text: /* GStreamer
   * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
   *                    2000 Wim Taymans <wtay@chello.be>
   *                    2005 Wim Taymans <wim@fluendo.com>
   *                    2007 Andy Wingo <wingo at pobox.com>
   *                    2008 Sebastian Dröge <slomo@circular-chaos.rg>
   *
   * interleave.c: interleave samples, mostly based on adder.
   *
   * 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., 51 Franklin St, Fifth Floor,
   * Boston, MA 02110-1301, USA.
   */
  
  /* TODO:
   *       - handle caps changes
   *       - handle more queries/events
   */
  
  /**
   * SECTION:element-interleave
   * @title: interleave
   * @see_also: deinterleave
   *
   * Merges separate mono inputs into one interleaved stream.
   *
   * This element handles all raw floating point sample formats and all signed integer sample formats. The first
   * caps on one of the sinkpads will set the caps of the output so usually an audioconvert element should be
   * placed before every sinkpad of interleave.
   *
   * It's possible to change the number of channels while the pipeline is running by adding or removing
   * some of the request pads but this will change the caps of the output buffers. Changing the input
   * caps is _not_ supported yet.
   *
   * The channel number of every sinkpad in the out can be retrieved from the "channel" property of the pad.
   *
   * ## Example launch line
   * |[
   * gst-launch-1.0 filesrc location=file.mp3 ! decodebin ! audioconvert ! "audio/x-raw,channels=2" ! deinterleave name=d  interleave name=i ! audioconvert ! wavenc ! filesink location=test.wav    d.src_0 ! queue ! audioconvert ! i.sink_1    d.src_1 ! queue ! audioconvert ! i.sink_0
   * ]| Decodes and deinterleaves a Stereo MP3 file into separate channels and
   * then interleaves the channels again to a WAV file with the channels
   * exchanged.
   * |[
   * gst-launch-1.0 interleave name=i ! audioconvert ! wavenc ! filesink location=file.wav  filesrc location=file1.wav ! decodebin ! audioconvert ! "audio/x-raw,channels=1,channel-mask=(bitmask)0x1" ! queue ! i.sink_0   filesrc location=file2.wav ! decodebin ! audioconvert ! "audio/x-raw,channels=1,channel-mask=(bitmask)0x2" ! queue ! i.sink_1
   * ]| Interleaves two Mono WAV files to a single Stereo WAV file. Having
   * channel-masks defined in the sink pads ensures a sane mapping of the mono
   * streams into the stereo stream. NOTE: the proper way to map channels in
   * code is by using the channel-positions property of the interleave element.
   *
   */
  
  /* FIXME 0.11: suppress warnings for deprecated API such as GValueArray
   * with newer GLib versions (>= 2.31.0) */
  #define GLIB_DISABLE_DEPRECATION_WARNINGS
  
  #ifdef HAVE_CONFIG_H
  #  include "config.h"
  #endif
  
  #include <gst/gst.h>
  #include <string.h>
  #include "interleave.h"
  
  #include <gst/audio/audio.h>
  #include <gst/audio/audio-enumtypes.h>
  
  GST_DEBUG_CATEGORY_STATIC (gst_interleave_debug);
  #define GST_CAT_DEFAULT gst_interleave_debug
  
  static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink_%u",
      GST_PAD_SINK,
      GST_PAD_REQUEST,
      GST_STATIC_CAPS ("audio/x-raw, "
          "rate = (int) [ 1, MAX ], "
          "channels = (int) 1, "
          "format = (string) " GST_AUDIO_FORMATS_ALL ", "
          "layout = (string) {non-interleaved, interleaved}")
      );
  
  static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
      GST_PAD_SRC,
      GST_PAD_ALWAYS,
      GST_STATIC_CAPS ("audio/x-raw, "
          "rate = (int) [ 1, MAX ], "
          "channels = (int) [ 1, MAX ], "
          "format = (string) " GST_AUDIO_FORMATS_ALL ", "
          "layout = (string) interleaved")
      );
  
  #define MAKE_FUNC(type) \
  static void interleave_##type (guint##type *out, guint##type *in, \
      guint stride, guint nframes) \
  { \
    gint i; \
    \
    for (i = 0; i < nframes; i++) { \
      *out = in[i]; \
      out += stride; \
    } \
  }
  
  MAKE_FUNC (8);
  MAKE_FUNC (16);
  MAKE_FUNC (32);
  MAKE_FUNC (64);
  
  static void
  interleave_24 (guint8 * out, guint8 * in, guint stride, guint nframes)
  {
    gint i;
  
    for (i = 0; i < nframes; i++) {
      memcpy (out, in, 3);
      out += stride * 3;
      in += 3;
    }
  }
  
  typedef struct
  {
    GstPad parent;
    guint channel;
  } GstInterleavePad;
  
  enum
  {
    PROP_PAD_0,
    PROP_PAD_CHANNEL
  };
  
  static void gst_interleave_pad_class_init (GstPadClass * klass);
  
  #define GST_TYPE_INTERLEAVE_PAD (gst_interleave_pad_get_type())
  #define GST_INTERLEAVE_PAD(pad) (G_TYPE_CHECK_INSTANCE_CAST((pad),GST_TYPE_INTERLEAVE_PAD,GstInterleavePad))
  #define GST_INTERLEAVE_PAD_CAST(pad) ((GstInterleavePad *) pad)
  #define GST_IS_INTERLEAVE_PAD(pad) (G_TYPE_CHECK_INSTANCE_TYPE((pad),GST_TYPE_INTERLEAVE_PAD))
  static GType
  gst_interleave_pad_get_type (void)
  {
    static GType type = 0;
  
    if (G_UNLIKELY (type == 0)) {
      type = g_type_register_static_simple (GST_TYPE_PAD,
          g_intern_static_string ("GstInterleavePad"), sizeof (GstPadClass),
          (GClassInitFunc) gst_interleave_pad_class_init,
          sizeof (GstInterleavePad), NULL, 0);
    }
    return type;
  }
  
  static void
  gst_interleave_pad_get_property (GObject * object,
      guint prop_id, GValue * value, GParamSpec * pspec)
  {
    GstInterleavePad *self = GST_INTERLEAVE_PAD (object);
  
    switch (prop_id) {
      case PROP_PAD_CHANNEL:
        g_value_set_uint (value, self->channel);
        break;
      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
    }
  }
  
  static void
  gst_interleave_pad_class_init (GstPadClass * klass)
  {
    GObjectClass *gobject_class = (GObjectClass *) klass;
  
    gobject_class->get_property = gst_interleave_pad_get_property;
  
    g_object_class_install_property (gobject_class,
        PROP_PAD_CHANNEL,
        g_param_spec_uint ("channel",
            "Channel number",
            "Number of the channel of this pad in the output", 0, G_MAXUINT, 0,
            G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
  }
  
  #define gst_interleave_parent_class parent_class
  G_DEFINE_TYPE (GstInterleave, gst_interleave, GST_TYPE_ELEMENT);
  
  enum
  {
    PROP_0,
    PROP_CHANNEL_POSITIONS,
    PROP_CHANNEL_POSITIONS_FROM_INPUT
  };
  
  static void gst_interleave_set_property (GObject * object,
      guint prop_id, const GValue * value, GParamSpec * pspec);
  static void gst_interleave_get_property (GObject * object,
      guint prop_id, GValue * value, GParamSpec * pspec);
  
  static GstPad *gst_interleave_request_new_pad (GstElement * element,
      GstPadTemplate * templ, const gchar * name, const GstCaps * caps);
  static void gst_interleave_release_pad (GstElement * element, GstPad * pad);
  
  static GstStateChangeReturn gst_interleave_change_state (GstElement * element,
      GstStateChange transition);
  
  static gboolean gst_interleave_src_query (GstPad * pad, GstObject * parent,
      GstQuery * query);
  
  static gboolean gst_interleave_src_event (GstPad * pad, GstObject * parent,
      GstEvent * event);
  
  static gboolean gst_interleave_sink_event (GstCollectPads * pads,
      GstCollectData * data, GstEvent * event, gpointer user_data);
  static gboolean gst_interleave_sink_query (GstCollectPads * pads,
      GstCollectData * data, GstQuery * query, gpointer user_data);
  
  static gboolean gst_interleave_sink_setcaps (GstInterleave * self,
      GstPad * pad, const GstCaps * caps, const GstAudioInfo * info);
  
  static GstCaps *gst_interleave_sink_getcaps (GstPad * pad, GstInterleave * self,
      GstCaps * filter);
  
  static GstFlowReturn gst_interleave_collected (GstCollectPads * pads,
      GstInterleave * self);
  
  static void
  gst_interleave_finalize (GObject * object)
  {
    GstInterleave *self = GST_INTERLEAVE (object);
  
    if (self->collect) {
      gst_object_unref (self->collect);
      self->collect = NULL;
    }
  
    if (self->channel_positions
        && self->channel_positions != self->input_channel_positions) {
      g_value_array_free (self->channel_positions);
      self->channel_positions = NULL;
    }
  
    if (self->input_channel_positions) {
      g_value_array_free (self->input_channel_positions);
      self->input_channel_positions = NULL;
    }
  
    gst_caps_replace (&self->sinkcaps, NULL);
  
    G_OBJECT_CLASS (parent_class)->finalize (object);
  }
  
  static gint
  compare_positions (gconstpointer a, gconstpointer b, gpointer user_data)
  {
    const gint i = *(const gint *) a;
    const gint j = *(const gint *) b;
    const gint *pos = (const gint *) user_data;
  
    if (pos[i] < pos[j])
      return -1;
    else if (pos[i] > pos[j])
      return 1;
    else
      return 0;
  }
  
  static gboolean
  gst_interleave_channel_positions_to_mask (GValueArray * positions,
      gint default_ordering_map[64], guint64 * mask)
  {
    gint i;
    guint channels;
    GstAudioChannelPosition *pos;
    gboolean ret;
  
    channels = positions->n_values;
    pos = g_new (GstAudioChannelPosition, channels);
  
    for (i = 0; i < channels; i++) {
      GValue *val;
  
      val = g_value_array_get_nth (positions, i);
      pos[i] = g_value_get_enum (val);
    }
  
    /* sort the default ordering map according to the position order */
    for (i = 0; i < channels; i++) {
      default_ordering_map[i] = i;
    }
    g_qsort_with_data (default_ordering_map, channels,
        sizeof (*default_ordering_map), compare_positions, pos);
  
    ret = gst_audio_channel_positions_to_mask (pos, channels, FALSE, mask);
    g_free (pos);
  
    return ret;
  }
  
  static void
  gst_interleave_set_channel_positions (GstInterleave * self, GstStructure * s)
  {
    if (self->channels <= 64 &&
        self->channel_positions != NULL &&
        self->channels == self->channel_positions->n_values) {
      if (!gst_interleave_channel_positions_to_mask (self->channel_positions,
              self->default_channels_ordering_map, &self->channel_mask)) {
        GST_WARNING_OBJECT (self, "Invalid channel positions, using NONE");
        self->channel_mask = 0;
      }
    } else {
      self->channel_mask = 0;
      if (self->channels <= 64) {
        GST_WARNING_OBJECT (self, "Using NONE channel positions");
      }
    }
    gst_structure_set (s, "channel-mask", GST_TYPE_BITMASK, self->channel_mask,
        NULL);
  }
  
  static void
  gst_interleave_send_stream_start (GstInterleave * self)
  {
    GST_OBJECT_LOCK (self);
    if (self->send_stream_start) {
      gchar s_id[32];
  
      self->send_stream_start = FALSE;
      GST_OBJECT_UNLOCK (self);
  
      /* stream-start (FIXME: create id based on input ids) */
      g_snprintf (s_id, sizeof (s_id), "interleave-%08x", g_random_int ());
      gst_pad_push_event (self->src, gst_event_new_stream_start (s_id));
    } else {
      GST_OBJECT_UNLOCK (self);
    }
  }
  
  static void
  gst_interleave_class_init (GstInterleaveClass * klass)
  {
    GstElementClass *gstelement_class;
    GObjectClass *gobject_class;
  
    gobject_class = G_OBJECT_CLASS (klass);
    gstelement_class = GST_ELEMENT_CLASS (klass);
  
    GST_DEBUG_CATEGORY_INIT (gst_interleave_debug, "interleave", 0,
        "interleave element");
  
    gst_element_class_set_static_metadata (gstelement_class, "Audio interleaver",
        "Filter/Converter/Audio",
        "Folds many mono channels into one interleaved audio stream",
        "Andy Wingo <wingo at pobox.com>, "
        "Sebastian Dröge <slomo@circular-chaos.org>");
  
    gst_element_class_add_static_pad_template (gstelement_class, &sink_template);
    gst_element_class_add_static_pad_template (gstelement_class, &src_template);
  
    /* Reference GstInterleavePad class to have the type registered from
     * a threadsafe context
     */
    g_type_class_ref (GST_TYPE_INTERLEAVE_PAD);
  
    gobject_class->finalize = gst_interleave_finalize;
    gobject_class->set_property = gst_interleave_set_property;
    gobject_class->get_property = gst_interleave_get_property;
  
    /**
     * GstInterleave:channel-positions
     *
     * Channel positions: This property controls the channel positions
     * that are used on the src caps. The number of elements should be
     * the same as the number of sink pads and the array should contain
     * a valid list of channel positions. The n-th element of the array
     * is the position of the n-th sink pad.
     *
     * These channel positions will only be used if they're valid and the
     * number of elements is the same as the number of channels. If this
     * is not given a NONE layout will be used.
     *
     */
    g_object_class_install_property (gobject_class, PROP_CHANNEL_POSITIONS,
        g_param_spec_value_array ("channel-positions", "Channel positions",
            "Channel positions used on the output",
            g_param_spec_enum ("channel-position", "Channel position",
                "Channel position of the n-th input",
                GST_TYPE_AUDIO_CHANNEL_POSITION,
                GST_AUDIO_CHANNEL_POSITION_NONE,
                G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
            G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  
    /**
     * GstInterleave:channel-positions-from-input
     *
     * Channel positions from input: If this property is set to %TRUE the channel
     * positions will be taken from the input caps if valid channel positions for
     * the output can be constructed from them. If this is set to %TRUE setting the
     * channel-positions property overwrites this property again.
     *
     */
    g_object_class_install_property (gobject_class,
        PROP_CHANNEL_POSITIONS_FROM_INPUT,
        g_param_spec_boolean ("channel-positions-from-input",
            "Channel positions from input",
            "Take channel positions from the input", TRUE,
            G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  
    gstelement_class->request_new_pad =
        GST_DEBUG_FUNCPTR (gst_interleave_request_new_pad);
    gstelement_class->release_pad =
        GST_DEBUG_FUNCPTR (gst_interleave_release_pad);
    gstelement_class->change_state =
        GST_DEBUG_FUNCPTR (gst_interleave_change_state);
  }
  
  static void
  gst_interleave_init (GstInterleave * self)
  {
    self->src = gst_pad_new_from_static_template (&src_template, "src");
  
    gst_pad_set_query_function (self->src,
        GST_DEBUG_FUNCPTR (gst_interleave_src_query));
    gst_pad_set_event_function (self->src,
        GST_DEBUG_FUNCPTR (gst_interleave_src_event));
  
    gst_element_add_pad (GST_ELEMENT (self), self->src);
  
    self->collect = gst_collect_pads_new ();
    gst_collect_pads_set_function (self->collect,
        (GstCollectPadsFunction) gst_interleave_collected, self);
  
    self->input_channel_positions = g_value_array_new (0);
    self->channel_positions_from_input = TRUE;
    self->channel_positions = self->input_channel_positions;
  }
  
  static void
  gst_interleave_set_property (GObject * object, guint prop_id,
      const GValue * value, GParamSpec * pspec)
  {
    GstInterleave *self = GST_INTERLEAVE (object);
  
    switch (prop_id) {
      case PROP_CHANNEL_POSITIONS:
        if (self->channel_positions &&
            self->channel_positions != self->input_channel_positions)
          g_value_array_free (self->channel_positions);
  
        self->channel_positions = g_value_dup_boxed (value);
        self->channel_positions_from_input = FALSE;
        break;
      case PROP_CHANNEL_POSITIONS_FROM_INPUT:
        self->channel_positions_from_input = g_value_get_boolean (value);
  
        if (self->channel_positions_from_input) {
          if (self->channel_positions &&
              self->channel_positions != self->input_channel_positions)
            g_value_array_free (self->channel_positions);
          self->channel_positions = self->input_channel_positions;
        }
        break;
      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
    }
  }
  
  static void
  gst_interleave_get_property (GObject * object, guint prop_id,
      GValue * value, GParamSpec * pspec)
  {
    GstInterleave *self = GST_INTERLEAVE (object);
  
    switch (prop_id) {
      case PROP_CHANNEL_POSITIONS:
        g_value_set_boxed (value, self->channel_positions);
        break;
      case PROP_CHANNEL_POSITIONS_FROM_INPUT:
        g_value_set_boolean (value, self->channel_positions_from_input);
        break;
      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
    }
  }
  
  static GstPad *
  gst_interleave_request_new_pad (GstElement * element, GstPadTemplate * templ,
      const gchar * req_name, const GstCaps * caps)
  {
    GstInterleave *self = GST_INTERLEAVE (element);
    GstPad *new_pad;
    gchar *pad_name;
    gint channel, padnumber;
    GValue val = { 0, };
  
    if (templ->direction != GST_PAD_SINK)
      goto not_sink_pad;
  
    padnumber = g_atomic_int_add (&self->padcounter, 1);
  
    channel = g_atomic_int_add (&self->channels, 1);
    if (!self->channel_positions_from_input)
      channel = padnumber;
  
    pad_name = g_strdup_printf ("sink_%u", padnumber);
    new_pad = GST_PAD_CAST (g_object_new (GST_TYPE_INTERLEAVE_PAD,
            "name", pad_name, "direction", templ->direction,
            "template", templ, NULL));
    GST_INTERLEAVE_PAD_CAST (new_pad)->channel = channel;
    GST_DEBUG_OBJECT (self, "requested new pad %s", pad_name);
    g_free (pad_name);
  
    gst_pad_use_fixed_caps (new_pad);
  
    gst_collect_pads_add_pad (self->collect, new_pad, sizeof (GstCollectData),
        NULL, TRUE);
  
    gst_collect_pads_set_event_function (self->collect,
        (GstCollectPadsEventFunction)
        GST_DEBUG_FUNCPTR (gst_interleave_sink_event), self);
  
    gst_collect_pads_set_query_function (self->collect,
        (GstCollectPadsQueryFunction)
        GST_DEBUG_FUNCPTR (gst_interleave_sink_query), self);
  
    if (!gst_element_add_pad (element, new_pad))
      goto could_not_add;
  
    g_value_init (&val, GST_TYPE_AUDIO_CHANNEL_POSITION);
    g_value_set_enum (&val, GST_AUDIO_CHANNEL_POSITION_NONE);
    self->input_channel_positions =
        g_value_array_append (self->input_channel_positions, &val);
    g_value_unset (&val);
  
    /* Update the src caps if we already have them */
    if (self->sinkcaps) {
      GstCaps *srccaps;
      GstStructure *s;
  
      /* Take lock to make sure processing finishes first */
      GST_OBJECT_LOCK (self->collect);
  
      srccaps = gst_caps_copy (self->sinkcaps);
      s = gst_caps_get_structure (srccaps, 0);
  
      gst_structure_set (s, "channels", G_TYPE_INT, self->channels, NULL);
      gst_interleave_set_channel_positions (self, s);
  
      gst_interleave_send_stream_start (self);
      gst_pad_set_caps (self->src, srccaps);
      gst_caps_unref (srccaps);
  
      GST_OBJECT_UNLOCK (self->collect);
    }
  
    return new_pad;
  
    /* errors */
  not_sink_pad:
    {
      g_warning ("interleave: requested new pad that is not a SINK pad\n");
      return NULL;
    }
  could_not_add:
    {
      GST_DEBUG_OBJECT (self, "could not add pad %s", GST_PAD_NAME (new_pad));
      gst_collect_pads_remove_pad (self->collect, new_pad);
      gst_object_unref (new_pad);
      return NULL;
    }
  }
  
  static void
  gst_interleave_release_pad (GstElement * element, GstPad * pad)
  {
    GstInterleave *self = GST_INTERLEAVE (element);
    GList *l;
    GstAudioChannelPosition position;
  
    g_return_if_fail (GST_IS_INTERLEAVE_PAD (pad));
  
    /* Take lock to make sure we're not changing this when processing buffers */
    GST_OBJECT_LOCK (self->collect);
  
    g_atomic_int_add (&self->channels, -1);
  
    if (gst_pad_has_current_caps (pad))
      g_atomic_int_add (&self->configured_sinkpads_counter, -1);
  
    position = GST_INTERLEAVE_PAD_CAST (pad)->channel;
    g_value_array_remove (self->input_channel_positions, position);
  
    /* Update channel numbers */
    GST_OBJECT_LOCK (self);
    for (l = GST_ELEMENT_CAST (self)->sinkpads; l != NULL; l = l->next) {
      GstInterleavePad *ipad = GST_INTERLEAVE_PAD (l->data);
  
      if (GST_INTERLEAVE_PAD_CAST (pad)->channel < ipad->channel)
        ipad->channel--;
    }
    GST_OBJECT_UNLOCK (self);
  
    /* Update the src caps if we already have them */
    if (self->sinkcaps) {
      if (self->channels > 0) {
        GstCaps *srccaps;
        GstStructure *s;
  
        srccaps = gst_caps_copy (self->sinkcaps);
        s = gst_caps_get_structure (srccaps, 0);
  
        gst_structure_set (s, "channels", G_TYPE_INT, self->channels, NULL);
        gst_interleave_set_channel_positions (self, s);
  
        gst_interleave_send_stream_start (self);
        gst_pad_set_caps (self->src, srccaps);
        gst_caps_unref (srccaps);
      } else {
        gst_caps_replace (&self->sinkcaps, NULL);
      }
    }
  
    GST_OBJECT_UNLOCK (self->collect);
  
    gst_collect_pads_remove_pad (self->collect, pad);
    gst_element_remove_pad (element, pad);
  }
  
  static GstStateChangeReturn
  gst_interleave_change_state (GstElement * element, GstStateChange transition)
  {
    GstInterleave *self;
    GstStateChangeReturn ret;
  
    self = GST_INTERLEAVE (element);
  
    switch (transition) {
      case GST_STATE_CHANGE_NULL_TO_READY:
        break;
      case GST_STATE_CHANGE_READY_TO_PAUSED:
        self->timestamp = 0;
        self->offset = 0;
        gst_event_replace (&self->pending_segment, NULL);
        self->send_stream_start = TRUE;
        gst_collect_pads_start (self->collect);
        break;
      case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
        break;
      default:
        break;
    }
  
    /* Stop before calling the parent's state change function as
     * GstCollectPads might take locks and we would deadlock in that
     * case
     */
    if (transition == GST_STATE_CHANGE_PAUSED_TO_READY)
      gst_collect_pads_stop (self->collect);
  
    ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
  
    switch (transition) {
      case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
        break;
      case GST_STATE_CHANGE_PAUSED_TO_READY:
        gst_caps_replace (&self->sinkcaps, NULL);
        gst_event_replace (&self->pending_segment, NULL);
        break;
      case GST_STATE_CHANGE_READY_TO_NULL:
        break;
      default:
        break;
    }
  
    return ret;
  }
  
  static void
  __remove_channels (GstCaps * caps)
  {
    GstStructure *s;
    gint i, size;
  
    size = gst_caps_get_size (caps);
    for (i = 0; i < size; i++) {
      s = gst_caps_get_structure (caps, i);
      gst_structure_remove_field (s, "channel-mask");
      gst_structure_remove_field (s, "channels");
    }
  }
  
  static void
  __set_channels (GstCaps * caps, gint channels)
  {
    GstStructure *s;
    gint i, size;
  
    size = gst_caps_get_size (caps);
    for (i = 0; i < size; i++) {
      s = gst_caps_get_structure (caps, i);
      if (channels > 0)
        gst_structure_set (s, "channels", G_TYPE_INT, channels, NULL);
      else
        gst_structure_set (s, "channels", GST_TYPE_INT_RANGE, 1, G_MAXINT, NULL);
    }
  }
  
  /* we can only accept caps that we and downstream can handle. */
  static GstCaps *
  gst_interleave_sink_getcaps (GstPad * pad, GstInterleave * self,
      GstCaps * filter)
  {
    GstCaps *result, *peercaps, *sinkcaps;
  
    GST_OBJECT_LOCK (self);
  
    /* If we already have caps on one of the sink pads return them */
    if (self->sinkcaps) {
      result = gst_caps_copy (self->sinkcaps);
    } else {
      /* get the downstream possible caps */
      peercaps = gst_pad_peer_query_caps (self->src, NULL);
  
      /* get the allowed caps on this sinkpad */
      sinkcaps = gst_caps_copy (gst_pad_get_pad_template_caps (pad));
      __remove_channels (sinkcaps);
      if (peercaps) {
        peercaps = gst_caps_make_writable (peercaps);
        __remove_channels (peercaps);
        /* if the peer has caps, intersect */
        GST_DEBUG_OBJECT (pad, "intersecting peer and template caps");
        result = gst_caps_intersect (peercaps, sinkcaps);
        gst_caps_unref (peercaps);
        gst_caps_unref (sinkcaps);
      } else {
        /* the peer has no caps (or there is no peer), just use the allowed caps
         * of this sinkpad. */
        GST_DEBUG_OBJECT (pad, "no peer caps, using sinkcaps");
        result = sinkcaps;
      }
      __set_channels (result, 1);
    }
  
    GST_OBJECT_UNLOCK (self);
  
    if (filter != NULL) {
      GstCaps *caps = result;
  
      GST_LOG_OBJECT (pad, "intersecting filter caps %" GST_PTR_FORMAT " with "
          "preliminary result %" GST_PTR_FORMAT, filter, caps);
  
      result = gst_caps_intersect_full (filter, caps, GST_CAPS_INTERSECT_FIRST);
      gst_caps_unref (caps);
    }
  
    GST_DEBUG_OBJECT (pad, "Returning caps %" GST_PTR_FORMAT, result);
  
    return result;
  }
  
  static void
  gst_interleave_set_process_function (GstInterleave * self)
  {
    switch (self->width) {
      case 8:
        self->func = (GstInterleaveFunc) interleave_8;
        break;
      case 16:
        self->func = (GstInterleaveFunc) interleave_16;
        break;
      case 24:
        self->func = (GstInterleaveFunc) interleave_24;
        break;
      case 32:
        self->func = (GstInterleaveFunc) interleave_32;
        break;
      case 64:
        self->func = (GstInterleaveFunc) interleave_64;
        break;
      default:
        g_assert_not_reached ();
        break;
    }
  }
  
  static gboolean
  gst_interleave_sink_setcaps (GstInterleave * self, GstPad * pad,
      const GstCaps * caps, const GstAudioInfo * info)
  {
    g_return_val_if_fail (GST_IS_INTERLEAVE_PAD (pad), FALSE);
  
    /* TODO: handle caps changes */
    if (self->sinkcaps && !gst_caps_is_subset (caps, self->sinkcaps)) {
      goto cannot_change_caps;
    } else {
      GstCaps *srccaps;
      GstStructure *s;
      gboolean res;
  
      self->width = GST_AUDIO_INFO_WIDTH (info);
      self->rate = GST_AUDIO_INFO_RATE (info);
  
      gst_interleave_set_process_function (self);
  
      srccaps = gst_caps_copy (caps);
      s = gst_caps_get_structure (srccaps, 0);
  
      gst_structure_remove_field (s, "channel-mask");
  
      gst_structure_set (s, "channels", G_TYPE_INT, self->channels, "layout",
          G_TYPE_STRING, "interleaved", NULL);
      gst_interleave_set_channel_positions (self, s);
  
      gst_interleave_send_stream_start (self);
      res = gst_pad_set_caps (self->src, srccaps);
      gst_caps_unref (srccaps);
  
      if (!res)
        goto src_did_not_accept;
    }
  
    if (!self->sinkcaps) {
      GstCaps *sinkcaps = gst_caps_copy (caps);
      GstStructure *s = gst_caps_get_structure (sinkcaps, 0);
  
      gst_structure_remove_field (s, "channel-mask");
  
      GST_DEBUG_OBJECT (self, "setting sinkcaps %" GST_PTR_FORMAT, sinkcaps);
  
      gst_caps_replace (&self->sinkcaps, sinkcaps);
  
      gst_caps_unref (sinkcaps);
    }
  
    return TRUE;
  
  cannot_change_caps:
    {
      GST_WARNING_OBJECT (self, "caps of %" GST_PTR_FORMAT " already set, can't "
          "change", self->sinkcaps);
      return FALSE;
    }
  src_did_not_accept:
    {
      GST_WARNING_OBJECT (self, "src did not accept setcaps()");
      return FALSE;
    }
  }
  
  static gboolean
  gst_interleave_sink_event (GstCollectPads * pads, GstCollectData * data,
      GstEvent * event, gpointer user_data)
  {
    GstInterleave *self = GST_INTERLEAVE (user_data);
    gboolean ret = TRUE;
  
    GST_DEBUG ("Got %s event on pad %s:%s", GST_EVENT_TYPE_NAME (event),
        GST_DEBUG_PAD_NAME (data->pad));
  
    switch (GST_EVENT_TYPE (event)) {
      case GST_EVENT_FLUSH_STOP:
        GST_OBJECT_LOCK (self);
        gst_event_replace (&self->pending_segment, NULL);
        GST_OBJECT_UNLOCK (self);
        break;
      case GST_EVENT_SEGMENT:
      {
        GST_OBJECT_LOCK (self);
        gst_event_replace (&self->pending_segment, event);
        GST_OBJECT_UNLOCK (self);
        break;
      }
      case GST_EVENT_CAPS:
      {
        GstCaps *caps;
        GstAudioInfo info;
        GValue *val;
        guint channel;
  
        gst_event_parse_caps (event, &caps);
  
        if (!gst_audio_info_from_caps (&info, caps)) {
          GST_WARNING_OBJECT (self, "invalid sink caps");
          gst_event_unref (event);
          event = NULL;
          ret = FALSE;
          break;
        }
  
        if (self->channel_positions_from_input
            && GST_AUDIO_INFO_CHANNELS (&info) == 1) {
          channel = GST_INTERLEAVE_PAD_CAST (data->pad)->channel;
          val = g_value_array_get_nth (self->input_channel_positions, channel);
          g_value_set_enum (val, GST_AUDIO_INFO_POSITION (&info, 0));
        }
  
        if (!gst_pad_has_current_caps (data->pad))
          g_atomic_int_add (&self->configured_sinkpads_counter, 1);
  
        /* Last caps that are set on a sink pad are used as output caps */
        if (g_atomic_int_get (&self->configured_sinkpads_counter) ==
            self->channels) {
          ret = gst_interleave_sink_setcaps (self, data->pad, caps, &info);
          gst_event_unref (event);
          event = NULL;
        }
        break;
      }
      case GST_EVENT_TAG:
        GST_FIXME_OBJECT (self, "FIXME: merge tags and send after stream-start");
        break;
      default:
        break;
    }
  
    /* now GstCollectPads can take care of the rest, e.g. EOS */
    if (event != NULL)
      return gst_collect_pads_event_default (pads, data, event, FALSE);
  
    return ret;
  }
  
  static gboolean
  gst_interleave_sink_query (GstCollectPads * pads,
      GstCollectData * data, GstQuery * query, gpointer user_data)
  {
    GstInterleave *self = GST_INTERLEAVE (user_data);
    gboolean ret = TRUE;
  
    GST_DEBUG ("Got %s query on pad %s:%s", GST_QUERY_TYPE_NAME (query),
        GST_DEBUG_PAD_NAME (data->pad));
  
    switch (GST_QUERY_TYPE (query)) {
      case GST_QUERY_CAPS:
      {
        GstCaps *filter, *caps;
  
        gst_query_parse_caps (query, &filter);
        caps = gst_interleave_sink_getcaps (data->pad, self, filter);
        gst_query_set_caps_result (query, caps);
        gst_caps_unref (caps);
        ret = TRUE;
        break;
      }
      default:
        ret = gst_collect_pads_query_default (pads, data, query, FALSE);
        break;
    }
  
    return ret;
  }
  
  static gboolean
  gst_interleave_src_query_duration (GstInterleave * self, GstQuery * query)
  {
    gint64 max;
    gboolean res;
    GstFormat format;
    GstIterator *it;
    gboolean done;
  
    /* parse format */
    gst_query_parse_duration (query, &format, NULL);
  
    max = -1;
    res = TRUE;
    done = FALSE;
  
    /* Take maximum of all durations */
    it = gst_element_iterate_sink_pads (GST_ELEMENT_CAST (self));
    while (!done) {
      GstIteratorResult ires;
  
      GValue item = { 0, };
  
      ires = gst_iterator_next (it, &item);
      switch (ires) {
        case GST_ITERATOR_DONE:
          done = TRUE;
          break;
        case GST_ITERATOR_OK:
        {
          GstPad *pad = GST_PAD_CAST (g_value_dup_object (&item));
  
          gint64 duration;
  
          /* ask sink peer for duration */
          res &= gst_pad_peer_query_duration (pad, format, &duration);
          /* take max from all valid return values */
          if (res) {
            /* valid unknown length, stop searching */
            if (duration == -1) {
              max = duration;
              done = TRUE;
            }
            /* else see if bigger than current max */
            else if (duration > max)
              max = duration;
          }
          gst_object_unref (pad);
          g_value_unset (&item);
          break;
        }
        case GST_ITERATOR_RESYNC:
          max = -1;
          res = TRUE;
          gst_iterator_resync (it);
          break;
        default:
          res = FALSE;
          done = TRUE;
          break;
      }
    }
    gst_iterator_free (it);
  
    if (res) {
      /* If in bytes format we have to multiply with the number of channels
       * to get the correct results. All other formats should be fine */
      if (format == GST_FORMAT_BYTES && max != -1)
        max *= self->channels;
  
      /* and store the max */
      GST_DEBUG_OBJECT (self, "Total duration in format %s: %"
          GST_TIME_FORMAT, gst_format_get_name (format), GST_TIME_ARGS (max));
      gst_query_set_duration (query, format, max);
    }
  
    return res;
  }
  
  static gboolean
  gst_interleave_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
  {
    GstInterleave *self = GST_INTERLEAVE (parent);
    gboolean res = FALSE;
  
    switch (GST_QUERY_TYPE (query)) {
      case GST_QUERY_POSITION:
      {
        GstFormat format;
  
        gst_query_parse_position (query, &format, NULL);
  
        switch (format) {
          case GST_FORMAT_TIME:
            /* FIXME, bring to stream time, might be tricky */
            gst_query_set_position (query, format, self->timestamp);
            res = TRUE;
            break;
          case GST_FORMAT_BYTES:
            gst_query_set_position (query, format,
                self->offset * self->channels * self->width);
            res = TRUE;
            break;
          case GST_FORMAT_DEFAULT:
            gst_query_set_position (query, format, self->offset);
            res = TRUE;
            break;
          default:
            break;
        }
        break;
      }
      case GST_QUERY_DURATION:
        res = gst_interleave_src_query_duration (self, query);
        break;
      default:
        /* FIXME, needs a custom query handler because we have multiple
         * sinkpads */
        res = gst_pad_query_default (pad, parent, query);
        break;
    }
  
    return res;
  }
  
  static gboolean
  forward_event_func (const GValue * item, GValue * ret, GstEvent * event)
  {
    GstPad *pad = GST_PAD_CAST (g_value_dup_object (item));
    gst_event_ref (event);
    GST_LOG_OBJECT (pad, "About to send event %s", GST_EVENT_TYPE_NAME (event));
    if (!gst_pad_push_event (pad, event)) {
      g_value_set_boolean (ret, FALSE);
      GST_WARNING_OBJECT (pad, "Sending event  %p (%s) failed.",
          event, GST_EVENT_TYPE_NAME (event));
    } else {
      GST_LOG_OBJECT (pad, "Sent event  %p (%s).",
          event, GST_EVENT_TYPE_NAME (event));
    }
    gst_object_unref (pad);
    return TRUE;
  }
  
  static gboolean
  forward_event (GstInterleave * self, GstEvent * event)
  {
    GstIterator *it;
    GValue vret = { 0 };
  
    GST_LOG_OBJECT (self, "Forwarding event %p (%s)", event,
        GST_EVENT_TYPE_NAME (event));
  
    g_value_init (&vret, G_TYPE_BOOLEAN);
    g_value_set_boolean (&vret, TRUE);
    it = gst_element_iterate_sink_pads (GST_ELEMENT_CAST (self));
    gst_iterator_fold (it, (GstIteratorFoldFunction) forward_event_func, &vret,
        event);
    gst_iterator_free (it);
    gst_event_unref (event);
  
    return g_value_get_boolean (&vret);
  }
  
  
  static gboolean
  gst_interleave_src_event (GstPad * pad, GstObject * parent, GstEvent * event)
  {
    GstInterleave *self = GST_INTERLEAVE (parent);
    gboolean result;
  
    switch (GST_EVENT_TYPE (event)) {
      case GST_EVENT_QOS:
        /* QoS might be tricky */
        result = FALSE;
        break;
      case GST_EVENT_SEEK:
      {
        GstSeekFlags flags;
  
        gst_event_parse_seek (event, NULL, NULL, &flags, NULL, NULL, NULL, NULL);
  
        /* check if we are flushing */
        if (flags & GST_SEEK_FLAG_FLUSH) {
          /* make sure we accept nothing anymore and return WRONG_STATE */
          gst_collect_pads_set_flushing (self->collect, TRUE);
  
          /* flushing seek, start flush downstream, the flush will be done
           * when all pads received a FLUSH_STOP. */
          gst_pad_push_event (self->src, gst_event_new_flush_start ());
        }
        result = forward_event (self, event);
        break;
      }
      case GST_EVENT_NAVIGATION:
        /* navigation is rather pointless. */
        result = FALSE;
        break;
      default:
        /* just forward the rest for now */
        result = forward_event (self, event);
        break;
    }
  
    return result;
  }
  
  static GstFlowReturn
  gst_interleave_collected (GstCollectPads * pads, GstInterleave * self)
  {
    guint size;
    GstBuffer *outbuf = NULL;
    GstFlowReturn ret = GST_FLOW_OK;
    GSList *collected;
    guint nsamples;
    guint ncollected = 0;
    gboolean empty = TRUE;
    gint width = self->width / 8;
    GstMapInfo write_info;
    GstClockTime timestamp = -1;
  
    size = gst_collect_pads_available (pads);
    if (size == 0)
      goto eos;
  
    g_return_val_if_fail (self->func != NULL, GST_FLOW_NOT_NEGOTIATED);
    g_return_val_if_fail (self->width > 0, GST_FLOW_NOT_NEGOTIATED);
    g_return_val_if_fail (self->channels > 0, GST_FLOW_NOT_NEGOTIATED);
    g_return_val_if_fail (self->rate > 0, GST_FLOW_NOT_NEGOTIATED);
  
    g_return_val_if_fail (size % width == 0, GST_FLOW_ERROR);
  
    GST_DEBUG_OBJECT (self, "Starting to collect %u bytes from %d channels", size,
        self->channels);
  
    nsamples = size / width;
  
    outbuf = gst_buffer_new_allocate (NULL, size * self->channels, NULL);
  
    if (outbuf == NULL || gst_buffer_get_size (outbuf) < size * self->channels) {
      gst_buffer_unref (outbuf);
      return GST_FLOW_NOT_NEGOTIATED;
    }
  
    gst_buffer_map (outbuf, &write_info, GST_MAP_WRITE);
    memset (write_info.data, 0, size * self->channels);
  
    for (collected = pads->data; collected != NULL; collected = collected->next) {
      GstCollectData *cdata;
      GstBuffer *inbuf;
      guint8 *outdata;
      GstMapInfo input_info;
      gint channel;
  
      cdata = (GstCollectData *) collected->data;
  
      inbuf = gst_collect_pads_take_buffer (pads, cdata, size);
      if (inbuf == NULL) {
        GST_DEBUG_OBJECT (cdata->pad, "No buffer available");
        goto next;
      }
      ncollected++;
  
      if (timestamp == -1)
        timestamp = GST_BUFFER_TIMESTAMP (inbuf);
  
      if (GST_BUFFER_FLAG_IS_SET (inbuf, GST_BUFFER_FLAG_GAP))
        goto next;
  
      empty = FALSE;
      channel = GST_INTERLEAVE_PAD_CAST (cdata->pad)->channel;
      if (self->channels <= 64 && self->channel_mask) {
        channel = self->default_channels_ordering_map[channel];
      }
      outdata = write_info.data + width * channel;
  
      gst_buffer_map (inbuf, &input_info, GST_MAP_READ);
      self->func (outdata, input_info.data, self->channels, nsamples);
      gst_buffer_unmap (inbuf, &input_info);
  
    next:
      if (inbuf)
        gst_buffer_unref (inbuf);
    }
  
    if (ncollected == 0) {
      gst_buffer_unmap (outbuf, &write_info);
      goto eos;
    }
  
    GST_OBJECT_LOCK (self);
    if (self->pending_segment) {
      GstEvent *event;
      GstSegment segment;
  
      event = self->pending_segment;
      self->pending_segment = NULL;
      GST_OBJECT_UNLOCK (self);
  
      /* convert the input segment to time now */
      gst_event_copy_segment (event, &segment);
  
      if (segment.format != GST_FORMAT_TIME) {
        gst_event_unref (event);
  
        /* not time, convert */
        switch (segment.format) {
          case GST_FORMAT_BYTES:
            segment.start *= width;
            if (segment.stop != -1)
              segment.stop *= width;
            if (segment.position != -1)
              segment.position *= width;
            /* fallthrough for the samples case */
          case GST_FORMAT_DEFAULT:
            segment.start =
                gst_util_uint64_scale_int (segment.start, GST_SECOND, self->rate);
            if (segment.stop != -1)
              segment.stop =
                  gst_util_uint64_scale_int (segment.stop, GST_SECOND,
                  self->rate);
            if (segment.position != -1)
              segment.position =
                  gst_util_uint64_scale_int (segment.position, GST_SECOND,
                  self->rate);
            break;
          default:
            GST_WARNING ("can't convert segment values");
            segment.start = 0;
            segment.stop = -1;
            segment.position = 0;
            break;
        }
        event = gst_event_new_segment (&segment);
      }
      gst_pad_push_event (self->src, event);
  
      GST_OBJECT_LOCK (self);
    }
    GST_OBJECT_UNLOCK (self);
  
    if (timestamp != -1) {
      self->offset = gst_util_uint64_scale_int (timestamp, self->rate,
          GST_SECOND);
      self->timestamp = timestamp;
    }
  
    GST_BUFFER_TIMESTAMP (outbuf) = self->timestamp;
    GST_BUFFER_OFFSET (outbuf) = self->offset;
  
    self->offset += nsamples;
    self->timestamp = gst_util_uint64_scale_int (self->offset,
        GST_SECOND, self->rate);
  
    GST_BUFFER_DURATION (outbuf) =
        self->timestamp - GST_BUFFER_TIMESTAMP (outbuf);
  
    if (empty)
      GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_GAP);
  
    gst_buffer_unmap (outbuf, &write_info);
  
    GST_LOG_OBJECT (self, "pushing outbuf, timestamp %" GST_TIME_FORMAT,
        GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (outbuf)));
    ret = gst_pad_push (self->src, outbuf);
  
    return ret;
  
  eos:
    {
      GST_DEBUG_OBJECT (self, "no data available, must be EOS");
      if (outbuf)
        gst_buffer_unref (outbuf);
      gst_pad_push_event (self->src, gst_event_new_eos ());
      return GST_FLOW_EOS;
    }
  }
  