gstreamer/gst/flv/gstflvmux.c

/* GStreamer
 *
 * Copyright (c) 2008,2009 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-flvmux
 *
 * flvmux muxes different streams into an FLV file.
 *
 * <refsect2>
 * <title>Example launch line</title>
 * |[
 * gst-launch -v filesrc location=/path/to/audio ! decodebin2 ! queue ! flvmux name=m ! filesink location=file.flv   filesrc location=/path/to/video ! decodebin2 ! queue ! m. 
 * ]| This pipeline muxes an audio and video file into a single FLV file.
 * </refsect2>
 */

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

#include <math.h>
#include <string.h>

#include "gstflvmux.h"

GST_DEBUG_CATEGORY_STATIC (flvmux_debug);
#define GST_CAT_DEFAULT flvmux_debug

static GstStaticPadTemplate src_templ = GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-flv")
    );

static GstStaticPadTemplate videosink_templ = GST_STATIC_PAD_TEMPLATE ("video",
    GST_PAD_SINK,
    GST_PAD_REQUEST,
    GST_STATIC_CAPS ("video/x-flash-video; "
        "video/x-flash-screen; "
        "video/x-vp6-flash; " "video/x-vp6-alpha; " "video/x-h264;")
    );

static GstStaticPadTemplate audiosink_templ = GST_STATIC_PAD_TEMPLATE ("audio",
    GST_PAD_SINK,
    GST_PAD_REQUEST,
    GST_STATIC_CAPS
    ("audio/x-adpcm, layout = (string) swf, channels = (int) { 1, 2 }, rate = (int) { 5512, 11025, 22050, 44100 }; "
        "audio/mpeg, mpegversion = (int) 1, layer = (int) 3, channels = (int) { 1, 2 }, rate = (int) { 5512, 8000, 11025, 22050, 44100 }, parsed = (boolean) TRUE; "
        "audio/mpeg, mpegversion = (int) 4, framed = (boolean) TRUE; "
        "audio/x-nellymoser, channels = (int) { 1, 2 }, rate = (int) { 5512, 8000, 11025, 16000, 22050, 44100 }; "
        "audio/x-raw-int, endianness = (int) LITTLE_ENDIAN, channels = (int) { 1, 2 }, width = (int) 8, depth = (int) 8, rate = (int) { 5512, 11025, 22050, 44100 }, signed = (boolean) FALSE; "
        "audio/x-raw-int, endianness = (int) LITTLE_ENDIAN, channels = (int) { 1, 2 }, width = (int) 16, depth = (int) 16, rate = (int) { 5512, 11025, 22050, 44100 }, signed = (boolean) TRUE; "
        "audio/x-alaw, channels = (int) { 1, 2 }, rate = (int) { 5512, 11025, 22050, 44100 }; "
        "audio/x-mulaw, channels = (int) { 1, 2 }, rate = (int) { 5512, 11025, 22050, 44100 }; "
        "audio/x-speex, channels = (int) { 1, 2 }, rate = (int) { 5512, 11025, 22050, 44100 };")
    );

#define _do_init(type)                                                          \
  G_STMT_START{                                                                 \
    static const GInterfaceInfo tag_setter_info = {                             \
      NULL,                                                                     \
      NULL,                                                                     \
      NULL                                                                      \
    };                                                                          \
    g_type_add_interface_static (type, GST_TYPE_TAG_SETTER,                     \
                                 &tag_setter_info);                             \
  }G_STMT_END

GST_BOILERPLATE_FULL (GstFlvMux, gst_flv_mux, GstElement, GST_TYPE_ELEMENT,
    _do_init);

static void gst_flv_mux_finalize (GObject * object);
static GstFlowReturn
gst_flv_mux_collected (GstCollectPads * pads, gpointer user_data);

static gboolean gst_flv_mux_handle_src_event (GstPad * pad, GstEvent * event);
static GstPad *gst_flv_mux_request_new_pad (GstElement * element,
    GstPadTemplate * templ, const gchar * name);
static void gst_flv_mux_release_pad (GstElement * element, GstPad * pad);

static GstStateChangeReturn
gst_flv_mux_change_state (GstElement * element, GstStateChange transition);

static void gst_flv_mux_reset (GstElement * element);

typedef struct
{
  gdouble position;
  gdouble time;
} GstFlvMuxIndexEntry;

static void
gst_flv_mux_index_entry_free (GstFlvMuxIndexEntry * entry)
{
  g_slice_free (GstFlvMuxIndexEntry, entry);
}

static void
gst_flv_mux_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 (&videosink_templ));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&audiosink_templ));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&src_templ));
  gst_element_class_set_details_simple (element_class, "FLV muxer",
      "Codec/Muxer",
      "Muxes video/audio streams into a FLV stream",
      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");

  GST_DEBUG_CATEGORY_INIT (flvmux_debug, "flvmux", 0, "FLV muxer");
}

static void
gst_flv_mux_class_init (GstFlvMuxClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  GST_DEBUG_CATEGORY_INIT (flvmux_debug, "flvmux", 0, "FLV muxer");

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

  gobject_class->finalize = gst_flv_mux_finalize;

  gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_flv_mux_change_state);
  gstelement_class->request_new_pad =
      GST_DEBUG_FUNCPTR (gst_flv_mux_request_new_pad);
  gstelement_class->release_pad = GST_DEBUG_FUNCPTR (gst_flv_mux_release_pad);
}

static void
gst_flv_mux_init (GstFlvMux * mux, GstFlvMuxClass * g_class)
{
  mux->srcpad = gst_pad_new_from_static_template (&src_templ, "src");
  gst_pad_set_event_function (mux->srcpad, gst_flv_mux_handle_src_event);
  gst_element_add_pad (GST_ELEMENT (mux), mux->srcpad);

  mux->collect = gst_collect_pads_new ();
  gst_collect_pads_set_function (mux->collect,
      (GstCollectPadsFunction) GST_DEBUG_FUNCPTR (gst_flv_mux_collected), mux);

  gst_flv_mux_reset (GST_ELEMENT (mux));
}

static void
gst_flv_mux_finalize (GObject * object)
{
  GstFlvMux *mux = GST_FLV_MUX (object);

  gst_object_unref (mux->collect);

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

static void
gst_flv_mux_reset (GstElement * element)
{
  GstFlvMux *mux = GST_FLV_MUX (element);
  GSList *sl;

  while ((sl = mux->collect->data) != NULL) {
    GstFlvPad *cpad = (GstFlvPad *) sl->data;

    gst_element_release_request_pad (element, cpad->collect.pad);
  }

  g_list_foreach (mux->index, (GFunc) gst_flv_mux_index_entry_free, NULL);
  g_list_free (mux->index);
  mux->index = NULL;
  mux->byte_count = 0;

  mux->have_audio = mux->have_video = FALSE;

  mux->state = GST_FLV_MUX_STATE_HEADER;

  /* tags */
  gst_tag_setter_reset_tags (GST_TAG_SETTER (mux));
}

static gboolean
gst_flv_mux_handle_src_event (GstPad * pad, GstEvent * event)
{
  GstEventType type;

  type = event ? GST_EVENT_TYPE (event) : GST_EVENT_UNKNOWN;

  switch (type) {
    case GST_EVENT_SEEK:
      /* disable seeking for now */
      return FALSE;
    default:
      break;
  }

  return gst_pad_event_default (pad, event);
}

static gboolean
gst_flv_mux_handle_sink_event (GstPad * pad, GstEvent * event)
{
  GstFlvMux *mux = GST_FLV_MUX (gst_pad_get_parent (pad));
  gboolean ret = TRUE;

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_TAG:{
      GstTagList *list;
      GstTagSetter *setter = GST_TAG_SETTER (mux);
      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);
      break;
    }
    case GST_EVENT_NEWSEGMENT:
      /* We don't support NEWSEGMENT events */
      ret = FALSE;
      gst_event_unref (event);
      break;
    default:
      break;
  }

  /* now GstCollectPads can take care of the rest, e.g. EOS */
  if (ret)
    ret = mux->collect_event (pad, event);
  gst_object_unref (mux);

  return ret;
}

static gboolean
gst_flv_mux_video_pad_setcaps (GstPad * pad, GstCaps * caps)
{
  GstFlvMux *mux = GST_FLV_MUX (gst_pad_get_parent (pad));
  GstFlvPad *cpad = (GstFlvPad *) gst_pad_get_element_private (pad);
  gboolean ret = TRUE;
  GstStructure *s;

  s = gst_caps_get_structure (caps, 0);

  if (strcmp (gst_structure_get_name (s), "video/x-flash-video") == 0) {
    cpad->video_codec = 2;
  } else if (strcmp (gst_structure_get_name (s), "video/x-flash-screen") == 0) {
    cpad->video_codec = 3;
  } else if (strcmp (gst_structure_get_name (s), "video/x-vp6-flash") == 0) {
    cpad->video_codec = 4;
  } else if (strcmp (gst_structure_get_name (s), "video/x-vp6-alpha") == 0) {
    cpad->video_codec = 5;
  } else if (strcmp (gst_structure_get_name (s), "video/x-h264") == 0) {
    cpad->video_codec = 7;
  } else {
    ret = FALSE;
  }

  if (ret && gst_structure_has_field (s, "codec_data")) {
    const GValue *val = gst_structure_get_value (s, "codec_data");

    if (val) {
      cpad->video_codec_data = gst_buffer_ref (gst_value_get_buffer (val));
      cpad->sent_codec_data = FALSE;
    } else {
      cpad->sent_codec_data = TRUE;
    }
  } else {
    cpad->sent_codec_data = TRUE;
  }

  gst_object_unref (mux);

  return ret;
}

static gboolean
gst_flv_mux_audio_pad_setcaps (GstPad * pad, GstCaps * caps)
{
  GstFlvMux *mux = GST_FLV_MUX (gst_pad_get_parent (pad));
  GstFlvPad *cpad = (GstFlvPad *) gst_pad_get_element_private (pad);
  gboolean ret = TRUE;
  GstStructure *s;

  s = gst_caps_get_structure (caps, 0);

  if (strcmp (gst_structure_get_name (s), "audio/x-adpcm") == 0) {
    const gchar *layout = gst_structure_get_string (s, "layout");
    if (layout && strcmp (layout, "swf") == 0) {
      cpad->audio_codec = 1;
    } else {
      ret = FALSE;
    }
  } else if (strcmp (gst_structure_get_name (s), "audio/mpeg") == 0) {
    gint mpegversion;

    if (gst_structure_get_int (s, "mpegversion", &mpegversion)) {
      if (mpegversion == 1) {
        gint layer;

        if (gst_structure_get_int (s, "layer", &layer) && layer == 3) {
          gint rate;

          if (gst_structure_get_int (s, "rate", &rate) && rate == 8000)
            cpad->audio_codec = 14;
          else
            cpad->audio_codec = 2;
        } else {
          ret = FALSE;
        }
      } else if (mpegversion == 4) {
        cpad->audio_codec = 10;
      } else {
        ret = FALSE;
      }
    } else {
      ret = FALSE;
    }
  } else if (strcmp (gst_structure_get_name (s), "audio/x-nellymoser") == 0) {
    gint rate, channels;

    if (gst_structure_get_int (s, "rate", &rate)
        && gst_structure_get_int (s, "channels", &channels)) {
      if (channels == 1 && rate == 16000)
        cpad->audio_codec = 4;
      else if (channels == 1 && rate == 8000)
        cpad->audio_codec = 5;
    } else {
      cpad->audio_codec = 6;
    }
  } else if (strcmp (gst_structure_get_name (s), "audio/x-raw-int") == 0) {
    gint endianness;

    if (gst_structure_get_int (s, "endianness", &endianness)
        && endianness == G_LITTLE_ENDIAN)
      cpad->audio_codec = 3;
    else
      ret = FALSE;
  } else if (strcmp (gst_structure_get_name (s), "audio/x-alaw") == 0) {
    cpad->audio_codec = 7;
  } else if (strcmp (gst_structure_get_name (s), "audio/x-mulaw") == 0) {
    cpad->audio_codec = 8;
  } else if (strcmp (gst_structure_get_name (s), "audio/x-speex") == 0) {
    cpad->audio_codec = 11;
  } else {
    ret = FALSE;
  }

  if (ret) {
    gint rate, channels, width;

    if (gst_structure_get_int (s, "rate", &rate)) {
      if (cpad->audio_codec == 10)
        cpad->rate = 3;
      else if (rate == 5512)
        cpad->rate = 0;
      else if (rate == 11025)
        cpad->rate = 1;
      else if (rate == 22050)
        cpad->rate = 2;
      else if (rate == 44100)
        cpad->rate = 3;
      else if (rate == 8000 && (cpad->audio_codec == 5
              || cpad->audio_codec == 14))
        cpad->rate = 0;
      else if (rate == 16000 && cpad->audio_codec == 4)
        cpad->rate = 0;
      else
        ret = FALSE;
    } else if (cpad->audio_codec == 10) {
      cpad->rate = 3;
    } else {
      ret = FALSE;
    }

    if (gst_structure_get_int (s, "channels", &channels)) {
      if (cpad->audio_codec == 4 || cpad->audio_codec == 5
          || cpad->audio_codec == 6)
        cpad->channels = 0;
      else if (cpad->audio_codec == 10)
        cpad->channels = 1;
      else if (channels == 1)
        cpad->channels = 0;
      else if (channels == 2)
        cpad->channels = 1;
      else
        ret = FALSE;
    } else if (cpad->audio_codec == 4 || cpad->audio_codec == 5
        || cpad->audio_codec == 6) {
      cpad->channels = 0;
    } else if (cpad->audio_codec == 10) {
      cpad->channels = 1;
    } else {
      ret = FALSE;
    }

    if (gst_structure_get_int (s, "width", &width)) {
      if (cpad->audio_codec != 3)
        cpad->width = 1;
      else if (width == 8)
        cpad->width = 0;
      else if (width == 16)
        cpad->width = 1;
      else
        ret = FALSE;
    } else if (cpad->audio_codec != 3) {
      cpad->width = 1;
    } else {
      ret = FALSE;
    }
  }

  if (ret && gst_structure_has_field (s, "codec_data")) {
    const GValue *val = gst_structure_get_value (s, "codec_data");

    if (val) {
      cpad->audio_codec_data = gst_buffer_ref (gst_value_get_buffer (val));
      cpad->sent_codec_data = FALSE;
    } else {
      cpad->sent_codec_data = TRUE;
    }
  } else {
    cpad->sent_codec_data = TRUE;
  }

  gst_object_unref (mux);

  return ret;
}

static GstPad *
gst_flv_mux_request_new_pad (GstElement * element,
    GstPadTemplate * templ, const gchar * pad_name)
{
  GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
  GstFlvMux *mux = GST_FLV_MUX (element);
  GstFlvPad *cpad;
  GstPad *pad = NULL;
  const gchar *name = NULL;
  GstPadSetCapsFunction setcapsfunc = NULL;
  gboolean video;

  if (mux->state != GST_FLV_MUX_STATE_HEADER) {
    GST_WARNING_OBJECT (mux, "Can't request pads after writing header");
    return NULL;
  }

  if (templ == gst_element_class_get_pad_template (klass, "audio")) {
    if (mux->have_audio) {
      GST_WARNING_OBJECT (mux, "Already have an audio pad");
      return NULL;
    }
    mux->have_audio = TRUE;
    name = "audio";
    video = FALSE;
    setcapsfunc = GST_DEBUG_FUNCPTR (gst_flv_mux_audio_pad_setcaps);
  } else if (templ == gst_element_class_get_pad_template (klass, "video")) {
    if (mux->have_video) {
      GST_WARNING_OBJECT (mux, "Already have a video pad");
      return NULL;
    }
    mux->have_video = TRUE;
    name = "video";
    video = TRUE;
    setcapsfunc = GST_DEBUG_FUNCPTR (gst_flv_mux_video_pad_setcaps);
  } else {
    GST_WARNING_OBJECT (mux, "Invalid template");
    return NULL;
  }

  pad = gst_pad_new_from_template (templ, name);
  cpad = (GstFlvPad *)
      gst_collect_pads_add_pad (mux->collect, pad, sizeof (GstFlvPad));

  cpad->video = video;

  cpad->audio_codec = G_MAXUINT;
  cpad->rate = G_MAXUINT;
  cpad->width = G_MAXUINT;
  cpad->channels = G_MAXUINT;
  cpad->audio_codec_data = NULL;

  cpad->video_codec = G_MAXUINT;
  cpad->video_codec_data = NULL;

  cpad->sent_codec_data = FALSE;

  cpad->last_timestamp = 0;

  /* FIXME: hacked way to override/extend the event function of
   * GstCollectPads; because it sets its own event function giving the
   * element no access to events.
   */
  mux->collect_event = (GstPadEventFunction) GST_PAD_EVENTFUNC (pad);
  gst_pad_set_event_function (pad,
      GST_DEBUG_FUNCPTR (gst_flv_mux_handle_sink_event));

  gst_pad_set_setcaps_function (pad, setcapsfunc);
  gst_pad_set_active (pad, TRUE);
  gst_element_add_pad (element, pad);

  return pad;
}

static void
gst_flv_mux_release_pad (GstElement * element, GstPad * pad)
{
  GstFlvMux *mux = GST_FLV_MUX (GST_PAD_PARENT (pad));
  GstFlvPad *cpad = (GstFlvPad *) gst_pad_get_element_private (pad);

  if (cpad && cpad->audio_codec_data)
    gst_buffer_unref (cpad->audio_codec_data);
  if (cpad && cpad->video_codec_data)
    gst_buffer_unref (cpad->video_codec_data);

  gst_collect_pads_remove_pad (mux->collect, pad);
  gst_element_remove_pad (element, pad);
}

static GstFlowReturn
gst_flv_mux_push (GstFlvMux * mux, GstBuffer * buffer)
{
  mux->byte_count += GST_BUFFER_SIZE (buffer);

  if (GST_BUFFER_TIMESTAMP_IS_VALID (buffer)) {
    GstFlvMuxIndexEntry *entry = g_slice_new (GstFlvMuxIndexEntry);
    entry->position = mux->byte_count;
    entry->time =
        gst_guint64_to_gdouble (GST_BUFFER_TIMESTAMP (buffer)) / GST_SECOND;
    mux->index = g_list_prepend (mux->index, entry);
  }

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

static GstFlowReturn
gst_flv_mux_write_metadata (GstFlvMux * mux)
{
  const GstTagList *tags;
  GstFlowReturn ret = GST_FLOW_OK;
  GstBuffer *script_tag, *tmp;
  guint8 *data;
  gint i, n_tags, tags_written = 0;
  GstClockTime duration = GST_CLOCK_TIME_NONE;

  tags = gst_tag_setter_get_tag_list (GST_TAG_SETTER (mux));

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

  script_tag = gst_buffer_new_and_alloc (11);
  data = GST_BUFFER_DATA (script_tag);

  data[0] = 18;

  /* Data size, unknown for now */
  data[1] = 0;
  data[2] = 0;
  data[3] = 0;

  /* Timestamp */
  data[4] = data[5] = data[6] = data[7] = 0;

  /* Stream ID */
  data[8] = data[9] = data[10] = 0;

  tmp = gst_buffer_new_and_alloc (13);
  data = GST_BUFFER_DATA (tmp);
  data[0] = 2;                  /* string */
  data[1] = 0;
  data[2] = 10;                 /* length 10 */
  memcpy (&data[3], "onMetaData", 10);

  script_tag = gst_buffer_join (script_tag, tmp);

  n_tags = (tags) ? gst_structure_n_fields ((GstStructure *) tags) : 0;
  tmp = gst_buffer_new_and_alloc (5);
  data = GST_BUFFER_DATA (tmp);
  data[0] = 8;                  /* ECMA array */
  GST_WRITE_UINT32_BE (data + 1, n_tags);
  script_tag = gst_buffer_join (script_tag, tmp);

  for (i = 0; tags && i < n_tags; i++) {
    const gchar *tag_name =
        gst_structure_nth_field_name ((const GstStructure *) tags, i);
    if (!strcmp (tag_name, GST_TAG_DURATION)) {
      guint64 dur;

      if (!gst_tag_list_get_uint64 (tags, GST_TAG_DURATION, &dur))
        continue;
      duration = dur;
    } else if (!strcmp (tag_name, GST_TAG_ARTIST) ||
        !strcmp (tag_name, GST_TAG_TITLE)) {
      gchar *s;
      const gchar *t = NULL;

      if (!strcmp (tag_name, GST_TAG_ARTIST))
        t = "creator";
      else if (!strcmp (tag_name, GST_TAG_TITLE))
        t = "title";

      if (!gst_tag_list_get_string (tags, tag_name, &s))
        continue;

      tmp = gst_buffer_new_and_alloc (2 + strlen (t) + 1 + 2 + strlen (s));
      data = GST_BUFFER_DATA (tmp);
      data[0] = 0;              /* tag name length */
      data[1] = strlen (t);
      memcpy (&data[2], t, strlen (t));
      data[2 + strlen (t)] = 2; /* string */
      data[3 + strlen (t)] = (strlen (s) >> 8) & 0xff;
      data[4 + strlen (t)] = (strlen (s)) & 0xff;
      memcpy (&data[5 + strlen (t)], s, strlen (s));
      script_tag = gst_buffer_join (script_tag, tmp);

      g_free (s);
      tags_written++;
    }
  }


  if (duration == GST_CLOCK_TIME_NONE) {
    GSList *l;

    GstFormat fmt = GST_FORMAT_TIME;
    guint64 dur;

    for (l = mux->collect->data; l; l = l->next) {
      GstCollectData *cdata = l->data;

      fmt = GST_FORMAT_TIME;

      if (gst_pad_query_peer_duration (cdata->pad, &fmt, (gint64 *) & dur) &&
          fmt == GST_FORMAT_TIME && dur != GST_CLOCK_TIME_NONE) {
        if (duration == GST_CLOCK_TIME_NONE)
          duration = dur;
        else
          duration = MAX (dur, duration);
      }
    }
  }

  if (duration != GST_CLOCK_TIME_NONE) {
    gdouble d;
    d = gst_guint64_to_gdouble (duration);
    d /= (gdouble) GST_SECOND;

    tmp = gst_buffer_new_and_alloc (2 + 8 + 1 + 8);
    data = GST_BUFFER_DATA (tmp);
    data[0] = 0;                /* 8 bytes name */
    data[1] = 8;
    memcpy (&data[2], "duration", 8);
    data[10] = 0;               /* double */
    GST_WRITE_DOUBLE_BE (data + 11, d);
    script_tag = gst_buffer_join (script_tag, tmp);
    tags_written++;
  }

  if (mux->have_video) {
    GstPad *video_pad = NULL;
    GSList *l = mux->collect->data;

    for (; l; l = l->next) {
      GstFlvPad *cpad = l->data;
      if (cpad && cpad->video) {
        video_pad = cpad->collect.pad;
        break;
      }
    }

    if (video_pad && GST_PAD_CAPS (video_pad)) {
      GstStructure *s = gst_caps_get_structure (GST_PAD_CAPS (video_pad), 0);
      gint par_x, par_y;

      if (gst_structure_get_fraction (s, "pixel-aspect-ratio", &par_x, &par_y)) {
        gdouble d;

        d = par_x;
        tmp = gst_buffer_new_and_alloc (2 + 12 + 1 + 8);
        data = GST_BUFFER_DATA (tmp);
        data[0] = 0;            /* 12 bytes name */
        data[1] = 12;
        memcpy (&data[2], "AspectRatioX", 12);
        data[14] = 0;           /* double */
        GST_WRITE_DOUBLE_BE (data + 15, d);
        script_tag = gst_buffer_join (script_tag, tmp);
        tags_written++;

        d = par_y;
        tmp = gst_buffer_new_and_alloc (2 + 12 + 1 + 8);
        data = GST_BUFFER_DATA (tmp);
        data[0] = 0;            /* 12 bytes name */
        data[1] = 12;
        memcpy (&data[2], "AspectRatioY", 12);
        data[14] = 0;           /* double */
        GST_WRITE_DOUBLE_BE (data + 15, d);
        script_tag = gst_buffer_join (script_tag, tmp);
        tags_written++;
      }
    }
  }

  {
    const gchar *s = "GStreamer FLV muxer";

    tmp = gst_buffer_new_and_alloc (2 + 15 + 1 + 2 + strlen (s));
    data = GST_BUFFER_DATA (tmp);
    data[0] = 0;                /* 15 bytes name */
    data[1] = 15;
    memcpy (&data[2], "metadatacreator", 15);
    data[17] = 2;               /* string */
    data[18] = (strlen (s) >> 8) & 0xff;
    data[19] = (strlen (s)) & 0xff;
    memcpy (&data[20], s, strlen (s));
    script_tag = gst_buffer_join (script_tag, tmp);

    tags_written++;
  }

  {
    GTimeVal tv = { 0, };
    time_t secs;
    struct tm *tm;
    gchar *s;
    static const gchar *weekdays[] = {
      "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
    };
    static const gchar *months[] = {
      "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
      "Aug", "Sep", "Oct", "Nov", "Dec"
    };

    g_get_current_time (&tv);
    secs = tv.tv_sec;
    tm = gmtime (&secs);

    s = g_strdup_printf ("%s %s %d %d:%d:%d %d", weekdays[tm->tm_wday],
        months[tm->tm_mon], tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec,
        tm->tm_year + 1900);

    tmp = gst_buffer_new_and_alloc (2 + 12 + 1 + 2 + strlen (s));
    data = GST_BUFFER_DATA (tmp);
    data[0] = 0;                /* 12 bytes name */
    data[1] = 12;
    memcpy (&data[2], "creationdate", 12);
    data[14] = 2;               /* string */
    data[15] = (strlen (s) >> 8) & 0xff;
    data[16] = (strlen (s)) & 0xff;
    memcpy (&data[17], s, strlen (s));
    script_tag = gst_buffer_join (script_tag, tmp);

    g_free (s);
    tags_written++;
  }

  tmp = gst_buffer_new_and_alloc (2 + 0 + 1);
  data = GST_BUFFER_DATA (tmp);
  data[0] = 0;                  /* 0 byte size */
  data[1] = 0;
  data[2] = 9;                  /* end marker */
  script_tag = gst_buffer_join (script_tag, tmp);
  tags_written++;


  tmp = gst_buffer_new_and_alloc (4);
  data = GST_BUFFER_DATA (tmp);
  GST_WRITE_UINT32_BE (data, GST_BUFFER_SIZE (script_tag));
  script_tag = gst_buffer_join (script_tag, tmp);

  data = GST_BUFFER_DATA (script_tag);
  data[1] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 16) & 0xff;
  data[2] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 8) & 0xff;
  data[3] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 0) & 0xff;

  GST_WRITE_UINT32_BE (data + 11 + 13 + 1, tags_written);

  gst_buffer_set_caps (script_tag, GST_PAD_CAPS (mux->srcpad));
  ret = gst_flv_mux_push (mux, script_tag);

  return ret;
}

static GstFlowReturn
gst_flv_mux_write_header (GstFlvMux * mux)
{
  GstBuffer *header = gst_buffer_new_and_alloc (9 + 4);
  guint8 *data = GST_BUFFER_DATA (header);
  GstFlowReturn ret;

  if (GST_PAD_CAPS (mux->srcpad) == NULL) {
    GstCaps *caps = gst_caps_new_simple ("video/x-flv", NULL);

    gst_pad_set_caps (mux->srcpad, caps);
    gst_caps_unref (caps);
  }
  gst_buffer_set_caps (header, GST_PAD_CAPS (mux->srcpad));

  data[0] = 'F';
  data[1] = 'L';
  data[2] = 'V';
  data[3] = 0x01;               /* Version */

  data[4] = (mux->have_audio << 2) | mux->have_video;   /* flags */
  GST_WRITE_UINT32_BE (data + 5, 9);    /* data offset */

  GST_WRITE_UINT32_BE (data + 9, 0);    /* previous tag size */

  ret = gst_flv_mux_push (mux, header);
  if (ret != GST_FLOW_OK)
    return ret;

  return gst_flv_mux_write_metadata (mux);
}

static GstFlowReturn
gst_flv_mux_write_buffer (GstFlvMux * mux, GstFlvPad * cpad)
{
  GstBuffer *tag;
  guint8 *data;
  guint size;
  GstBuffer *buffer =
      gst_collect_pads_pop (mux->collect, (GstCollectData *) cpad);
  guint32 timestamp =
      (GST_BUFFER_TIMESTAMP_IS_VALID (buffer)) ? GST_BUFFER_TIMESTAMP (buffer) /
      GST_MSECOND : cpad->last_timestamp / GST_MSECOND;
  gboolean second_run = FALSE;
  GstFlowReturn ret;

next:
  size = 11;
  if (cpad->video) {
    size += 1;
    if (cpad->video_codec == 7 && !cpad->sent_codec_data)
      size += 4 + GST_BUFFER_SIZE (cpad->video_codec_data);
    else if (cpad->video_codec == 7)
      size += 4 + GST_BUFFER_SIZE (buffer);
    else
      size += GST_BUFFER_SIZE (buffer);
  } else {
    size += 1;
    if (cpad->audio_codec == 10 && !cpad->sent_codec_data)
      size += 1 + GST_BUFFER_SIZE (cpad->audio_codec_data);
    else if (cpad->audio_codec == 10)
      size += 1 + GST_BUFFER_SIZE (buffer);
    else
      size += GST_BUFFER_SIZE (buffer);
  }
  size += 4;

  tag = gst_buffer_new_and_alloc (size);
  GST_BUFFER_TIMESTAMP (tag) = timestamp * GST_MSECOND;
  data = GST_BUFFER_DATA (tag);
  memset (data, 0, size);

  data[0] = (cpad->video) ? 9 : 8;

  data[1] = ((size - 11 - 4) >> 16) & 0xff;
  data[2] = ((size - 11 - 4) >> 8) & 0xff;
  data[3] = ((size - 11 - 4) >> 0) & 0xff;

  data[4] = (timestamp >> 16) & 0xff;
  data[5] = (timestamp >> 8) & 0xff;
  data[6] = (timestamp >> 0) & 0xff;
  data[7] = (timestamp >> 24) & 0xff;

  data[8] = data[9] = data[10] = 0;

  if (cpad->video) {
    if (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DELTA_UNIT))
      data[11] |= 2 << 4;
    else
      data[11] |= 1 << 4;

    data[11] |= cpad->video_codec & 0x0f;

    if (cpad->video_codec == 7 && !cpad->sent_codec_data) {
      data[12] = 0;
      data[13] = data[14] = data[15] = 0;

      memcpy (data + 11 + 1 + 4, GST_BUFFER_DATA (cpad->video_codec_data),
          GST_BUFFER_SIZE (cpad->video_codec_data));
      second_run = TRUE;
    } else if (cpad->video_codec == 7) {
      data[12] = 1;

      /* FIXME: what to do about composition time */
      data[13] = data[14] = data[15] = 0;

      memcpy (data + 11 + 1 + 4, GST_BUFFER_DATA (buffer),
          GST_BUFFER_SIZE (buffer));
    } else {
      memcpy (data + 11 + 1, GST_BUFFER_DATA (buffer),
          GST_BUFFER_SIZE (buffer));
    }
  } else {
    data[11] |= (cpad->audio_codec << 4) & 0xf0;
    data[11] |= (cpad->rate << 2) & 0x0c;
    data[11] |= (cpad->width << 1) & 0x02;
    data[11] |= (cpad->channels << 0) & 0x01;

    if (cpad->audio_codec == 10 && !cpad->sent_codec_data) {
      data[12] = 0;

      memcpy (data + 11 + 1 + 1, GST_BUFFER_DATA (cpad->audio_codec_data),
          GST_BUFFER_SIZE (cpad->audio_codec_data));
      second_run = TRUE;
    } else if (cpad->audio_codec == 10) {
      data[12] = 1;

      memcpy (data + 11 + 1 + 1, GST_BUFFER_DATA (buffer),
          GST_BUFFER_SIZE (buffer));
    } else {
      memcpy (data + 11 + 1, GST_BUFFER_DATA (buffer),
          GST_BUFFER_SIZE (buffer));
    }
  }

  GST_WRITE_UINT32_BE (data + size - 4, size - 4);

  gst_buffer_set_caps (tag, GST_PAD_CAPS (mux->srcpad));

  if (second_run) {
    second_run = FALSE;
    cpad->sent_codec_data = TRUE;

    ret = gst_flv_mux_push (mux, tag);
    if (ret != GST_FLOW_OK) {
      gst_buffer_unref (buffer);
      return ret;
    }

    cpad->last_timestamp = timestamp;

    tag = NULL;
    goto next;
  }

  gst_buffer_copy_metadata (tag, buffer, GST_BUFFER_COPY_TIMESTAMPS);
  GST_BUFFER_OFFSET (tag) = GST_BUFFER_OFFSET_END (tag) =
      GST_BUFFER_OFFSET_NONE;

  gst_buffer_unref (buffer);

  ret = gst_flv_mux_push (mux, tag);

  if (ret == GST_FLOW_OK)
    cpad->last_timestamp = timestamp;

  return ret;
}

static GstFlowReturn
gst_flv_mux_write_index (GstFlvMux * mux)
{
  GstFlowReturn ret = GST_FLOW_OK;
  GstBuffer *script_tag, *tmp;
  guint8 *data;
  GList *l;
  guint32 index_len;
  guint32 i, index_skip;

  if (!mux->index)
    return GST_FLOW_OK;

  script_tag = gst_buffer_new_and_alloc (11);
  data = GST_BUFFER_DATA (script_tag);

  data[0] = 18;

  /* Data size, unknown for now */
  data[1] = 0;
  data[2] = 0;
  data[3] = 0;

  /* Timestamp */
  data[4] = data[5] = data[6] = data[7] = 0;

  /* Stream ID */
  data[8] = data[9] = data[10] = 0;

  tmp = gst_buffer_new_and_alloc (13);
  data = GST_BUFFER_DATA (tmp);
  data[0] = 2;                  /* string */
  data[1] = 0;
  data[2] = 0x0a;               /* length 10 */
  memcpy (&data[3], "onMetaData", 10);

  script_tag = gst_buffer_join (script_tag, tmp);

  tmp = gst_buffer_new_and_alloc (5);
  data = GST_BUFFER_DATA (tmp);
  data[0] = 8;                  /* ECMA array */
  GST_WRITE_UINT32_BE (data + 1, 2);
  script_tag = gst_buffer_join (script_tag, tmp);

  mux->index = g_list_reverse (mux->index);
  index_len = g_list_length (mux->index);

  /* We write at most 128 elements */
  index_skip = (index_len > 128) ? 1 + index_len / 128 : 1;
  index_len =
      (index_len <=
      128) ? index_len : (index_len + index_skip - 1) / index_skip;

  tmp = gst_buffer_new_and_alloc (2 + 5 + 1 + 4 + index_len * (1 + 8));
  data = GST_BUFFER_DATA (tmp);
  data[0] = 0;                  /* 5 bytes name */
  data[1] = 5;
  memcpy (&data[2], "times", 5);
  data[7] = 10;                 /* array */
  GST_WRITE_UINT32_BE (&data[8], index_len);
  data += 12;

  for (i = 0, l = mux->index; l; l = l->next, i++) {
    GstFlvMuxIndexEntry *entry = l->data;

    if (i % index_skip != 0)
      continue;

    data[0] = 0;
    GST_WRITE_DOUBLE_BE (&data[1], entry->time);
    data += 9;
  }
  script_tag = gst_buffer_join (script_tag, tmp);

  tmp = gst_buffer_new_and_alloc (2 + 13 + 1 + 4 + index_len * (1 + 8));
  data = GST_BUFFER_DATA (tmp);
  data[0] = 0;                  /* 13 bytes name */
  data[1] = 13;
  memcpy (&data[2], "filepositions", 13);
  data[15] = 10;                /* array */
  GST_WRITE_UINT32_BE (&data[16], index_len);
  data += 20;

  for (i = 0, l = mux->index; l; l = l->next, i++) {
    GstFlvMuxIndexEntry *entry = l->data;

    if (i % index_skip != 0)
      continue;
    data[0] = 0;
    GST_WRITE_DOUBLE_BE (&data[1], entry->position);
    data += 9;
  }
  script_tag = gst_buffer_join (script_tag, tmp);

  tmp = gst_buffer_new_and_alloc (3);
  data = GST_BUFFER_DATA (tmp);
  GST_WRITE_UINT24_BE (data, 9);        /* finish the ECMA array */
  script_tag = gst_buffer_join (script_tag, tmp);

  tmp = gst_buffer_new_and_alloc (4);
  data = GST_BUFFER_DATA (tmp);
  GST_WRITE_UINT32_BE (data, GST_BUFFER_SIZE (script_tag));
  script_tag = gst_buffer_join (script_tag, tmp);

  data = GST_BUFFER_DATA (script_tag);
  data[1] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 16) & 0xff;
  data[2] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 8) & 0xff;
  data[3] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 0) & 0xff;

  gst_buffer_set_caps (script_tag, GST_PAD_CAPS (mux->srcpad));
  ret = gst_flv_mux_push (mux, script_tag);

  return ret;
}

static GstFlowReturn
gst_flv_mux_collected (GstCollectPads * pads, gpointer user_data)
{
  GstFlvMux *mux = GST_FLV_MUX (user_data);
  GstFlvPad *best;
  GstClockTime best_time;
  GstFlowReturn ret;
  GSList *sl;
  gboolean eos = TRUE;

  if (mux->state == GST_FLV_MUX_STATE_HEADER) {
    if (mux->collect->data == NULL) {
      GST_ELEMENT_ERROR (mux, STREAM, MUX, (NULL),
          ("No input streams configured"));
      return GST_FLOW_ERROR;
    }

    if (gst_pad_push_event (mux->srcpad,
            gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_BYTES, 0, -1, 0)))
      ret = gst_flv_mux_write_header (mux);
    else
      ret = GST_FLOW_ERROR;

    if (ret != GST_FLOW_OK)
      return ret;
    mux->state = GST_FLV_MUX_STATE_DATA;
  }

  best = NULL;
  best_time = GST_CLOCK_TIME_NONE;
  for (sl = mux->collect->data; sl; sl = sl->next) {
    GstFlvPad *cpad = sl->data;
    GstBuffer *buffer = gst_collect_pads_peek (pads, (GstCollectData *) cpad);
    GstClockTime time;

    if (!buffer)
      continue;

    eos = FALSE;

    time = GST_BUFFER_TIMESTAMP (buffer);
    gst_buffer_unref (buffer);

    /* Use buffers without valid timestamp first */
    if (!GST_CLOCK_TIME_IS_VALID (time)) {
      GST_WARNING_OBJECT (pads, "Buffer without valid timestamp");

      best_time = cpad->last_timestamp;
      best = cpad;
      break;
    }


    if (best == NULL || (GST_CLOCK_TIME_IS_VALID (best_time)
            && time < best_time)) {
      best = cpad;
      best_time = time;
    }
  }

  if (GST_CLOCK_TIME_IS_VALID (best_time)
      && best_time / GST_MSECOND > G_MAXUINT32) {
    GST_WARNING_OBJECT (mux, "Timestamp larger than FLV supports - EOS");
    eos = TRUE;
  }

  if (!eos && best) {
    return gst_flv_mux_write_buffer (mux, best);
  } else if (eos) {
    gst_flv_mux_write_index (mux);
    gst_pad_push_event (mux->srcpad, gst_event_new_eos ());
    return GST_FLOW_UNEXPECTED;
  } else {
    return GST_FLOW_OK;
  }
}

static GstStateChangeReturn
gst_flv_mux_change_state (GstElement * element, GstStateChange transition)
{
  GstStateChangeReturn ret;
  GstFlvMux *mux = GST_FLV_MUX (element);

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      gst_collect_pads_start (mux->collect);
      break;
    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
      break;
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      gst_collect_pads_stop (mux->collect);
      break;
    default:
      break;
  }

  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_flv_mux_reset (GST_ELEMENT (mux));
      break;
    case GST_STATE_CHANGE_READY_TO_NULL:
      break;
    default:
      break;
  }

  return ret;
}