gstreamer/ext/lame/gstlamemp3enc.c

/* GStreamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 * Copyright (C) <2004> Wim Taymans <wim@fluendo.com>
 * Copyright (C) <2005> Thomas Vander Stichele <thomas at apestaart dot org>
 * Copyright (C) <2009> 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.
 */

/**
 * SECTION:element-lamemp3enc
 * @see_also: lame, mad, vorbisenc
 *
 * This element encodes raw integer audio into an MPEG-1 layer 3 (MP3) stream.
 * Note that <ulink url="http://en.wikipedia.org/wiki/MP3">MP3</ulink> is not
 * a free format, there are licensing and patent issues to take into
 * consideration. See <ulink url="http://www.vorbis.com/">Ogg/Vorbis</ulink>
 * for a royalty free (and often higher quality) alternative.
 *
 * <refsect2>
 * <title>Output sample rate</title>
 * If no fixed output sample rate is negotiated on the element's src pad,
 * the element will choose an optimal sample rate to resample to internally.
 * For example, a 16-bit 44.1 KHz mono audio stream encoded at 48 kbit will
 * get resampled to 32 KHz.  Use filter caps on the src pad to force a
 * particular sample rate.
 * </refsect2>
 * <refsect2>
 * <title>Example pipelines</title>
 * |[
 * gst-launch -v audiotestsrc wave=sine num-buffers=100 ! audioconvert ! lamemp3enc ! filesink location=sine.mp3
 * ]| Encode a test sine signal to MP3.
 * |[
 * gst-launch -v alsasrc ! audioconvert ! lamemp3enc target=bitrate bitrate=192 ! filesink location=alsasrc.mp3
 * ]| Record from a sound card using ALSA and encode to MP3 with an average bitrate of 192kbps
 * |[
 * gst-launch -v filesrc location=music.wav ! decodebin ! audioconvert ! audioresample ! lamemp3enc target=quality quality=0 ! id3v2mux ! filesink location=music.mp3
 * ]| Transcode from a .wav file to MP3 (the id3v2mux element is optional) with best VBR quality
 * |[
 * gst-launch -v cdda://5 ! audioconvert ! lamemp3enc target=bitrate cbr=true bitrate=192 ! filesink location=track5.mp3
 * ]| Encode Audio CD track 5 to MP3 with a constant bitrate of 192kbps
 * |[
 * gst-launch -v audiotestsrc num-buffers=10 ! audio/x-raw-int,rate=44100,channels=1 ! lamemp3enc target=bitrate cbr=true bitrate=48 ! filesink location=test.mp3
 * ]| Encode to a fixed sample rate
 * </refsect2>
 *
 * Since: 0.10.12
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>
#include "gstlamemp3enc.h"
#include <gst/gst-i18n-plugin.h>

/* lame < 3.98 */
#ifndef HAVE_LAME_SET_VBR_QUALITY
#define lame_set_VBR_quality(flags,q) lame_set_VBR_q((flags),(int)(q))
#endif

GST_DEBUG_CATEGORY_STATIC (debug);
#define GST_CAT_DEFAULT debug

/* elementfactory information */

/* LAMEMP3ENC can do MPEG-1, MPEG-2, and MPEG-2.5, so it has 9 possible
 * sample rates it supports */
static GstStaticPadTemplate gst_lamemp3enc_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-raw-int, "
        "endianness = (int) " G_STRINGIFY (G_BYTE_ORDER) ", "
        "signed = (boolean) true, "
        "width = (int) 16, "
        "depth = (int) 16, "
        "rate = (int) { 8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000 }, "
        "channels = (int) [ 1, 2 ]")
    );

static GstStaticPadTemplate gst_lamemp3enc_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/mpeg, "
        "mpegversion = (int) 1, "
        "layer = (int) 3, "
        "rate = (int) { 8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000 }, "
        "channels = (int) [ 1, 2 ]")
    );

/********** Define useful types for non-programmatic interfaces **********/
enum
{
  LAMEMP3ENC_TARGET_QUALITY = 0,
  LAMEMP3ENC_TARGET_BITRATE
};

#define GST_TYPE_LAMEMP3ENC_TARGET (gst_lamemp3enc_target_get_type())
static GType
gst_lamemp3enc_target_get_type (void)
{
  static GType lame_target_type = 0;
  static GEnumValue lame_targets[] = {
    {LAMEMP3ENC_TARGET_QUALITY, "Quality", "quality"},
    {LAMEMP3ENC_TARGET_BITRATE, "Bitrate", "bitrate"},
    {0, NULL, NULL}
  };

  if (!lame_target_type) {
    lame_target_type =
        g_enum_register_static ("GstLameMP3EncTarget", lame_targets);
  }
  return lame_target_type;
}

enum
{
  LAMEMP3ENC_ENCODING_ENGINE_QUALITY_FAST = 0,
  LAMEMP3ENC_ENCODING_ENGINE_QUALITY_STANDARD,
  LAMEMP3ENC_ENCODING_ENGINE_QUALITY_HIGH
};

#define GST_TYPE_LAMEMP3ENC_ENCODING_ENGINE_QUALITY (gst_lamemp3enc_encoding_engine_quality_get_type())
static GType
gst_lamemp3enc_encoding_engine_quality_get_type (void)
{
  static GType lame_encoding_engine_quality_type = 0;
  static GEnumValue lame_encoding_engine_quality[] = {
    {0, "Fast", "fast"},
    {1, "Standard", "standard"},
    {2, "High", "high"},
    {0, NULL, NULL}
  };

  if (!lame_encoding_engine_quality_type) {
    lame_encoding_engine_quality_type =
        g_enum_register_static ("GstLameMP3EncEncodingEngineQuality",
        lame_encoding_engine_quality);
  }
  return lame_encoding_engine_quality_type;
}

/********** Standard stuff for signals and arguments **********/

enum
{
  ARG_0,
  ARG_TARGET,
  ARG_BITRATE,
  ARG_CBR,
  ARG_QUALITY,
  ARG_ENCODING_ENGINE_QUALITY,
  ARG_MONO
};

#define DEFAULT_TARGET LAMEMP3ENC_TARGET_QUALITY
#define DEFAULT_BITRATE 128
#define DEFAULT_CBR FALSE
#define DEFAULT_QUALITY 4
#define DEFAULT_ENCODING_ENGINE_QUALITY LAMEMP3ENC_ENCODING_ENGINE_QUALITY_STANDARD
#define DEFAULT_MONO FALSE

static void gst_lamemp3enc_base_init (gpointer g_class);
static void gst_lamemp3enc_class_init (GstLameMP3EncClass * klass);
static void gst_lamemp3enc_init (GstLameMP3Enc * gst_lame);

static void gst_lamemp3enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_lamemp3enc_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static gboolean gst_lamemp3enc_sink_event (GstPad * pad, GstEvent * event);
static GstFlowReturn gst_lamemp3enc_chain (GstPad * pad, GstBuffer * buf);
static gboolean gst_lamemp3enc_setup (GstLameMP3Enc * lame);
static GstStateChangeReturn gst_lamemp3enc_change_state (GstElement * element,
    GstStateChange transition);

static GstElementClass *parent_class = NULL;

GType
gst_lamemp3enc_get_type (void)
{
  static GType gst_lamemp3enc_type = 0;

  if (!gst_lamemp3enc_type) {
    static const GTypeInfo gst_lamemp3enc_info = {
      sizeof (GstLameMP3EncClass),
      gst_lamemp3enc_base_init,
      NULL,
      (GClassInitFunc) gst_lamemp3enc_class_init,
      NULL,
      NULL,
      sizeof (GstLameMP3Enc),
      0,
      (GInstanceInitFunc) gst_lamemp3enc_init,
    };
    static const GInterfaceInfo preset_info = {
      NULL,
      NULL,
      NULL
    };

    gst_lamemp3enc_type =
        g_type_register_static (GST_TYPE_ELEMENT, "GstLameMP3Enc",
        &gst_lamemp3enc_info, 0);
    g_type_add_interface_static (gst_lamemp3enc_type, GST_TYPE_PRESET,
        &preset_info);
  }
  return gst_lamemp3enc_type;
}

static void
gst_lamemp3enc_release_memory (GstLameMP3Enc * lame)
{
  if (lame->lgf) {
    lame_close (lame->lgf);
    lame->lgf = NULL;
  }
}

static void
gst_lamemp3enc_finalize (GObject * obj)
{
  gst_lamemp3enc_release_memory (GST_LAMEMP3ENC (obj));

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

static void
gst_lamemp3enc_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 (&gst_lamemp3enc_src_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_lamemp3enc_sink_template));
  gst_element_class_set_details_simple (element_class, "L.A.M.E. mp3 encoder",
      "Codec/Encoder/Audio",
      "High-quality free MP3 encoder",
      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
}

static void
gst_lamemp3enc_class_init (GstLameMP3EncClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

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

  parent_class = g_type_class_peek_parent (klass);

  gobject_class->set_property = gst_lamemp3enc_set_property;
  gobject_class->get_property = gst_lamemp3enc_get_property;
  gobject_class->finalize = gst_lamemp3enc_finalize;

  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TARGET,
      g_param_spec_enum ("target", "Target",
          "Optimize for quality or bitrate", GST_TYPE_LAMEMP3ENC_TARGET,
          DEFAULT_TARGET, G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_BITRATE,
      g_param_spec_int ("bitrate", "Bitrate (kb/s)",
          "Bitrate in kbit/sec (Only valid if target is bitrate, for CBR one "
          "of 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, "
          "256 or 320)", 8, 320, DEFAULT_BITRATE, G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_CBR,
      g_param_spec_boolean ("cbr", "CBR", "Enforce constant bitrate encoding "
          "(Only valid if target is bitrate)", DEFAULT_CBR, G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_QUALITY,
      g_param_spec_float ("quality", "Quality",
          "VBR Quality from 0 to 10, 0 being the best "
          "(Only valid if target is quality)", 0.0, 9.999,
          DEFAULT_QUALITY, G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass),
      ARG_ENCODING_ENGINE_QUALITY, g_param_spec_enum ("encoding-engine-quality",
          "Encoding Engine Quality", "Quality/speed of the encoding engine, "
          "this does not affect the bitrate!",
          GST_TYPE_LAMEMP3ENC_ENCODING_ENGINE_QUALITY,
          DEFAULT_ENCODING_ENGINE_QUALITY, G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_MONO,
      g_param_spec_boolean ("mono", "Mono", "Enforce mono encoding",
          DEFAULT_MONO, G_PARAM_READWRITE));

  gstelement_class->change_state =
      GST_DEBUG_FUNCPTR (gst_lamemp3enc_change_state);
}

static gboolean
gst_lamemp3enc_src_setcaps (GstPad * pad, GstCaps * caps)
{
  GST_DEBUG_OBJECT (pad, "caps: %" GST_PTR_FORMAT, caps);
  return TRUE;
}

static gboolean
gst_lamemp3enc_sink_setcaps (GstPad * pad, GstCaps * caps)
{
  GstLameMP3Enc *lame;
  gint out_samplerate;
  gint version;
  GstStructure *structure;
  GstCaps *othercaps;

  lame = GST_LAMEMP3ENC (GST_PAD_PARENT (pad));
  structure = gst_caps_get_structure (caps, 0);

  if (!gst_structure_get_int (structure, "rate", &lame->samplerate))
    goto no_rate;
  if (!gst_structure_get_int (structure, "channels", &lame->num_channels))
    goto no_channels;

  GST_DEBUG_OBJECT (lame, "setting up lame");
  if (!gst_lamemp3enc_setup (lame))
    goto setup_failed;


  out_samplerate = lame_get_out_samplerate (lame->lgf);
  if (out_samplerate == 0)
    goto zero_output_rate;
  if (out_samplerate != lame->samplerate) {
    GST_WARNING_OBJECT (lame,
        "output samplerate %d is different from incoming samplerate %d",
        out_samplerate, lame->samplerate);
  }

  version = lame_get_version (lame->lgf);
  if (version == 0)
    version = 2;
  else if (version == 1)
    version = 1;
  else if (version == 2)
    version = 3;

  othercaps =
      gst_caps_new_simple ("audio/mpeg",
      "mpegversion", G_TYPE_INT, 1,
      "mpegaudioversion", G_TYPE_INT, version,
      "layer", G_TYPE_INT, 3,
      "channels", G_TYPE_INT, lame->mono ? 1 : lame->num_channels,
      "rate", G_TYPE_INT, out_samplerate, NULL);

  /* and use these caps */
  gst_pad_set_caps (lame->srcpad, othercaps);
  gst_caps_unref (othercaps);

  return TRUE;

no_rate:
  {
    GST_ERROR_OBJECT (lame, "input caps have no sample rate field");
    return FALSE;
  }
no_channels:
  {
    GST_ERROR_OBJECT (lame, "input caps have no channels field");
    return FALSE;
  }
zero_output_rate:
  {
    GST_ELEMENT_ERROR (lame, LIBRARY, SETTINGS, (NULL),
        ("LAMEMP3ENC decided on a zero sample rate"));
    return FALSE;
  }
setup_failed:
  {
    GST_ELEMENT_ERROR (lame, LIBRARY, SETTINGS,
        (_("Failed to configure LAMEMP3ENC encoder. Check your encoding parameters.")), (NULL));
    return FALSE;
  }
}

static void
gst_lamemp3enc_init (GstLameMP3Enc * lame)
{
  GST_DEBUG_OBJECT (lame, "starting initialization");

  lame->sinkpad =
      gst_pad_new_from_static_template (&gst_lamemp3enc_sink_template, "sink");
  gst_pad_set_event_function (lame->sinkpad,
      GST_DEBUG_FUNCPTR (gst_lamemp3enc_sink_event));
  gst_pad_set_chain_function (lame->sinkpad,
      GST_DEBUG_FUNCPTR (gst_lamemp3enc_chain));
  gst_pad_set_setcaps_function (lame->sinkpad,
      GST_DEBUG_FUNCPTR (gst_lamemp3enc_sink_setcaps));
  gst_element_add_pad (GST_ELEMENT (lame), lame->sinkpad);

  lame->srcpad =
      gst_pad_new_from_static_template (&gst_lamemp3enc_src_template, "src");
  gst_pad_set_setcaps_function (lame->srcpad,
      GST_DEBUG_FUNCPTR (gst_lamemp3enc_src_setcaps));
  gst_element_add_pad (GST_ELEMENT (lame), lame->srcpad);

  lame->samplerate = 44100;
  lame->num_channels = 2;
  lame->setup = FALSE;

  /* Set default settings */
  lame->target = DEFAULT_TARGET;
  lame->bitrate = DEFAULT_BITRATE;
  lame->cbr = DEFAULT_CBR;
  lame->quality = DEFAULT_QUALITY;
  lame->encoding_engine_quality = DEFAULT_ENCODING_ENGINE_QUALITY;
  lame->mono = DEFAULT_MONO;

  GST_DEBUG_OBJECT (lame, "done initializing");
}

/* <php-emulation-mode>three underscores for ___rate is really really really
 * private as opposed to one underscore<php-emulation-mode> */
/* call this MACRO outside of the NULL state so that we have a higher chance
 * of actually having a pipeline and bus to get the message through */

#define CHECK_AND_FIXUP_BITRATE(obj,param,rate)		 		  \
G_STMT_START {                                                            \
  gint ___rate = rate;                                                    \
  gint maxrate = 320;							  \
  gint multiplier = 64;							  \
  if (rate == 0) {                                                        \
    ___rate = rate;                                                       \
  } else if (rate <= 64) {				                  \
    maxrate = 64; multiplier = 8;                                         \
    if ((rate % 8) != 0) ___rate = GST_ROUND_UP_8 (rate); 		  \
  } else if (rate <= 128) {						  \
    maxrate = 128; multiplier = 16;                                       \
    if ((rate % 16) != 0) ___rate = GST_ROUND_UP_16 (rate);               \
  } else if (rate <= 256) {						  \
    maxrate = 256; multiplier = 32;                                       \
    if ((rate % 32) != 0) ___rate = GST_ROUND_UP_32 (rate);               \
  } else if (rate <= 320) { 						  \
    maxrate = 320; multiplier = 64;                                       \
    if ((rate % 64) != 0) ___rate = GST_ROUND_UP_64 (rate);               \
  }                                                                       \
  if (___rate != rate) {                                                  \
    GST_ELEMENT_WARNING (obj, LIBRARY, SETTINGS,			  \
      (_("The requested bitrate %d kbit/s for property '%s' "             \
       "is not allowed. "  					          \
       "The bitrate was changed to %d kbit/s."), rate,		          \
         param,  ___rate), 					          \
       ("A bitrate below %d should be a multiple of %d.", 		  \
          maxrate, multiplier));		  			  \
    rate = ___rate;                                                       \
  }                                                                       \
} G_STMT_END

static void
gst_lamemp3enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstLameMP3Enc *lame;

  lame = GST_LAMEMP3ENC (object);

  switch (prop_id) {
    case ARG_TARGET:
      lame->target = g_value_get_enum (value);
      break;
    case ARG_BITRATE:
      lame->bitrate = g_value_get_int (value);
      break;
    case ARG_CBR:
      lame->cbr = g_value_get_boolean (value);
      break;
    case ARG_QUALITY:
      lame->quality = g_value_get_float (value);
      break;
    case ARG_ENCODING_ENGINE_QUALITY:
      lame->encoding_engine_quality = g_value_get_enum (value);
      break;
    case ARG_MONO:
      lame->mono = g_value_get_boolean (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_lamemp3enc_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstLameMP3Enc *lame;

  lame = GST_LAMEMP3ENC (object);

  switch (prop_id) {
    case ARG_TARGET:
      g_value_set_enum (value, lame->target);
      break;
    case ARG_BITRATE:
      g_value_set_int (value, lame->bitrate);
      break;
    case ARG_CBR:
      g_value_set_boolean (value, lame->cbr);
      break;
    case ARG_QUALITY:
      g_value_set_float (value, lame->quality);
      break;
    case ARG_ENCODING_ENGINE_QUALITY:
      g_value_set_enum (value, lame->encoding_engine_quality);
      break;
    case ARG_MONO:
      g_value_set_boolean (value, lame->mono);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static gboolean
gst_lamemp3enc_sink_event (GstPad * pad, GstEvent * event)
{
  gboolean ret;
  GstLameMP3Enc *lame;

  lame = GST_LAMEMP3ENC (gst_pad_get_parent (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_EOS:{
      GST_DEBUG_OBJECT (lame, "handling EOS event");

      if (lame->lgf != NULL) {
        GstBuffer *buf;
        gint size;

        buf = gst_buffer_new_and_alloc (7200);
        size = lame_encode_flush (lame->lgf, GST_BUFFER_DATA (buf), 7200);

        if (size > 0 && lame->last_flow == GST_FLOW_OK) {
          gint64 duration;

          duration = gst_util_uint64_scale (size, 8 * GST_SECOND,
              1000 * lame->bitrate);

          if (lame->last_ts == GST_CLOCK_TIME_NONE) {
            lame->last_ts = lame->eos_ts;
            lame->last_duration = duration;
          } else {
            lame->last_duration += duration;
          }

          GST_BUFFER_TIMESTAMP (buf) = lame->last_ts;
          GST_BUFFER_DURATION (buf) = lame->last_duration;
          lame->last_ts = GST_CLOCK_TIME_NONE;
          GST_BUFFER_SIZE (buf) = size;
          GST_DEBUG_OBJECT (lame, "pushing final packet of %u bytes", size);
          gst_buffer_set_caps (buf, GST_PAD_CAPS (lame->srcpad));
          gst_pad_push (lame->srcpad, buf);
        } else {
          GST_DEBUG_OBJECT (lame, "no final packet (size=%d, last_flow=%s)",
              size, gst_flow_get_name (lame->last_flow));
          gst_buffer_unref (buf);
        }
      }

      ret = gst_pad_event_default (pad, event);
      break;
    }
    case GST_EVENT_FLUSH_START:
      GST_DEBUG_OBJECT (lame, "handling FLUSH start event");
      /* forward event */
      ret = gst_pad_push_event (lame->srcpad, event);
      break;
    case GST_EVENT_FLUSH_STOP:
    {
      guchar *mp3_data = NULL;
      gint mp3_buffer_size;

      GST_DEBUG_OBJECT (lame, "handling FLUSH stop event");

      /* clear buffers */
      mp3_buffer_size = 7200;
      mp3_data = g_malloc (mp3_buffer_size);
      lame_encode_flush (lame->lgf, mp3_data, mp3_buffer_size);
      g_free (mp3_data);

      ret = gst_pad_push_event (lame->srcpad, event);
      break;
    }
    case GST_EVENT_TAG:
      GST_DEBUG_OBJECT (lame, "ignoring TAG event, passing it on");
      ret = gst_pad_push_event (lame->srcpad, event);
      break;
    default:
      ret = gst_pad_event_default (pad, event);
      break;
  }
  gst_object_unref (lame);
  return ret;
}

static GstFlowReturn
gst_lamemp3enc_chain (GstPad * pad, GstBuffer * buf)
{
  GstLameMP3Enc *lame;
  guchar *mp3_data;
  gint mp3_buffer_size, mp3_size;
  gint64 duration;
  GstFlowReturn result;
  gint num_samples;
  guint8 *data;
  guint size;

  lame = GST_LAMEMP3ENC (GST_PAD_PARENT (pad));

  GST_LOG_OBJECT (lame, "entered chain");

  if (!lame->setup)
    goto not_setup;

  data = GST_BUFFER_DATA (buf);
  size = GST_BUFFER_SIZE (buf);

  num_samples = size / 2;

  /* allocate space for output */
  mp3_buffer_size = 1.25 * num_samples + 7200;
  mp3_data = g_malloc (mp3_buffer_size);

  /* lame seems to be too stupid to get mono interleaved going */
  if (lame->num_channels == 1) {
    mp3_size = lame_encode_buffer (lame->lgf,
        (short int *) data,
        (short int *) data, num_samples, mp3_data, mp3_buffer_size);
  } else {
    mp3_size = lame_encode_buffer_interleaved (lame->lgf,
        (short int *) data,
        num_samples / lame->num_channels, mp3_data, mp3_buffer_size);
  }

  GST_LOG_OBJECT (lame, "encoded %d bytes of audio to %d bytes of mp3",
      size, mp3_size);

  duration = gst_util_uint64_scale_int (size, GST_SECOND,
      2 * lame->samplerate * lame->num_channels);

  if (GST_BUFFER_DURATION (buf) != GST_CLOCK_TIME_NONE &&
      GST_BUFFER_DURATION (buf) != duration) {
    GST_DEBUG_OBJECT (lame, "incoming buffer had incorrect duration %"
        GST_TIME_FORMAT ", outgoing buffer will have correct duration %"
        GST_TIME_FORMAT,
        GST_TIME_ARGS (GST_BUFFER_DURATION (buf)), GST_TIME_ARGS (duration));
  }

  if (lame->last_ts == GST_CLOCK_TIME_NONE) {
    lame->last_ts = GST_BUFFER_TIMESTAMP (buf);
    lame->last_offs = GST_BUFFER_OFFSET (buf);
    lame->last_duration = duration;
  } else {
    lame->last_duration += duration;
  }

  gst_buffer_unref (buf);

  if (mp3_size < 0) {
    g_warning ("error %d", mp3_size);
  }

  if (mp3_size > 0) {
    GstBuffer *outbuf;

    outbuf = gst_buffer_new ();
    GST_BUFFER_DATA (outbuf) = mp3_data;
    GST_BUFFER_MALLOCDATA (outbuf) = mp3_data;
    GST_BUFFER_SIZE (outbuf) = mp3_size;
    GST_BUFFER_TIMESTAMP (outbuf) = lame->last_ts;
    GST_BUFFER_OFFSET (outbuf) = lame->last_offs;
    GST_BUFFER_DURATION (outbuf) = lame->last_duration;
    gst_buffer_set_caps (outbuf, GST_PAD_CAPS (lame->srcpad));

    result = gst_pad_push (lame->srcpad, outbuf);
    lame->last_flow = result;
    if (result != GST_FLOW_OK) {
      GST_DEBUG_OBJECT (lame, "flow return: %s", gst_flow_get_name (result));
    }

    if (GST_CLOCK_TIME_IS_VALID (lame->last_ts))
      lame->eos_ts = lame->last_ts + lame->last_duration;
    else
      lame->eos_ts = GST_CLOCK_TIME_NONE;
    lame->last_ts = GST_CLOCK_TIME_NONE;
  } else {
    g_free (mp3_data);
    result = GST_FLOW_OK;
  }

  return result;

  /* ERRORS */
not_setup:
  {
    gst_buffer_unref (buf);
    GST_ELEMENT_ERROR (lame, CORE, NEGOTIATION, (NULL),
        ("encoder not initialized (input is not audio?)"));
    return GST_FLOW_ERROR;
  }
}

/* set up the encoder state */
static gboolean
gst_lamemp3enc_setup (GstLameMP3Enc * lame)
{

#define CHECK_ERROR(command) G_STMT_START {\
  if ((command) < 0) { \
    GST_ERROR_OBJECT (lame, "setup failed: " G_STRINGIFY (command)); \
    return FALSE; \
  } \
}G_STMT_END

  int retval;
  GstCaps *allowed_caps;

  GST_DEBUG_OBJECT (lame, "starting setup");

  /* check if we're already setup; if we are, we might want to check
   * if this initialization is compatible with the previous one */
  /* FIXME: do this */
  if (lame->setup) {
    GST_WARNING_OBJECT (lame, "already setup");
    lame->setup = FALSE;
  }

  lame->lgf = lame_init ();

  if (lame->lgf == NULL)
    return FALSE;

  /* copy the parameters over */
  lame_set_in_samplerate (lame->lgf, lame->samplerate);

  /* let lame choose default samplerate unless outgoing sample rate is fixed */
  allowed_caps = gst_pad_get_allowed_caps (lame->srcpad);

  if (allowed_caps != NULL) {
    GstStructure *structure;
    gint samplerate;

    structure = gst_caps_get_structure (allowed_caps, 0);

    if (gst_structure_get_int (structure, "rate", &samplerate)) {
      GST_DEBUG_OBJECT (lame, "Setting sample rate to %d as fixed in src caps",
          samplerate);
      lame_set_out_samplerate (lame->lgf, samplerate);
    } else {
      GST_DEBUG_OBJECT (lame, "Letting lame choose sample rate");
      lame_set_out_samplerate (lame->lgf, 0);
    }
    gst_caps_unref (allowed_caps);
    allowed_caps = NULL;
  } else {
    GST_DEBUG_OBJECT (lame, "No peer yet, letting lame choose sample rate");
    lame_set_out_samplerate (lame->lgf, 0);
  }

  CHECK_ERROR (lame_set_num_channels (lame->lgf, lame->num_channels));
  CHECK_ERROR (lame_set_bWriteVbrTag (lame->lgf, 0));

  if (lame->target == LAMEMP3ENC_TARGET_QUALITY) {
    CHECK_ERROR (lame_set_VBR (lame->lgf, vbr_default));
    CHECK_ERROR (lame_set_VBR_quality (lame->lgf, lame->quality));
  } else {
    if (lame->cbr) {
      CHECK_AND_FIXUP_BITRATE (lame, "bitrate", lame->bitrate);
      CHECK_ERROR (lame_set_VBR (lame->lgf, vbr_off));
      CHECK_ERROR (lame_set_brate (lame->lgf, lame->bitrate));
    } else {
      CHECK_ERROR (lame_set_VBR (lame->lgf, vbr_abr));
      CHECK_ERROR (lame_set_VBR_mean_bitrate_kbps (lame->lgf, lame->bitrate));
    }
  }

  if (lame->encoding_engine_quality == LAMEMP3ENC_ENCODING_ENGINE_QUALITY_FAST)
    CHECK_ERROR (lame_set_quality (lame->lgf, 7));
  else if (lame->encoding_engine_quality ==
      LAMEMP3ENC_ENCODING_ENGINE_QUALITY_HIGH)
    CHECK_ERROR (lame_set_quality (lame->lgf, 2));
  /* else default */

  if (lame->mono)
    CHECK_ERROR (lame_set_mode (lame->lgf, MONO));

  /* initialize the lame encoder */
  if ((retval = lame_init_params (lame->lgf)) >= 0) {
    lame->setup = TRUE;
    /* FIXME: it would be nice to print out the mode here */
    GST_INFO
        ("lame encoder setup (target %s, quality %f, bitrate %d, %d Hz, %d channels)",
        (lame->target == LAMEMP3ENC_TARGET_QUALITY) ? "quality" : "bitrate",
        lame->quality, lame->bitrate, lame->samplerate, lame->num_channels);
  } else {
    GST_ERROR_OBJECT (lame, "lame_init_params returned %d", retval);
  }

  GST_DEBUG_OBJECT (lame, "done with setup");

  return lame->setup;
#undef CHECK_ERROR
}

static GstStateChangeReturn
gst_lamemp3enc_change_state (GstElement * element, GstStateChange transition)
{
  GstLameMP3Enc *lame;
  GstStateChangeReturn result;

  lame = GST_LAMEMP3ENC (element);

  switch (transition) {
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      lame->last_flow = GST_FLOW_OK;
      lame->last_ts = GST_CLOCK_TIME_NONE;
      lame->eos_ts = GST_CLOCK_TIME_NONE;
      break;
    default:
      break;
  }

  result = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);

  switch (transition) {
    case GST_STATE_CHANGE_READY_TO_NULL:
      gst_lamemp3enc_release_memory (lame);
      break;
    default:
      break;
  }

  return result;
}

gboolean
gst_lamemp3enc_register (GstPlugin * plugin)
{
  GST_DEBUG_CATEGORY_INIT (debug, "lamemp3enc", 0, "lame mp3 encoder");

  if (!gst_element_register (plugin, "lamemp3enc", GST_RANK_PRIMARY,
          GST_TYPE_LAMEMP3ENC))
    return FALSE;

  return TRUE;
}