gstreamer/ext/opus/gstopusenc.c

/* GStreamer Opus 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-opusenc
 * @see_also: opusdec, oggmux
 *
 * This element encodes raw audio to OPUS.
 *
 * <refsect2>
 * <title>Example pipelines</title>
 * |[
 * gst-launch -v audiotestsrc wave=sine num-buffers=100 ! audioconvert ! opusenc ! oggmux ! filesink location=sine.ogg
 * ]| Encode a test sine signal to Ogg/OPUS.
 * </refsect2>
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <math.h>
#include <opus/opus.h>

#include <gst/gsttagsetter.h>
#include <gst/tag/tag.h>
#include <gst/audio/audio.h>
#include "gstopusenc.h"

GST_DEBUG_CATEGORY_STATIC (opusenc_debug);
#define GST_CAT_DEFAULT opusenc_debug

#define GST_OPUS_ENC_TYPE_BANDWIDTH (gst_opus_enc_bandwidth_get_type())
static GType
gst_opus_enc_bandwidth_get_type (void)
{
  static const GEnumValue values[] = {
    {OPUS_BANDWIDTH_NARROWBAND, "Narrow band", "narrowband"},
    {OPUS_BANDWIDTH_MEDIUMBAND, "Medium band", "mediumband"},
    {OPUS_BANDWIDTH_WIDEBAND, "Wide band", "wideband"},
    {OPUS_BANDWIDTH_SUPERWIDEBAND, "Super wide band", "superwideband"},
    {OPUS_BANDWIDTH_FULLBAND, "Full band", "fullband"},
    {OPUS_AUTO, "Auto", "auto"},
    {0, NULL, NULL}
  };
  static volatile GType id = 0;

  if (g_once_init_enter ((gsize *) & id)) {
    GType _id;

    _id = g_enum_register_static ("GstOpusEncBandwidth", values);

    g_once_init_leave ((gsize *) & id, _id);
  }

  return id;
}

static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-raw, "
        "format = (string) { S16LE }, "
        "rate = (int) { 8000, 12000, 16000, 24000, 48000 }, "
        "channels = (int) [ 1, 2 ] ")
    );

static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-opus, "
        "rate = (int) { 8000, 12000, 16000, 24000, 48000 }, "
        "channels = (int) [ 1, 2 ], " "frame-size = (int) [ 2, 60 ]")
    );

#define DEFAULT_AUDIO           TRUE
#define DEFAULT_BITRATE         64000
#define DEFAULT_BANDWIDTH       OPUS_BANDWIDTH_FULLBAND
#define DEFAULT_FRAMESIZE       20
#define DEFAULT_CBR             TRUE
#define DEFAULT_CONSTRAINED_VBR TRUE
#define DEFAULT_COMPLEXITY      10
#define DEFAULT_INBAND_FEC      FALSE
#define DEFAULT_DTX             FALSE
#define DEFAULT_PACKET_LOSS_PERCENT 0

enum
{
  PROP_0,
  PROP_AUDIO,
  PROP_BITRATE,
  PROP_BANDWIDTH,
  PROP_FRAME_SIZE,
  PROP_CBR,
  PROP_CONSTRAINED_VBR,
  PROP_COMPLEXITY,
  PROP_INBAND_FEC,
  PROP_DTX,
  PROP_PACKET_LOSS_PERCENT
};

static void gst_opus_enc_finalize (GObject * object);

static gboolean gst_opus_enc_sinkevent (GstPad * pad, GstEvent * event);
static GstFlowReturn gst_opus_enc_chain (GstPad * pad, GstBuffer * buf);
static gboolean gst_opus_enc_setup (GstOpusEnc * enc);

static void gst_opus_enc_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static void gst_opus_enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static GstStateChangeReturn gst_opus_enc_change_state (GstElement * element,
    GstStateChange transition);

static GstFlowReturn gst_opus_enc_encode (GstOpusEnc * enc, gboolean flush);

#define gst_opus_enc_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstOpusEnc, gst_opus_enc, GST_TYPE_ELEMENT,
    G_IMPLEMENT_INTERFACE (GST_TYPE_TAG_SETTER, NULL);
    G_IMPLEMENT_INTERFACE (GST_TYPE_PRESET, NULL));

static void
gst_opus_enc_class_init (GstOpusEncClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *element_class;

  gobject_class = (GObjectClass *) klass;
  element_class = (GstElementClass *) klass;

  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, "Opus audio encoder",
      "Codec/Encoder/Audio",
      "Encodes audio in Opus format",
      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");

  gobject_class->set_property = gst_opus_enc_set_property;
  gobject_class->get_property = gst_opus_enc_get_property;

  g_object_class_install_property (gobject_class, PROP_AUDIO,
      g_param_spec_boolean ("audio", "Audio or voice",
          "Audio or voice", DEFAULT_AUDIO,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  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).",
          1, 320000, DEFAULT_BITRATE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_BANDWIDTH,
      g_param_spec_enum ("bandwidth", "Band Width",
          "Audio Band Width", GST_OPUS_ENC_TYPE_BANDWIDTH, DEFAULT_BANDWIDTH,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_FRAME_SIZE,
      g_param_spec_int ("frame-size", "Frame Size",
          "The duration of an audio frame, in ms", 2, 60, DEFAULT_FRAMESIZE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_CBR,
      g_param_spec_boolean ("cbr", "Constant bit rate",
          "Constant bit rate", DEFAULT_CBR,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_CONSTRAINED_VBR,
      g_param_spec_boolean ("constrained-cbr", "Constrained VBR",
          "Constrained VBR", DEFAULT_CONSTRAINED_VBR,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_COMPLEXITY,
      g_param_spec_int ("complexity", "Complexity",
          "Complexity", 0, 10, DEFAULT_COMPLEXITY,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_INBAND_FEC,
      g_param_spec_boolean ("inband-fec", "In-band FEC",
          "Enable forward error correction", DEFAULT_INBAND_FEC,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_DTX,
      g_param_spec_boolean ("dtx", "DTX",
          "DTX", DEFAULT_DTX, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (G_OBJECT_CLASS (klass),
      PROP_PACKET_LOSS_PERCENT, g_param_spec_int ("packet-loss-percentage",
          "Loss percentage", "Packet loss percentage", 0, 100,
          DEFAULT_PACKET_LOSS_PERCENT,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_opus_enc_finalize);

  element_class->change_state = GST_DEBUG_FUNCPTR (gst_opus_enc_change_state);

  GST_DEBUG_CATEGORY_INIT (opusenc_debug, "opusenc", 0, "Opus encoder");
}

static void
gst_opus_enc_finalize (GObject * object)
{
  GstOpusEnc *enc;

  enc = GST_OPUS_ENC (object);

  g_object_unref (enc->adapter);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static gboolean
gst_opus_enc_sink_setcaps (GstPad * pad, GstCaps * caps)
{
  GstOpusEnc *enc;
  GstStructure *structure;
  GstCaps *otherpadcaps;

  enc = GST_OPUS_ENC (GST_PAD_PARENT (pad));
  enc->setup = FALSE;
  enc->frame_size = DEFAULT_FRAMESIZE;
  otherpadcaps = gst_pad_get_allowed_caps (pad);

  structure = gst_caps_get_structure (caps, 0);
  gst_structure_get_int (structure, "channels", &enc->n_channels);
  gst_structure_get_int (structure, "rate", &enc->sample_rate);

  if (otherpadcaps) {
    if (!gst_caps_is_empty (otherpadcaps)) {
      GstStructure *ps = gst_caps_get_structure (otherpadcaps, 0);
      gst_structure_get_int (ps, "frame-size", &enc->frame_size);
    }
    gst_caps_unref (otherpadcaps);
  }

  GST_DEBUG_OBJECT (pad, "channels=%d rate=%d frame-size=%d",
      enc->n_channels, enc->sample_rate, enc->frame_size);
  switch (enc->frame_size) {
    case 2:
      enc->frame_samples = enc->sample_rate / 400;
      break;
    case 5:
      enc->frame_samples = enc->sample_rate / 200;
      break;
    case 10:
      enc->frame_samples = enc->sample_rate / 100;
      break;
    case 20:
      enc->frame_samples = enc->sample_rate / 50;
      break;
    case 40:
      enc->frame_samples = enc->sample_rate / 25;
      break;
    case 60:
      enc->frame_samples = 3 * enc->sample_rate / 50;
      break;
    default:
      GST_WARNING_OBJECT (enc, "Unsupported frame size: %d", enc->frame_size);
      return FALSE;
      break;
  }
  GST_DEBUG_OBJECT (pad, "frame_samples %d", enc->frame_samples);

  gst_opus_enc_setup (enc);

  return TRUE;
}


static GstCaps *
gst_opus_enc_sink_getcaps (GstPad * pad, GstCaps * filter)
{
  GstCaps *caps = gst_caps_copy (gst_pad_get_pad_template_caps (pad));
  GstCaps *peercaps = NULL;
  GstOpusEnc *enc = GST_OPUS_ENC (gst_pad_get_parent_element (pad));

  peercaps = gst_pad_peer_get_caps (enc->srcpad, NULL);

  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);

  if (filter) {
    GstCaps *new_caps =
        gst_caps_intersect_full (filter, caps, GST_CAPS_INTERSECT_FIRST);
    gst_caps_unref (caps);
    caps = new_caps;
  }

  return caps;
}


static gboolean
gst_opus_enc_convert_src (GstPad * pad, GstFormat src_format, gint64 src_value,
    GstFormat * dest_format, gint64 * dest_value)
{
  gboolean res = TRUE;
  GstOpusEnc *enc;
  gint64 avg;

  enc = GST_OPUS_ENC (GST_PAD_PARENT (pad));

  if (enc->samples_in == 0 || enc->bytes_out == 0 || enc->sample_rate == 0)
    return FALSE;

  avg = (enc->bytes_out * enc->sample_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_opus_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;
  GstOpusEnc *enc;

  enc = GST_OPUS_ENC (GST_PAD_PARENT (pad));

  bytes_per_sample = enc->n_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->sample_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->sample_rate == 0)
            return FALSE;
          *dest_value = src_value * GST_SECOND / enc->sample_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->sample_rate / GST_SECOND;
          break;
        default:
          res = FALSE;
      }
      break;
    default:
      res = FALSE;
  }
  return res;
}

static gint64
gst_opus_enc_get_latency (GstOpusEnc * enc)
{
  return gst_util_uint64_scale (enc->frame_samples, GST_SECOND,
      enc->sample_rate);
}

static gboolean
gst_opus_enc_src_query (GstPad * pad, GstQuery * query)
{
  gboolean res = TRUE;
  GstOpusEnc *enc;

  enc = GST_OPUS_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_opus_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 (enc->sinkpad, query))) {
        gst_query_parse_latency (query, &live, &min_latency, &max_latency);

        latency = gst_opus_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_opus_enc_sink_query (GstPad * pad, GstQuery * query)
{
  gboolean res = TRUE;

  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_opus_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_opus_enc_init (GstOpusEnc * enc)
{
  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_opus_enc_sinkevent));
  gst_pad_set_chain_function (enc->sinkpad,
      GST_DEBUG_FUNCPTR (gst_opus_enc_chain));
  gst_pad_set_getcaps_function (enc->sinkpad,
      GST_DEBUG_FUNCPTR (gst_opus_enc_sink_getcaps));
  gst_pad_set_query_function (enc->sinkpad,
      GST_DEBUG_FUNCPTR (gst_opus_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_opus_enc_src_query));
  gst_element_add_pad (GST_ELEMENT (enc), enc->srcpad);

  enc->n_channels = -1;
  enc->sample_rate = -1;
  enc->frame_samples = 0;

  enc->bitrate = DEFAULT_BITRATE;
  enc->bandwidth = DEFAULT_BANDWIDTH;
  enc->frame_size = DEFAULT_FRAMESIZE;
  enc->cbr = DEFAULT_CBR;
  enc->constrained_vbr = DEFAULT_CONSTRAINED_VBR;
  enc->complexity = DEFAULT_COMPLEXITY;
  enc->inband_fec = DEFAULT_INBAND_FEC;
  enc->dtx = DEFAULT_DTX;
  enc->packet_loss_percentage = DEFAULT_PACKET_LOSS_PERCENT;

  enc->setup = FALSE;
  enc->header_sent = FALSE;

  enc->adapter = gst_adapter_new ();
}

#if 0
static GstBuffer *
gst_opus_enc_create_metadata_buffer (GstOpusEnc * enc)
{
  const GstTagList *tags;
  GstTagList *empty_tags = NULL;
  GstBuffer *comments = NULL;

  tags = gst_tag_setter_get_tag_list (GST_TAG_SETTER (enc));

  GST_DEBUG_OBJECT (enc, "tags = %" GST_PTR_FORMAT, tags);

  if (tags == NULL) {
    /* FIXME: better fix chain of callers to not write metadata at all,
     * if there is none */
    empty_tags = gst_tag_list_new ();
    tags = empty_tags;
  }
  comments = gst_tag_list_to_vorbiscomment_buffer (tags, NULL,
      0, "Encoded with GStreamer Opusenc");

  GST_BUFFER_OFFSET (comments) = enc->bytes_out;
  GST_BUFFER_OFFSET_END (comments) = 0;

  if (empty_tags)
    gst_tag_list_free (empty_tags);

  return comments;
}
#endif

static gboolean
gst_opus_enc_setup (GstOpusEnc * enc)
{
  int error = OPUS_OK;

  enc->setup = FALSE;

  enc->state = opus_encoder_create (enc->sample_rate, enc->n_channels,
      enc->audio_or_voip ? OPUS_APPLICATION_AUDIO : OPUS_APPLICATION_VOIP,
      &error);
  if (!enc->state || error != OPUS_OK)
    goto encoder_creation_failed;

  opus_encoder_ctl (enc->state, OPUS_SET_BITRATE (enc->bitrate), 0);
  opus_encoder_ctl (enc->state, OPUS_SET_BANDWIDTH (enc->bandwidth), 0);
  opus_encoder_ctl (enc->state, OPUS_SET_VBR (!enc->cbr), 0);
  opus_encoder_ctl (enc->state, OPUS_SET_VBR_CONSTRAINT (enc->constrained_vbr),
      0);
  opus_encoder_ctl (enc->state, OPUS_SET_COMPLEXITY (enc->complexity), 0);
  opus_encoder_ctl (enc->state, OPUS_SET_INBAND_FEC (enc->inband_fec), 0);
  opus_encoder_ctl (enc->state, OPUS_SET_DTX (enc->dtx), 0);
  opus_encoder_ctl (enc->state,
      OPUS_SET_PACKET_LOSS_PERC (enc->packet_loss_percentage), 0);

  GST_LOG_OBJECT (enc, "we have frame size %d", enc->frame_size);

  enc->setup = TRUE;

  return TRUE;

#if 0
mode_initialization_failed:
  GST_ERROR_OBJECT (enc, "Mode initialization failed: %d", error);
  return FALSE;
#endif

encoder_creation_failed:
  GST_ERROR_OBJECT (enc, "Encoder creation failed");
  return FALSE;
}


/* push out the buffer and do internal bookkeeping */
static GstFlowReturn
gst_opus_enc_push_buffer (GstOpusEnc * enc, GstBuffer * buffer)
{
  gsize size;

  size = gst_buffer_get_size (buffer);

  enc->bytes_out += size;

  GST_DEBUG_OBJECT (enc, "pushing output buffer of size %u", size);

  return gst_pad_push (enc->srcpad, buffer);
}

#if 0
static GstCaps *
gst_opus_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;
}
#endif


static gboolean
gst_opus_enc_sinkevent (GstPad * pad, GstEvent * event)
{
  gboolean res = TRUE;
  GstOpusEnc *enc;

  enc = GST_OPUS_ENC (gst_pad_get_parent (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_EOS:
      gst_opus_enc_encode (enc, TRUE);
      res = gst_pad_event_default (pad, event);
      break;
    case GST_EVENT_TAG:
    {
      GstTagList *list;
      GstTagSetter *setter = GST_TAG_SETTER (enc);
      const GstTagMergeMode mode = gst_tag_setter_get_tag_merge_mode (setter);

      gst_event_parse_tag (event, &list);
      gst_tag_setter_merge_tags (setter, list, mode);
      res = gst_pad_event_default (pad, event);
      break;
    }
    case GST_EVENT_CAPS:
    {
      GstCaps *caps;

      gst_event_parse_caps (event, &caps);
      res = gst_opus_enc_sink_setcaps (pad, caps);
      gst_event_unref (event);
      break;
    }

    default:
      res = gst_pad_event_default (pad, event);
      break;
  }

  gst_object_unref (enc);

  return res;
}

static GstFlowReturn
gst_opus_enc_encode (GstOpusEnc * enc, gboolean flush)
{

  GstFlowReturn ret = GST_FLOW_OK;
  gint bytes = enc->frame_samples * 2 * enc->n_channels;
  gint bytes_per_packet;

  bytes_per_packet =
      (enc->bitrate * enc->frame_samples / enc->sample_rate + 4) / 8;

  if (flush && gst_adapter_available (enc->adapter) % bytes != 0) {
    guint diff = bytes - gst_adapter_available (enc->adapter) % bytes;
    GstBuffer *buf = gst_buffer_new_and_alloc (diff);

    gst_buffer_memset (buf, 0, 0, diff);
    gst_adapter_push (enc->adapter, buf);
  }


  while (gst_adapter_available (enc->adapter) >= bytes) {
    gint16 *data;
    gint encoded_size;
    unsigned char *out_data;
    gsize out_size;
    GstBuffer *outbuf;

    outbuf = gst_buffer_new_and_alloc (bytes_per_packet);
    if (!outbuf)
      goto done;

    data = (gint16 *) gst_adapter_take (enc->adapter, bytes);
    enc->samples_in += enc->frame_samples;

    GST_DEBUG_OBJECT (enc, "encoding %d samples (%d bytes)",
        enc->frame_samples, bytes);

    out_data = gst_buffer_map (outbuf, &out_size, NULL, GST_MAP_WRITE);
    encoded_size = opus_encode (enc->state, data, enc->frame_samples,
        out_data, bytes_per_packet);
    gst_buffer_unmap (outbuf, out_data, out_size);

    g_free (data);

    if (encoded_size < 0) {
      GST_ERROR_OBJECT (enc, "Encoding failed: %d", encoded_size);
      ret = GST_FLOW_ERROR;
      goto done;
    } else if (encoded_size != bytes_per_packet) {
      GST_WARNING_OBJECT (enc,
          "Encoded size %d is different from %d bytes per packet", encoded_size,
          bytes_per_packet);
      ret = GST_FLOW_ERROR;
      goto done;
    }

    GST_BUFFER_TIMESTAMP (outbuf) = enc->start_ts +
        gst_util_uint64_scale_int (enc->frameno_out * enc->frame_samples,
        GST_SECOND, enc->sample_rate);
    GST_BUFFER_DURATION (outbuf) =
        gst_util_uint64_scale_int (enc->frame_samples, GST_SECOND,
        enc->sample_rate);
    GST_BUFFER_OFFSET (outbuf) =
        gst_util_uint64_scale_int (GST_BUFFER_OFFSET_END (outbuf), GST_SECOND,
        enc->sample_rate);

    enc->frameno++;
    enc->frameno_out++;

    ret = gst_opus_enc_push_buffer (enc, outbuf);

    if ((GST_FLOW_OK != ret) && (GST_FLOW_NOT_LINKED != ret))
      goto done;
  }

done:

  return ret;
}

static GstFlowReturn
gst_opus_enc_chain (GstPad * pad, GstBuffer * buf)
{
  GstOpusEnc *enc;
  GstFlowReturn ret = GST_FLOW_OK;

  enc = GST_OPUS_ENC (GST_PAD_PARENT (pad));

  if (!enc->setup)
    goto not_setup;

  if (!enc->header_sent) {
    GstCaps *caps;

    caps = gst_pad_get_caps (enc->srcpad, NULL);
    caps = gst_caps_copy (caps);
    gst_caps_set_simple (caps,
        "rate", G_TYPE_INT, enc->sample_rate,
        "channels", G_TYPE_INT, enc->n_channels,
        "frame-size", G_TYPE_INT, enc->frame_size, NULL);

    /* negotiate with these caps */
    GST_DEBUG_OBJECT (enc, "here are the caps: %" GST_PTR_FORMAT, caps);
    GST_LOG_OBJECT (enc, "rate=%d channels=%d frame-size=%d",
        enc->sample_rate, enc->n_channels, enc->frame_size);
    gst_pad_set_caps (enc->srcpad, caps);
    gst_caps_unref (caps);

    enc->header_sent = TRUE;
  }

  GST_DEBUG_OBJECT (enc, "received buffer of %u bytes",
      gst_buffer_get_size (buf));

  /* Save the timestamp of the first buffer. This will be later
   * used as offset for all following buffers */
  if (enc->start_ts == GST_CLOCK_TIME_NONE) {
    if (GST_BUFFER_TIMESTAMP_IS_VALID (buf)) {
      enc->start_ts = GST_BUFFER_TIMESTAMP (buf);
    } else {
      enc->start_ts = 0;
    }
  }


  /* Check if we have a continous stream, if not drop some samples or the buffer or
   * insert some silence samples */
  if (enc->next_ts != GST_CLOCK_TIME_NONE &&
      GST_BUFFER_TIMESTAMP (buf) < enc->next_ts) {
    guint64 diff = enc->next_ts - GST_BUFFER_TIMESTAMP (buf);
    guint64 diff_bytes;

    GST_WARNING_OBJECT (enc, "Buffer is older than previous "
        "timestamp + duration (%" GST_TIME_FORMAT "< %" GST_TIME_FORMAT
        "), cannot handle. Clipping buffer.",
        GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)),
        GST_TIME_ARGS (enc->next_ts));

    diff_bytes =
        GST_CLOCK_TIME_TO_FRAMES (diff, enc->sample_rate) * enc->n_channels * 2;
    if (diff_bytes >= gst_buffer_get_size (buf)) {
      gst_buffer_unref (buf);
      return GST_FLOW_OK;
    }
    buf = gst_buffer_make_writable (buf);
    gst_buffer_resize (buf, diff_bytes, gst_buffer_get_size (buf) - diff_bytes);

    GST_BUFFER_TIMESTAMP (buf) += diff;
    if (GST_BUFFER_DURATION_IS_VALID (buf))
      GST_BUFFER_DURATION (buf) -= diff;
  }

  if (enc->next_ts != GST_CLOCK_TIME_NONE
      && GST_BUFFER_TIMESTAMP_IS_VALID (buf)) {
    guint64 max_diff =
        gst_util_uint64_scale (enc->frame_size, GST_SECOND, enc->sample_rate);

    if (GST_BUFFER_TIMESTAMP (buf) != enc->next_ts &&
        GST_BUFFER_TIMESTAMP (buf) - enc->next_ts > max_diff) {
      GST_WARNING_OBJECT (enc,
          "Discontinuity detected: %" G_GUINT64_FORMAT " > %" G_GUINT64_FORMAT,
          GST_BUFFER_TIMESTAMP (buf) - enc->next_ts, max_diff);

      gst_opus_enc_encode (enc, TRUE);

      enc->frameno_out = 0;
      enc->start_ts = GST_BUFFER_TIMESTAMP (buf);
    }
  }

  if (GST_BUFFER_TIMESTAMP_IS_VALID (buf)
      && GST_BUFFER_DURATION_IS_VALID (buf))
    enc->next_ts = GST_BUFFER_TIMESTAMP (buf) + GST_BUFFER_DURATION (buf);
  else
    enc->next_ts = GST_CLOCK_TIME_NONE;

  /* push buffer to adapter */
  gst_adapter_push (enc->adapter, buf);
  buf = NULL;

  ret = gst_opus_enc_encode (enc, FALSE);

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_opus_enc_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstOpusEnc *enc;

  enc = GST_OPUS_ENC (object);

  switch (prop_id) {
    case PROP_AUDIO:
      g_value_set_boolean (value, enc->audio_or_voip);
      break;
    case PROP_BITRATE:
      g_value_set_int (value, enc->bitrate);
      break;
    case PROP_BANDWIDTH:
      g_value_set_enum (value, enc->bandwidth);
      break;
    case PROP_FRAME_SIZE:
      g_value_set_int (value, enc->frame_size);
      break;
    case PROP_CBR:
      g_value_set_boolean (value, enc->cbr);
      break;
    case PROP_CONSTRAINED_VBR:
      g_value_set_boolean (value, enc->constrained_vbr);
      break;
    case PROP_COMPLEXITY:
      g_value_set_int (value, enc->complexity);
      break;
    case PROP_INBAND_FEC:
      g_value_set_boolean (value, enc->inband_fec);
      break;
    case PROP_DTX:
      g_value_set_boolean (value, enc->dtx);
      break;
    case PROP_PACKET_LOSS_PERCENT:
      g_value_set_int (value, enc->packet_loss_percentage);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_opus_enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstOpusEnc *enc;

  enc = GST_OPUS_ENC (object);

  switch (prop_id) {
    case PROP_AUDIO:
      enc->audio_or_voip = g_value_get_boolean (value);
      break;
    case PROP_BITRATE:
      enc->bitrate = g_value_get_int (value);
      break;
    case PROP_BANDWIDTH:
      enc->bandwidth = g_value_get_enum (value);
      break;
    case PROP_FRAME_SIZE:
      enc->frame_size = g_value_get_int (value);
      break;
    case PROP_CBR:
      enc->cbr = g_value_get_boolean (value);
      break;
    case PROP_CONSTRAINED_VBR:
      enc->constrained_vbr = g_value_get_boolean (value);
      break;
    case PROP_COMPLEXITY:
      enc->complexity = g_value_get_int (value);
      break;
    case PROP_INBAND_FEC:
      enc->inband_fec = g_value_get_boolean (value);
      break;
    case PROP_DTX:
      enc->dtx = g_value_get_boolean (value);
      break;
    case PROP_PACKET_LOSS_PERCENT:
      enc->packet_loss_percentage = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstStateChangeReturn
gst_opus_enc_change_state (GstElement * element, GstStateChange transition)
{
  GstOpusEnc *enc = GST_OPUS_ENC (element);
  GstStateChangeReturn res;

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      enc->frameno = 0;
      enc->samples_in = 0;
      enc->frameno_out = 0;
      enc->start_ts = GST_CLOCK_TIME_NONE;
      enc->next_ts = GST_CLOCK_TIME_NONE;
      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) {
        opus_encoder_destroy (enc->state);
        enc->state = NULL;
      }
      break;
    case GST_STATE_CHANGE_READY_TO_NULL:
      gst_tag_setter_reset_tags (GST_TAG_SETTER (enc));
    default:
      break;
  }

  return res;
}