ext/metadata/gstbasemetadata.c

/*
 * GStreamer
 * Copyright 2007 Edgard Lima <edgard.lima@indt.org.br>
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Alternatively, the contents of this file may be used under the
 * GNU Lesser General Public License Version 2.1 (the "LGPL"), in
 * which case the following provisions apply instead of the ones
 * mentioned above:
 *
 * 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: gstbasemetadata
 * @short_description: Base class for metadata handling elements
 *
 * This is a generice base class for metadata handling elements. The following
 * types of elements are supported:
 * <itemizedlist>
 *   <listitem><para>parsers (only parse data)</para></listitem>
 *   <listitem><para>demuxers (parse data and remove metadata chunks)</para>
 *   </listitem>
 *   <listitem><para>muxers</para></listitem>
 *   <listitem><para>any other kind of element that wants to handle chunks in
 *     file formats based on chunks</para></listitem>
 * </itemizedlist>
 *
 * <refsect2>
 * <para>
 * This a abstract element that parses a stream and find chunks and offset
 * where new chunks could be injected into it.
 * Basically, the only thing need by implementors (parsers, (de)muxers) is to
 * set virtual methods that will be used to setup the caps and do some
 * 'processing', which is called after the stream is completely parsed and
 * before the first buffer is sent to the next element. Usualy the 'processing'
 * function will send tags messages and event in case of parsers and demuxers,
 * and add chunks to be injected (using the helper function
 * #gst_base_metadata_update_inject_segment_with_new_data in case of muxers.
 * </para>
 * <para>
 * This can work in 'pull' and 'push' scheduling modes. In case of push mode,
 * the stream will be parsed during sink activation if #gst_pad_get_range is
 * available on upstream element. If get_range function is not available
 * upstream, then the data will be hold until the stream is completly parsed,
 * and then after that the fisrt buffer will be pushed downstream. The same
 * happens with pull mode, if the downstream element calls gst_pad_get_range
 * it will only gets data after the stream has been completely parsed.
 * </para>
 * <para>
 * Seek, and query duration will only be available after the stream has been
 * parsed. Query position will always be 0 (zero) before the stream is
 * completely parsed.
 * </para>
 * <para>
 * Currently there is implementation for JPEG and PNG (demux mode only)
 * stream types and EXIF, IPTC and XMP metadatas.
 * </para>
 * </refsect2>
 * 
 * Last reviewed on 2008-01-21 (0.10.15)
 */

/*
 * includes
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <gst/gst.h>

#include "gstbasemetadata.h"

#include "metadataxmp.h"

#include <string.h>

/*
 * enum and types
 */

enum
{
  LAST_SIGNAL
};

enum
{
  ARG_0,
  ARG_EXIF,
  ARG_IPTC,
  ARG_XMP
};

/*
 * defines and static global vars
 */

GST_DEBUG_CATEGORY_STATIC (gst_base_metadata_debug);
#define GST_CAT_DEFAULT gst_base_metadata_debug

static GstBaseMetadataClass *parent_class = NULL;

/*
 * static helper functions declaration
 */

static void gst_base_metadata_init_members (GstBaseMetadata * filter);

static void gst_base_metadata_dispose_members (GstBaseMetadata * filter);

const gchar *gst_base_metadata_get_type_name (int img_type);

static gboolean gst_base_metadata_pull_range_parse (GstBaseMetadata * filter);

static gboolean gst_base_metadata_configure_caps (GstBaseMetadata * filter);

static gboolean gst_base_metadata_processing (GstBaseMetadata * filter);

static void gst_base_metadata_reset_streaming (GstBaseMetadata * filter);

static void gst_base_metadata_reset_parsing (GstBaseMetadata * filter);

static int
gst_base_metadata_parse (GstBaseMetadata * filter, const guint8 * buf,
    guint32 size);

static gboolean
gst_base_metadata_strip_push_buffer (GstBaseMetadata * base,
    const gint64 offset_orig, GstBuffer ** prepend, GstBuffer ** buf,
    gboolean inject_begin);

static int
gst_base_metadata_buf_get_intersection_seg (const gint64 offset, guint32 size,
    const gint64 seg_offset, const guint32 seg_size,
    gint64 * boffset, guint32 * bsize);

static gboolean
gst_base_metadata_translate_pos_to_orig (GstBaseMetadata * base,
    gint64 pos, gint64 * orig_pos, GstBuffer ** buf, guint32 max_size);

static gboolean gst_base_metadata_calculate_offsets (GstBaseMetadata * base);


/*
 * GObject callback functions declaration
 */

static void gst_base_metadata_base_init (gpointer gclass);

static void gst_base_metadata_class_init (GstBaseMetadataClass * klass);

static void
gst_base_metadata_init (GstBaseMetadata * filter,
    GstBaseMetadataClass * gclass);

static void gst_base_metadata_dispose (GObject * object);

static void gst_base_metadata_finalize (GObject * object);

static void gst_base_metadata_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);

static void gst_base_metadata_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

/*
 * GStreamer callback functions declaration
 */

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

static gboolean gst_base_metadata_src_event (GstPad * pad, GstEvent * event);

static gboolean gst_base_metadata_sink_event (GstPad * pad, GstEvent * event);

static gboolean gst_base_metadata_checkgetrange (GstPad * srcpad);

static GstFlowReturn
gst_base_metadata_get_range (GstPad * pad, guint64 offset_orig, guint size,
    GstBuffer ** buf);

static GstFlowReturn gst_base_metadata_chain (GstPad * pad, GstBuffer * buf);

static gboolean gst_base_metadata_sink_activate (GstPad * pad);

static gboolean
gst_base_metadata_src_activate_pull (GstPad * pad, gboolean active);

static const GstQueryType *gst_base_metadata_get_query_types (GstPad * pad);

static gboolean gst_base_metadata_src_query (GstPad * pad, GstQuery * query);

/*
 * GST BOILERPLATE
 */

GType
gst_base_metadata_get_type (void)
{
  static GType base_metadata_type = 0;

  if (G_UNLIKELY (base_metadata_type == 0)) {
    static const GTypeInfo base_metadata_info = {
      sizeof (GstBaseMetadataClass),
      (GBaseInitFunc) gst_base_metadata_base_init,
      NULL,
      (GClassInitFunc) gst_base_metadata_class_init,
      NULL,
      NULL,
      sizeof (GstBaseMetadata),
      0,
      (GInstanceInitFunc) gst_base_metadata_init,
    };

    base_metadata_type = g_type_register_static (GST_TYPE_ELEMENT,
        "GstBaseMetadata", &base_metadata_info, G_TYPE_FLAG_ABSTRACT);
  }
  return base_metadata_type;
}

/*
 *static helper functions implementation
 */

static void
gst_base_metadata_init_members (GstBaseMetadata * filter)
{

  filter->metadata = NULL;

  filter->img_type = IMG_NONE;

  filter->duration_orig = 0;
  filter->duration = 0;

  filter->state = MT_STATE_NULL;

  filter->options = META_OPT_EXIF | META_OPT_IPTC | META_OPT_XMP;

  filter->need_processing = FALSE;

  filter->adapter_parsing = NULL;
  filter->adapter_holding = NULL;
  filter->next_offset = 0;
  filter->next_size = 0;
  filter->need_more_data = FALSE;
  filter->offset_orig = 0;
  filter->offset = 0;

  filter->append_buffer = NULL;
  filter->prepend_buffer = NULL;

}

static void
gst_base_metadata_dispose_members (GstBaseMetadata * filter)
{

  /* buffers used to build output buffer */

  if (filter->prepend_buffer) {
    gst_buffer_unref (filter->prepend_buffer);
    filter->prepend_buffer = NULL;
  }

  if (filter->append_buffer) {
    gst_buffer_unref (filter->append_buffer);
    filter->append_buffer = NULL;
  }

  /* adapter used during parsing process */

  if (filter->adapter_parsing) {
    g_object_unref (filter->adapter_parsing);
    filter->adapter_parsing = NULL;
  }

  if (filter->adapter_holding) {
    g_object_unref (filter->adapter_holding);
    filter->adapter_holding = NULL;
  }

  metadata_dispose (&filter->metadata);

}

const gchar *
gst_base_metadata_get_type_name (int img_type)
{
  const gchar *type_name = NULL;

  switch (img_type) {
    case IMG_JPEG:
      type_name = "jpeg";
      break;
    case IMG_PNG:
      type_name = "png";
      break;
    default:
      type_name = "invalid type";
      break;
  }
  return type_name;
}

static gboolean
gst_base_metadata_pull_range_parse (GstBaseMetadata * filter)
{

  int res;
  gboolean ret = TRUE;
  guint32 offset = 0;
  gint64 duration = 0;
  GstFormat format = GST_FORMAT_BYTES;

  if (!(ret =
          gst_pad_query_peer_duration (filter->sinkpad, &format, &duration))) {
    /* this should never happen, but try chain anyway */
    ret = TRUE;
    goto done;
  }
  filter->duration_orig = duration;

  if (format != GST_FORMAT_BYTES) {
    /* this should never happen, but try chain anyway */
    ret = TRUE;
    goto done;
  }

  do {
    GstFlowReturn flow;
    GstBuffer *buf = NULL;

    offset += filter->next_offset;

    /* 'filter->next_size' only says the minimum required number of bytes.
       We try provided more bytes (4096) just to avoid a lot of calls to
       'metadata_parse'
       returning META_PARSING_NEED_MORE_DATA */
    if (filter->next_size < 4096) {
      if (duration - offset < 4096) {
        /* In case there is no 4096 bytes available upstream.
           It should be done upstream but we do here for safety */
        filter->next_size = duration - offset;
      } else {
        filter->next_size = 4096;
      }
    }

    flow =
        gst_pad_pull_range (filter->sinkpad, offset, filter->next_size, &buf);
    if (GST_FLOW_OK != flow) {
      ret = FALSE;
      goto done;
    }

    res =
        gst_base_metadata_parse (filter, GST_BUFFER_DATA (buf),
        GST_BUFFER_SIZE (buf));
    if (res == META_PARSING_ERROR) {
      ret = FALSE;
      goto done;
    }

    gst_buffer_unref (buf);

  } while (res == META_PARSING_NEED_MORE_DATA);

done:

  return ret;

}

static gboolean
gst_base_metadata_configure_caps (GstBaseMetadata * filter)
{
  GstCaps *caps = NULL;
  gboolean ret = FALSE;
  const gchar *mime = NULL;
  GstPad *peer = NULL;

  peer = gst_pad_get_peer (filter->sinkpad);

  switch (filter->img_type) {
    case IMG_JPEG:
      mime = "image/jpeg";
      break;
    case IMG_PNG:
      mime = "image/png";
      break;
    default:
      goto done;
      break;
  }

  caps = gst_caps_new_simple (mime, NULL);

  if (!gst_pad_set_caps (peer, caps)) {
    goto done;
  }

  ret = gst_pad_set_caps (filter->sinkpad, caps);

done:

  if (caps) {
    gst_caps_unref (caps);
    caps = NULL;
  }

  if (peer) {
    gst_object_unref (peer);
    peer = NULL;
  }

  return ret;

}

/*
 * gst_base_metadata_processing:
 * @filter: the base metadata instance
 *
 * Do some external 'process', if not done yet, just after parse the stream
 * and before give the fisrt buffer downstream.
 * Typically here the tag message and events will be sent, in case of demuxer
 * and new chunks will be added in case of muxers.
 * @see_also: #gst_base_metadata_calculate_offsets
 *
 * Returns:
 * <itemizedlist>
 * <listitem><para>%TRUE no need futher processing, or the processing has
 * been done</para></listitem>
 * <listitem><para>%FALSE, if error. It is, need futher processing but
 * #gst_base_metadata_calculate_offsets fails</para></listitem>
 * </itemizedlist>
 *
 */

static gboolean
gst_base_metadata_processing (GstBaseMetadata * filter)
{
  gboolean ret = TRUE;
  GstBaseMetadataClass *bclass = GST_BASE_METADATA_GET_CLASS (filter);

  if (filter->need_processing) {
    bclass->processing (filter);
    if (gst_base_metadata_calculate_offsets (filter)) {
      filter->need_processing = FALSE;
    } else {
      ret = FALSE;
    }
  }

  return ret;

}

/*
 * gst_base_metadata_reset_streaming:
 * @filter: the base metadata instance
 *
 * Clean the streaming process. The parser status is not changed.
 * @see_also: #gst_base_metadata_reset_parsing
 *
 * Returns: nothing
 *
 */

static void
gst_base_metadata_reset_streaming (GstBaseMetadata * filter)
{
  filter->offset_orig = 0;
  filter->offset = 0;
  if (filter->adapter_holding)
    gst_adapter_clear (filter->adapter_holding);
}

/*
 * gst_base_metadata_reset_parsing:
 * @filter: the base metadata instance
 *
 * Reset the parsing process to start from the beginning again.
 * @see_also: #gst_base_metadata_reset_streaming
 *
 * Returns: nothing
 *
 */

static void
gst_base_metadata_reset_parsing (GstBaseMetadata * filter)
{
  if (filter->prepend_buffer) {
    gst_buffer_unref (filter->prepend_buffer);
    filter->prepend_buffer = NULL;
  }

  if (filter->append_buffer) {
    gst_buffer_unref (filter->append_buffer);
    filter->append_buffer = NULL;
  }

  if (filter->adapter_parsing)
    gst_adapter_clear (filter->adapter_parsing);

  if (filter->adapter_holding)
    gst_adapter_clear (filter->adapter_holding);

  filter->img_type = IMG_NONE;
  filter->duration_orig = 0;
  filter->duration = 0;
  filter->state = MT_STATE_NULL;
  filter->need_processing = FALSE;
  filter->next_offset = 0;
  filter->next_size = 0;
  filter->need_more_data = FALSE;
  filter->offset_orig = 0;
  filter->offset = 0;

  metadata_dispose (&filter->metadata);

}

/*
 * gst_base_metadata_parse
 * @filter: the base metadata instance
 * @buf: buffer to be parsed
 * @size: size of the buffer in bytes
 *
 * Parse the current buffer.
 * This buffer must be provided by another function wich keeps track of the
 * correct offset in the input stream.* 
 * If this function returns META_PARSING_NEED_MORE_DATA, the calling function
 * must look at @filter->next_offset and @filter->next_size to jump (forward)
 * in input stream to provide the correct data in @buf for the next call.
 * @see_also: #gst_base_metadata_pull_range_parse #gst_base_metadata_chain
 *
 * Returns:
 * <itemizedlist>
 * <listitem><para>%META_PARSING_ERROR if there was an error</para></listitem>
 * <listitem><para>%META_PARSING_DONE if the parse has completly finished
 * </para></listitem>
 * <listitem><para>%META_PARSING_NEED_MORE_DATA if need another buffer</para>
 * </listitem>
 * </itemizedlist>
 */

static int
gst_base_metadata_parse (GstBaseMetadata * filter, const guint8 * buf,
    guint32 size)
{

  int ret = META_PARSING_ERROR;

  filter->next_offset = 0;
  filter->next_size = 0;

  ret = metadata_parse (filter->metadata, buf, size,
      &filter->next_offset, &filter->next_size);

  if (ret == META_PARSING_ERROR) {
    if (META_DATA_IMG_TYPE (filter->metadata) == IMG_NONE) {
      /* image type not recognized */
      GST_ELEMENT_ERROR (filter, STREAM, TYPE_NOT_FOUND, (NULL),
          ("Only jpeg and png are supported"));
      goto done;
    } else {
      GST_ELEMENT_ERROR (filter, STREAM, FAILED, (NULL),
          ("Failed to parse stream."));
      goto done;
    }
  } else if (ret == META_PARSING_NEED_MORE_DATA) {
    filter->need_more_data = TRUE;
  } else {
    filter->state = MT_STATE_PARSED;
    filter->need_more_data = FALSE;
    filter->need_processing = TRUE;
  }

  /* reconfigure caps if it is different from type detected by 'base_metadata'
     function */
  if (filter->img_type != META_DATA_IMG_TYPE (filter->metadata)) {
    filter->img_type = META_DATA_IMG_TYPE (filter->metadata);
    if (!gst_base_metadata_configure_caps (filter)) {
      GST_ELEMENT_ERROR (filter, STREAM, FORMAT, (NULL),
          ("Couldn't reconfigure caps for %s",
              gst_base_metadata_get_type_name (filter->img_type)));
      ret = META_PARSING_ERROR;
      goto done;
    }
  }

done:

  return ret;

}


/*
 * gst_base_metadata_strip_push_buffer:
 * @base: the base metadata instance
 * @offset_orig: the offset in original input stream of the buffer that will
 * have data striped or injected
 * @prepend: a buffer (can be NULL) that will be completely injected in the
 * beginning og @buf
 * @buf: a pointer to a buffer that will be modified (data striped/injected or
 * prepended)
 * @inject_begin: is TRUE can inject a chunk start exactly in @offset_orig
 *
 * Strip bytes from @buf that are part of some chunk that will be striped. Add
 * a whole injected chunk if some inject chunk starts into the buffer. Prepend
 * additonal data if @prepend is not NULL. After using the @prepend buffer it
 * will be release and set to NULL.
 * @see_also: #gst_base_metadata_get_range #gst_base_metadata_chain
 * #gst_base_metadata_buf_get_intersection_seg
 *
 * Returns:
 * <itemizedlist>
 * <listitem><para>%TRUE if the buffer has been striped or injected (@prepend
 * doesn't change the return value).</para></listitem>
 * <listitem><para>%FALSE if it hasn't changed.</para></listitem>
 * </itemizedlist>
 *
 */

static gboolean
gst_base_metadata_strip_push_buffer (GstBaseMetadata * base,
    const gint64 offset_orig, GstBuffer ** prepend, GstBuffer ** buf,
    gboolean inject_begin)
{
  MetadataChunk *strip = META_DATA_STRIP_CHUNKS (base->metadata).chunk;
  MetadataChunk *inject = META_DATA_INJECT_CHUNKS (base->metadata).chunk;
  const gsize strip_len = META_DATA_STRIP_CHUNKS (base->metadata).len;
  const gsize inject_len = META_DATA_INJECT_CHUNKS (base->metadata).len;

  gboolean buffer_is_ok_to_change = FALSE;

  guint32 size_buf_in = GST_BUFFER_SIZE (*buf);

  gint64 *boffset_strip = NULL;
  guint32 *bsize_strip = NULL;

  int i, j;
  gboolean need_free_strip = FALSE;

  guint32 striped_bytes = 0;
  guint32 injected_bytes = 0;

  guint32 prepend_size = prepend && *prepend ? GST_BUFFER_SIZE (*prepend) : 0;

  /*
   * check all the 'inject chunks' having the 'original offset' starting into
   * the buffer
   * and calculates how many bytes will be injectd
   */

  if (inject_len) {

    for (i = 0; i < inject_len; ++i) {
      if (inject[i].offset_orig >= offset_orig) {
        if (G_LIKELY (inject_begin || inject[i].offset_orig > offset_orig)) {
          if (inject[i].offset_orig < offset_orig + size_buf_in) {
            injected_bytes += inject[i].size;
          } else {
            /* segment is after size (segments are sorted) */
            break;
          }
        }
      }
    }

  }

  /*
   * strip step
   */

  if (strip_len == 0)
    goto inject;

  /* just try to do fast allocation on stack */
  if (G_UNLIKELY (strip_len > 16)) {
    boffset_strip = g_new (gint64, strip_len);
    bsize_strip = g_new (guint32, strip_len);
    need_free_strip = TRUE;
  } else {
    boffset_strip = g_alloca (sizeof (boffset_strip[0]) * strip_len);
    bsize_strip = g_alloca (sizeof (bsize_strip[0]) * strip_len);
  }

  memset (bsize_strip, 0x00, sizeof (bsize_strip[0]) * strip_len);

  /*
   * calculate the number of bytes from the buffer bytes that intersect some
   * 'strip chunk'.
   * also get the position and size of segments into current buffer
   * (boffset_strip[i] and bsize_strip[i])
   * that will be striped
   */

  for (i = 0; i < strip_len; ++i) {
    int res;

    res = gst_base_metadata_buf_get_intersection_seg (offset_orig, size_buf_in,
        strip[i].offset_orig, strip[i].size,
        &boffset_strip[i], &bsize_strip[i]);

    /* segment is after size (segments are sorted) */
    striped_bytes += bsize_strip[i];
    if (res > 0) {
      break;
    }

  }

  if (striped_bytes) {

    guint8 *data;

    if (!buffer_is_ok_to_change) {
      /* create a new buffer if there is no space on currect buffer or if is
         read-only */
      buffer_is_ok_to_change = TRUE;
      if (injected_bytes + prepend_size > striped_bytes) {
        GstBuffer *new_buf =
            gst_buffer_new_and_alloc (GST_BUFFER_SIZE (*buf) + injected_bytes +
            prepend_size - striped_bytes);

        memcpy (GST_BUFFER_DATA (new_buf), GST_BUFFER_DATA (*buf),
            GST_BUFFER_SIZE (*buf));

        gst_buffer_unref (*buf);
        *buf = new_buf;

      } else if (GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_READONLY)) {
        GstBuffer *new_buf = gst_buffer_copy (*buf);

        gst_buffer_unref (*buf);
        *buf = new_buf;
        GST_BUFFER_FLAG_UNSET (*buf, GST_BUFFER_FLAG_READONLY);
        GST_BUFFER_SIZE (*buf) += injected_bytes + prepend_size - striped_bytes;
      }
    }

    data = GST_BUFFER_DATA (*buf);

    /* strip out the bytes from buffer */
    striped_bytes = 0;
    for (i = 0; i < strip_len; ++i) {
      /* intersect */
      if (bsize_strip[i]) {
        memmove (data + boffset_strip[i] - striped_bytes,
            data + boffset_strip[i] + bsize_strip[i] - striped_bytes,
            size_buf_in - boffset_strip[i] - bsize_strip[i]);
        striped_bytes += bsize_strip[i];
      }
    }
    size_buf_in -= striped_bytes;

  }

inject:

  /*
   * inject segments
   */

  if (inject_len) {

    guint8 *data;
    guint32 striped_so_far;

    if (!buffer_is_ok_to_change) {
      /* create a new buffer fs there is no space on currect buffer or if is
         read-only */
      buffer_is_ok_to_change = TRUE;
      if (injected_bytes + prepend_size > striped_bytes) {
        GstBuffer *new_buf =
            gst_buffer_new_and_alloc (GST_BUFFER_SIZE (*buf) + injected_bytes +
            prepend_size - striped_bytes);

        memcpy (GST_BUFFER_DATA (new_buf), GST_BUFFER_DATA (*buf),
            GST_BUFFER_SIZE (*buf));

        gst_buffer_unref (*buf);
        *buf = new_buf;

      } else if (GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_READONLY)) {
        GstBuffer *new_buf = gst_buffer_copy (*buf);

        gst_buffer_unref (*buf);
        *buf = new_buf;
        GST_BUFFER_FLAG_UNSET (*buf, GST_BUFFER_FLAG_READONLY);
        GST_BUFFER_SIZE (*buf) += injected_bytes + prepend_size - striped_bytes;
      }
    }

    data = GST_BUFFER_DATA (*buf);

    injected_bytes = 0;
    striped_so_far = 0;
    j = 0;
    for (i = 0; i < inject_len; ++i) {
      while (j < strip_len) {
        if (strip[j].offset_orig < inject[i].offset_orig)
          striped_so_far += bsize_strip[j++];
        else
          break;
      }

      /* inject the whole inject chunk if the 'original offset' is inside the
         original buffer */

      if (inject[i].offset_orig >= offset_orig) {
        if (G_LIKELY (inject_begin || inject[i].offset_orig > offset_orig)) {
          if (inject[i].offset_orig <
              offset_orig + size_buf_in + striped_bytes - injected_bytes) {
            /* insert */
            guint32 buf_off =
                inject[i].offset_orig - offset_orig - striped_so_far +
                injected_bytes;
            memmove (data + buf_off + inject[i].size, data + buf_off,
                size_buf_in - buf_off);
            memcpy (data + buf_off, inject[i].data, inject[i].size);
            injected_bytes += inject[i].size;
            size_buf_in += inject[i].size;
          } else {
            /* segment is after size (segments are sorted) */
            break;
          }
        }
      }
    }

  }

  if (prepend_size) {
    if (injected_bytes == 0 && striped_bytes == 0) {
      GstBuffer *new_buf =
          gst_buffer_new_and_alloc (size_buf_in + prepend_size);

      memcpy (GST_BUFFER_DATA (new_buf) + prepend_size, GST_BUFFER_DATA (*buf),
          size_buf_in);

      gst_buffer_unref (*buf);
      *buf = new_buf;
    } else {
      memmove (GST_BUFFER_DATA (*buf) + prepend_size, GST_BUFFER_DATA (*buf),
          size_buf_in);
    }
    memcpy (GST_BUFFER_DATA (*buf), GST_BUFFER_DATA (*prepend), prepend_size);
    gst_buffer_unref (*prepend);
    *prepend = NULL;
  }

  GST_BUFFER_SIZE (*buf) = size_buf_in + prepend_size;

  if (need_free_strip) {
    g_free (boffset_strip);
    g_free (bsize_strip);
  }

  return injected_bytes || striped_bytes;

}

/*
 * gst_base_metadata_buf_get_intersection_seg:
 * @offset: offset of buffer in original stream
 * @size: size of buffer
 * @seg_offset: offset of segment in original stream
 * @seg_size: size of segment
 * @boffset: offset inside buffer where segment starts (-1 for no intersection)
 * @bsize:size of intersection
 *
 * Calculate which bytes into the buffer given by @offset and @size intersetcs
 * the segment given by @seg_offset and @seg_size
 * @see_also: #gst_base_metadata_strip_push_buffer
 *
 * Returns:
 * <itemizedlist>
 * <listitem><para>%-1 if the segment is completly before the buffer</para>
 * </listitem>
 * <listitem><para>%0 if the segment intersects</para></listitem>
 * <listitem><para>%1 if the segment is after the buffer</para></listitem>
 * </itemizedlist>
 */

static int
gst_base_metadata_buf_get_intersection_seg (const gint64 offset, guint32 size,
    const gint64 seg_offset, const guint32 seg_size,
    gint64 * boffset, guint32 * bsize)
{
  int ret = -1;

  *boffset = -1;
  *bsize = 0;

  /* all segment after buffer */
  if (seg_offset >= offset + size) {
    ret = 1;
    goto done;
  }

  if (seg_offset < offset) {
    /* segment start somewhere before buffer */

    /* all segment before buffer */
    if (seg_offset + seg_size <= offset) {
      ret = -1;
      goto done;
    }

    *boffset = 0;

    if (seg_offset + seg_size >= offset + size) {
      /* segment cover all buffer */
      *bsize = size;
    } else {
      /* segment goes from start of buffer to somewhere before end */
      *bsize = seg_size - (offset - seg_offset);
    }

    ret = 0;

  } else {
    /* segment start somewhere into buffer */

    *boffset = seg_offset - offset;

    if (seg_offset + seg_size <= offset + size) {
      /* all segment into buffer */
      *bsize = seg_size;
    } else {
      *bsize = size - *boffset;
    }

    ret = 0;

  }

done:

  return ret;

}

/*
 * gst_base_metadata_translate_pos_to_orig:
 * @base: the base metadata instance
 * @pos: position in output stream
 * @orig_pos: position in original stream
 * @buf: if not NULL, will have data that starts at some point into a injected
 * chunk
 * @max_size: the maximum size to allocate to @buf. pass 0 if don't care
 *
 * Given a position in output stream (@pos), returns the position in original 
 * stream (@orig_pos) that contains the same data. If @pos is into a injected
 * chunk, @orig_pos will contains the position just after the position in which
 * the chunk has been insert and @buf (if non null) will be filled with
 * injected bytes starting in @pos until the and of injected chunk.
 * @see_also: #gst_base_metadata_src_event #gst_base_metadata_get_range
 *
 * Returns:
 * <itemizedlist>
 * <listitem><para>%TRUE if @pos is in original buffer</para></listitem>
 * <listitem><para>%FALSE if @pos is into a injected chunk</para></listitem>
 * </itemizedlist>
 *
 */

static gboolean
gst_base_metadata_translate_pos_to_orig (GstBaseMetadata * base,
    gint64 pos, gint64 * orig_pos, GstBuffer ** buf, guint32 max_size)
{
  MetadataChunk *strip = META_DATA_STRIP_CHUNKS (base->metadata).chunk;
  MetadataChunk *inject = META_DATA_INJECT_CHUNKS (base->metadata).chunk;
  const gsize strip_len = META_DATA_STRIP_CHUNKS (base->metadata).len;
  const gsize inject_len = META_DATA_INJECT_CHUNKS (base->metadata).len;
  const gint64 duration_orig = base->duration_orig;
  const gint64 duration = base->duration;
  gboolean ret = TRUE;
  const gint64 saved_pos = pos;

  int i;

  guint64 new_buf_size = 0;
  guint64 injected_before = 0;

  if (G_UNLIKELY (pos == -1)) {
    *orig_pos = -1;
    return TRUE;
  } else if (G_UNLIKELY (pos >= duration)) {
    /* this should never happen */
    *orig_pos = duration_orig;
    return TRUE;
  }

  /* calculate for injected */

  /* just calculate size */
  for (i = 0; i < inject_len; ++i) {
    if (pos >= inject[i].offset) {
      if (pos < inject[i].offset + inject[i].size) {
        /* pos is inside the chunk */
        const guint32 offset_in_chunk = pos - inject[i].offset;

        ret = FALSE;
        pos = inject[i].offset + inject[i].size;        /* put pos just after chunk */
        new_buf_size += inject[i].size - offset_in_chunk;
        /* we still continue, 'cause the next chunk could be just after this */
      } else {
        /* in case pos is not inside a injected chunk */
        injected_before += inject[i].size;
      }
    } else {
      /* pos is before the chunk */
      break;
    }
  }

  /* alloc buffer and calcute original pos */
  if (ret == FALSE) {

    *orig_pos = pos;

    if (buf) {
      guint8 *data;

      if (max_size > 0)
        if (new_buf_size > max_size)
          new_buf_size = max_size;

      if (*buf)
        gst_buffer_unref (*buf);
      *buf = gst_buffer_new_and_alloc (new_buf_size);
      data = GST_BUFFER_DATA (*buf);
      pos = saved_pos;
      for (i = 0; i < inject_len && new_buf_size > 0; ++i) {
        if (inject[i].offset > pos) {
          break;
        }
        if (pos < inject[i].offset + inject[i].size) {
          const guint32 offset = pos - inject[i].offset;
          guint32 size = inject[i].size - offset;

          if (size > new_buf_size)
            size = new_buf_size;
          memcpy (data, inject[i].data + offset, size);
          data += size;
          pos = inject[i].offset + inject[i].size;
          new_buf_size -= size;
        }
      }
    }

    goto done;
  }

  /* calculate for striped */

  *orig_pos = saved_pos - injected_before;
  for (i = 0; i < strip_len; ++i) {
    if (strip[i].offset_orig > pos) {
      break;
    }
    *orig_pos += strip[i].size;
  }

done:

  if (G_UNLIKELY (*orig_pos >= duration_orig)) {
    *orig_pos = duration_orig - 1;
  }

  return ret;

}

/*
 * gst_base_metadata_calculate_offsets:
 * @base: the base metadata instance
 *
 * Recalculates the offset of injected chunks after take in account new sizes
 * written by the 'muxers elements' and wrapped with bytes by the correct
 * file type handler.
 * @see_also: #gst_base_metadata_processing #metadata_lazy_update
 * #gst_base_metadata_update_inject_segment_with_new_data
 *
 * Returns:
 * <itemizedlist>
 * <listitem><para>%TRUE if succeded</para></listitem>
 * <listitem><para>%FALSE if fails. Which happens if the stream hasn't been
 * completely parsed yet</para></listitem>
 * </itemizedlist>
 */

static gboolean
gst_base_metadata_calculate_offsets (GstBaseMetadata * base)
{
  int i, j;
  guint32 bytes_striped, bytes_inject;
  MetadataChunk *strip = META_DATA_STRIP_CHUNKS (base->metadata).chunk;
  MetadataChunk *inject = META_DATA_INJECT_CHUNKS (base->metadata).chunk;
  gsize strip_len;
  gsize inject_len;
  gboolean ret = TRUE;

  if (base->state != MT_STATE_PARSED) {
    ret = FALSE;
    GST_ELEMENT_ERROR (base, STREAM, FAILED, (NULL), ("Invalid state."));
    goto done;
  }

  metadata_chunk_array_remove_zero_size (&META_DATA_INJECT_CHUNKS
      (base->metadata));

  metadata_lazy_update (base->metadata);

  strip_len = META_DATA_STRIP_CHUNKS (base->metadata).len;
  inject_len = META_DATA_INJECT_CHUNKS (base->metadata).len;

  bytes_striped = 0;
  bytes_inject = 0;

  /* calculate the new position off injected chunks */
  j = 0;
  for (i = 0; i < inject_len; ++i) {
    for (; j < strip_len; ++j) {
      if (strip[j].offset_orig >= inject[i].offset_orig) {
        break;
      }
      bytes_striped += strip[j].size;
    }
    inject[i].offset = inject[i].offset_orig - bytes_striped + bytes_inject;
    bytes_inject += inject[i].size;
  }

  /* FIXME (append): For the time being we don't have append buffers 'cause
     in the case of files we are handling it is not possible to append after
     the last byte on original stream (which is part of a kind of end-of-file
     chunk) */
#if 0
  /* calculate append buffer */
  append_size = 0;
  for (i = inject_len - 1; i >= 0; --i) {
    if (inject[i].offset_orig == base->duration_orig)
      append_size += inject[i].size;
    else
      break;
  }
  if (append_size) {
    guint8 *data;

    base->append_buffer = gst_buffer_new_and_alloc (append_size);
    GST_BUFFER_FLAG_SET (base->append_buffer, GST_BUFFER_FLAG_READONLY);
    data = GST_BUFFER_DATA (base->append_buffer);
    for (i = inject_len - 1; i >= 0; --i) {
      if (inject[i].offset_orig == base->duration_orig) {
        memcpy (data, inject[i].data, inject[i].size);
        data += inject[i].size;
      } else {
        break;
      }
    }
  }
#endif

  if (base->duration_orig) {
    base->duration = base->duration_orig;
    for (i = 0; i < inject_len; ++i) {
      base->duration += inject[i].size;
    }
    for (i = 0; i < strip_len; ++i) {
      base->duration -= strip[i].size;
    }
  }

done:

  return ret;

}


/*
 * GObject callback functions implementation
 */

static void
gst_base_metadata_base_init (gpointer gclass)
{
  GST_DEBUG_CATEGORY_INIT (gst_base_metadata_debug, "basemetadata", 0,
      "basemetadata element");
}

static void
gst_base_metadata_class_init (GstBaseMetadataClass * 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->dispose = GST_DEBUG_FUNCPTR (gst_base_metadata_dispose);
  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_base_metadata_finalize);

  gobject_class->set_property = gst_base_metadata_set_property;
  gobject_class->get_property = gst_base_metadata_get_property;

  g_object_class_install_property (gobject_class, ARG_EXIF,
      g_param_spec_boolean ("exif", "EXIF", "Send EXIF metadata ?",
          TRUE, G_PARAM_READWRITE));

  g_object_class_install_property (gobject_class, ARG_IPTC,
      g_param_spec_boolean ("iptc", "IPTC", "Send IPTC metadata ?",
          TRUE, G_PARAM_READWRITE));

  g_object_class_install_property (gobject_class, ARG_XMP,
      g_param_spec_boolean ("xmp", "XMP", "Send XMP metadata ?",
          TRUE, G_PARAM_READWRITE));

  gstelement_class->change_state = gst_base_metadata_change_state;

}

static void
gst_base_metadata_init (GstBaseMetadata * filter, GstBaseMetadataClass * gclass)
{
  /* sink pad */

  filter->sinkpad =
      gst_pad_new_from_template (gst_element_class_get_pad_template
      (GST_ELEMENT_CLASS (gclass), "sink"), "sink");
  gst_pad_set_setcaps_function (filter->sinkpad,
      GST_DEBUG_FUNCPTR (gclass->set_caps));
  gst_pad_set_getcaps_function (filter->sinkpad,
      GST_DEBUG_FUNCPTR (gclass->get_sink_caps));
  gst_pad_set_event_function (filter->sinkpad, gst_base_metadata_sink_event);
  gst_pad_set_chain_function (filter->sinkpad,
      GST_DEBUG_FUNCPTR (gst_base_metadata_chain));
  gst_pad_set_activate_function (filter->sinkpad,
      gst_base_metadata_sink_activate);

  /* source pad */

  filter->srcpad =
      gst_pad_new_from_template (gst_element_class_get_pad_template
      (GST_ELEMENT_CLASS (gclass), "src"), "src");
  gst_pad_set_getcaps_function (filter->srcpad,
      GST_DEBUG_FUNCPTR (gclass->get_src_caps));
  gst_pad_set_event_function (filter->srcpad, gst_base_metadata_src_event);
  gst_pad_set_query_function (filter->srcpad,
      GST_DEBUG_FUNCPTR (gst_base_metadata_src_query));
  gst_pad_set_query_type_function (filter->srcpad,
      GST_DEBUG_FUNCPTR (gst_base_metadata_get_query_types));
  gst_pad_use_fixed_caps (filter->srcpad);

  gst_pad_set_checkgetrange_function (filter->srcpad,
      GST_DEBUG_FUNCPTR (gst_base_metadata_checkgetrange));
  gst_pad_set_getrange_function (filter->srcpad, gst_base_metadata_get_range);

  gst_pad_set_activatepull_function (filter->srcpad,
      GST_DEBUG_FUNCPTR (gst_base_metadata_src_activate_pull));
  /* addind pads */

  gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);
  gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);

  metadata_xmp_init ();
  /* init members */

  gst_base_metadata_init_members (filter);

}

static void
gst_base_metadata_dispose (GObject * object)
{
  GstBaseMetadata *filter = NULL;

  filter = GST_BASE_METADATA (object);

  gst_base_metadata_dispose_members (filter);

  metadata_xmp_dispose ();

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

static void
gst_base_metadata_finalize (GObject * object)
{
  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static void
gst_base_metadata_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstBaseMetadata *filter = GST_BASE_METADATA (object);

  switch (prop_id) {
    case ARG_EXIF:
      if (g_value_get_boolean (value))
        filter->options |= META_OPT_EXIF;
      else
        filter->options &= ~META_OPT_EXIF;
      break;
    case ARG_IPTC:
      if (g_value_get_boolean (value))
        filter->options |= META_OPT_IPTC;
      else
        filter->options &= ~META_OPT_IPTC;
      break;
    case ARG_XMP:
      if (g_value_get_boolean (value))
        filter->options |= META_OPT_XMP;
      else
        filter->options &= ~META_OPT_XMP;
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_base_metadata_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstBaseMetadata *filter = GST_BASE_METADATA (object);

  switch (prop_id) {
    case ARG_EXIF:
      g_value_set_boolean (value, filter->options & META_OPT_EXIF);
      break;
    case ARG_IPTC:
      g_value_set_boolean (value, filter->options & META_OPT_IPTC);
      break;
    case ARG_XMP:
      g_value_set_boolean (value, filter->options & META_OPT_XMP);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}


/*
 * GStreamer callback functions declaration
 */

static GstStateChangeReturn
gst_base_metadata_change_state (GstElement * element, GstStateChange transition)
{
  GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
  GstBaseMetadata *filter = GST_BASE_METADATA (element);

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      gst_base_metadata_reset_parsing (filter);
      metadata_init (&filter->metadata, filter->options);
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      if (filter->metadata == NULL)
        metadata_init (&filter->metadata, filter->options);
      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_PAUSED_TO_READY:
      gst_base_metadata_reset_streaming (filter);
      if (filter->state == MT_STATE_PARSED)
        gst_base_metadata_reset_parsing (filter);
      break;
    default:
      break;
  }

done:

  return ret;
}

static gboolean
gst_base_metadata_src_event (GstPad * pad, GstEvent * event)
{
  GstBaseMetadata *filter = NULL;
  gboolean ret = FALSE;

  filter = GST_BASE_METADATA (gst_pad_get_parent (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_SEEK:
    {
      gdouble rate;
      GstFormat format;
      GstSeekFlags flags;
      GstSeekType start_type;
      gint64 start;
      GstSeekType stop_type;
      gint64 stop;

      /* we don't know where are the chunks to be stripped before base */
      if (!gst_base_metadata_processing (filter)) {
        ret = FALSE;
        goto done;
      }

      gst_event_parse_seek (event, &rate, &format, &flags,
          &start_type, &start, &stop_type, &stop);

      switch (format) {
        case GST_FORMAT_BYTES:
          break;
        case GST_FORMAT_PERCENT:
          if (filter->duration < 0)
            goto done;
          start = start * filter->duration / 100;
          stop = stop * filter->duration / 100;
          break;
        default:
          goto done;
      }
      format = GST_FORMAT_BYTES;

      if (start_type == GST_SEEK_TYPE_CUR)
        start = filter->offset + start;
      else if (start_type == GST_SEEK_TYPE_END) {
        if (filter->duration < 0)
          goto done;
        start = filter->duration + start;
      }
      start_type = GST_SEEK_TYPE_SET;

      if (filter->prepend_buffer) {
        gst_buffer_unref (filter->prepend_buffer);
        filter->prepend_buffer = NULL;
      }

      /* FIXME (append): if some chunk is injected after the end of original
         file (which is not the case for any file type currently handled),
         appending a buffer should be taken in account */

      /* translate position and setup filter-prepend to be prepend to the
         striped/injected buffer in next 'chain' calling */
      filter->offset = start;
      gst_base_metadata_translate_pos_to_orig (filter, start, &start,
          &filter->prepend_buffer, 0);
      filter->offset_orig = start;

      if (stop_type == GST_SEEK_TYPE_CUR)
        stop = filter->offset + stop;
      else if (stop_type == GST_SEEK_TYPE_END) {
        if (filter->duration < 0)
          goto done;
        stop = filter->duration + stop;
      }
      stop_type = GST_SEEK_TYPE_SET;

      gst_base_metadata_translate_pos_to_orig (filter, stop, &stop, NULL, 0);

      gst_event_unref (event);
      event = gst_event_new_seek (rate, format, flags,
          start_type, start, stop_type, stop);

    }
      break;
    default:
      break;
  }

  ret = gst_pad_event_default (pad, event);
  event = NULL;

done:

  if (event) {
    gst_event_unref (event);
  }

  gst_object_unref (filter);

  return ret;

}

static gboolean
gst_base_metadata_sink_event (GstPad * pad, GstEvent * event)
{
  GstBaseMetadata *filter = NULL;
  gboolean ret = FALSE;
  GstBaseMetadataClass *bclass;

  filter = GST_BASE_METADATA (gst_pad_get_parent (pad));
  bclass = GST_BASE_METADATA_GET_CLASS (filter);

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_EOS:
      if (filter->need_more_data) {
        GST_ELEMENT_WARNING (filter, STREAM, DECODE, (NULL),
            ("Need more data. Unexpected EOS"));
      }
      break;
    case GST_EVENT_TAG:
      break;
    default:
      break;
  }

  ret = bclass->sink_event (pad, event);

  gst_object_unref (filter);

  return ret;

}

static gboolean
gst_base_metadata_checkgetrange (GstPad * srcpad)
{
  GstBaseMetadata *filter = NULL;

  filter = GST_BASE_METADATA (GST_PAD_PARENT (srcpad));

  return gst_pad_check_pull_range (filter->sinkpad);
}

static GstFlowReturn
gst_base_metadata_get_range (GstPad * pad,
    guint64 offset, guint size, GstBuffer ** buf)
{
  GstBaseMetadata *filter = NULL;
  GstFlowReturn ret = GST_FLOW_OK;
  gint64 offset_orig = 0;
  guint size_orig;
  GstBuffer *prepend = NULL;
  gboolean need_append = FALSE;
  gboolean into_inject;

  filter = GST_BASE_METADATA (GST_PAD_PARENT (pad));

  if (!gst_base_metadata_processing (filter)) {
    ret = GST_FLOW_ERROR;
    goto done;
  }

  if (offset + size > filter->duration) {
    size = filter->duration - offset;
  }

  size_orig = size;

  into_inject = !gst_base_metadata_translate_pos_to_orig (filter, offset,
      &offset_orig, &prepend, size);

  if (into_inject) {
    size_orig = GST_BUFFER_SIZE (prepend) < size_orig ?
        size_orig - GST_BUFFER_SIZE (prepend) : 0;
  }

  if (size_orig == 0) {
    /* enough data in prepend */
    *buf = prepend;
    goto done;
  }

  if (size_orig > 1) {
    gint64 pos;

    pos = offset + size - 1;
    into_inject = gst_base_metadata_translate_pos_to_orig (filter, pos, &pos,
        NULL, 0);
    size_orig = pos + 1 - offset_orig;
  }

  ret = gst_pad_pull_range (filter->sinkpad, offset_orig, size_orig, buf);

  if (ret == GST_FLOW_OK && *buf) {
    gst_base_metadata_strip_push_buffer (filter, offset_orig, &prepend, buf,
        FALSE);

    if (GST_BUFFER_SIZE (*buf) < size) {
      /* need append */
      need_append = TRUE;
    } else {
      /* hide extra bytes */
      GST_BUFFER_SIZE (*buf) = size;
    }
  }


done:

  if (need_append) {
    /* FIXME (append): together with SEEK and
       gst_base_metadata_translate_pos_to_orig this way if chunk is added in
       the end we are in trouble ...still not implemented 'cause it will not be
       the case for the time being (All the file types handled have a kind of
       end-of-file chunk (or mark, so nothing will be injected after it) */
  }

  return ret;

}


static GstFlowReturn
gst_base_metadata_chain (GstPad * pad, GstBuffer * buf)
{
  GstBaseMetadata *filter = NULL;
  GstFlowReturn ret = GST_FLOW_ERROR;
  guint32 buf_size = 0;
  guint32 new_buf_size = 0;
  gboolean append = FALSE;

  filter = GST_BASE_METADATA (gst_pad_get_parent (pad));

  if (filter->state != MT_STATE_PARSED) {
    guint32 adpt_size;

    if (G_UNLIKELY (filter->adapter_parsing == NULL))
      filter->adapter_parsing = gst_adapter_new ();

    adpt_size = gst_adapter_available (filter->adapter_parsing);

    if (filter->next_offset) {
      if (filter->next_offset >= adpt_size) {
        /* clean adapter */
        gst_adapter_clear (filter->adapter_parsing);
        filter->next_offset -= adpt_size;
        if (filter->next_offset >= GST_BUFFER_SIZE (buf)) {
          /* we don't need data in this buffer */
          filter->next_offset -= GST_BUFFER_SIZE (buf);
        } else {
          GstBuffer *new_buf;

          /* add to adapter just need part from buf */
          new_buf =
              gst_buffer_new_and_alloc (GST_BUFFER_SIZE (buf) -
              filter->next_offset);
          memcpy (GST_BUFFER_DATA (new_buf),
              GST_BUFFER_DATA (buf) + filter->next_offset,
              GST_BUFFER_SIZE (buf) - filter->next_offset);
          filter->next_offset = 0;
          gst_adapter_push (filter->adapter_parsing, new_buf);
        }
      } else {
        /* remove first bytes and add buffer */
        gst_adapter_flush (filter->adapter_parsing, filter->next_offset);
        filter->next_offset = 0;
        gst_adapter_push (filter->adapter_parsing, gst_buffer_copy (buf));
      }
    } else {
      /* just push buffer */
      gst_adapter_push (filter->adapter_parsing, gst_buffer_copy (buf));
    }

    adpt_size = gst_adapter_available (filter->adapter_parsing);

    if (adpt_size && filter->next_size <= adpt_size) {
      const guint8 *new_buf =
          gst_adapter_peek (filter->adapter_parsing, adpt_size);

      if (gst_base_metadata_parse (filter, new_buf,
              adpt_size) == META_PARSING_ERROR) {
        ret = GST_FLOW_ERROR;
        goto done;
      }
    }
  }

  if (filter->state == MT_STATE_PARSED) {

    if (!gst_base_metadata_processing (filter)) {
      ret = GST_FLOW_ERROR;
      goto done;
    }

    if (filter->adapter_holding) {
      gst_adapter_push (filter->adapter_holding, buf);
      buf = gst_adapter_take_buffer (filter->adapter_holding,
          gst_adapter_available (filter->adapter_holding));
      g_object_unref (filter->adapter_holding);
      filter->adapter_holding = NULL;
    }

    if (filter->offset_orig + GST_BUFFER_SIZE (buf) == filter->duration_orig)
      append = TRUE;

    buf_size = GST_BUFFER_SIZE (buf);

    gst_base_metadata_strip_push_buffer (filter, filter->offset_orig,
        &filter->prepend_buffer, &buf, TRUE);

    if (buf) {                  /* may be all buffer has been striped */
      gst_buffer_set_caps (buf, GST_PAD_CAPS (filter->srcpad));
      new_buf_size = GST_BUFFER_SIZE (buf);

      ret = gst_pad_push (filter->srcpad, buf);
      buf = NULL;               /* this function don't owner it anymore */
      if (ret != GST_FLOW_OK)
        goto done;
    } else {
      ret = GST_FLOW_OK;
    }

    if (append && filter->append_buffer) {
      gst_buffer_set_caps (filter->append_buffer,
          GST_PAD_CAPS (filter->srcpad));
      gst_buffer_ref (filter->append_buffer);
      ret = gst_pad_push (filter->srcpad, filter->append_buffer);
      if (ret != GST_FLOW_OK)
        goto done;
    }

    filter->offset_orig += buf_size;
    filter->offset += new_buf_size;

  } else {
    /* just store while still not parsed */
    if (!filter->adapter_holding)
      filter->adapter_holding = gst_adapter_new ();
    gst_adapter_push (filter->adapter_holding, buf);
    buf = NULL;
    ret = GST_FLOW_OK;
  }

done:


  if (buf) {
    /* there was an error and buffer wasn't pushed */
    gst_buffer_unref (buf);
    buf = NULL;
  }

  gst_object_unref (filter);

  return ret;

}

static gboolean
gst_base_metadata_sink_activate (GstPad * pad)
{
  GstBaseMetadata *filter = NULL;
  gboolean ret = TRUE;


  filter = GST_BASE_METADATA (GST_PAD_PARENT (pad));

  if (!gst_pad_check_pull_range (pad) ||
      !gst_pad_activate_pull (filter->sinkpad, TRUE)) {
    /* Fail here ? nothing to be done by now, activate push mode */
    return gst_pad_activate_push (pad, TRUE);
  }

  /* try to base */
  if (filter->state == MT_STATE_NULL) {
    ret = gst_base_metadata_pull_range_parse (filter);
  }

  if (ret) {
    GstActivateMode mode;

    /* in gst_base_metadata_pull_range_parse() we could have triggered
     * negotiation and plugged new downstream elements.
     * If GST_PAD_ACTIVATE_MODE (filter->srcpad) is GST_ACTIVATE_PULL it means
     * that downstream is active in pull mode so we don't deactivate pull mode.
     */
    GST_OBJECT_LOCK (filter->srcpad);
    mode = GST_PAD_ACTIVATE_MODE (filter->srcpad);
    GST_OBJECT_UNLOCK (filter->srcpad);

    if (mode != GST_ACTIVATE_PULL) {
      /* change from PULL to PUSH */
      gst_pad_activate_push (pad, TRUE);
    }
  }

  return ret;
}

static gboolean
gst_base_metadata_src_activate_pull (GstPad * pad, gboolean active)
{
  GstBaseMetadata *filter = NULL;
  gboolean ret;

  filter = GST_BASE_METADATA (gst_pad_get_parent (pad));

  ret = gst_pad_activate_pull (filter->sinkpad, active);

  if (ret && filter->state == MT_STATE_NULL) {
    ret = gst_base_metadata_pull_range_parse (filter);
  }

  gst_object_unref (filter);

  return ret;
}

static const GstQueryType *
gst_base_metadata_get_query_types (GstPad * pad)
{
  static const GstQueryType gst_base_metadata_src_query_types[] = {
    GST_QUERY_POSITION,
    GST_QUERY_DURATION,
    GST_QUERY_FORMATS,
    0
  };

  return gst_base_metadata_src_query_types;
}

static gboolean
gst_base_metadata_src_query (GstPad * pad, GstQuery * query)
{
  gboolean ret = FALSE;
  GstFormat format;
  GstBaseMetadata *filter = GST_BASE_METADATA (gst_pad_get_parent (pad));

  switch (GST_QUERY_TYPE (query)) {
    case GST_QUERY_POSITION:
      gst_query_parse_position (query, &format, NULL);

      if (format == GST_FORMAT_BYTES) {
        gst_query_set_position (query, GST_FORMAT_BYTES, filter->offset);
        ret = TRUE;
      }

      break;
    case GST_QUERY_DURATION:

      if (!gst_base_metadata_processing (filter)) {
        ret = FALSE;
        goto done;
      }

      gst_query_parse_duration (query, &format, NULL);

      if (format == GST_FORMAT_BYTES) {
        if (filter->duration >= 0) {
          gst_query_set_duration (query, GST_FORMAT_BYTES, filter->duration);
          ret = TRUE;
        }
      }

      break;
    case GST_QUERY_FORMATS:
      gst_query_set_formats (query, 1, GST_FORMAT_BYTES);
      ret = TRUE;
      break;
    default:
      break;
  }

done:

  gst_object_unref (filter);

  return ret;

}

/*
 * extern functions declaration
 */

/**
 * gst_base_metadata_set_option_flag:
 * @base: the base metadata instance
 * @options: mode of operation
 *
 * Set how the this base class will behaviour. As a demuxer or muxer. Hanlding
 * EXIF, IPTC, XMP or not.
 * @see_also: #gst_base_metadata_unset_option_flag
 * #gst_base_metadata_get_option_flag 
 */
void
gst_base_metadata_set_option_flag (GstBaseMetadata * base, MetaOptions options)
{
  base->options |= options;
}

/**
 * gst_base_metadata_unset_option_flag:
 * @base: the base metadata instance
 * @options: mode of operation
 *
 * Set how the this base class will behaviour. As a demuxer or muxer. Hanlding
 * EXIF, IPTC, XMP or not.
 * @see_also: #gst_base_metadata_set_option_flag
 * #gst_base_metadata_get_option_flag 
 */
void
gst_base_metadata_unset_option_flag (GstBaseMetadata * base,
    MetaOptions options)
{
  base->options &= ~options;
}

/**
 * gst_base_metadata_get_option_flag:
 * @base: the base metadata instance
 *
 * Check how the this base class will behaviour. As a demuxer or muxer.
 * Hanlding EXIF, IPTC, XMP or not.
 * @see_also: #gst_base_metadata_set_option_flag
 * #gst_base_metadata_unset_option_flag
 *
 * Returns: The current mode of operation
 */
MetaOptions
gst_base_metadata_get_option_flag (const GstBaseMetadata * base)
{
  return base->options;
}


/**
 * gst_base_metadata_update_inject_segment_with_new_data:
 * @base: the base metadata instance
 * @data: new data to be injected
 * @size: the size in bytes of @data
 * @type: kind of metadata chunk it is (currently EXIF, IPTC or XMP)
 *
 * If the file type specification of the parsed stream allows a chunk of @type,
 * set the @data and @size of the segment to be injected. This the @data has
 * been injected (metadata type supported by the stream @type) then, the
 * the @data ownership will be taken and @data and @size willl be set to 0;
 * Hanlding EXIF, IPTC, XMP or not.
 * @see_also: #gst_base_metadata_calculate_offsets
 */
void gst_base_metadata_update_inject_segment_with_new_data
    (GstBaseMetadata * base,
    guint8 ** data, guint32 * size, MetadataChunkType type)
{
  int i;
  MetadataChunk *inject = META_DATA_INJECT_CHUNKS (base->metadata).chunk;
  const gsize inject_len = META_DATA_INJECT_CHUNKS (base->metadata).len;

  if (!(data && size && *data && *size))
    goto done;

  for (i = 0; i < inject_len; ++i) {
    if (inject[i].type == type) {
      inject[i].size = *size;
      g_free (inject[i].data);
      inject[i].data = *data;
      *size = 0;
      *data = 0;
      break;
    }
  }

done:

  return;

}