gstreamer/gst/avi/gstavimux.c

/* AVI muxer plugin for GStreamer
 * Copyright (C) 2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
 *           (C) 2006 Mark Nauwelaerts <manauw@skynet.be>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/* based on:
 * - the old avimuxer (by Wim Taymans)
 * - xawtv's aviwriter (by Gerd Knorr)
 * - mjpegtools' avilib (by Rainer Johanni)
 * - openDML large-AVI docs
 */

/**
 * SECTION:element-avimux
 *
 * <refsect2>
 * <para>
 * Muxes raw or compressed audio and/or video streams into an AVI file.
 * </para>
 * <title>Example launch line</title>
 * <para>
 * (write everything in one line, without the backslash characters)
 * <programlisting>
 * gst-launch-0.10 videotestsrc num-buffers=250 \
 * ! 'video/x-raw-yuv,format=(fourcc)I420,width=320,height=240,framerate=(fraction)25/1' \
 * ! queue ! mux. \
 * audiotestsrc num-buffers=440 ! audioconvert \
 * ! 'audio/x-raw-int,rate=44100,channels=2' ! queue ! mux. \
 * avimux name=mux ! filesink location=test.avi
 * </programlisting>
 * This will create an .AVI file containing an uncompressed video stream
 * with a test picture and an uncompressed audio stream containing a 
 * test sound.
 * </para>
 * <title>Another example launch line</title>
 * <para>
 * (write everything in one line, without the backslash characters)
 * <programlisting>
 * gst-launch-0.10 videotestsrc num-buffers=250 \
 * ! 'video/x-raw-yuv,format=(fourcc)I420,width=320,height=240,framerate=(fraction)25/1' \
 * ! xvidenc ! queue ! mux. \
 * audiotestsrc num-buffers=440 ! audioconvert ! 'audio/x-raw-int,rate=44100,channels=2' \
 * ! lame ! queue ! mux. \
 * avimux name=mux ! filesink location=test.avi
 * </programlisting>
 * This will create an .AVI file containing the same test video and sound
 * as above, only that both streams will be compressed this time. This will
 * only work if you have the necessary encoder elements installed of course.
 * </para>
 * </refsect2>
 *
 */

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

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

#include <gst/video/video.h>

#include "gstavimux.h"

GST_DEBUG_CATEGORY_STATIC (avimux_debug);
#define GST_CAT_DEFAULT avimux_debug

enum
{
  ARG_0,
  ARG_BIGFILE
};

#define DEFAULT_BIGFILE TRUE

static const GstElementDetails gst_avi_mux_details =
GST_ELEMENT_DETAILS ("Avi muxer",
    "Codec/Muxer",
    "Muxes audio and video into an avi stream",
    "Ronald Bultje <rbultje@ronald.bitfreak.net>");

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

static GstStaticPadTemplate video_sink_factory =
    GST_STATIC_PAD_TEMPLATE ("video_%d",
    GST_PAD_SINK,
    GST_PAD_REQUEST,
    GST_STATIC_CAPS ("video/x-raw-yuv, "
        "format = (fourcc) { YUY2, I420 }, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ]; "
        "image/jpeg, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ]; "
        "video/x-divx, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ], "
        "divxversion = (int) [ 3, 5 ]; "
        "video/x-xvid, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ]; "
        "video/x-3ivx, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ]; "
        "video/x-msmpeg, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ], "
        "msmpegversion = (int) [ 41, 43 ]; "
        "video/mpeg, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ], "
        "mpegversion = (int) { 1, 2, 4}, "
        "systemstream = (boolean) FALSE; "
        "video/x-h263, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ]; "
        "video/x-h264, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "framerate = (fraction) [ 0, MAX ]; "
        "video/x-dv, "
        "width = (int) 720, "
        "height = (int) { 576, 480 }, "
        "framerate = (fraction) [ 0, MAX ], "
        "systemstream = (boolean) FALSE; "
        "video/x-huffyuv, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], " "framerate = (fraction) [ 0, MAX ]")
    );

static GstStaticPadTemplate audio_sink_factory =
    GST_STATIC_PAD_TEMPLATE ("audio_%d",
    GST_PAD_SINK,
    GST_PAD_REQUEST,
    GST_STATIC_CAPS ("audio/x-raw-int, "
        "endianness = (int) LITTLE_ENDIAN, "
        "signed = (boolean) { TRUE, FALSE }, "
        "width = (int) { 8, 16 }, "
        "depth = (int) { 8, 16 }, "
        "rate = (int) [ 1000, 96000 ], "
        "channels = (int) [ 1, 2 ]; "
        "audio/mpeg, "
        "mpegversion = (int) 1, "
        "layer = (int) [ 1, 3 ], "
        "rate = (int) [ 1000, 96000 ], " "channels = (int) [ 1, 2 ]; "
        "audio/mpeg, "
        "mpegversion = (int) 4, "
        "rate = (int) [ 1000, 96000 ], " "channels = (int) [ 1, 2 ]; "
/*#if 0 VC6 doesn't support #if here ...
        "audio/x-vorbis, "
        "rate = (int) [ 1000, 96000 ], " "channels = (int) [ 1, 2 ]; "
#endif*/
        "audio/x-ac3, "
        "rate = (int) [ 1000, 96000 ], " "channels = (int) [ 1, 2 ]")
    );


static void gst_avi_mux_base_init (gpointer g_class);
static void gst_avi_mux_class_init (GstAviMuxClass * klass);
static void gst_avi_mux_init (GstAviMux * avimux);
static void gst_avi_mux_pad_reset (GstAviPad * avipad, gboolean free);

static GstFlowReturn gst_avi_mux_collect_pads (GstCollectPads * pads,
    GstAviMux * avimux);
static gboolean gst_avi_mux_handle_event (GstPad * pad, GstEvent * event);
static GstPad *gst_avi_mux_request_new_pad (GstElement * element,
    GstPadTemplate * templ, const gchar * name);
static void gst_avi_mux_release_pad (GstElement * element, GstPad * pad);
static void gst_avi_mux_set_property (GObject * object,
    guint prop_id, const GValue * value, GParamSpec * pspec);
static void gst_avi_mux_get_property (GObject * object,
    guint prop_id, GValue * value, GParamSpec * pspec);
static GstStateChangeReturn gst_avi_mux_change_state (GstElement * element,
    GstStateChange transition);

static GstElementClass *parent_class = NULL;

GType
gst_avi_mux_get_type (void)
{
  static GType avimux_type = 0;

  if (!avimux_type) {
    static const GTypeInfo avimux_info = {
      sizeof (GstAviMuxClass),
      gst_avi_mux_base_init,
      NULL,
      (GClassInitFunc) gst_avi_mux_class_init,
      NULL,
      NULL,
      sizeof (GstAviMux),
      0,
      (GInstanceInitFunc) gst_avi_mux_init,
    };
    static const GInterfaceInfo tag_setter_info = {
      NULL,
      NULL,
      NULL
    };

    avimux_type =
        g_type_register_static (GST_TYPE_ELEMENT, "GstAviMux", &avimux_info, 0);
    g_type_add_interface_static (avimux_type, GST_TYPE_TAG_SETTER,
        &tag_setter_info);
  }
  return avimux_type;
}

static void
gst_avi_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 (&src_factory));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&audio_sink_factory));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&video_sink_factory));

  gst_element_class_set_details (element_class, &gst_avi_mux_details);

  GST_DEBUG_CATEGORY_INIT (avimux_debug, "avimux", 0, "Muxer for AVI streams");
}

static void
gst_avi_mux_finalize (GObject * object)
{
  GstAviMux *mux = GST_AVI_MUX (object);
  GSList *node;

  /* completely free each sinkpad */
  node = mux->sinkpads;
  while (node) {
    GstAviPad *avipad = (GstAviPad *) node->data;

    node = node->next;

    gst_avi_mux_pad_reset (avipad, TRUE);
    g_free (avipad);
  }
  g_slist_free (mux->sinkpads);
  mux->sinkpads = NULL;

  g_free (mux->idx);
  mux->idx = NULL;

  gst_object_unref (mux->collect);

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

static void
gst_avi_mux_class_init (GstAviMuxClass * 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->get_property = gst_avi_mux_get_property;
  gobject_class->set_property = gst_avi_mux_set_property;
  gobject_class->finalize = gst_avi_mux_finalize;

  g_object_class_install_property (gobject_class, ARG_BIGFILE,
      g_param_spec_boolean ("bigfile", "Bigfile Support (>2GB)",
          "Support for openDML-2.0 (big) AVI files", DEFAULT_BIGFILE,
          G_PARAM_READWRITE));

  gstelement_class->request_new_pad =
      GST_DEBUG_FUNCPTR (gst_avi_mux_request_new_pad);
  gstelement_class->release_pad = GST_DEBUG_FUNCPTR (gst_avi_mux_release_pad);
  gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_avi_mux_change_state);
}

/* reset pad to initial state
 * free - if true, release all, not only stream related, data */
static void
gst_avi_mux_pad_reset (GstAviPad * avipad, gboolean free)
{
  /* generic part */
  memset (&(avipad->hdr), 0, sizeof (gst_riff_strh));
  avipad->hdr.rate = 1;
  avipad->hdr.quality = 0xFFFFFFFF;

  memset (&(avipad->idx[0]), 0, sizeof (avipad->idx));

  if (free) {
    g_free (avipad->tag);
    avipad->tag = NULL;
    g_free (avipad->idx_tag);
    avipad->idx_tag = NULL;
  }

  if (avipad->is_video) {
    GstAviVideoPad *vidpad = (GstAviVideoPad *) avipad;

    if (vidpad->vids_codec_data) {
      gst_buffer_unref (vidpad->vids_codec_data);
      vidpad->vids_codec_data = NULL;
    }

    memset (&(vidpad->vids), 0, sizeof (gst_riff_strf_vids));
  } else {
    GstAviAudioPad *audpad = (GstAviAudioPad *) avipad;

    if (audpad->auds_codec_data) {
      gst_buffer_unref (audpad->auds_codec_data);
      audpad->auds_codec_data = NULL;
    }

    memset (&(audpad->auds), 0, sizeof (gst_riff_strf_auds));
  }
}

static void
gst_avi_mux_reset (GstAviMux * avimux)
{
  GSList *node, *newlist = NULL;

  /* free and reset each sinkpad */
  node = avimux->sinkpads;
  while (node) {
    GstAviPad *avipad = (GstAviPad *) node->data;

    node = node->next;

    gst_avi_mux_pad_reset (avipad, FALSE);
    /* if this pad has collectdata, keep it, otherwise dump it completely */
    if (avipad->collect)
      newlist = g_slist_append (newlist, avipad);
    else {
      gst_avi_mux_pad_reset (avipad, TRUE);
      g_free (avipad);
    }
  }

  /* free the old list of sinkpads, only keep the real collecting ones */
  g_slist_free (avimux->sinkpads);
  avimux->sinkpads = newlist;

  /* avi data */
  avimux->num_frames = 0;
  memset (&(avimux->avi_hdr), 0, sizeof (gst_riff_avih));
  avimux->avi_hdr.max_bps = 10000000;
  avimux->codec_data_size = 0;

  if (avimux->tags) {
    gst_tag_list_free (avimux->tags);
    avimux->tags = NULL;
  }
  if (avimux->tags_snap) {
    gst_tag_list_free (avimux->tags_snap);
    avimux->tags_snap = NULL;
  }

  g_free (avimux->idx);
  avimux->idx = NULL;

  /* state info */
  avimux->write_header = TRUE;
}

static void
gst_avi_mux_init (GstAviMux * avimux)
{
  avimux->srcpad = gst_pad_new_from_static_template (&src_factory, "src");
  gst_pad_use_fixed_caps (avimux->srcpad);
  gst_element_add_pad (GST_ELEMENT (avimux), avimux->srcpad);

  /* property */
  avimux->enable_large_avi = DEFAULT_BIGFILE;

  avimux->collect = gst_collect_pads_new ();
  gst_collect_pads_set_function (avimux->collect,
      (GstCollectPadsFunction) (GST_DEBUG_FUNCPTR (gst_avi_mux_collect_pads)),
      avimux);

  /* set to clean state */
  gst_avi_mux_reset (avimux);
}

static gboolean
gst_avi_mux_vidsink_set_caps (GstPad * pad, GstCaps * vscaps)
{
  GstAviMux *avimux;
  GstAviVideoPad *avipad;
  GstAviCollectData *collect_pad;
  GstStructure *structure;
  const gchar *mimetype;
  const GValue *fps;
  const GValue *codec_data;
  gint width, height;

  avimux = GST_AVI_MUX (gst_pad_get_parent (pad));

  /* find stream data */
  collect_pad = (GstAviCollectData *) gst_pad_get_element_private (pad);
  g_assert (collect_pad);
  avipad = (GstAviVideoPad *) collect_pad->avipad;
  g_assert (avipad);
  g_assert (avipad->parent.is_video);
  g_assert (avipad->parent.hdr.type == GST_MAKE_FOURCC ('v', 'i', 'd', 's'));

  GST_DEBUG_OBJECT (avimux, "%s:%s, caps=%" GST_PTR_FORMAT,
      GST_DEBUG_PAD_NAME (pad), vscaps);

  structure = gst_caps_get_structure (vscaps, 0);
  mimetype = gst_structure_get_name (structure);

  /* global */
  avipad->vids.size = sizeof (gst_riff_strf_vids);
  avipad->vids.planes = 1;
  if (!gst_structure_get_int (structure, "width", &width) ||
      !gst_structure_get_int (structure, "height", &height)) {
    goto refuse_caps;
  }

  avipad->vids.width = width;
  avipad->vids.height = height;

  fps = gst_structure_get_value (structure, "framerate");
  if (fps == NULL || !GST_VALUE_HOLDS_FRACTION (fps))
    goto refuse_caps;

  avipad->parent.hdr.rate = gst_value_get_fraction_numerator (fps);
  avipad->parent.hdr.scale = gst_value_get_fraction_denominator (fps);

  /* codec initialization data, if any */
  codec_data = gst_structure_get_value (structure, "codec_data");
  if (codec_data) {
    avipad->vids_codec_data = gst_value_get_buffer (codec_data);
    gst_buffer_ref (avipad->vids_codec_data);
    /* keep global track of size */
    avimux->codec_data_size += GST_BUFFER_SIZE (avipad->vids_codec_data);
  }

  if (!strcmp (mimetype, "video/x-raw-yuv")) {
    guint32 format;

    gst_structure_get_fourcc (structure, "format", &format);
    avipad->vids.compression = format;
    switch (format) {
      case GST_MAKE_FOURCC ('Y', 'U', 'Y', '2'):
        avipad->vids.bit_cnt = 16;
        break;
      case GST_MAKE_FOURCC ('I', '4', '2', '0'):
        avipad->vids.bit_cnt = 12;
        break;
    }
  } else {
    avipad->vids.bit_cnt = 24;
    avipad->vids.compression = 0;

    /* find format */
    if (!strcmp (mimetype, "video/x-huffyuv")) {
      avipad->vids.compression = GST_MAKE_FOURCC ('H', 'F', 'Y', 'U');
    } else if (!strcmp (mimetype, "image/jpeg")) {
      avipad->vids.compression = GST_MAKE_FOURCC ('M', 'J', 'P', 'G');
    } else if (!strcmp (mimetype, "video/x-divx")) {
      gint divxversion;

      gst_structure_get_int (structure, "divxversion", &divxversion);
      switch (divxversion) {
        case 3:
          avipad->vids.compression = GST_MAKE_FOURCC ('D', 'I', 'V', '3');
          break;
        case 4:
          avipad->vids.compression = GST_MAKE_FOURCC ('D', 'I', 'V', 'X');
          break;
        case 5:
          avipad->vids.compression = GST_MAKE_FOURCC ('D', 'X', '5', '0');
          break;
      }
    } else if (!strcmp (mimetype, "video/x-xvid")) {
      avipad->vids.compression = GST_MAKE_FOURCC ('X', 'V', 'I', 'D');
    } else if (!strcmp (mimetype, "video/x-3ivx")) {
      avipad->vids.compression = GST_MAKE_FOURCC ('3', 'I', 'V', '2');
    } else if (gst_structure_has_name (structure, "video/x-msmpeg")) {
      gint msmpegversion;

      gst_structure_get_int (structure, "msmpegversion", &msmpegversion);
      switch (msmpegversion) {
        case 41:
          avipad->vids.compression = GST_MAKE_FOURCC ('M', 'P', 'G', '4');
          break;
        case 42:
          avipad->vids.compression = GST_MAKE_FOURCC ('M', 'P', '4', '2');
          break;
        case 43:
          avipad->vids.compression = GST_MAKE_FOURCC ('M', 'P', '4', '3');
          break;
        default:
          GST_INFO ("unhandled msmpegversion : %d, fall back to fourcc=MPEG",
              msmpegversion);
          avipad->vids.compression = GST_MAKE_FOURCC ('M', 'P', 'E', 'G');
          break;
      }
    } else if (!strcmp (mimetype, "video/x-dv")) {
      avipad->vids.compression = GST_MAKE_FOURCC ('D', 'V', 'S', 'D');
    } else if (!strcmp (mimetype, "video/x-h263")) {
      avipad->vids.compression = GST_MAKE_FOURCC ('H', '2', '6', '3');
    } else if (!strcmp (mimetype, "video/x-h264")) {
      avipad->vids.compression = GST_MAKE_FOURCC ('H', '2', '6', '4');
    } else if (!strcmp (mimetype, "video/mpeg")) {
      gint mpegversion;

      gst_structure_get_int (structure, "mpegversion", &mpegversion);

      switch (mpegversion) {
        case 2:
          avipad->vids.compression = GST_MAKE_FOURCC ('M', 'P', 'G', '2');
          break;
        case 4:
          /* mplayer/ffmpeg might not work with DIVX, but with FMP4 */
          avipad->vids.compression = GST_MAKE_FOURCC ('D', 'I', 'V', 'X');
          break;
        default:
          GST_INFO ("unhandled mpegversion : %d, fall back to fourcc=MPEG",
              mpegversion);
          avipad->vids.compression = GST_MAKE_FOURCC ('M', 'P', 'E', 'G');
          break;
      }
    }

    if (!avipad->vids.compression)
      goto refuse_caps;
  }

  avipad->parent.hdr.fcc_handler = avipad->vids.compression;
  avipad->vids.image_size = avipad->vids.height * avipad->vids.width;
  /* hm, maybe why avi only handles one stream well ... */
  avimux->avi_hdr.width = avipad->vids.width;
  avimux->avi_hdr.height = avipad->vids.height;
  avimux->avi_hdr.us_frame = 1000000. * avipad->parent.hdr.scale /
      avipad->parent.hdr.rate;

  gst_object_unref (avimux);
  return TRUE;

refuse_caps:
  {
    GST_WARNING_OBJECT (avimux, "refused caps %" GST_PTR_FORMAT, vscaps);
    gst_object_unref (avimux);
    return FALSE;
  }
}

static gboolean
gst_avi_mux_audsink_set_caps (GstPad * pad, GstCaps * vscaps)
{
  GstAviMux *avimux;
  GstAviAudioPad *avipad;
  GstAviCollectData *collect_pad;
  GstStructure *structure;
  const gchar *mimetype;
  const GValue *codec_data;
  gint channels, rate;

  avimux = GST_AVI_MUX (gst_pad_get_parent (pad));

  /* find stream data */
  collect_pad = (GstAviCollectData *) gst_pad_get_element_private (pad);
  g_assert (collect_pad);
  avipad = (GstAviAudioPad *) collect_pad->avipad;
  g_assert (avipad);
  g_assert (!avipad->parent.is_video);
  g_assert (avipad->parent.hdr.type == GST_MAKE_FOURCC ('a', 'u', 'd', 's'));

  GST_DEBUG_OBJECT (avimux, "%s:%s, caps=%" GST_PTR_FORMAT,
      GST_DEBUG_PAD_NAME (pad), vscaps);

  structure = gst_caps_get_structure (vscaps, 0);
  mimetype = gst_structure_get_name (structure);

  /* we want these for all */
  if (!gst_structure_get_int (structure, "channels", &channels) ||
      !gst_structure_get_int (structure, "rate", &rate)) {
    goto refuse_caps;
  }

  avipad->auds.channels = channels;
  avipad->auds.rate = rate;

  /* codec initialization data, if any */
  codec_data = gst_structure_get_value (structure, "codec_data");
  if (codec_data) {
    avipad->auds_codec_data = gst_value_get_buffer (codec_data);
    gst_buffer_ref (avipad->auds_codec_data);
    /* keep global track of size */
    avimux->codec_data_size += GST_BUFFER_SIZE (avipad->auds_codec_data);
  }

  if (!strcmp (mimetype, "audio/x-raw-int")) {
    gint width, depth;

    avipad->auds.format = GST_RIFF_WAVE_FORMAT_PCM;

    if (!gst_structure_get_int (structure, "width", &width) ||
        (width != 8 && !gst_structure_get_int (structure, "depth", &depth))) {
      goto refuse_caps;
    }

    avipad->auds.blockalign = width;
    avipad->auds.size = (width == 8) ? 8 : depth;

    /* set some more info straight */
    avipad->auds.blockalign /= 8;
    avipad->auds.blockalign *= avipad->auds.channels;
    avipad->auds.av_bps = avipad->auds.blockalign * avipad->auds.rate;
  } else if (!strcmp (mimetype, "audio/mpeg") ||
      !strcmp (mimetype, "audio/x-vorbis") ||
      !strcmp (mimetype, "audio/x-ac3")) {
    avipad->auds.format = 0;

    if (!strcmp (mimetype, "audio/mpeg")) {
      gint mpegversion;

      gst_structure_get_int (structure, "mpegversion", &mpegversion);
      switch (mpegversion) {
        case 1:{
          gint layer = 3;

          gst_structure_get_int (structure, "layer", &layer);
          switch (layer) {
            case 3:
              avipad->auds.format = GST_RIFF_WAVE_FORMAT_MPEGL3;
              break;
            case 1:
            case 2:
              avipad->auds.format = GST_RIFF_WAVE_FORMAT_MPEGL12;
              break;
          }
          break;
        }
        case 4:
          GST_WARNING ("AAC");
          avipad->auds.format = GST_RIFF_WAVE_FORMAT_AAC;
          break;
      }
    } else if (!strcmp (mimetype, "audio/x-vorbis")) {
      avipad->auds.format = GST_RIFF_WAVE_FORMAT_VORBIS3;
    } else if (!strcmp (mimetype, "audio/x-ac3")) {
      avipad->auds.format = GST_RIFF_WAVE_FORMAT_A52;
    }

    avipad->auds.blockalign = 1;
    avipad->auds.av_bps = 0;
    avipad->auds.size = 16;

    if (!avipad->auds.format)
      goto refuse_caps;
  }

  avipad->parent.hdr.rate = avipad->auds.blockalign * avipad->auds.rate;
  avipad->parent.hdr.samplesize = avipad->auds.blockalign;
  avipad->parent.hdr.scale = 1;

  gst_object_unref (avimux);
  return TRUE;

refuse_caps:
  {
    GST_WARNING_OBJECT (avimux, "refused caps %" GST_PTR_FORMAT, vscaps);
    gst_object_unref (avimux);
    return FALSE;
  }
}


static GstPad *
gst_avi_mux_request_new_pad (GstElement * element,
    GstPadTemplate * templ, const gchar * req_name)
{
  GstAviMux *avimux;
  GstPad *newpad;
  GstAviPad *avipad;
  GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);

  g_return_val_if_fail (templ != NULL, NULL);

  if (templ->direction != GST_PAD_SINK) {
    g_warning ("avimux: request pad that is not a SINK pad\n");
    return NULL;
  }

  g_return_val_if_fail (GST_IS_AVI_MUX (element), NULL);

  avimux = GST_AVI_MUX (element);

  if (!avimux->write_header) {
    g_warning ("avimux: request pad cannot be added after streaming started\n");
    return NULL;
  }

  if (templ == gst_element_class_get_pad_template (klass, "audio_%d")) {
    gchar *name;

    /* setup pad */
    name = g_strdup_printf ("audio_%02d", avimux->audio_pads);
    newpad = gst_pad_new_from_template (templ, name);
    g_free (name);
    gst_pad_set_setcaps_function (newpad,
        GST_DEBUG_FUNCPTR (gst_avi_mux_audsink_set_caps));

    /* init pad specific data */
    avipad = g_malloc0 (sizeof (GstAviAudioPad));
    avipad->is_video = FALSE;
    avipad->hdr.type = GST_MAKE_FOURCC ('a', 'u', 'd', 's');
    avimux->audio_pads++;
    /* audio goes last */
    avimux->sinkpads = g_slist_append (avimux->sinkpads, avipad);
  } else if (templ == gst_element_class_get_pad_template (klass, "video_%d")) {
    /* though streams are pretty generic and relatively self-contained,
     * some video info goes in a single avi header -and therefore mux struct-
     * so video restricted to one stream */
    if (avimux->video_pads > 0)
      return NULL;
    /* setup pad */
    newpad = gst_pad_new_from_template (templ, "video_00");
    gst_pad_set_setcaps_function (newpad,
        GST_DEBUG_FUNCPTR (gst_avi_mux_vidsink_set_caps));
    avipad = g_malloc0 (sizeof (GstAviVideoPad));

    /* init pad specific data */
    avipad->is_video = TRUE;
    avipad->hdr.type = GST_MAKE_FOURCC ('v', 'i', 'd', 's');
    avimux->video_pads++;
    /* video goes first */
    avimux->sinkpads = g_slist_prepend (avimux->sinkpads, avipad);
  } else {
    g_warning ("avimux: this is not our template!\n");
    return NULL;
  }

  avipad->collect = gst_collect_pads_add_pad (avimux->collect,
      newpad, sizeof (GstAviCollectData));
  ((GstAviCollectData *) (avipad->collect))->avipad = avipad;
  /* 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 */
  avimux->collect_event = (GstPadEventFunction) GST_PAD_EVENTFUNC (newpad);
  gst_pad_set_event_function (newpad,
      GST_DEBUG_FUNCPTR (gst_avi_mux_handle_event));

  gst_element_add_pad (element, newpad);

  return newpad;
}

static void
gst_avi_mux_release_pad (GstElement * element, GstPad * pad)
{
  GstAviMux *avimux = GST_AVI_MUX (element);
  GSList *node;

  node = avimux->sinkpads;
  while (node) {
    GstAviPad *avipad = (GstAviPad *) node->data;

    if (avipad->collect->pad == pad) {
      /* pad count should not be adjusted,
       * as it also represent number of streams present */
      avipad->collect = NULL;
      GST_DEBUG_OBJECT (avimux, "removed pad '%s'", GST_PAD_NAME (pad));
      gst_collect_pads_remove_pad (avimux->collect, pad);
      gst_element_remove_pad (element, pad);
      /* if not started yet, we can remove any sign this pad ever existed */
      /* in this case _start will take care of the real pad count */
      if (avimux->write_header) {
        avimux->sinkpads = g_slist_remove (avimux->sinkpads, avipad);
        gst_avi_mux_pad_reset (avipad, TRUE);
        g_free (avipad);
      }
      return;
    }

    node = node->next;
  }

  g_warning ("Unknown pad %s", GST_PAD_NAME (pad));
}

/* maybe some of these functions should be moved to riff.h? */

/* DISCLAIMER: this function is fairly ugly. So be it (i.e. it makes the rest easier)
 * so is this struct */

typedef struct _GstMarkedBuffer
{
  guint *highmark;
  GstBuffer *buffer;
} GstMarkedBuffer;

static void
gst_avi_mux_write_tag (const GstTagList * list, const gchar * tag,
    gpointer data)
{
  const struct
  {
    guint32 fcc;
    gchar *tag;
  } rifftags[] = {
    {
    GST_RIFF_INFO_ICMT, GST_TAG_COMMENT}, {
    GST_RIFF_INFO_INAM, GST_TAG_TITLE}, {
    GST_RIFF_INFO_ISFT, GST_TAG_ENCODER}, {
    GST_RIFF_INFO_IGNR, GST_TAG_GENRE}, {
    GST_RIFF_INFO_ICOP, GST_TAG_COPYRIGHT}, {
    GST_RIFF_INFO_IART, GST_TAG_ARTIST}, {
    GST_RIFF_INFO_IARL, GST_TAG_LOCATION}, {
    0, NULL}
  };
  gint n, len, plen;
  GstBuffer *buf = ((GstMarkedBuffer *) data)->buffer;
  guint *highmark = ((GstMarkedBuffer *) data)->highmark;
  guint8 *buffdata = GST_BUFFER_DATA (buf) + *highmark;
  gchar *str;

  for (n = 0; rifftags[n].fcc != 0; n++) {
    if (!strcmp (rifftags[n].tag, tag) &&
        gst_tag_list_get_string (list, tag, &str)) {
      len = strlen (str);
      plen = len + 1;
      if (plen & 1)
        plen++;
      if (GST_BUFFER_SIZE (buf) >= *highmark + 8 + plen) {
        GST_WRITE_UINT32_LE (buffdata, rifftags[n].fcc);
        GST_WRITE_UINT32_LE (buffdata + 4, len + 1);
        memcpy (buffdata + 8, str, len);
        buffdata[8 + len] = 0;
        *highmark += 8 + plen;
        GST_DEBUG ("writing tag in buffer %p, highmark at %d", buf, *highmark);
      }
      g_free (str);
      break;
    }
  }
}

#define ODML_SUPERINDEX_SIZE    \
    (32 + GST_AVI_SUPERINDEX_COUNT * sizeof (gst_avi_superindex_entry))

static GstBuffer *
gst_avi_mux_riff_get_avi_header (GstAviMux * avimux)
{
  GstTagList *tags;
  const GstTagList *iface_tags;
  GstBuffer *buffer;
  guint8 *buffdata;
  guint size = 0;
  guint highmark = 0;

  /* pointer to list size field */
  guint8 *riff_size, *hdrl_size;
  GSList *node;

  GST_DEBUG_OBJECT (avimux, "creating avi header, data_size %u, idx_size %u",
      avimux->data_size, avimux->idx_size);

  /* need to take snapshot of tags now */
  iface_tags = gst_tag_setter_get_tag_list (GST_TAG_SETTER (avimux));
  if ((iface_tags || avimux->tags) && !avimux->tags_snap) {
    if (iface_tags && avimux->tags) {
      tags = gst_tag_list_merge (iface_tags, avimux->tags,
          GST_TAG_MERGE_APPEND);
    } else if (iface_tags) {
      tags = gst_tag_list_copy (iface_tags);
    } else {
      tags = gst_tag_list_copy (avimux->tags);
    }
    gst_tag_list_add (tags, GST_TAG_MERGE_REPLACE, GST_TAG_ENCODER,
        PACKAGE_STRING " AVI muxer", NULL);
  } else {
    tags = avimux->tags_snap;
  }
  avimux->tags_snap = tags;
  if (avimux->tags_snap)
    size += 1024;

  /* allocate the buffer, starting with some wild/safe upper bound */
  size += avimux->codec_data_size + 100 + sizeof (gst_riff_avih)
      + (g_slist_length (avimux->sinkpads) * (100 + sizeof (gst_riff_strh)
          + sizeof (gst_riff_strf_vids)
          + sizeof (gst_riff_strf_auds)
          + ODML_SUPERINDEX_SIZE));
  buffer = gst_buffer_new_and_alloc (size);
  buffdata = GST_BUFFER_DATA (buffer);
  highmark = 0;
  GST_DEBUG_OBJECT (avimux, "creating buffer %p, size %d, highmark at 0",
      buffer, GST_BUFFER_SIZE (buffer));

  /* avi header metadata */
  memcpy (buffdata + 0, "RIFF", 4);
  /* fill in RIFF size later */
  riff_size = buffdata + 4;
  memcpy (buffdata + 8, "AVI ", 4);
  memcpy (buffdata + 12, "LIST", 4);
  /* fill in header size later */
  hdrl_size = buffdata + 16;
  memcpy (buffdata + 20, "hdrl", 4);
  memcpy (buffdata + 24, "avih", 4);
  GST_WRITE_UINT32_LE (buffdata + 28, sizeof (gst_riff_avih));
  buffdata += 32;
  highmark += 32;

  /* the AVI header itself */
  GST_WRITE_UINT32_LE (buffdata + 0, avimux->avi_hdr.us_frame);
  GST_WRITE_UINT32_LE (buffdata + 4, avimux->avi_hdr.max_bps);
  GST_WRITE_UINT32_LE (buffdata + 8, avimux->avi_hdr.pad_gran);
  GST_WRITE_UINT32_LE (buffdata + 12, avimux->avi_hdr.flags);
  GST_WRITE_UINT32_LE (buffdata + 16, avimux->avi_hdr.tot_frames);
  GST_WRITE_UINT32_LE (buffdata + 20, avimux->avi_hdr.init_frames);
  GST_WRITE_UINT32_LE (buffdata + 24, avimux->avi_hdr.streams);
  GST_WRITE_UINT32_LE (buffdata + 28, avimux->avi_hdr.bufsize);
  GST_WRITE_UINT32_LE (buffdata + 32, avimux->avi_hdr.width);
  GST_WRITE_UINT32_LE (buffdata + 36, avimux->avi_hdr.height);
  GST_WRITE_UINT32_LE (buffdata + 40, avimux->avi_hdr.scale);
  GST_WRITE_UINT32_LE (buffdata + 44, avimux->avi_hdr.rate);
  GST_WRITE_UINT32_LE (buffdata + 48, avimux->avi_hdr.start);
  GST_WRITE_UINT32_LE (buffdata + 52, avimux->avi_hdr.length);
  buffdata += 56;
  highmark += 56;

  /* stream data */
  node = avimux->sinkpads;
  while (node) {
    GstAviPad *avipad = (GstAviPad *) node->data;
    GstAviVideoPad *vidpad = (GstAviVideoPad *) avipad;
    GstAviAudioPad *audpad = (GstAviAudioPad *) avipad;
    guint codec_size = 0, strl_size = 0;

    if (avipad->is_video) {
      if (vidpad->vids_codec_data)
        codec_size = GST_BUFFER_SIZE (vidpad->vids_codec_data);
      strl_size = sizeof (gst_riff_strh) + sizeof (gst_riff_strf_vids)
          + codec_size + 4 * 5 + ODML_SUPERINDEX_SIZE;
    } else {
      if (audpad->auds_codec_data)
        codec_size = GST_BUFFER_SIZE (audpad->auds_codec_data);
      strl_size = sizeof (gst_riff_strh) + sizeof (gst_riff_strf_auds)
          + codec_size + 4 * 5 + ODML_SUPERINDEX_SIZE;
    }

    /* stream list metadata */
    memcpy (buffdata + 0, "LIST", 4);
    GST_WRITE_UINT32_LE (buffdata + 4, strl_size);
    memcpy (buffdata + 8, "strl", 4);
    /* generic header */
    memcpy (buffdata + 12, "strh", 4);
    GST_WRITE_UINT32_LE (buffdata + 16, sizeof (gst_riff_strh));
    /* the actual header */
    GST_WRITE_UINT32_LE (buffdata + 20, avipad->hdr.type);
    GST_WRITE_UINT32_LE (buffdata + 24, avipad->hdr.fcc_handler);
    GST_WRITE_UINT32_LE (buffdata + 28, avipad->hdr.flags);
    GST_WRITE_UINT32_LE (buffdata + 32, avipad->hdr.priority);
    GST_WRITE_UINT32_LE (buffdata + 36, avipad->hdr.init_frames);
    GST_WRITE_UINT32_LE (buffdata + 40, avipad->hdr.scale);
    GST_WRITE_UINT32_LE (buffdata + 44, avipad->hdr.rate);
    GST_WRITE_UINT32_LE (buffdata + 48, avipad->hdr.start);
    GST_WRITE_UINT32_LE (buffdata + 52, avipad->hdr.length);
    GST_WRITE_UINT32_LE (buffdata + 56, avipad->hdr.bufsize);
    GST_WRITE_UINT32_LE (buffdata + 60, avipad->hdr.quality);
    GST_WRITE_UINT32_LE (buffdata + 64, avipad->hdr.samplesize);

    if (avipad->is_video) {
      /* the video header */
      memcpy (buffdata + 68, "strf", 4);
      GST_WRITE_UINT32_LE (buffdata + 72,
          sizeof (gst_riff_strf_vids) + codec_size);
      /* the actual header */
      GST_WRITE_UINT32_LE (buffdata + 76, vidpad->vids.size + codec_size);
      GST_WRITE_UINT32_LE (buffdata + 80, vidpad->vids.width);
      GST_WRITE_UINT32_LE (buffdata + 84, vidpad->vids.height);
      GST_WRITE_UINT16_LE (buffdata + 88, vidpad->vids.planes);
      GST_WRITE_UINT16_LE (buffdata + 90, vidpad->vids.bit_cnt);
      GST_WRITE_UINT32_LE (buffdata + 92, vidpad->vids.compression);
      GST_WRITE_UINT32_LE (buffdata + 96, vidpad->vids.image_size);
      GST_WRITE_UINT32_LE (buffdata + 100, vidpad->vids.xpels_meter);
      GST_WRITE_UINT32_LE (buffdata + 104, vidpad->vids.ypels_meter);
      GST_WRITE_UINT32_LE (buffdata + 108, vidpad->vids.num_colors);
      GST_WRITE_UINT32_LE (buffdata + 112, vidpad->vids.imp_colors);
      buffdata += 116;
      highmark += 116;

      /* include codec data, if any */
      if (codec_size) {
        memcpy (buffdata, GST_BUFFER_DATA (vidpad->vids_codec_data),
            codec_size);

        buffdata += codec_size;
        highmark += codec_size;
      }
    } else {
      /* the audio header */
      memcpy (buffdata + 68, "strf", 4);
      GST_WRITE_UINT32_LE (buffdata + 72,
          sizeof (gst_riff_strf_auds) + codec_size);
      /* the actual header */
      GST_WRITE_UINT16_LE (buffdata + 76, audpad->auds.format);
      GST_WRITE_UINT16_LE (buffdata + 78, audpad->auds.channels);
      GST_WRITE_UINT32_LE (buffdata + 80, audpad->auds.rate);
      GST_WRITE_UINT32_LE (buffdata + 84, audpad->auds.av_bps);
      GST_WRITE_UINT16_LE (buffdata + 88, audpad->auds.blockalign);
      GST_WRITE_UINT16_LE (buffdata + 90, audpad->auds.size);
      buffdata += 92;
      highmark += 92;

      /* include codec data, if any */
      if (codec_size) {
        memcpy (buffdata, GST_BUFFER_DATA (audpad->auds_codec_data),
            codec_size);

        buffdata += codec_size;
        highmark += codec_size;
      }
    }

    /* odml superindex chunk */
    if (avipad->idx_index > 0)
      memcpy (buffdata, "indx", 4);
    else
      memcpy (buffdata, "JUNK", 4);
    GST_WRITE_UINT32_LE (buffdata + 4, ODML_SUPERINDEX_SIZE - 8);       /* chunk size */
    GST_WRITE_UINT16_LE (buffdata + 8, 4);      /* bytes per entry */
    buffdata[10] = 0;           /* index subtype */
    buffdata[11] = GST_AVI_INDEX_OF_INDEXES;    /* index type */
    GST_WRITE_UINT32_LE (buffdata + 12, avipad->idx_index);     /* entries in use */
    memcpy (buffdata + 16, avipad->tag, 4);     /* stream id */
    GST_WRITE_UINT32_LE (buffdata + 20, 0);     /* reserved */
    GST_WRITE_UINT32_LE (buffdata + 24, 0);     /* reserved */
    GST_WRITE_UINT32_LE (buffdata + 28, 0);     /* reserved */
    memcpy (buffdata + 32, avipad->idx,
        GST_AVI_SUPERINDEX_COUNT * sizeof (gst_avi_superindex_entry));
    buffdata += ODML_SUPERINDEX_SIZE;
    highmark += ODML_SUPERINDEX_SIZE;

    node = node->next;
  }

  if (avimux->video_pads > 0) {
    /* odml header */
    memcpy (buffdata + 0, "LIST", 4);
    GST_WRITE_UINT32_LE (buffdata + 4, sizeof (guint32) + 4 * 3);
    memcpy (buffdata + 8, "odml", 4);
    memcpy (buffdata + 12, "dmlh", 4);
    GST_WRITE_UINT32_LE (buffdata + 16, sizeof (guint32));
    GST_WRITE_UINT32_LE (buffdata + 20, avimux->total_frames);
    buffdata += 24;
    highmark += 24;
  }

  GST_WRITE_UINT32_LE (hdrl_size, (guint32) (buffdata - hdrl_size) - 4);

  /* tags */
  if (tags) {
    guint8 *ptr;
    guint startsize;
    GstMarkedBuffer data = { &highmark, buffer };

    memcpy (buffdata + 0, "LIST", 4);
    ptr = buffdata + 4;         /* fill in later */
    startsize = highmark + 4;
    memcpy (buffdata + 8, "INFO", 4);
    buffdata += 12;
    highmark += 12;

    /* 12 bytes is needed for data header */
    GST_BUFFER_SIZE (buffer) -= 12;
    gst_tag_list_foreach (tags, gst_avi_mux_write_tag, &data);
    /* do not free tags here, as it refers to the tag snapshot */
    GST_BUFFER_SIZE (buffer) += 12;
    buffdata = GST_BUFFER_DATA (buffer) + highmark;

    /* update list size */
    GST_WRITE_UINT32_LE (ptr, highmark - startsize - 4);
  }

  /* avi data header */
  memcpy (buffdata + 0, "LIST", 4);
  GST_WRITE_UINT32_LE (buffdata + 4, avimux->data_size);
  memcpy (buffdata + 8, "movi", 4);
  buffdata += 12;
  highmark += 12;

  /* finally we can fill in the RIFF size */
  /* note that riff only counts the first avi chunk */
  GST_WRITE_UINT32_LE (riff_size, (guint32) (buffdata - riff_size - 4)  /* header and movi tags */
      +avimux->idx_size + avimux->data_size - 4);       /* movi data and index */

  {                             /* only the part that is filled in actually makes up the header
                                 *  unref the parent as we only need this part from now on */
    GstBuffer *subbuffer = gst_buffer_create_sub (buffer, 0, highmark);

    gst_buffer_unref (buffer);
    return subbuffer;
  }
}

static GstBuffer *
gst_avi_mux_riff_get_avix_header (guint32 datax_size)
{
  GstBuffer *buffer;
  guint8 *buffdata;

  buffer = gst_buffer_new_and_alloc (24);
  buffdata = GST_BUFFER_DATA (buffer);

  memcpy (buffdata + 0, "RIFF", 4);
  GST_WRITE_UINT32_LE (buffdata + 4, datax_size + 3 * 4);
  memcpy (buffdata + 8, "AVIX", 4);
  memcpy (buffdata + 12, "LIST", 4);
  GST_WRITE_UINT32_LE (buffdata + 16, datax_size);
  memcpy (buffdata + 20, "movi", 4);

  return buffer;
}

static inline GstBuffer *
gst_avi_mux_riff_get_header (GstAviPad * avipad, guint32 video_frame_size)
{
  GstBuffer *buffer;
  guint8 *buffdata;

  buffer = gst_buffer_new_and_alloc (8);
  buffdata = GST_BUFFER_DATA (buffer);
  memcpy (buffdata + 0, avipad->tag, 4);
  GST_WRITE_UINT32_LE (buffdata + 4, video_frame_size);

  return buffer;
}

/* write an odml index chunk in the movi list */
static GstFlowReturn
gst_avi_mux_write_avix_index (GstAviMux * avimux, gchar * code,
    gchar * chunk, gst_avi_superindex_entry * super_index,
    gint * super_index_count)
{
  GstFlowReturn res;
  GstBuffer *buffer;
  guint8 *buffdata, *data;
  gst_riff_index_entry *entry;
  gint i;
  guint32 size, entry_count;

  /* allocate the maximum possible */
  buffer = gst_buffer_new_and_alloc (32 + 8 * avimux->idx_index);
  buffdata = GST_BUFFER_DATA (buffer);

  /* general index chunk info */
  memcpy (buffdata + 0, chunk, 4);      /* chunk id */
  GST_WRITE_UINT32_LE (buffdata + 4, 0);        /* chunk size; fill later */
  GST_WRITE_UINT16_LE (buffdata + 8, 2);        /* index entry is 2 words */
  buffdata[10] = 0;             /* index subtype */
  buffdata[11] = GST_AVI_INDEX_OF_CHUNKS;       /* index type: AVI_INDEX_OF_CHUNKS */
  GST_WRITE_UINT32_LE (buffdata + 12, 0);       /* entries in use; fill later */
  memcpy (buffdata + 16, code, 4);      /* stream to which index refers */
  GST_WRITE_UINT64_LE (buffdata + 20, avimux->avix_start);      /* base offset */
  GST_WRITE_UINT32_LE (buffdata + 28, 0);       /* reserved */
  buffdata += 32;

  /* now the actual index entries */
  i = avimux->idx_index;
  entry = avimux->idx;
  while (i > 0) {
    if (memcmp (&entry->id, code, 4) == 0) {
      /* enter relative offset to the data (!) */
      GST_WRITE_UINT32_LE (buffdata, GUINT32_FROM_LE (entry->offset) + 8);
      /* msb is set if not (!) keyframe */
      GST_WRITE_UINT32_LE (buffdata + 4, GUINT32_FROM_LE (entry->size)
          | (GUINT32_FROM_LE (entry->flags)
              & GST_RIFF_IF_KEYFRAME ? 0 : 1U << 31));
      buffdata += 8;
    }
    i--;
    entry++;
  }

  /* ok, now we know the size and no of entries, fill in where needed */
  data = GST_BUFFER_DATA (buffer);
  GST_BUFFER_SIZE (buffer) = size = buffdata - data;
  GST_WRITE_UINT32_LE (data + 4, size - 8);
  entry_count = (size - 32) / 8;
  GST_WRITE_UINT32_LE (data + 12, entry_count);

  /* decorate and send */
  gst_buffer_set_caps (buffer, GST_PAD_CAPS (avimux->srcpad));
  if ((res = gst_pad_push (avimux->srcpad, buffer)) != GST_FLOW_OK)
    return res;

  /* keep track of this in superindex (if room) ... */
  if (*super_index_count < GST_AVI_SUPERINDEX_COUNT) {
    i = *super_index_count;
    super_index[i].offset = GUINT64_TO_LE (avimux->total_data);
    super_index[i].size = GUINT32_TO_LE (size);
    super_index[i].duration = GUINT32_TO_LE (entry_count);
    (*super_index_count)++;
  } else
    GST_WARNING_OBJECT (avimux, "No more room in superindex of stream %s",
        code);

  /* ... and in size */
  avimux->total_data += size;
  if (avimux->is_bigfile)
    avimux->datax_size += size;
  else
    avimux->data_size += size;

  return GST_FLOW_OK;
}

/* some other usable functions (thankyou xawtv ;-) ) */

static void
gst_avi_mux_add_index (GstAviMux * avimux, gchar * code, guint32 flags,
    guint32 size)
{
  if (avimux->idx_index == avimux->idx_count) {
    avimux->idx_count += 256;
    avimux->idx =
        g_realloc (avimux->idx,
        avimux->idx_count * sizeof (gst_riff_index_entry));
  }
  memcpy (&(avimux->idx[avimux->idx_index].id), code, 4);
  avimux->idx[avimux->idx_index].flags = GUINT32_TO_LE (flags);
  avimux->idx[avimux->idx_index].offset = GUINT32_TO_LE (avimux->idx_offset);
  avimux->idx[avimux->idx_index].size = GUINT32_TO_LE (size);
  avimux->idx_index++;
}

static GstFlowReturn
gst_avi_mux_write_index (GstAviMux * avimux)
{
  GstFlowReturn res;
  GstBuffer *buffer;
  guint8 *buffdata;

  buffer = gst_buffer_new_and_alloc (8);
  buffdata = GST_BUFFER_DATA (buffer);
  memcpy (buffdata + 0, "idx1", 4);
  GST_WRITE_UINT32_LE (buffdata + 4,
      avimux->idx_index * sizeof (gst_riff_index_entry));

  gst_buffer_set_caps (buffer, GST_PAD_CAPS (avimux->srcpad));
  res = gst_pad_push (avimux->srcpad, buffer);
  if (res != GST_FLOW_OK)
    return res;

  buffer = gst_buffer_new ();
  GST_BUFFER_SIZE (buffer) = avimux->idx_index * sizeof (gst_riff_index_entry);
  GST_BUFFER_DATA (buffer) = (guint8 *) avimux->idx;
  GST_BUFFER_MALLOCDATA (buffer) = GST_BUFFER_DATA (buffer);
  avimux->idx = NULL;           /* will be free()'ed by gst_buffer_unref() */
  avimux->total_data += GST_BUFFER_SIZE (buffer) + 8;

  gst_buffer_set_caps (buffer, GST_PAD_CAPS (avimux->srcpad));
  res = gst_pad_push (avimux->srcpad, buffer);
  if (res != GST_FLOW_OK)
    return res;

  avimux->idx_size += avimux->idx_index * sizeof (gst_riff_index_entry) + 8;

  /* update header */
  avimux->avi_hdr.flags |= GST_RIFF_AVIH_HASINDEX;
  return GST_FLOW_OK;
}

static GstFlowReturn
gst_avi_mux_bigfile (GstAviMux * avimux, gboolean last)
{
  GstFlowReturn res = GST_FLOW_OK;
  GstBuffer *header;
  GstEvent *event;
  GSList *node;

  /* first some odml standard index chunks in the movi list */
  node = avimux->sinkpads;
  while (node) {
    GstAviPad *avipad = (GstAviPad *) node->data;

    node = node->next;

    res = gst_avi_mux_write_avix_index (avimux, avipad->tag,
        avipad->idx_tag, avipad->idx, &avipad->idx_index);
    if (res != GST_FLOW_OK)
      return res;
  }

  if (avimux->is_bigfile) {
    /* search back */
    event = gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_BYTES,
        avimux->avix_start, GST_CLOCK_TIME_NONE, avimux->avix_start);
    /* if the event succeeds */
    gst_pad_push_event (avimux->srcpad, event);

    /* rewrite AVIX header */
    header = gst_avi_mux_riff_get_avix_header (avimux->datax_size);
    gst_buffer_set_caps (header, GST_PAD_CAPS (avimux->srcpad));
    res = gst_pad_push (avimux->srcpad, header);

    /* go back to current location, at least try */
    event = gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_BYTES,
        avimux->total_data, GST_CLOCK_TIME_NONE, avimux->total_data);
    gst_pad_push_event (avimux->srcpad, event);

    if (res != GST_FLOW_OK)
      return res;
  } else {                      /* write a standard index in the first riff chunk */
    res = gst_avi_mux_write_index (avimux);
    /* the index data/buffer is freed by pushing it */
    avimux->idx_count = 0;
    if (res != GST_FLOW_OK)
      return res;
  }

  avimux->avix_start = avimux->total_data;

  if (last)
    return res;

  avimux->is_bigfile = TRUE;
  avimux->numx_frames = 0;
  avimux->datax_size = 4;       /* movi tag */
  avimux->idx_index = 0;

  header = gst_avi_mux_riff_get_avix_header (0);
  avimux->total_data += GST_BUFFER_SIZE (header);
  /* avix_start is used as base offset for the odml index chunk */
  avimux->idx_offset = avimux->total_data - avimux->avix_start;
  gst_buffer_set_caps (header, GST_PAD_CAPS (avimux->srcpad));
  return gst_pad_push (avimux->srcpad, header);
}

/* enough header blabla now, let's go on to actually writing the headers */

static GstFlowReturn
gst_avi_mux_start_file (GstAviMux * avimux)
{
  GstFlowReturn res;
  GstBuffer *header;
  GSList *node;

  avimux->total_data = 0;
  avimux->total_frames = 0;
  avimux->data_size = 4;        /* movi tag */
  avimux->datax_size = 0;
  avimux->num_frames = 0;
  avimux->numx_frames = 0;
  avimux->avix_start = 0;

  avimux->idx_index = 0;
  avimux->idx_offset = 0;       /* see 10 lines below */
  avimux->idx_size = 0;
  avimux->idx_count = 0;
  avimux->idx = NULL;

  /* state */
  avimux->write_header = FALSE;
  avimux->restart = FALSE;

  /* init streams, see what we've got */
  node = avimux->sinkpads;
  avimux->audio_pads = avimux->video_pads = 0;
  while (node) {
    GstAviPad *avipad = (GstAviPad *) node->data;

    node = node->next;

    if (!avipad->is_video) {
      avipad->tag = g_strdup_printf ("%02uwb", avimux->audio_pads);
      avipad->idx_tag = g_strdup_printf ("ix%02u", avimux->audio_pads++);
    } else {
      avipad->tag = g_strdup_printf ("%02udb", avimux->video_pads);
      avipad->idx_tag = g_strdup_printf ("ix%02u", avimux->video_pads++);
    }
  }

  /* header */
  avimux->avi_hdr.streams = g_slist_length (avimux->sinkpads);
  avimux->is_bigfile = FALSE;

  header = gst_avi_mux_riff_get_avi_header (avimux);
  avimux->total_data += GST_BUFFER_SIZE (header);

  gst_buffer_set_caps (header, GST_PAD_CAPS (avimux->srcpad));
  res = gst_pad_push (avimux->srcpad, header);

  avimux->idx_offset = avimux->total_data;

  return res;
}

static GstFlowReturn
gst_avi_mux_stop_file (GstAviMux * avimux)
{
  GstFlowReturn res = GST_FLOW_OK;
  GstEvent *event;
  GstBuffer *header;
  GSList *node;

  /* if bigfile, rewrite header, else write indexes */
  /* don't bail out at once if error, still try to re-write header */
  if (avimux->video_pads > 0) {
    if (avimux->is_bigfile) {
      res = gst_avi_mux_bigfile (avimux, TRUE);
    } else {
      res = gst_avi_mux_write_index (avimux);
    }
  }

  /* we do our best to make it interleaved at least ... */
  if (avimux->audio_pads > 0 && avimux->video_pads > 0)
    avimux->avi_hdr.flags |= GST_RIFF_AVIH_ISINTERLEAVED;

  /* set rate and everything having to do with that */
  avimux->avi_hdr.max_bps = 0;
  node = avimux->sinkpads;
  while (node) {
    GstAviPad *avipad = (GstAviPad *) node->data;

    node = node->next;

    if (!avipad->is_video) {
      GstAviAudioPad *audpad = (GstAviAudioPad *) avipad;

      /* calculate bps if needed */
      if (!audpad->auds.av_bps) {
        if (audpad->audio_time) {
          audpad->auds.av_bps =
              (GST_SECOND * audpad->audio_size) / audpad->audio_time;
          /* round bps to nearest multiple of 8;
           * which is much more likely to be the (cbr) bitrate in use;
           * which in turn results in better timestamp calculation on playback */
          audpad->auds.av_bps = GST_ROUND_UP_8 (audpad->auds.av_bps - 4);
        } else {
          GST_ELEMENT_WARNING (avimux, STREAM, MUX,
              (_("No or invalid input audio, AVI stream will be corrupt.")),
              (NULL));
          audpad->auds.av_bps = 0;
        }
        avipad->hdr.rate = audpad->auds.av_bps * avipad->hdr.scale;
      }
      avimux->avi_hdr.max_bps += audpad->auds.av_bps;
      avipad->hdr.length = (audpad->audio_time * avipad->hdr.rate) / GST_SECOND;
    } else {
      GstAviVideoPad *vidpad = (GstAviVideoPad *) avipad;

      avimux->avi_hdr.max_bps += ((vidpad->vids.bit_cnt + 7) / 8) *
          (1000000. / avimux->avi_hdr.us_frame) * vidpad->vids.image_size;
      avipad->hdr.length = avimux->total_frames;
    }
  }

  /* statistics/total_frames/... */
  avimux->avi_hdr.tot_frames = avimux->num_frames;

  /* seek and rewrite the header */
  header = gst_avi_mux_riff_get_avi_header (avimux);
  event = gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_BYTES,
      0, GST_CLOCK_TIME_NONE, 0);
  gst_pad_push_event (avimux->srcpad, event);

  gst_buffer_set_caps (header, GST_PAD_CAPS (avimux->srcpad));
  /* the first error survives */
  if (res == GST_FLOW_OK)
    res = gst_pad_push (avimux->srcpad, header);
  else
    gst_pad_push (avimux->srcpad, header);

  event = gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_BYTES,
      avimux->total_data, GST_CLOCK_TIME_NONE, avimux->total_data);
  gst_pad_push_event (avimux->srcpad, event);

  avimux->write_header = TRUE;

  return res;
}

static GstFlowReturn
gst_avi_mux_restart_file (GstAviMux * avimux)
{
  GstFlowReturn res;

  if ((res = gst_avi_mux_stop_file (avimux)) != GST_FLOW_OK)
    return res;

  gst_pad_push_event (avimux->srcpad, gst_event_new_eos ());

  return gst_avi_mux_start_file (avimux);
}

/* handle events (search) */
static gboolean
gst_avi_mux_handle_event (GstPad * pad, GstEvent * event)
{
  GstAviMux *avimux;
  GstTagList *list;
  gboolean ret;

  avimux = GST_AVI_MUX (gst_pad_get_parent (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_TAG:
      gst_event_parse_tag (event, &list);
      if (avimux->tags) {
        gst_tag_list_insert (avimux->tags, list, GST_TAG_MERGE_PREPEND);
      } else {
        avimux->tags = gst_tag_list_copy (list);
      }
      break;
    default:
      break;
  }

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

  gst_object_unref (avimux);

  return ret;
}

/* send extra 'padding' data */
static GstFlowReturn
gst_avi_mux_send_pad_data (GstAviMux * avimux, gulong num_bytes)
{
  GstBuffer *buffer;

  buffer = gst_buffer_new_and_alloc (num_bytes);
  memset (GST_BUFFER_DATA (buffer), 0, num_bytes);
  gst_buffer_set_caps (buffer, GST_PAD_CAPS (avimux->srcpad));
  return gst_pad_push (avimux->srcpad, buffer);
}

/* do buffer */
static GstFlowReturn
gst_avi_mux_do_buffer (GstAviMux * avimux, GstAviPad * avipad)
{
  GstFlowReturn res;
  GstBuffer *data, *header;
  gulong total_size, pad_bytes = 0;
  guint flags;

  data = gst_collect_pads_pop (avimux->collect, avipad->collect);

  if (avimux->restart) {
    if ((res = gst_avi_mux_restart_file (avimux)) != GST_FLOW_OK)
      return res;
  }

  /* need to restart or start a next avix chunk ? */
  if ((avimux->is_bigfile ? avimux->datax_size : avimux->data_size) +
      GST_BUFFER_SIZE (data) > 1024 * 1024 * 2000) {
    if (avimux->enable_large_avi) {
      if ((res = gst_avi_mux_bigfile (avimux, FALSE)) != GST_FLOW_OK)
        return res;
    } else {
      if ((res = gst_avi_mux_restart_file (avimux)) != GST_FLOW_OK)
        return res;
    }
  }

  /* get header and record some stats */
  if (GST_BUFFER_SIZE (data) & 1) {
    pad_bytes = 2 - (GST_BUFFER_SIZE (data) & 1);
  }
  header = gst_avi_mux_riff_get_header (avipad, GST_BUFFER_SIZE (data));
  total_size = GST_BUFFER_SIZE (header) + GST_BUFFER_SIZE (data) + pad_bytes;

  if (avimux->is_bigfile) {
    avimux->datax_size += total_size;
  } else {
    avimux->data_size += total_size;
  }

  if (avipad->is_video) {
    avimux->total_frames++;

    if (avimux->is_bigfile) {
      avimux->numx_frames++;
    } else {
      avimux->num_frames++;
    }

    flags = 0x02;
    if (!GST_BUFFER_FLAG_IS_SET (data, GST_BUFFER_FLAG_DELTA_UNIT))
      flags |= 0x10;
  } else {
    GstAviAudioPad *audpad = (GstAviAudioPad *) avipad;

    flags = 0;
    audpad->audio_size += GST_BUFFER_SIZE (data);
    audpad->audio_time += GST_BUFFER_DURATION (data);
  }

  gst_avi_mux_add_index (avimux, avipad->tag, flags, GST_BUFFER_SIZE (data));

  /* prepare buffers for sending */
  gst_buffer_set_caps (header, GST_PAD_CAPS (avimux->srcpad));
  data = gst_buffer_make_metadata_writable (data);
  gst_buffer_set_caps (data, GST_PAD_CAPS (avimux->srcpad));

  GST_DEBUG ("pushing buffers: head, data");

  if ((res = gst_pad_push (avimux->srcpad, header)) != GST_FLOW_OK)
    return res;
  if ((res = gst_pad_push (avimux->srcpad, data)) != GST_FLOW_OK)
    return res;

  if (pad_bytes) {
    if ((res = gst_avi_mux_send_pad_data (avimux, pad_bytes)) != GST_FLOW_OK)
      return res;
  }

  /* if any push above fails, we're in trouble with file consistency anyway */
  avimux->total_data += total_size;
  avimux->idx_offset += total_size;

  return res;
}

/* pick the oldest buffer from the pads and push it */
static GstFlowReturn
gst_avi_mux_do_one_buffer (GstAviMux * avimux)
{
  GstAviPad *avipad, *best_pad;
  GSList *node;
  GstBuffer *buffer;
  GstClockTime time, best_time;

  node = avimux->sinkpads;
  best_pad = NULL;
  best_time = GST_CLOCK_TIME_NONE;
  for (; node; node = node->next) {
    avipad = (GstAviPad *) node->data;

    if (!avipad->collect)
      continue;

    buffer = gst_collect_pads_peek (avimux->collect, avipad->collect);
    if (!buffer)
      continue;
    time = GST_BUFFER_TIMESTAMP (buffer);
    gst_buffer_unref (buffer);

    /* invalid timestamp buffers pass first,
     * these are probably initialization buffers */
    if (best_pad == NULL || !GST_CLOCK_TIME_IS_VALID (time)
        || (GST_CLOCK_TIME_IS_VALID (best_time) && time < best_time)) {
      best_pad = avipad;
      best_time = time;
    }
  }

  if (best_pad) {
    GST_DEBUG_OBJECT (avimux, "selected pad %s with time %" GST_TIME_FORMAT,
        GST_PAD_NAME (best_pad->collect->pad), GST_TIME_ARGS (best_time));

    return gst_avi_mux_do_buffer (avimux, best_pad);
  } else {
    /* simply finish off the file and send EOS */
    gst_avi_mux_stop_file (avimux);
    gst_pad_push_event (avimux->srcpad, gst_event_new_eos ());
    return GST_FLOW_UNEXPECTED;
  }
}

static GstFlowReturn
gst_avi_mux_collect_pads (GstCollectPads * pads, GstAviMux * avimux)
{
  GstFlowReturn res;

  if (G_UNLIKELY (avimux->write_header)) {
    if ((res = gst_avi_mux_start_file (avimux)) != GST_FLOW_OK)
      return res;
  }

  return gst_avi_mux_do_one_buffer (avimux);
}


static void
gst_avi_mux_get_property (GObject * object,
    guint prop_id, GValue * value, GParamSpec * pspec)
{
  GstAviMux *avimux;

  avimux = GST_AVI_MUX (object);

  switch (prop_id) {
    case ARG_BIGFILE:
      g_value_set_boolean (value, avimux->enable_large_avi);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_avi_mux_set_property (GObject * object,
    guint prop_id, const GValue * value, GParamSpec * pspec)
{
  GstAviMux *avimux;

  avimux = GST_AVI_MUX (object);

  switch (prop_id) {
    case ARG_BIGFILE:
      avimux->enable_large_avi = g_value_get_boolean (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstStateChangeReturn
gst_avi_mux_change_state (GstElement * element, GstStateChange transition)
{
  GstAviMux *avimux;
  GstStateChangeReturn ret;

  avimux = GST_AVI_MUX (element);

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

  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
  if (ret == GST_STATE_CHANGE_FAILURE)
    goto done;

  switch (transition) {
    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
      break;
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      gst_avi_mux_reset (avimux);
      break;
    case GST_STATE_CHANGE_READY_TO_NULL:
      break;
    default:
      break;
  }

done:
  return ret;
}