gstreamer/gst/mpeg4videoparse/mpeg4videoparse.c

/* GStreamer
 * Copyright (C) <2008> Mindfruit B.V.
 *   @author Sjoerd Simons <sjoerd@luon.net>
 * Copyright (C) <2007> Julien Moutte <julien@fluendo.com>
 *
 * 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.
 */

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

#include <string.h>
#include "mpeg4videoparse.h"

GST_DEBUG_CATEGORY_STATIC (mpeg4v_parse_debug);
#define GST_CAT_DEFAULT mpeg4v_parse_debug

/* elementfactory information */
static GstElementDetails mpeg4vparse_details =
GST_ELEMENT_DETAILS ("MPEG 4 video elementary stream parser",
    "Codec/Parser/Video",
    "Parses MPEG-4 Part 2 elementary video streams",
    "Julien Moutte <julien@fluendo.com>");

static GstStaticPadTemplate src_template =
GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/mpeg, "
        "mpegversion = (int) 4, "
        "parsed = (boolean) true, " "systemstream = (boolean) false")
    );

static GstStaticPadTemplate sink_template =
GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/mpeg, "
        "mpegversion = (int) 4, "
        "parsed = (boolean) false, " "systemstream = (boolean) false")
    );

/* Properties */
#define DEFAULT_PROP_DROP	TRUE

enum
{
  PROP_0,
  PROP_DROP,
  PROP_LAST
};

GST_BOILERPLATE (GstMpeg4VParse, gst_mpeg4vparse, GstElement, GST_TYPE_ELEMENT);

static gboolean
gst_mpeg4vparse_set_new_caps (GstMpeg4VParse * parse,
    guint16 time_increment_resolution, guint16 fixed_time_increment,
    gint aspect_ratio_width, gint aspect_ratio_height, gint width, gint height)
{
  gboolean res;
  GstCaps *out_caps = gst_caps_new_simple ("video/mpeg",
      "mpegversion", G_TYPE_INT, 4,
      "systemstream", G_TYPE_BOOLEAN, FALSE,
      "parsed", G_TYPE_BOOLEAN, TRUE, NULL);

  if (parse->profile != 0) {
    gchar *profile = NULL;

    /* FIXME does it make sense to expose the profile in the caps ? */
    profile = g_strdup_printf ("%d", parse->profile);
    gst_caps_set_simple (out_caps, "profile-level-id",
        G_TYPE_STRING, profile, NULL);
    g_free (profile);
  }

  if (parse->config != NULL) {
    gst_caps_set_simple (out_caps, "codec_data",
        GST_TYPE_BUFFER, parse->config, NULL);
  }

  if (fixed_time_increment != 0) {
    /* we have  a framerate */
    gst_caps_set_simple (out_caps, "framerate",
        GST_TYPE_FRACTION, time_increment_resolution, fixed_time_increment,
        NULL);
    parse->frame_duration = gst_util_uint64_scale_int (GST_SECOND,
        fixed_time_increment, time_increment_resolution);
  } else {
    /* unknown duration */
    parse->frame_duration = 0;
  }

  if (aspect_ratio_width > 0 && aspect_ratio_height > 0) {
    gst_caps_set_simple (out_caps, "pixel-aspect-ratio",
        GST_TYPE_FRACTION, aspect_ratio_width, aspect_ratio_height, NULL);
  }

  if (width > 0 && height > 0) {
    gst_caps_set_simple (out_caps,
        "width", G_TYPE_INT, width, "height", G_TYPE_INT, height, NULL);
  }

  GST_DEBUG_OBJECT (parse, "setting downstream caps to %" GST_PTR_FORMAT,
      out_caps);
  res = gst_pad_set_caps (parse->srcpad, out_caps);
  gst_caps_unref (out_caps);

  return res;
}

#define VIDEO_OBJECT_STARTCODE_MIN      0x00
#define VIDEO_OBJECT_STARTCODE_MAX      0x1F
#define VOS_STARTCODE                   0xB0
#define VOS_ENDCODE                     0xB1
#define USER_DATA_STARTCODE             0xB2
#define GOP_STARTCODE                   0xB3
#define VISUAL_OBJECT_STARTCODE         0xB5
#define VOP_STARTCODE                   0xB6

#define START_MARKER                    0x000001
#define VISUAL_OBJECT_STARTCODE_MARKER  ((START_MARKER << 8) + VISUAL_OBJECT_STARTCODE)
#define USER_DATA_STARTCODE_MARKER      ((START_MARKER << 8) + USER_DATA_STARTCODE)

typedef struct
{
  const guint8 *data;
  /* byte offset */
  gsize offset;
  /* bit offset */
  gsize b_offset;

  /* size in bytes */
  gsize size;
} bitstream_t;

static gboolean
get_bits (bitstream_t * b, int num, guint32 * bits)
{
  *bits = 0;

  if (b->offset + ((b->b_offset + num) / 8) > b->size)
    return FALSE;

  if (b->b_offset + num <= 8) {
    *bits = b->data[b->offset];
    *bits = (*bits >> (8 - num - b->b_offset)) & (((1 << num)) - 1);

    b->offset += (b->b_offset + num) / 8;
    b->b_offset = (b->b_offset + num) % 8;
    return TRUE;
  } else {
    /* going over the edge.. */
    int next;

    next = (8 - b->b_offset);
    do {
      guint32 t;

      if (!get_bits (b, next, &t))
        return FALSE;
      *bits <<= next;
      *bits |= t;
      num -= next;
      next = MIN (8, num);
    } while (num > 0);

    return TRUE;
  }
}

#define GET_BITS(b, num, bits) G_STMT_START { \
  if (!get_bits(b, num, bits))                \
    goto failed;                              \
} G_STMT_END

#define MARKER_BIT(b) G_STMT_START {  \
  guint32 i;                          \
  GET_BITS(b, 1, &i);                 \
  if (i != 0x1)                       \
    goto failed;                      \
} G_STMT_END

static inline gboolean
next_start_code (bitstream_t * b)
{
  guint32 bits;

  GET_BITS (b, 1, &bits);
  if (bits != 0)
    goto failed;

  while (b->b_offset != 0) {
    GET_BITS (b, 1, &bits);
    if (bits != 0x1)
      goto failed;
  }

  return TRUE;

failed:
  return FALSE;
}

static gint aspect_ratio_table[6][2] = { {-1, -1}, {1, 1}, {12, 11},
{10, 11}, {16, 11}, {40, 33}
};

/* Handle parsing a video object */
static gboolean
gst_mpeg4vparse_handle_vo (GstMpeg4VParse * parse, const guint8 * data,
    gsize size)
{
  guint32 bits;
  bitstream_t bs = { data, 0, 0, size };
  guint16 time_increment_resolution = 0;
  guint16 fixed_time_increment = 0;
  gint aspect_ratio_width = -1, aspect_ratio_height = -1;
  gint height = -1, width = -1;

  /* expecting a video object startcode */
  GET_BITS (&bs, 32, &bits);
  if (bits > 0x11F)
    goto failed;

  /* expecting a video object layer startcode */
  GET_BITS (&bs, 32, &bits);
  if (bits < 0x120 || bits > 0x12F)
    goto failed;

  /* ignore random accessible vol  and video object type indication */
  GET_BITS (&bs, 9, &bits);

  GET_BITS (&bs, 1, &bits);
  if (bits) {
    /* skip video object layer verid and priority */
    GET_BITS (&bs, 7, &bits);
  }

  /* aspect ratio info */
  GET_BITS (&bs, 4, &bits);
  if (bits == 0)
    goto failed;

  /* check if aspect ratio info  is extended par */
  if (bits == 0xf) {
    GET_BITS (&bs, 8, &bits);
    aspect_ratio_width = bits;
    GET_BITS (&bs, 8, &bits);
    aspect_ratio_height = bits;
  } else if (bits < 0x6) {
    aspect_ratio_width = aspect_ratio_table[bits][0];
    aspect_ratio_height = aspect_ratio_table[bits][1];
  }

  GET_BITS (&bs, 1, &bits);
  if (bits) {
    /* vol control parameters, skip chroma and low delay */
    GET_BITS (&bs, 3, &bits);
    GET_BITS (&bs, 1, &bits);
    if (bits) {
      /* skip vbv_parameters */
      GET_BITS (&bs, 79, &bits);
    }
  }

  /* layer shape */
  GET_BITS (&bs, 2, &bits);
  /* only support rectangular */
  if (bits != 0)
    goto failed;

  MARKER_BIT (&bs);
  GET_BITS (&bs, 16, &bits);
  time_increment_resolution = bits;
  MARKER_BIT (&bs);

  GST_DEBUG_OBJECT (parse, "time increment resolution %d",
      time_increment_resolution);

  GET_BITS (&bs, 1, &bits);
  if (bits) {
    /* fixed time increment */
    int n;

    /* Length of the time increment is the minimal number of bits needed to
     * represent time_increment_resolution */
    for (n = 0; (time_increment_resolution >> n) != 0; n++);
    GET_BITS (&bs, n, &bits);

    fixed_time_increment = bits;
  } else {
    /* When fixed_vop_rate is not set we can't guess any framerate */
    fixed_time_increment = 0;
  }
  GST_DEBUG_OBJECT (parse, "fixed time increment %d", fixed_time_increment);

  /* assuming rectangular shape */
  MARKER_BIT (&bs);
  GET_BITS (&bs, 13, &bits);
  width = bits;
  MARKER_BIT (&bs);
  GET_BITS (&bs, 13, &bits);
  height = bits;
  MARKER_BIT (&bs);

  /* ok we know there is enough data in the stream to decode it and we can start
   * pushing the data */
  parse->have_config = TRUE;

out:
  return gst_mpeg4vparse_set_new_caps (parse, time_increment_resolution,
      fixed_time_increment, aspect_ratio_width, aspect_ratio_height,
      width, height);

  /* ERRORS */
failed:
  {
    GST_WARNING_OBJECT (parse, "Failed to parse config data");
    goto out;
  }
}

static inline gboolean
skip_user_data (bitstream_t * bs, guint32 * bits)
{
  while (*bits == USER_DATA_STARTCODE_MARKER) {
    guint32 b;

    do {
      GET_BITS (bs, 8, &b);
      *bits = (*bits << 8) | b;
    } while ((*bits >> 8) != START_MARKER);
  }

  return TRUE;

failed:
  return FALSE;
}

/* Handle parsing a visual object sequence.
   Returns whether we successfully set the caps downstream if needed */
static gboolean
gst_mpeg4vparse_handle_vos (GstMpeg4VParse * parse, const guint8 * data,
    gsize size)
{
  /* Skip the startcode */
  guint32 bits;

  guint8 profile;
  gboolean equal;
  bitstream_t bs = { data, 0, 0, size };

  if (size < 5)
    goto failed;

  /* Parse the config from the VOS frame */
  bs.offset = 5;

  profile = data[4];

  /* invalid profile, yikes */
  if (profile == 0) {
    GST_WARNING_OBJECT (parse, "Invalid profile in VOS");
    return FALSE;
  }

  equal = FALSE;
  if (G_LIKELY (parse->config && size == GST_BUFFER_SIZE (parse->config) &&
          memcmp (GST_BUFFER_DATA (parse->config), data, size) == 0))
    equal = TRUE;

  if (G_LIKELY (parse->profile == profile && equal)) {
    /* We know this profile and config data, so we can just keep the same caps
     */
    return TRUE;
  }

  /* Even if we fail to parse, then some other element might succeed, so always
   * put the VOS in the config */
  parse->profile = profile;
  if (parse->config != NULL)
    gst_buffer_unref (parse->config);

  parse->config = gst_buffer_new_and_alloc (size);
  memcpy (GST_BUFFER_DATA (parse->config), data, size);

  parse->have_config = TRUE;

  /* Expect Visual Object startcode */
  GET_BITS (&bs, 32, &bits);

  /* but skip optional user data */
  if (!skip_user_data (&bs, &bits))
    goto failed;

  if (bits != VISUAL_OBJECT_STARTCODE_MARKER)
    goto failed;

  GET_BITS (&bs, 1, &bits);
  if (bits == 0x1) {
    /* Skip visual_object_verid and priority */
    GET_BITS (&bs, 7, &bits);
  }

  GET_BITS (&bs, 4, &bits);
  /* Only support video ID */
  if (bits != 0x1)
    goto failed;

  /* video signal type */
  GET_BITS (&bs, 1, &bits);

  if (bits == 0x1) {
    /* video signal type, ignore format and range */
    GET_BITS (&bs, 4, &bits);

    GET_BITS (&bs, 1, &bits);
    if (bits == 0x1) {
      /* ignore color description */
      GET_BITS (&bs, 24, &bits);
    }
  }

  if (!next_start_code (&bs))
    goto failed;

  /* skip optional user data */
  GET_BITS (&bs, 32, &bits);
  if (!skip_user_data (&bs, &bits))
    goto failed;
  /* rewind to start code */
  bs.offset -= 4;

  data = &bs.data[bs.offset];
  size -= bs.offset;

  return gst_mpeg4vparse_handle_vo (parse, data, size);

out:
  return gst_mpeg4vparse_set_new_caps (parse, 0, 0, -1, -1, -1, -1);

  /* ERRORS */
failed:
  {
    GST_WARNING_OBJECT (parse, "Failed to parse config data");
    goto out;
  }
}

static void
gst_mpeg4vparse_push (GstMpeg4VParse * parse, gsize size)
{
  if (G_UNLIKELY (!parse->have_config && parse->drop)) {
    GST_LOG_OBJECT (parse, "Dropping %d bytes", parse->offset);
    gst_adapter_flush (parse->adapter, size);
  } else {
    GstBuffer *out_buf;

    out_buf = gst_adapter_take_buffer (parse->adapter, parse->offset);

    if (out_buf) {
      /* Set GST_BUFFER_FLAG_DELTA_UNIT if it's not an intra frame */
      if (!parse->intra_frame) {
        GST_BUFFER_FLAG_SET (out_buf, GST_BUFFER_FLAG_DELTA_UNIT);
      }
      gst_buffer_set_caps (out_buf, GST_PAD_CAPS (parse->srcpad));
      GST_BUFFER_TIMESTAMP (out_buf) = parse->timestamp;
      gst_pad_push (parse->srcpad, out_buf);
    }
  }

  /* Restart now that we flushed data */
  parse->offset = 0;
  parse->state = PARSE_NEED_START;
  parse->intra_frame = FALSE;
}

static GstFlowReturn
gst_mpeg4vparse_drain (GstMpeg4VParse * parse, GstBuffer * last_buffer)
{
  GstFlowReturn ret = GST_FLOW_OK;
  const guint8 *data = NULL;
  guint available = 0;

  available = gst_adapter_available (parse->adapter);
  /* We do a quick check here to avoid the _peek() below. */
  if (G_UNLIKELY (available < 5)) {
    GST_DEBUG_OBJECT (parse, "we need more data, %d < 5", available);
    goto beach;
  }
  data = gst_adapter_peek (parse->adapter, available);

  /* Need at least 5 more bytes, 4 for the startcode, 1 to optionally determine
   * the VOP frame type */
  while (available >= 5 && parse->offset < available - 5) {
    if (data[parse->offset] == 0 && data[parse->offset + 1] == 0 &&
        data[parse->offset + 2] == 1) {

      switch (parse->state) {
        case PARSE_NEED_START:
        {
          gboolean found = FALSE;
          guint8 code;

          code = data[parse->offset + 3];

          switch (code) {
            case VOP_STARTCODE:
            case VOS_STARTCODE:
            case GOP_STARTCODE:
              found = TRUE;
              break;
            default:
              if (code <= 0x1f)
                found = TRUE;
              break;
          }
          if (found) {
            /* valid starts of a frame */
            parse->state = PARSE_START_FOUND;
            if (parse->offset > 0) {
              GST_LOG_OBJECT (parse, "Flushing %u bytes", parse->offset);
              gst_adapter_flush (parse->adapter, parse->offset);
              parse->offset = 0;
              available = gst_adapter_available (parse->adapter);
              data = gst_adapter_peek (parse->adapter, available);
            }
          } else
            parse->offset += 4;
          break;
        }
        case PARSE_START_FOUND:
        {
          guint8 code;

          code = data[parse->offset + 3];

          switch (code) {
            case VOP_STARTCODE:
              GST_LOG_OBJECT (parse, "found VOP start marker at %u",
                  parse->offset);
              parse->intra_frame = ((data[parse->offset + 4] >> 6 & 0x3) == 0);
              /* Ensure that the timestamp of the outgoing buffer is the same
               * as the one the VOP header is found in */
              parse->timestamp = GST_BUFFER_TIMESTAMP (last_buffer);
              parse->state = PARSE_VOP_FOUND;
              break;
            case VOS_STARTCODE:
              GST_LOG_OBJECT (parse, "found VOS start marker at %u",
                  parse->offset);
              parse->vos_offset = parse->offset;
              parse->state = PARSE_VOS_FOUND;
              break;
            default:
              if (code <= 0x1f) {
                GST_LOG_OBJECT (parse, "found VO start marker at %u",
                    parse->offset);
                parse->vos_offset = parse->offset;
                parse->state = PARSE_VO_FOUND;
              }
              break;
          }
          /* Jump over it */
          parse->offset += 4;
          break;
        }
        case PARSE_VO_FOUND:
          switch (data[parse->offset + 3]) {
            case GOP_STARTCODE:
            case VOP_STARTCODE:
              /* end of VOS found, interpret the config data and restart the
               * search for the VOP */
              gst_mpeg4vparse_handle_vo (parse, data + parse->vos_offset,
                  parse->offset - parse->vos_offset);
              parse->state = PARSE_START_FOUND;
              break;
            default:
              parse->offset += 4;
          }
          break;
        case PARSE_VOS_FOUND:
          switch (data[parse->offset + 3]) {
            case GOP_STARTCODE:
            case VOP_STARTCODE:
              /* end of VOS found, interpret the config data and restart the
               * search for the VOP */
              gst_mpeg4vparse_handle_vos (parse, data + parse->vos_offset,
                  parse->offset - parse->vos_offset);
              parse->state = PARSE_START_FOUND;
              break;
            default:
              parse->offset += 4;
          }
          break;
        case PARSE_VOP_FOUND:
        {                       /* We were in a VOP already, any start code marks the end of it */
          GST_LOG_OBJECT (parse, "found VOP end marker at %u", parse->offset);

          gst_mpeg4vparse_push (parse, parse->offset);

          available = gst_adapter_available (parse->adapter);
          data = gst_adapter_peek (parse->adapter, available);
          break;
        }
        default:
          GST_WARNING_OBJECT (parse, "unexpected parse state (%d)",
              parse->state);
          ret = GST_FLOW_UNEXPECTED;
          goto beach;
      }
    } else {                    /* Continue searching */
      parse->offset++;
    }
  }

beach:
  return ret;
}

static GstFlowReturn
gst_mpeg4vparse_chain (GstPad * pad, GstBuffer * buffer)
{
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (gst_pad_get_parent (pad));
  GstFlowReturn ret = GST_FLOW_OK;

  GST_DEBUG_OBJECT (parse, "received buffer of %u bytes with ts %"
      GST_TIME_FORMAT " and offset %" G_GINT64_FORMAT, GST_BUFFER_SIZE (buffer),
      GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)),
      GST_BUFFER_OFFSET (buffer));

  gst_adapter_push (parse->adapter, buffer);

  /* Drain the accumulated blocks frame per frame */
  ret = gst_mpeg4vparse_drain (parse, buffer);

  gst_object_unref (parse);

  return ret;
}

static gboolean
gst_mpeg4vparse_sink_setcaps (GstPad * pad, GstCaps * caps)
{
  gboolean res = TRUE;
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (gst_pad_get_parent (pad));
  GstStructure *s;
  const GValue *value;

  GST_DEBUG_OBJECT (parse, "setcaps called with %" GST_PTR_FORMAT, caps);

  s = gst_caps_get_structure (caps, 0);

  if ((value = gst_structure_get_value (s, "codec_data")) != NULL
      && G_VALUE_HOLDS (value, GST_TYPE_BUFFER)) {
    GstBuffer *buf = gst_value_get_buffer (value);

    /* Set the config from this codec_data immediately so that in the worst
       case, we don't just discard it.
       Note that in most cases, this will be freed and overwritten when we
       manage to parse the codec_data. */
    if (!parse->config) {
      parse->config = gst_buffer_copy (buf);
    }

    if (GST_BUFFER_SIZE (buf) < 4) {
      GST_WARNING_OBJECT (parse, "codec_data too short, ignoring");
      goto failed_parse;
    } else {
      const guint8 *data = GST_BUFFER_DATA (buf);

      if (data[0] == 0 && data[1] == 0 && data[2] == 1) {
        if (data[3] == VOS_STARTCODE) {
          /* Usually the codec data will be a visual object sequence, containing
             a visual object, with a video object/video object layer. */
          res = gst_mpeg4vparse_handle_vos (parse, data, GST_BUFFER_SIZE (buf));
        } else if (data[3] >= VIDEO_OBJECT_STARTCODE_MIN &&
            data[3] <= VIDEO_OBJECT_STARTCODE_MAX) {
          /* Sometimes, instead, it'll just have the video object/video object
             layer data. We can parse that too, though it'll give us slightly
             less information. */
          res = gst_mpeg4vparse_handle_vo (parse, data, GST_BUFFER_SIZE (buf));
        }
      } else {
        GST_WARNING_OBJECT (parse,
            "codec_data does not begin with start code, invalid");
        goto failed_parse;
      }
    }
  } else {
    /* No codec data; treat the same a failed codec data */
    goto failed_parse;
  }

done:
  gst_object_unref (parse);
  return res;

failed_parse:
  /* No codec data, or obviously-invalid, so set minimal new caps.
     VOS parsing later will (hopefully) fill in the other fields */
  res = gst_mpeg4vparse_set_new_caps (parse, 0, 0, 0, 0, 0, 0);
  goto done;
}

static gboolean
gst_mpeg4vparse_sink_event (GstPad * pad, GstEvent * event)
{
  gboolean res = TRUE;
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (gst_pad_get_parent (pad));

  GST_DEBUG_OBJECT (parse, "handling event type %s",
      GST_EVENT_TYPE_NAME (event));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_EOS:
      if (parse->state == PARSE_VOP_FOUND) {
        /* If we've found the start of the VOP assume what's left in the
         * adapter is the complete VOP. This might cause us to send an
         * incomplete VOP out, but prevents the last video frame from
         * potentially being dropped */
        gst_mpeg4vparse_push (parse, gst_adapter_available (parse->adapter));
      }
      /* fallthrough */
    default:
      res = gst_pad_event_default (pad, event);
      break;
  }

  gst_object_unref (parse);

  return res;
}

static gboolean
gst_mpeg4vparse_src_query (GstPad * pad, GstQuery * query)
{
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (gst_pad_get_parent (pad));
  gboolean res;

  switch (GST_QUERY_TYPE (query)) {
    case GST_QUERY_LATENCY:
    {
      /* We need to send the query upstream and add the returned latency to our
       * own */
      GstClockTime min_latency, max_latency;

      gboolean us_live;

      GstClockTime our_latency;

      if ((res = gst_pad_peer_query (parse->sinkpad, query))) {
        gst_query_parse_latency (query, &us_live, &min_latency, &max_latency);

        GST_DEBUG_OBJECT (parse, "Peer latency: min %"
            GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
            GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));

        /* our latency is 1 frame, find the frame duration */
        our_latency = parse->frame_duration;

        GST_DEBUG_OBJECT (parse, "Our latency: %" GST_TIME_FORMAT,
            GST_TIME_ARGS (our_latency));

        /* we add some latency */
        min_latency += our_latency;
        if (max_latency != -1)
          max_latency += our_latency;

        GST_DEBUG_OBJECT (parse, "Calculated total latency : min %"
            GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
            GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));

        gst_query_set_latency (query, us_live, min_latency, max_latency);
      }
      break;
    }
    default:
      res = gst_pad_peer_query (parse->sinkpad, query);
      break;
  }
  gst_object_unref (parse);

  return res;
}

static void
gst_mpeg4vparse_cleanup (GstMpeg4VParse * parse)
{
  if (parse->adapter) {
    gst_adapter_clear (parse->adapter);
  }
  if (parse->config != NULL) {
    gst_buffer_unref (parse->config);
    parse->config = NULL;
  }

  parse->state = PARSE_NEED_START;
  parse->have_config = FALSE;
  parse->offset = 0;
}

static GstStateChangeReturn
gst_mpeg4vparse_change_state (GstElement * element, GstStateChange transition)
{
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (element);

  GstStateChangeReturn ret;

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

  switch (transition) {
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      gst_mpeg4vparse_cleanup (parse);
      break;
    default:
      break;
  }
  return ret;
}

static void
gst_mpeg4vparse_dispose (GObject * object)
{
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (object);

  if (parse->adapter) {
    g_object_unref (parse->adapter);
    parse->adapter = NULL;
  }
  if (parse->config != NULL) {
    gst_buffer_unref (parse->config);
    parse->config = NULL;
  }

  GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
}

static void
gst_mpeg4vparse_base_init (gpointer klass)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&src_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&sink_template));

  gst_element_class_set_details (element_class, &mpeg4vparse_details);
}

static void
gst_mpeg4vparse_set_property (GObject * object, guint property_id,
    const GValue * value, GParamSpec * pspec)
{
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (object);

  switch (property_id) {
    case PROP_DROP:
      parse->drop = g_value_get_boolean (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
  }
}

static void
gst_mpeg4vparse_get_property (GObject * object, guint property_id,
    GValue * value, GParamSpec * pspec)
{
  GstMpeg4VParse *parse = GST_MPEG4VIDEOPARSE (object);

  switch (property_id) {
    case PROP_DROP:
      g_value_set_boolean (value, parse->drop);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
  }
}

static void
gst_mpeg4vparse_class_init (GstMpeg4VParseClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;
  gstelement_class = (GstElementClass *) klass;
  gobject_class = G_OBJECT_CLASS (klass);

  parent_class = g_type_class_peek_parent (klass);

  gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_mpeg4vparse_dispose);

  gobject_class->set_property = gst_mpeg4vparse_set_property;
  gobject_class->get_property = gst_mpeg4vparse_get_property;

  g_object_class_install_property (gobject_class, PROP_DROP,
      g_param_spec_boolean ("drop", "drop",
          "Drop data untill valid configuration data is received either "
          "in the stream or through caps", DEFAULT_PROP_DROP,
          G_PARAM_CONSTRUCT | G_PARAM_READWRITE));

  gstelement_class->change_state =
      GST_DEBUG_FUNCPTR (gst_mpeg4vparse_change_state);
}

static void
gst_mpeg4vparse_init (GstMpeg4VParse * parse, GstMpeg4VParseClass * g_class)
{
  parse->sinkpad = gst_pad_new_from_static_template (&sink_template, "sink");
  gst_pad_set_chain_function (parse->sinkpad,
      GST_DEBUG_FUNCPTR (gst_mpeg4vparse_chain));
  gst_pad_set_event_function (parse->sinkpad,
      GST_DEBUG_FUNCPTR (gst_mpeg4vparse_sink_event));
  gst_pad_set_setcaps_function (parse->sinkpad,
      GST_DEBUG_FUNCPTR (gst_mpeg4vparse_sink_setcaps));
  gst_element_add_pad (GST_ELEMENT (parse), parse->sinkpad);

  parse->srcpad = gst_pad_new_from_static_template (&src_template, "src");
  gst_pad_set_query_function (parse->srcpad,
      GST_DEBUG_FUNCPTR (gst_mpeg4vparse_src_query));
  gst_pad_use_fixed_caps (parse->srcpad);
  gst_element_add_pad (GST_ELEMENT (parse), parse->srcpad);

  parse->adapter = gst_adapter_new ();

  gst_mpeg4vparse_cleanup (parse);
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  GST_DEBUG_CATEGORY_INIT (mpeg4v_parse_debug, "mpeg4videoparse", 0,
      "MPEG-4 video parser");

  if (!gst_element_register (plugin, "mpeg4videoparse", GST_RANK_SECONDARY,
          gst_mpeg4vparse_get_type ()))
    return FALSE;

  return TRUE;
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "mpeg4videoparse",
    "MPEG-4 video parser",
    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)