Add CELT encoder and decoder elements based on the Speex elements.

Original commit message from CVS:
* configure.ac:
* ext/Makefile.am:
* ext/celt/Makefile.am:
* ext/celt/gstcelt.c: (plugin_init):
* ext/celt/gstceltdec.c: (gst_celt_dec_base_init),
(gst_celt_dec_class_init), (gst_celt_dec_reset),
(gst_celt_dec_init), (celt_dec_convert),
(celt_get_sink_query_types), (celt_dec_sink_query),
(celt_get_src_query_types), (celt_dec_src_query),
(celt_dec_src_event), (celt_dec_sink_event),
(celt_dec_chain_parse_header), (celt_dec_chain_parse_comments),
(celt_dec_chain_parse_data), (celt_dec_chain),
(celt_dec_change_state):
* ext/celt/gstceltdec.h:
* ext/celt/gstceltenc.c: (gst_celt_enc_setup_interfaces),
(gst_celt_enc_base_init), (gst_celt_enc_class_init),
(gst_celt_enc_finalize), (gst_celt_enc_sink_setcaps),
(gst_celt_enc_sink_getcaps), (gst_celt_enc_convert_src),
(gst_celt_enc_convert_sink), (gst_celt_enc_get_latency),
(gst_celt_enc_get_query_types), (gst_celt_enc_src_query),
(gst_celt_enc_sink_query), (gst_celt_enc_init),
(gst_celt_enc_create_metadata_buffer), (gst_celt_enc_setup),
(gst_celt_enc_buffer_from_data), (gst_celt_enc_push_buffer),
(gst_celt_enc_set_header_on_caps), (gst_celt_enc_sinkevent),
(gst_celt_enc_chain), (gst_celt_enc_get_property),
(gst_celt_enc_set_property), (gst_celt_enc_change_state):
* ext/celt/gstceltenc.h:
Add CELT encoder and decoder elements based on the Speex elements.

1 files changed, 943 insertions, 0 deletions

diff --git a/ext/celt/gstceltenc.c b/ext/celt/gstceltenc.c
new file mode 100644
index 00000000..7723f7cb
--- /dev/null
+++ b/ext/celt/gstceltenc.c
@@ -0,0 +1,943 @@
+/* GStreamer Celt Encoder
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ * Copyright (C) <2008> Sebastian Dröge <sebastian.droege@collabora.co.uk>
+ *
+ * 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.
+ */
+
+/*
+ * Based on the speexenc element
+ */
+
+/**
+ * SECTION:element-celtenc
+ * @short_description: an encoder that encodes raw audio to CELT
+ * @see_also: celtdec, oggmux
+ *
+ * <refsect2>
+ * <para>
+ * This element raw audio to CELT.
+ * </para>
+ * <title>Example pipelines</title>
+ * <para>
+ * <programlisting>
+ * gst-launch -v audiotestsrc wave=sine num-buffers=100 ! audioconvert ! celtenc ! oggmux ! filesink location=sine.ogg
+ * </programlisting>
+ * Encode a test sine signal to Ogg/CELT.
+ * </para>
+ * </refsect2>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <math.h>
+#include <celt/celt.h>
+#include <celt/celt_header.h>
+
+#include <gst/gsttagsetter.h>
+#include <gst/tag/tag.h>
+#include "gstceltenc.h"
+
+GST_DEBUG_CATEGORY_STATIC (celtenc_debug);
+#define GST_CAT_DEFAULT celtenc_debug
+
+static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("audio/x-raw-int, "
+        "rate = (int) [ 32000, 64000 ], "
+        "channels = (int) [ 1, 2 ], "
+        "endianness = (int) BYTE_ORDER, "
+        "signed = (boolean) TRUE, " "width = (int) 16, " "depth = (int) 16")
+    );
+
+static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("audio/x-celt, "
+        "rate = (int) [ 32000, 64000 ], " "channels = (int) [ 1, 2 ]")
+    );
+
+static const GstElementDetails celtenc_details =
+GST_ELEMENT_DETAILS ("Celt audio encoder",
+    "Codec/Encoder/Audio",
+    "Encodes audio in Celt format",
+    "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
+
+#define DEFAULT_BITRATE         128
+#define DEFAULT_FRAMESIZE       256
+
+enum
+{
+  PROP_0,
+  PROP_BITRATE,
+  PROP_FRAMESIZE
+};
+
+static void gst_celt_enc_finalize (GObject * object);
+
+static gboolean gst_celt_enc_sinkevent (GstPad * pad, GstEvent * event);
+static GstFlowReturn gst_celt_enc_chain (GstPad * pad, GstBuffer * buf);
+static gboolean gst_celt_enc_setup (GstCeltEnc * enc);
+
+static void gst_celt_enc_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_celt_enc_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static GstStateChangeReturn gst_celt_enc_change_state (GstElement * element,
+    GstStateChange transition);
+
+static void
+gst_celt_enc_setup_interfaces (GType celtenc_type)
+{
+  static const GInterfaceInfo tag_setter_info = { NULL, NULL, NULL };
+
+  g_type_add_interface_static (celtenc_type, GST_TYPE_TAG_SETTER,
+      &tag_setter_info);
+
+  GST_DEBUG_CATEGORY_INIT (celtenc_debug, "celtenc", 0, "Celt encoder");
+}
+
+GST_BOILERPLATE_FULL (GstCeltEnc, gst_celt_enc, GstElement, GST_TYPE_ELEMENT,
+    gst_celt_enc_setup_interfaces);
+
+static void
+gst_celt_enc_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&src_factory));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&sink_factory));
+  gst_element_class_set_details_simple (element_class, "Celt audio encoder",
+      "Codec/Encoder/Audio",
+      "Encodes audio in Celt format",
+      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
+}
+
+static void
+gst_celt_enc_class_init (GstCeltEncClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+
+  gobject_class->set_property = gst_celt_enc_set_property;
+  gobject_class->get_property = gst_celt_enc_get_property;
+
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_BITRATE,
+      g_param_spec_int ("bitrate", "Encoding Bit-rate",
+          "Specify an encoding bit-rate (in bps). (0 = automatic)",
+          0, 150, DEFAULT_BITRATE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_FRAMESIZE,
+      g_param_spec_int ("framesize", "Frame Size",
+          "The number of samples per frame", 64, 256, DEFAULT_FRAMESIZE,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_celt_enc_finalize);
+
+  gstelement_class->change_state =
+      GST_DEBUG_FUNCPTR (gst_celt_enc_change_state);
+}
+
+static void
+gst_celt_enc_finalize (GObject * object)
+{
+  GstCeltEnc *enc;
+
+  enc = GST_CELT_ENC (object);
+
+  g_object_unref (enc->adapter);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static gboolean
+gst_celt_enc_sink_setcaps (GstPad * pad, GstCaps * caps)
+{
+  GstCeltEnc *enc;
+  GstStructure *structure;
+
+  enc = GST_CELT_ENC (GST_PAD_PARENT (pad));
+  enc->setup = FALSE;
+
+  structure = gst_caps_get_structure (caps, 0);
+  gst_structure_get_int (structure, "channels", &enc->channels);
+  gst_structure_get_int (structure, "rate", &enc->rate);
+
+  gst_celt_enc_setup (enc);
+
+  return enc->setup;
+}
+
+
+static GstCaps *
+gst_celt_enc_sink_getcaps (GstPad * pad)
+{
+  GstCaps *caps = gst_caps_copy (gst_pad_get_pad_template_caps (pad));
+  GstCaps *peercaps = NULL;
+  GstCeltEnc *enc = GST_CELT_ENC (gst_pad_get_parent_element (pad));
+
+  peercaps = gst_pad_peer_get_caps (enc->srcpad);
+
+  if (peercaps) {
+    if (!gst_caps_is_empty (peercaps) && !gst_caps_is_any (peercaps)) {
+      GstStructure *ps = gst_caps_get_structure (peercaps, 0);
+      GstStructure *s = gst_caps_get_structure (caps, 0);
+      gint rate, channels;
+
+      if (gst_structure_get_int (ps, "rate", &rate)) {
+        gst_structure_fixate_field_nearest_int (s, "rate", rate);
+      }
+
+      if (gst_structure_get_int (ps, "channels", &channels)) {
+        gst_structure_fixate_field_nearest_int (s, "channels", channels);
+      }
+    }
+    gst_caps_unref (peercaps);
+  }
+
+  gst_object_unref (enc);
+
+  return caps;
+}
+
+
+static gboolean
+gst_celt_enc_convert_src (GstPad * pad, GstFormat src_format, gint64 src_value,
+    GstFormat * dest_format, gint64 * dest_value)
+{
+  gboolean res = TRUE;
+  GstCeltEnc *enc;
+  gint64 avg;
+
+  enc = GST_CELT_ENC (GST_PAD_PARENT (pad));
+
+  if (enc->samples_in == 0 || enc->bytes_out == 0 || enc->rate == 0)
+    return FALSE;
+
+  avg = (enc->bytes_out * enc->rate) / (enc->samples_in);
+
+  switch (src_format) {
+    case GST_FORMAT_BYTES:
+      switch (*dest_format) {
+        case GST_FORMAT_TIME:
+          *dest_value = src_value * GST_SECOND / avg;
+          break;
+        default:
+          res = FALSE;
+      }
+      break;
+    case GST_FORMAT_TIME:
+      switch (*dest_format) {
+        case GST_FORMAT_BYTES:
+          *dest_value = src_value * avg / GST_SECOND;
+          break;
+        default:
+          res = FALSE;
+      }
+      break;
+    default:
+      res = FALSE;
+  }
+  return res;
+}
+
+static gboolean
+gst_celt_enc_convert_sink (GstPad * pad, GstFormat src_format,
+    gint64 src_value, GstFormat * dest_format, gint64 * dest_value)
+{
+  gboolean res = TRUE;
+  guint scale = 1;
+  gint bytes_per_sample;
+  GstCeltEnc *enc;
+
+  enc = GST_CELT_ENC (GST_PAD_PARENT (pad));
+
+  bytes_per_sample = enc->channels * 2;
+
+  switch (src_format) {
+    case GST_FORMAT_BYTES:
+      switch (*dest_format) {
+        case GST_FORMAT_DEFAULT:
+          if (bytes_per_sample == 0)
+            return FALSE;
+          *dest_value = src_value / bytes_per_sample;
+          break;
+        case GST_FORMAT_TIME:
+        {
+          gint byterate = bytes_per_sample * enc->rate;
+
+          if (byterate == 0)
+            return FALSE;
+          *dest_value = src_value * GST_SECOND / byterate;
+          break;
+        }
+        default:
+          res = FALSE;
+      }
+      break;
+    case GST_FORMAT_DEFAULT:
+      switch (*dest_format) {
+        case GST_FORMAT_BYTES:
+          *dest_value = src_value * bytes_per_sample;
+          break;
+        case GST_FORMAT_TIME:
+          if (enc->rate == 0)
+            return FALSE;
+          *dest_value = src_value * GST_SECOND / enc->rate;
+          break;
+        default:
+          res = FALSE;
+      }
+      break;
+    case GST_FORMAT_TIME:
+      switch (*dest_format) {
+        case GST_FORMAT_BYTES:
+          scale = bytes_per_sample;
+          /* fallthrough */
+        case GST_FORMAT_DEFAULT:
+          *dest_value = src_value * scale * enc->rate / GST_SECOND;
+          break;
+        default:
+          res = FALSE;
+      }
+      break;
+    default:
+      res = FALSE;
+  }
+  return res;
+}
+
+static gint64
+gst_celt_enc_get_latency (GstCeltEnc * enc)
+{
+  return gst_util_uint64_scale (enc->frame_size, GST_SECOND, enc->rate);
+}
+
+static const GstQueryType *
+gst_celt_enc_get_query_types (GstPad * pad)
+{
+  static const GstQueryType gst_celt_enc_src_query_types[] = {
+    GST_QUERY_POSITION,
+    GST_QUERY_DURATION,
+    GST_QUERY_CONVERT,
+    GST_QUERY_LATENCY,
+    0
+  };
+
+  return gst_celt_enc_src_query_types;
+}
+
+static gboolean
+gst_celt_enc_src_query (GstPad * pad, GstQuery * query)
+{
+  gboolean res = TRUE;
+  GstCeltEnc *enc;
+
+  enc = GST_CELT_ENC (gst_pad_get_parent (pad));
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_POSITION:
+    {
+      GstFormat fmt, req_fmt;
+      gint64 pos, val;
+
+      gst_query_parse_position (query, &req_fmt, NULL);
+      if ((res = gst_pad_query_peer_position (enc->sinkpad, &req_fmt, &val))) {
+        gst_query_set_position (query, req_fmt, val);
+        break;
+      }
+
+      fmt = GST_FORMAT_TIME;
+      if (!(res = gst_pad_query_peer_position (enc->sinkpad, &fmt, &pos)))
+        break;
+
+      if ((res =
+              gst_pad_query_peer_convert (enc->sinkpad, fmt, pos, &req_fmt,
+                  &val)))
+        gst_query_set_position (query, req_fmt, val);
+
+      break;
+    }
+    case GST_QUERY_DURATION:
+    {
+      GstFormat fmt, req_fmt;
+      gint64 dur, val;
+
+      gst_query_parse_duration (query, &req_fmt, NULL);
+      if ((res = gst_pad_query_peer_duration (enc->sinkpad, &req_fmt, &val))) {
+        gst_query_set_duration (query, req_fmt, val);
+        break;
+      }
+
+      fmt = GST_FORMAT_TIME;
+      if (!(res = gst_pad_query_peer_duration (enc->sinkpad, &fmt, &dur)))
+        break;
+
+      if ((res =
+              gst_pad_query_peer_convert (enc->sinkpad, fmt, dur, &req_fmt,
+                  &val))) {
+        gst_query_set_duration (query, req_fmt, val);
+      }
+      break;
+    }
+    case GST_QUERY_CONVERT:
+    {
+      GstFormat src_fmt, dest_fmt;
+      gint64 src_val, dest_val;
+
+      gst_query_parse_convert (query, &src_fmt, &src_val, &dest_fmt, &dest_val);
+      if (!(res = gst_celt_enc_convert_src (pad, src_fmt, src_val, &dest_fmt,
+                  &dest_val)))
+        goto error;
+      gst_query_set_convert (query, src_fmt, src_val, dest_fmt, dest_val);
+      break;
+    }
+    case GST_QUERY_LATENCY:
+    {
+      gboolean live;
+      GstClockTime min_latency, max_latency;
+      gint64 latency;
+
+      if ((res = gst_pad_peer_query (pad, query))) {
+        gst_query_parse_latency (query, &live, &min_latency, &max_latency);
+
+        latency = gst_celt_enc_get_latency (enc);
+
+        /* add our latency */
+        min_latency += latency;
+        if (max_latency != -1)
+          max_latency += latency;
+
+        gst_query_set_latency (query, live, min_latency, max_latency);
+      }
+      break;
+    }
+    default:
+      res = gst_pad_peer_query (pad, query);
+      break;
+  }
+
+error:
+
+  gst_object_unref (enc);
+
+  return res;
+}
+
+static gboolean
+gst_celt_enc_sink_query (GstPad * pad, GstQuery * query)
+{
+  gboolean res = TRUE;
+  GstCeltEnc *enc;
+
+  enc = GST_CELT_ENC (GST_PAD_PARENT (pad));
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_CONVERT:
+    {
+      GstFormat src_fmt, dest_fmt;
+      gint64 src_val, dest_val;
+
+      gst_query_parse_convert (query, &src_fmt, &src_val, &dest_fmt, &dest_val);
+      if (!(res =
+              gst_celt_enc_convert_sink (pad, src_fmt, src_val, &dest_fmt,
+                  &dest_val)))
+        goto error;
+      gst_query_set_convert (query, src_fmt, src_val, dest_fmt, dest_val);
+      break;
+    }
+    default:
+      res = gst_pad_query_default (pad, query);
+      break;
+  }
+
+error:
+  return res;
+}
+
+static void
+gst_celt_enc_init (GstCeltEnc * enc, GstCeltEncClass * klass)
+{
+  enc->sinkpad = gst_pad_new_from_static_template (&sink_factory, "sink");
+  gst_element_add_pad (GST_ELEMENT (enc), enc->sinkpad);
+  gst_pad_set_event_function (enc->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_celt_enc_sinkevent));
+  gst_pad_set_chain_function (enc->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_celt_enc_chain));
+  gst_pad_set_setcaps_function (enc->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_celt_enc_sink_setcaps));
+  gst_pad_set_getcaps_function (enc->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_celt_enc_sink_getcaps));
+  gst_pad_set_query_function (enc->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_celt_enc_sink_query));
+
+  enc->srcpad = gst_pad_new_from_static_template (&src_factory, "src");
+  gst_pad_set_query_function (enc->srcpad,
+      GST_DEBUG_FUNCPTR (gst_celt_enc_src_query));
+  gst_pad_set_query_type_function (enc->srcpad,
+      GST_DEBUG_FUNCPTR (gst_celt_enc_get_query_types));
+  gst_element_add_pad (GST_ELEMENT (enc), enc->srcpad);
+
+  enc->channels = -1;
+  enc->rate = -1;
+
+  enc->bitrate = DEFAULT_BITRATE;
+  enc->frame_size = DEFAULT_FRAMESIZE;
+
+  enc->setup = FALSE;
+  enc->header_sent = FALSE;
+
+  enc->adapter = gst_adapter_new ();
+}
+
+static GstBuffer *
+gst_celt_enc_create_metadata_buffer (GstCeltEnc * enc)
+{
+  const GstTagList *user_tags;
+  GstTagList *merged_tags;
+  GstBuffer *comments = NULL;
+
+  user_tags = gst_tag_setter_get_tag_list (GST_TAG_SETTER (enc));
+
+  GST_DEBUG_OBJECT (enc, "upstream tags = %" GST_PTR_FORMAT, enc->tags);
+  GST_DEBUG_OBJECT (enc, "user-set tags = %" GST_PTR_FORMAT, user_tags);
+
+  /* gst_tag_list_merge() will handle NULL for either or both lists fine */
+  merged_tags = gst_tag_list_merge (user_tags, enc->tags,
+      gst_tag_setter_get_tag_merge_mode (GST_TAG_SETTER (enc)));
+
+  if (merged_tags == NULL)
+    merged_tags = gst_tag_list_new ();
+
+  GST_DEBUG_OBJECT (enc, "merged   tags = %" GST_PTR_FORMAT, merged_tags);
+  comments = gst_tag_list_to_vorbiscomment_buffer (merged_tags, NULL,
+      0, "Encoded with GStreamer Celtenc");
+  gst_tag_list_free (merged_tags);
+
+  GST_BUFFER_OFFSET (comments) = enc->bytes_out;
+  GST_BUFFER_OFFSET_END (comments) = 0;
+
+  return comments;
+}
+
+static gboolean
+gst_celt_enc_setup (GstCeltEnc * enc)
+{
+  gint error = CELT_OK;
+  gint bytes_per_packet;
+
+  enc->setup = FALSE;
+
+  /* Fix bitrate */
+  if (enc->channels == 1) {
+    if (enc->bitrate <= 0)
+      enc->bitrate = 64;
+    else if (enc->bitrate < 32)
+      enc->bitrate = 32;
+    else if (enc->bitrate > 110)
+      enc->bitrate = 110;
+  } else {
+    if (enc->bitrate <= 0)
+      enc->bitrate = 128;
+    else if (enc->bitrate < 64)
+      enc->bitrate = 64;
+    else if (enc->bitrate > 150)
+      enc->bitrate = 150;
+  }
+
+  enc->mode =
+      celt_mode_create (enc->rate, enc->channels, enc->frame_size, &error);
+  if (!enc->mode)
+    goto mode_initialization_failed;
+
+  celt_mode_info (enc->mode, CELT_GET_FRAME_SIZE, &enc->frame_size);
+
+  bytes_per_packet =
+      (enc->bitrate * 1000 * enc->frame_size / enc->rate + 4) / 8;
+
+  celt_header_init (&enc->header, enc->mode);
+  enc->header.nb_channels = enc->channels;
+
+  enc->state = celt_encoder_create (enc->mode);
+  if (!enc->state)
+    goto encoder_creation_failed;
+
+  GST_LOG_OBJECT (enc, "we have frame size %d", enc->frame_size);
+
+  enc->setup = TRUE;
+
+  return TRUE;
+
+mode_initialization_failed:
+  GST_ERROR_OBJECT (enc, "Mode initialization failed: %d", error);
+  return FALSE;
+
+encoder_creation_failed:
+  GST_ERROR_OBJECT (enc, "Encoder creation failed");
+  return FALSE;
+}
+
+/* prepare a buffer for transmission */
+static GstBuffer *
+gst_celt_enc_buffer_from_data (GstCeltEnc * enc, guchar * data,
+    gint data_len, guint64 granulepos)
+{
+  GstBuffer *outbuf;
+
+  outbuf = gst_buffer_new_and_alloc (data_len);
+  memcpy (GST_BUFFER_DATA (outbuf), data, data_len);
+  GST_BUFFER_OFFSET (outbuf) = enc->bytes_out;
+  GST_BUFFER_OFFSET_END (outbuf) = granulepos;
+
+  GST_LOG_OBJECT (enc, "encoded buffer of %d bytes", GST_BUFFER_SIZE (outbuf));
+  return outbuf;
+}
+
+
+/* push out the buffer and do internal bookkeeping */
+static GstFlowReturn
+gst_celt_enc_push_buffer (GstCeltEnc * enc, GstBuffer * buffer)
+{
+  guint size;
+
+  size = GST_BUFFER_SIZE (buffer);
+
+  enc->bytes_out += size;
+
+  GST_DEBUG_OBJECT (enc, "pushing output buffer of size %u", size);
+
+  return gst_pad_push (enc->srcpad, buffer);
+}
+
+static GstCaps *
+gst_celt_enc_set_header_on_caps (GstCaps * caps, GstBuffer * buf1,
+    GstBuffer * buf2)
+{
+  GstStructure *structure = NULL;
+  GstBuffer *buf;
+  GValue array = { 0 };
+  GValue value = { 0 };
+
+  caps = gst_caps_make_writable (caps);
+  structure = gst_caps_get_structure (caps, 0);
+
+  g_assert (gst_buffer_is_metadata_writable (buf1));
+  g_assert (gst_buffer_is_metadata_writable (buf2));
+
+  /* mark buffers */
+  GST_BUFFER_FLAG_SET (buf1, GST_BUFFER_FLAG_IN_CAPS);
+  GST_BUFFER_FLAG_SET (buf2, GST_BUFFER_FLAG_IN_CAPS);
+
+  /* put buffers in a fixed list */
+  g_value_init (&array, GST_TYPE_ARRAY);
+  g_value_init (&value, GST_TYPE_BUFFER);
+  buf = gst_buffer_copy (buf1);
+  gst_value_set_buffer (&value, buf);
+  gst_buffer_unref (buf);
+  gst_value_array_append_value (&array, &value);
+  g_value_unset (&value);
+  g_value_init (&value, GST_TYPE_BUFFER);
+  buf = gst_buffer_copy (buf2);
+  gst_value_set_buffer (&value, buf);
+  gst_buffer_unref (buf);
+  gst_value_array_append_value (&array, &value);
+  gst_structure_set_value (structure, "streamheader", &array);
+  g_value_unset (&value);
+  g_value_unset (&array);
+
+  return caps;
+}
+
+
+static gboolean
+gst_celt_enc_sinkevent (GstPad * pad, GstEvent * event)
+{
+  gboolean res = TRUE;
+  GstCeltEnc *enc;
+
+  enc = GST_CELT_ENC (gst_pad_get_parent (pad));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_EOS:
+      enc->eos = TRUE;
+      res = gst_pad_event_default (pad, event);
+      break;
+    case GST_EVENT_TAG:
+    {
+      GstTagList *list;
+
+      gst_event_parse_tag (event, &list);
+      if (enc->tags) {
+        gst_tag_list_insert (enc->tags, list,
+            gst_tag_setter_get_tag_merge_mode (GST_TAG_SETTER (enc)));
+      }
+      res = gst_pad_event_default (pad, event);
+      break;
+    }
+    default:
+      res = gst_pad_event_default (pad, event);
+      break;
+  }
+
+  gst_object_unref (enc);
+
+  return res;
+}
+
+
+static GstFlowReturn
+gst_celt_enc_chain (GstPad * pad, GstBuffer * buf)
+{
+  GstCeltEnc *enc;
+  GstFlowReturn ret = GST_FLOW_OK;
+
+  enc = GST_CELT_ENC (GST_PAD_PARENT (pad));
+
+  if (!enc->setup)
+    goto not_setup;
+
+  if (!enc->header_sent) {
+    /* Celt streams begin with two headers; the initial header (with
+       most of the codec setup parameters) which is mandated by the Ogg
+       bitstream spec.  The second header holds any comment fields.
+       We merely need to make the headers, then pass them to libcelt 
+       one at a time; libcelt handles the additional Ogg bitstream 
+       constraints */
+    GstBuffer *buf1, *buf2;
+    GstCaps *caps;
+    guchar data[100];
+
+    /* create header buffer */
+    celt_header_to_packet (&enc->header, data, 100);
+    buf1 = gst_celt_enc_buffer_from_data (enc, data, 100, 0);
+
+    /* create comment buffer */
+    buf2 = gst_celt_enc_create_metadata_buffer (enc);
+
+    /* mark and put on caps */
+    caps = gst_pad_get_caps (enc->srcpad);
+    caps = gst_celt_enc_set_header_on_caps (caps, buf1, buf2);
+
+    gst_caps_set_simple (caps,
+        "rate", G_TYPE_INT, enc->rate,
+        "channels", G_TYPE_INT, enc->channels, NULL);
+
+    /* negotiate with these caps */
+    GST_DEBUG_OBJECT (enc, "here are the caps: %" GST_PTR_FORMAT, caps);
+    gst_pad_set_caps (enc->srcpad, caps);
+
+    gst_buffer_set_caps (buf1, caps);
+    gst_buffer_set_caps (buf2, caps);
+    gst_caps_unref (caps);
+
+    /* push out buffers */
+    ret = gst_celt_enc_push_buffer (enc, buf1);
+
+    if (ret != GST_FLOW_OK) {
+      gst_buffer_unref (buf2);
+      goto done;
+    }
+
+    ret = gst_celt_enc_push_buffer (enc, buf2);
+
+    if (ret != GST_FLOW_OK)
+      goto done;
+
+    enc->header_sent = TRUE;
+  }
+
+  {
+    gint frame_size = enc->frame_size;
+    gint bytes = frame_size * 2 * enc->channels;
+    gint bytes_per_packet =
+        (enc->bitrate * 1000 * enc->frame_size / enc->rate + 4) / 8;
+
+    GST_DEBUG_OBJECT (enc, "received buffer of %u bytes",
+        GST_BUFFER_SIZE (buf));
+
+    /* push buffer to adapter */
+    gst_adapter_push (enc->adapter, buf);
+    buf = NULL;
+
+    while (gst_adapter_available (enc->adapter) >= bytes) {
+      gint16 *data;
+      gint outsize;
+      GstBuffer *outbuf;
+
+      ret = gst_pad_alloc_buffer_and_set_caps (enc->srcpad,
+          GST_BUFFER_OFFSET_NONE, bytes_per_packet, GST_PAD_CAPS (enc->srcpad),
+          &outbuf);
+
+      if (GST_FLOW_OK != ret)
+        goto done;
+
+      data = (gint16 *) gst_adapter_take (enc->adapter, bytes);
+      enc->samples_in += frame_size;
+
+      GST_DEBUG_OBJECT (enc, "encoding %d samples (%d bytes)", frame_size,
+          bytes);
+
+      outsize =
+          celt_encode (enc->state, data, GST_BUFFER_DATA (outbuf),
+          bytes_per_packet);
+
+      g_free (data);
+
+      if (outsize < 0) {
+        GST_ERROR_OBJECT (enc, "Encoding failed: %d", outsize);
+        ret = GST_FLOW_ERROR;
+        goto done;
+      }
+
+      enc->frameno++;
+
+      GST_BUFFER_TIMESTAMP (outbuf) =
+          gst_util_uint64_scale_int (enc->frameno * frame_size, GST_SECOND,
+          enc->rate);
+      GST_BUFFER_DURATION (outbuf) =
+          gst_util_uint64_scale_int (frame_size, GST_SECOND, enc->rate);
+      /* set gp time and granulepos; see gst-plugins-base/ext/ogg/README */
+      GST_BUFFER_OFFSET_END (outbuf) = ((enc->frameno + 1) * frame_size);
+      GST_BUFFER_OFFSET (outbuf) =
+          gst_util_uint64_scale_int (GST_BUFFER_OFFSET_END (outbuf), GST_SECOND,
+          enc->rate);
+
+      ret = gst_celt_enc_push_buffer (enc, outbuf);
+
+      if ((GST_FLOW_OK != ret) && (GST_FLOW_NOT_LINKED != ret))
+        goto done;
+    }
+  }
+
+done:
+
+  if (buf)
+    gst_buffer_unref (buf);
+
+  return ret;
+
+  /* ERRORS */
+not_setup:
+  {
+    GST_ELEMENT_ERROR (enc, CORE, NEGOTIATION, (NULL),
+        ("encoder not initialized (input is not audio?)"));
+    ret = GST_FLOW_NOT_NEGOTIATED;
+    goto done;
+  }
+
+}
+
+
+static void
+gst_celt_enc_get_property (GObject * object, guint prop_id, GValue * value,
+    GParamSpec * pspec)
+{
+  GstCeltEnc *enc;
+
+  enc = GST_CELT_ENC (object);
+
+  switch (prop_id) {
+    case PROP_BITRATE:
+      g_value_set_int (value, enc->bitrate);
+      break;
+    case PROP_FRAMESIZE:
+      g_value_set_int (value, enc->frame_size);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_celt_enc_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstCeltEnc *enc;
+
+  enc = GST_CELT_ENC (object);
+
+  switch (prop_id) {
+    case PROP_BITRATE:
+      enc->bitrate = g_value_get_int (value);
+      break;
+    case PROP_FRAMESIZE:
+      enc->frame_size = g_value_get_int (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static GstStateChangeReturn
+gst_celt_enc_change_state (GstElement * element, GstStateChange transition)
+{
+  GstCeltEnc *enc = GST_CELT_ENC (element);
+  GstStateChangeReturn res;
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      enc->tags = gst_tag_list_new ();
+      break;
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      enc->frameno = 0;
+      enc->samples_in = 0;
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+      /* fall through */
+    default:
+      break;
+  }
+
+  res = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+  if (res == GST_STATE_CHANGE_FAILURE)
+    return res;
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      enc->setup = FALSE;
+      enc->header_sent = FALSE;
+      if (enc->state) {
+        celt_encoder_destroy (enc->state);
+        enc->state = NULL;
+      }
+      if (enc->mode) {
+        celt_mode_destroy (enc->mode);
+        enc->mode = NULL;
+      }
+      memset (&enc->header, 0, sizeof (enc->header));
+      break;
+    case GST_STATE_CHANGE_READY_TO_NULL:
+      gst_tag_list_free (enc->tags);
+      enc->tags = NULL;
+    default:
+      break;
+  }
+
+  return res;
+}