIZE (buffer) / sizeof (float);
+
+  g_assert (self->pending_in != 0);
+
+  self->pending_in--;
+
+  return;
+
+  /* ERRORS */
+had_buffer:
+  {
+    GST_WARNING ("Pad %s:%s already has penned buffer",
+        GST_DEBUG_PAD_NAME (pad));
+    gst_buffer_unref (buffer);
+    return;
+  }
+}
+
+static void
+gst_signal_processor_flush (GstSignalProcessor * self)
+{
+  GList *pads;
+  GstSignalProcessorClass *klass;
+
+  klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  GST_INFO_OBJECT (self, "flush()");
+
+  /* release enqueued buffers */
+  for (pads = GST_ELEMENT (self)->pads; pads; pads = pads->next) {
+    GstSignalProcessorPad *spad = (GstSignalProcessorPad *) pads->data;
+
+    if (spad->pen) {
+      gst_buffer_unref (spad->pen);
+      spad->pen = NULL;
+      spad->data = NULL;
+      spad->samples_avail = 0;
+    }
+  }
+
+  /* no outputs prepared and inputs for each pad needed */
+  self->pending_out = 0;
+  self->pending_in = klass->num_audio_in;
+}
+
+static void
+gst_signal_processor_do_pulls (GstSignalProcessor * self, guint nframes)
+{
+  GList *sinkpads;
+
+  /* FIXME: not threadsafe atm */
+
+  sinkpads = GST_ELEMENT (self)->sinkpads;
+
+  for (; sinkpads; sinkpads = sinkpads->next) {
+    GstSignalProcessorPad *spad = (GstSignalProcessorPad *) sinkpads->data;
+    GstFlowReturn ret = GST_FLOW_OK;
+    GstBuffer *buf;
+
+    if (spad->pen) {
+      g_warning ("Unexpectedly full buffer pen for pad %s:%s",
+          GST_DEBUG_PAD_NAME (spad));
+      continue;
+    }
+
+    ret =
+        gst_pad_pull_range (GST_PAD (spad), -1, nframes * sizeof (gfloat),
+        &buf);
+
+    if (ret != GST_FLOW_OK) {
+      gst_signal_processor_flush (self);
+      self->flow_state = ret;
+      return;
+    } else if (!buf) {
+      g_critical ("Pull failed to make a buffer!");
+      self->flow_state = GST_FLOW_ERROR;
+      return;
+    } else {
+      gst_signal_processor_pen_buffer (self, GST_PAD (spad), buf);
+    }
+  }
+
+  if (self->pending_in != 0) {
+    g_critical ("Something wierd happened...");
+    self->flow_state = GST_FLOW_ERROR;
+  } else {
+    gst_signal_processor_process (self, nframes);
+  }
+}
+
+static GstFlowReturn
+gst_signal_processor_getrange (GstPad * pad, guint64 offset,
+    guint length, GstBuffer ** buffer)
+{
+  GstSignalProcessor *self;
+  GstSignalProcessorPad *spad = (GstSignalProcessorPad *) pad;
+  GstFlowReturn ret = GST_FLOW_ERROR;
+
+  self = GST_SIGNAL_PROCESSOR (gst_pad_get_parent (pad));
+
+  if (spad->pen) {
+    *buffer = spad->pen;
+    spad->pen = NULL;
+    g_assert (self->pending_out != 0);
+    self->pending_out--;
+    ret = GST_FLOW_OK;
+  } else {
+    gst_signal_processor_do_pulls (self, length / sizeof (gfloat));
+    if (!spad->pen) {
+      /* this is an error condition */
+      *buffer = NULL;
+      ret = self->flow_state;
+    } else {
+      *buffer = spad->pen;
+      spad->pen = NULL;
+      self->pending_out--;
+      ret = GST_FLOW_OK;
+    }
+  }
+
+  GST_DEBUG_OBJECT (self, "returns %s", gst_flow_get_name (ret));
+
+  gst_object_unref (self);
+
+  return ret;
+}
+
+static void
+gst_signal_processor_do_pushes (GstSignalProcessor * self)
+{
+  GList *srcpads;
+
+  /* not threadsafe atm */
+
+  srcpads = GST_ELEMENT (self)->srcpads;
+
+  for (; srcpads; srcpads = srcpads->next) {
+    GstSignalProcessorPad *spad = (GstSignalProcessorPad *) srcpads->data;
+    GstFlowReturn ret = GST_FLOW_OK;
+    GstBuffer *buffer;
+
+    if (!spad->pen) {
+      g_warning ("Unexpectedly empty buffer pen for pad %s:%s",
+          GST_DEBUG_PAD_NAME (spad));
+      continue;
+    }
+
+    /* take buffer from pen */
+    buffer = spad->pen;
+    spad->pen = NULL;
+
+    ret = gst_pad_push (GST_PAD (spad), buffer);
+
+    if (ret != GST_FLOW_OK) {
+      gst_signal_processor_flush (self);
+      self->flow_state = ret;
+      return;
+    } else {
+      g_assert (self->pending_out > 0);
+      self->pending_out--;
+    }
+  }
+
+  if (self->pending_out != 0) {
+    g_critical ("Something wierd happened...");
+    self->flow_state = GST_FLOW_ERROR;
+  }
+}
+
+static GstFlowReturn
+gst_signal_processor_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstSignalProcessor *self;
+
+  self = GST_SIGNAL_PROCESSOR (gst_pad_get_parent (pad));
+
+  gst_signal_processor_pen_buffer (self, pad, buffer);
+
+  if (self->pending_in == 0) {
+    gst_signal_processor_process (self, G_MAXUINT);
+
+    gst_signal_processor_do_pushes (self);
+  }
+
+  gst_object_unref (self);
+
+  return self->flow_state;
+}
+
+static gboolean
+gst_signal_processor_sink_activate_push (GstPad * pad, gboolean active)
+{
+  gboolean result = TRUE;
+  GstSignalProcessor *self;
+  GstSignalProcessorClass *bclass;
+
+  self = GST_SIGNAL_PROCESSOR (gst_pad_get_parent (pad));
+  bclass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  if (active) {
+    if (self->mode == GST_ACTIVATE_NONE) {
+      self->mode = GST_ACTIVATE_PUSH;
+      result = TRUE;
+    } else if (self->mode == GST_ACTIVATE_PUSH) {
+      result = TRUE;
+    } else {
+      g_warning ("foo");
+      result = FALSE;
+    }
+  } else {
+    if (self->mode == GST_ACTIVATE_NONE) {
+      result = TRUE;
+    } else if (self->mode == GST_ACTIVATE_PUSH) {
+      self->mode = GST_ACTIVATE_NONE;
+      result = TRUE;
+    } else {
+      g_warning ("foo");
+      result = FALSE;
+    }
+  }
+
+  GST_DEBUG_OBJECT (self, "result : %d", result);
+
+  gst_object_unref (self);
+
+  return result;
+}
+
+static gboolean
+gst_signal_processor_src_activate_pull (GstPad * pad, gboolean active)
+{
+  gboolean result = TRUE;
+  GstSignalProcessor *self;
+  GstSignalProcessorClass *bclass;
+
+  self = GST_SIGNAL_PROCESSOR (gst_pad_get_parent (pad));
+  bclass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+
+  if (active) {
+    if (self->mode == GST_ACTIVATE_NONE) {
+      GList *l;
+
+      for (l = GST_ELEMENT (self)->sinkpads; l; l = l->next)
+        result &= gst_pad_activate_pull (pad, active);
+      if (result)
+        self->mode = GST_ACTIVATE_PULL;
+    } else if (self->mode == GST_ACTIVATE_PULL) {
+      result = TRUE;
+    } else {
+      g_warning ("foo");
+      result = FALSE;
+    }
+  } else {
+    if (self->mode == GST_ACTIVATE_NONE) {
+      result = TRUE;
+    } else if (self->mode == GST_ACTIVATE_PULL) {
+      GList *l;
+
+      for (l = GST_ELEMENT (self)->sinkpads; l; l = l->next)
+        result &= gst_pad_activate_pull (pad, active);
+      if (result)
+        self->mode = GST_ACTIVATE_NONE;
+      result = TRUE;
+    } else {
+      g_warning ("foo");
+      result = FALSE;
+    }
+  }
+
+  GST_DEBUG_OBJECT (self, "result : %d", result);
+
+  gst_object_unref (self);
+
+  return result;
+}
+
+static GstStateChangeReturn
+gst_signal_processor_change_state (GstElement * element,
+    GstStateChange transition)
+{
+  GstSignalProcessor *self;
+  GstStateChangeReturn result;
+
+  self = GST_SIGNAL_PROCESSOR (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      break;
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      self->flow_state = GST_FLOW_OK;
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+      break;
+    default:
+      break;
+  }
+
+  if ((result =
+          GST_ELEMENT_CLASS (parent_class)->change_state (element,
+              transition)) == GST_STATE_CHANGE_FAILURE)
+    goto failure;
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      if (GST_SIGNAL_PROCESSOR_IS_RUNNING (self))
+        gst_signal_processor_stop (self);
+      gst_signal_processor_flush (self);
+      break;
+    case GST_STATE_CHANGE_READY_TO_NULL:
+      if (GST_SIGNAL_PROCESSOR_IS_INITIALIZED (self))
+        gst_signal_processor_cleanup (self);
+      break;
+    default:
+      break;
+  }
+
+  return result;
+
+  /* ERRORS */
+failure:
+  {
+    GST_DEBUG_OBJECT (element, "parent failed state change");
+    return result;
+  }
+}
diff --git a/gst-libs/gst/signalprocessor/gstsignalprocessor.h b/gst-libs/gst/signalprocessor/gstsignalprocessor.h
new file mode 100644
index 00000000..d6f0d0b0
--- /dev/null
+++ b/gst-libs/gst/signalprocessor/gstsignalprocessor.h
@@ -0,0 +1,124 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *
+ * gstsignalprocessor.h:
+ *
+ * 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_SIGNAL_PROCESSOR_H__
+#define __GST_SIGNAL_PROCESSOR_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+
+typedef enum 
+{
+  GST_SIGNAL_PROCESSOR_CLASS_FLAG_CAN_PROCESS_IN_PLACE = 1<<0
+} GstSignalProcessorClassFlags;
+
+#define GST_SIGNAL_PROCESSOR_CLASS_CAN_PROCESS_IN_PLACE(klass)		\
+  (GST_SIGNAL_PROCESSOR_CLASS (klass)->flags & 				\
+   GST_SIGNAL_PROCESSOR_CLASS_FLAG_CAN_PROCESS_IN_PLACE)
+#define GST_SIGNAL_PROCESSOR_CLASS_SET_CAN_PROCESS_IN_PLACE(klass)	\
+  GST_SIGNAL_PROCESSOR_CLASS (klass)->flags |=				\
+    GST_SIGNAL_PROCESSOR_CLASS_FLAG_CAN_PROCESS_IN_PLACE
+
+typedef enum 
+{
+  GST_SIGNAL_PROCESSOR_STATE_NULL,
+  GST_SIGNAL_PROCESSOR_STATE_INITIALIZED,
+  GST_SIGNAL_PROCESSOR_STATE_RUNNING
+} GstSignalProcessorState;
+
+
+#define GST_TYPE_SIGNAL_PROCESSOR            (gst_signal_processor_get_type())
+#define GST_SIGNAL_PROCESSOR(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_SIGNAL_PROCESSOR,GstSignalProcessor))
+#define GST_SIGNAL_PROCESSOR_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_SIGNAL_PROCESSOR,GstSignalProcessorClass))
+#define GST_SIGNAL_PROCESSOR_GET_CLASS(obj) \
+        (G_TYPE_INSTANCE_GET_CLASS ((obj),GST_TYPE_SIGNAL_PROCESSOR,GstSignalProcessorClass))
+#define GST_IS_SIGNAL_PROCESSOR(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_SIGNAL_PROCESSOR))
+#define GST_IS_SIGNAL_PROCESSOR_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_SIGNAL_PROCESSOR))
+
+#define GST_SIGNAL_PROCESSOR_IS_INITIALIZED(obj) \
+  (GST_SIGNAL_PROCESSOR (obj)->state >= GST_SIGNAL_PROCESSOR_STATE_INITIALIZED)
+#define GST_SIGNAL_PROCESSOR_IS_RUNNING(obj) \
+  (GST_SIGNAL_PROCESSOR (obj)->state == GST_SIGNAL_PROCESSOR_STATE_RUNNING)
+
+typedef struct _GstSignalProcessor GstSignalProcessor;
+typedef struct _GstSignalProcessorClass GstSignalProcessorClass;
+
+
+struct _GstSignalProcessor {
+  GstElement     element;
+
+  GstCaps *caps;
+
+  guint sample_rate;
+
+  GstSignalProcessorState state;
+
+  GstFlowReturn flow_state;
+
+  GstActivateMode mode;
+
+  /* pending inputs before processing can take place */
+  guint pending_in;
+  /* panding outputs to be filled */
+  guint pending_out;
+
+  gfloat *control_in;
+  gfloat **audio_in;
+  gfloat *control_out;
+  gfloat **audio_out;
+};
+
+struct _GstSignalProcessorClass {
+  GstElementClass parent_class;
+
+  /*< public >*/
+  guint num_control_in;
+  guint num_audio_in;
+  guint num_control_out;
+  guint num_audio_out;
+
+  guint flags;
+
+  /* virtual methods for subclasses */
+
+  gboolean      (*setup)        (GstSignalProcessor *self, guint sample_rate);
+  gboolean      (*start)        (GstSignalProcessor *self);
+  void          (*stop)         (GstSignalProcessor *self);
+  void          (*cleanup)      (GstSignalProcessor *self);
+  void          (*process)      (GstSignalProcessor *self, guint num_frames);
+  gboolean      (*event)        (GstSignalProcessor *self, GstEvent *event);
+};
+
+
+GType gst_signal_processor_get_type (void);
+void gst_signal_processor_class_add_pad_template (GstSignalProcessorClass *klass,
+    const gchar *name, GstPadDirection direction, guint index);
+
+
+
+G_END_DECLS
+
+
+#endif /* __GST_SIGNAL_PROCESSOR_H__ */