gstreamer/gst/mpegtsmux/mpegtsmux.c

/* 
 * Copyright 2006, 2007, 2008 Fluendo S.A. 
 *  Authors: Jan Schmidt <jan@fluendo.com>
 *           Kapil Agrawal <kapil@fluendo.com>
 *           Julien Moutte <julien@fluendo.com>
 *
 * This library is licensed under 4 different licenses and you
 * can choose to use it under the terms of any one of them. The
 * four licenses are the MPL 1.1, the LGPL, the GPL and the MIT
 * license.
 *
 * MPL:
 * 
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * LGPL:
 *
 * 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.
 *
 * GPL:
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * MIT:
 *
 * Unless otherwise indicated, Source Code is licensed under MIT license.
 * See further explanation attached in License Statement (distributed in the file
 * LICENSE).
 * 
 * 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.
 *
 */

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

#include "mpegtsmux.h"

#include "mpegtsmux_h264.h"
#include "mpegtsmux_aac.h"

GST_DEBUG_CATEGORY (mpegtsmux_debug);
#define GST_CAT_DEFAULT mpegtsmux_debug

enum
{
  ARG_0,
  ARG_M2TS_MODE
};

static GstStaticPadTemplate mpegtsmux_sink_factory =
    GST_STATIC_PAD_TEMPLATE ("sink_%d",
    GST_PAD_SINK,
    GST_PAD_REQUEST,
    GST_STATIC_CAPS ("video/mpeg, mpegversion=(int) { 1, 2 }, "
        "systemstream = (boolean) false; "
        "video/x-dirac;"
        "video/x-h264;" "audio/mpeg, mpegversion = (int) { 1, 2, 4 }")
    );

static GstStaticPadTemplate mpegtsmux_src_factory =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/mpegts, "
        "systemstream = (boolean) true, " "packetsize = (int) { 188, 192} ")
    );

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

static void mpegtsmux_dispose (GObject * object);
static gboolean new_packet_cb (guint8 * data, guint len, void *user_data,
    gint64 new_pcr);
static void release_buffer_cb (guint8 * data, void *user_data);

static gboolean mpegtsdemux_prepare_srcpad (MpegTsMux * mux);
static GstFlowReturn mpegtsmux_collected (GstCollectPads * pads,
    MpegTsMux * mux);
static GstPad *mpegtsmux_request_new_pad (GstElement * element,
    GstPadTemplate * templ, const gchar * name);
static void mpegtsmux_release_pad (GstElement * element, GstPad * pad);
static GstStateChangeReturn mpegtsmux_change_state (GstElement * element,
    GstStateChange transition);

GST_BOILERPLATE (MpegTsMux, mpegtsmux, GstElement, GST_TYPE_ELEMENT);

static void
mpegtsmux_base_init (gpointer g_class)
{
  const GstElementDetails mpegtsmux_details = {
    "MPEG Transport Stream Muxer",
    "Codec/Muxer",
    "Multiplexes media streams into an MPEG Transport Stream",
    "Fluendo <contact@fluendo.com>"
  };
  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&mpegtsmux_sink_factory));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&mpegtsmux_src_factory));

  gst_element_class_set_details (element_class, &mpegtsmux_details);
}

static void
mpegtsmux_class_init (MpegTsMuxClass * klass)
{
  GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_mpegtsmux_set_property);
  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_mpegtsmux_get_property);
  gobject_class->dispose = mpegtsmux_dispose;

  gstelement_class->request_new_pad = mpegtsmux_request_new_pad;
  gstelement_class->release_pad = mpegtsmux_release_pad;
  gstelement_class->change_state = mpegtsmux_change_state;

  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_M2TS_MODE,
      g_param_spec_boolean ("m2ts_mode", "M2TS(192 bytes) Mode",
          "Defines what packet size to use, normal TS format ie .ts(188 bytes) "
          "or Blue-Ray disc ie .m2ts(192 bytes).", FALSE, G_PARAM_READWRITE));

}

static void
mpegtsmux_init (MpegTsMux * mux, MpegTsMuxClass * g_class)
{
  mux->srcpad =
      gst_pad_new_from_template (gst_static_pad_template_get
      (&mpegtsmux_src_factory), "src");
  gst_pad_use_fixed_caps (mux->srcpad);
  gst_element_add_pad (GST_ELEMENT (mux), mux->srcpad);

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

  mux->tsmux = tsmux_new ();
  tsmux_set_write_func (mux->tsmux, new_packet_cb, mux);
  mux->program = tsmux_program_new (mux->tsmux);

  mux->first = TRUE;
  mux->last_flow_ret = GST_FLOW_OK;
  mux->adapter = gst_adapter_new ();
  mux->m2ts_mode = FALSE;
  mux->first_pcr = TRUE;
  mux->last_ts = 0;
}

static void
mpegtsmux_dispose (GObject * object)
{
  MpegTsMux *mux = GST_MPEG_TSMUX (object);

  if (mux->adapter) {
    gst_adapter_clear (mux->adapter);
    gst_object_unref (mux->adapter);
    mux->adapter = NULL;
  }
  if (mux->collect) {
    gst_object_unref (mux->collect);
    mux->collect = NULL;
  }
  if (mux->tsmux) {
    tsmux_free (mux->tsmux);
    mux->tsmux = NULL;
  }

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

static void
gst_mpegtsmux_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  MpegTsMux *mux = GST_MPEG_TSMUX (object);

  switch (prop_id) {
    case ARG_M2TS_MODE:
      /*set incase if the output stream need to be of 192 bytes */
      mux->m2ts_mode = g_value_get_boolean (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_mpegtsmux_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  MpegTsMux *mux = GST_MPEG_TSMUX (object);

  switch (prop_id) {
    case ARG_M2TS_MODE:
      g_value_set_boolean (value, mux->m2ts_mode);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
release_buffer_cb (guint8 * data, void *user_data)
{
  GstBuffer *buf = (GstBuffer *) user_data;
  gst_buffer_unref (buf);
}

static GstFlowReturn
mpegtsmux_create_stream (MpegTsMux * mux, MpegTsPadData * ts_data, GstPad * pad)
{
  GstFlowReturn ret = GST_FLOW_ERROR;
  GstCaps *caps = gst_pad_get_negotiated_caps (pad);
  GstStructure *s;

  if (caps == NULL) {
    GST_DEBUG_OBJECT (pad, "Sink pad caps were not set before pushing");
    return GST_FLOW_NOT_NEGOTIATED;
  }

  s = gst_caps_get_structure (caps, 0);
  g_return_val_if_fail (s != NULL, FALSE);

  if (gst_structure_has_name (s, "video/x-dirac")) {
    GST_DEBUG_OBJECT (pad, "Creating Dirac stream with PID 0x%04x",
        ts_data->pid);
    ts_data->stream = tsmux_create_stream (mux->tsmux, TSMUX_ST_VIDEO_DIRAC,
        ts_data->pid);
  } else if (gst_structure_has_name (s, "video/x-h264")) {
    const GValue *value;
    GST_DEBUG_OBJECT (pad, "Creating H264 stream with PID 0x%04x",
        ts_data->pid);
    /* Codec data contains SPS/PPS which need to go in stream for valid ES */
    value = gst_structure_get_value (s, "codec_data");
    if (value) {
      ts_data->codec_data = gst_buffer_ref (gst_value_get_buffer (value));
      GST_DEBUG_OBJECT (pad, "we have additional codec data (%d bytes)",
          GST_BUFFER_SIZE (ts_data->codec_data));
      ts_data->prepare_func = mpegtsmux_prepare_h264;
    } else {
      ts_data->codec_data = NULL;
    }
    ts_data->stream = tsmux_create_stream (mux->tsmux, TSMUX_ST_VIDEO_H264,
        ts_data->pid);
  } else if (gst_structure_has_name (s, "audio/mpeg")) {
    gint mpegversion;
    if (!gst_structure_get_int (s, "mpegversion", &mpegversion)) {
      GST_ELEMENT_ERROR (pad, STREAM, FORMAT,
          ("Invalid data format presented"),
          ("Caps with type audio/mpeg did not have mpegversion"));
      goto beach;
    }

    switch (mpegversion) {
      case 1:
        GST_DEBUG_OBJECT (pad, "Creating MPEG Audio, version 1 stream with "
            "PID 0x%04x", ts_data->pid);
        ts_data->stream = tsmux_create_stream (mux->tsmux, TSMUX_ST_AUDIO_MPEG1,
            ts_data->pid);
        break;
      case 2:
        GST_DEBUG_OBJECT (pad, "Creating MPEG Audio, version 2 stream with "
            "PID 0x%04x", ts_data->pid);
        ts_data->stream = tsmux_create_stream (mux->tsmux, TSMUX_ST_AUDIO_MPEG2,
            ts_data->pid);
        break;
      case 4:
      {
        const GValue *value;
        /* Codec data contains SPS/PPS which need to go in stream for valid ES */
        value = gst_structure_get_value (s, "codec_data");
        if (value) {
          ts_data->codec_data = gst_buffer_ref (gst_value_get_buffer (value));
          GST_DEBUG_OBJECT (pad, "we have additional codec data (%d bytes)",
              GST_BUFFER_SIZE (ts_data->codec_data));
          ts_data->prepare_func = mpegtsmux_prepare_aac;
        } else {
          ts_data->codec_data = NULL;
        }
        GST_DEBUG_OBJECT (pad, "Creating MPEG Audio, version 4 stream with "
            "PID 0x%04x", ts_data->pid);
        ts_data->stream = tsmux_create_stream (mux->tsmux, TSMUX_ST_AUDIO_AAC,
            ts_data->pid);
        break;
      }
      default:
        GST_WARNING_OBJECT (pad, "unsupported mpegversion %d", mpegversion);
        goto beach;
    }
  } else if (gst_structure_has_name (s, "video/mpeg")) {
    gint mpegversion;
    if (!gst_structure_get_int (s, "mpegversion", &mpegversion)) {
      GST_ELEMENT_ERROR (mux, STREAM, FORMAT,
          ("Invalid data format presented"),
          ("Caps with type video/mpeg did not have mpegversion"));
      goto beach;
    }

    if (mpegversion == 1) {
      GST_DEBUG_OBJECT (pad,
          "Creating MPEG Video, version 1 stream with PID 0x%04x",
          ts_data->pid);
      ts_data->stream = tsmux_create_stream (mux->tsmux, TSMUX_ST_VIDEO_MPEG1,
          ts_data->pid);
    } else {
      GST_DEBUG_OBJECT (pad,
          "Creating MPEG Video, version 2 stream with PID 0x%04x",
          ts_data->pid);
      ts_data->stream = tsmux_create_stream (mux->tsmux, TSMUX_ST_VIDEO_MPEG2,
          ts_data->pid);
    }
  }

  if (ts_data->stream != NULL) {
    tsmux_stream_set_buffer_release_func (ts_data->stream, release_buffer_cb);
    tsmux_program_add_stream (mux->program, ts_data->stream);

    ret = GST_FLOW_OK;
  }

beach:
  return ret;
}

static GstFlowReturn
mpegtsmux_create_streams (MpegTsMux * mux)
{
  GstFlowReturn ret = GST_FLOW_OK;
  GSList *walk = mux->collect->data;

  /* Create the streams */
  while (walk) {
    GstCollectData *c_data = (GstCollectData *) walk->data;
    MpegTsPadData *ts_data = (MpegTsPadData *) walk->data;

    walk = g_slist_next (walk);

    if (ts_data->stream == NULL) {
      ret = mpegtsmux_create_stream (mux, ts_data, c_data->pad);
      if (ret != GST_FLOW_OK)
        goto no_stream;
    }
  }

  return GST_FLOW_OK;
no_stream:
  GST_ELEMENT_ERROR (mux, STREAM, MUX,
      ("Could not create handler for stream"), (NULL));
  return ret;
}

static MpegTsPadData *
mpegtsmux_choose_best_stream (MpegTsMux * mux)
{
  MpegTsPadData *best = NULL;
  GSList *walk;

  for (walk = mux->collect->data; walk != NULL; walk = g_slist_next (walk)) {
    GstCollectData *c_data = (GstCollectData *) walk->data;
    MpegTsPadData *ts_data = (MpegTsPadData *) walk->data;

    if (ts_data->eos == FALSE) {
      if (ts_data->queued_buf == NULL) {
        GstBuffer *buf;

        ts_data->queued_buf = buf = gst_collect_pads_pop (mux->collect, c_data);

        if (buf != NULL) {
          if (ts_data->prepare_func) {
            buf = ts_data->prepare_func (buf, ts_data, mux);
            if (buf) {          /* Take the prepared buffer instead */
              gst_buffer_unref (ts_data->queued_buf);
              ts_data->queued_buf = buf;
            } else {            /* If data preparation returned NULL, use unprepared one */
              buf = ts_data->queued_buf;
            }
          }
          if (GST_BUFFER_TIMESTAMP (buf) != GST_CLOCK_TIME_NONE) {
            /* Ignore timestamps that go backward for now. FIXME: Handle all
             * incoming PTS */
            if (ts_data->last_ts == GST_CLOCK_TIME_NONE ||
                ts_data->last_ts < GST_BUFFER_TIMESTAMP (buf)) {
              ts_data->cur_ts = ts_data->last_ts =
                  gst_segment_to_running_time (&c_data->segment,
                  GST_FORMAT_TIME, GST_BUFFER_TIMESTAMP (buf));
            } else {
              GST_DEBUG_OBJECT (mux, "Ignoring PTS that has gone backward");
            }
          } else
            ts_data->cur_ts = GST_CLOCK_TIME_NONE;

          GST_DEBUG_OBJECT (mux, "Pulled buffer with ts %" GST_TIME_FORMAT
              " (uncorrected ts %" GST_TIME_FORMAT " %" G_GUINT64_FORMAT
              ") for PID 0x%04x",
              GST_TIME_ARGS (ts_data->cur_ts),
              GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)),
              GST_BUFFER_TIMESTAMP (buf), ts_data->pid);

          /* Choose a stream we've never seen a timestamp for to ensure
           * we push enough buffers from it to reach a timestamp */
          if (ts_data->last_ts == GST_CLOCK_TIME_NONE)
            best = ts_data;
        } else {
          ts_data->eos = TRUE;
          continue;
        }
      }

      /* If we don't yet have a best pad, take this one, otherwise take
       * whichever has the oldest timestamp */
      if (best != NULL) {
        if (ts_data->last_ts != GST_CLOCK_TIME_NONE &&
            best->last_ts != GST_CLOCK_TIME_NONE &&
            ts_data->last_ts < best->last_ts) {
          best = ts_data;
        }
      } else {
        best = ts_data;
      }
    }
  }

  return best;
}

static GstFlowReturn
mpegtsmux_collected (GstCollectPads * pads, MpegTsMux * mux)
{
  GstFlowReturn ret = GST_FLOW_OK;
  MpegTsPadData *best = NULL;

  GST_DEBUG_OBJECT (mux, "Pads collected");

  if (mux->first) {
    ret = mpegtsmux_create_streams (mux);
    if (G_UNLIKELY (ret != GST_FLOW_OK))
      return ret;

    best = mpegtsmux_choose_best_stream (mux);

    if (mux->pcr_stream == NULL) {
      if (best) {
        GstCollectData *c_data = (GstCollectData *) best;
        /* Take the first data stream for the PCR */
        GST_DEBUG_OBJECT (mux, "Use stream from pad %" GST_PTR_FORMAT " as PCR",
            c_data->pad);
        mux->pcr_stream = best->stream;
      }
    }

    /* Set the chosen PCR stream */
    g_return_val_if_fail (mux->pcr_stream != NULL, GST_FLOW_ERROR);
    tsmux_program_set_pcr_stream (mux->program, mux->pcr_stream);

    if (!mpegtsdemux_prepare_srcpad (mux)) {
      GST_DEBUG_OBJECT (mux, "Failed to send new segment");
      goto new_seg_fail;
    }

    mux->first = FALSE;
  } else {
    best = mpegtsmux_choose_best_stream (mux);
  }

  if (best != NULL) {
    GstBuffer *buf = best->queued_buf;
    GstCollectData *c_data = (GstCollectData *) best;
    gint64 pts = -1;

    g_return_val_if_fail (buf != NULL, GST_FLOW_ERROR);

    GST_DEBUG_OBJECT (mux,
        "Chose stream from pad %" GST_PTR_FORMAT " for output (PID: 0x%04x)",
        c_data->pad, best->pid);

    if (GST_CLOCK_TIME_IS_VALID (best->cur_ts)) {
      pts = GSTTIME_TO_MPEGTIME (best->cur_ts);
      GST_DEBUG_OBJECT (mux, "Buffer has TS %" GST_TIME_FORMAT " pts %"
          G_GINT64_FORMAT, GST_TIME_ARGS (best->cur_ts), pts);
    }

    tsmux_stream_add_data (best->stream, GST_BUFFER_DATA (buf),
        GST_BUFFER_SIZE (buf), buf, pts, -1);
    best->queued_buf = NULL;

    while (tsmux_stream_bytes_in_buffer (best->stream) > 0) {
      if (!tsmux_write_stream_packet (mux->tsmux, best->stream)) {
        GST_DEBUG_OBJECT (mux, "Failed to write data packet");
        goto write_fail;
      }
    }
    if (mux->pcr_stream == best->stream) {
      mux->last_ts = best->last_ts;
    }
  } else {
    /* FIXME: Drain all remaining streams */
    /* At EOS */
    gst_pad_push_event (mux->srcpad, gst_event_new_eos ());
  }

  return ret;
new_seg_fail:
  return GST_FLOW_ERROR;
write_fail:
  /* FIXME: Failed writing data for some reason. Should set appropriate error */
  return mux->last_flow_ret;
}

static GstPad *
mpegtsmux_request_new_pad (GstElement * element,
    GstPadTemplate * templ, const gchar * name)
{
  MpegTsMux *mux = GST_MPEG_TSMUX (element);
  gint pid = -1;
  gchar *pad_name = NULL;
  GstPad *pad = NULL;
  MpegTsPadData *pad_data = NULL;

  if (name != NULL && sscanf (name, "sink_%d", &pid) == 1) {
    if (tsmux_find_stream (mux->tsmux, pid))
      goto stream_exists;
  } else {
    pid = tsmux_get_new_pid (mux->tsmux);
  }

  pad_name = g_strdup_printf ("sink_%d", pid);
  pad = gst_pad_new_from_template (templ, pad_name);
  g_free (pad_name);

  pad_data = (MpegTsPadData *) gst_collect_pads_add_pad (mux->collect, pad,
      sizeof (MpegTsPadData));
  if (pad_data == NULL)
    goto pad_failure;

  pad_data->pid = pid;
  pad_data->last_ts = GST_CLOCK_TIME_NONE;
  pad_data->codec_data = NULL;
  pad_data->prepare_func = NULL;

  if (G_UNLIKELY (!gst_element_add_pad (element, pad)))
    goto could_not_add;

  return pad;

stream_exists:
  GST_ELEMENT_ERROR (element, STREAM, MUX, ("Duplicate PID requested"), (NULL));
  return NULL;

could_not_add:
  GST_ELEMENT_ERROR (element, STREAM, FAILED,
      ("Internal data stream error."), ("Could not add pad to element"));
  gst_collect_pads_remove_pad (mux->collect, pad);
  gst_object_unref (pad);
  return NULL;
pad_failure:
  GST_ELEMENT_ERROR (element, STREAM, FAILED,
      ("Internal data stream error."), ("Could not add pad to collectpads"));
  gst_object_unref (pad);
  return NULL;
}

static void
mpegtsmux_release_pad (GstElement * element, GstPad * pad)
{
  MpegTsMux *mux = GST_MPEG_TSMUX (element);
  MpegTsPadData *pad_data = NULL;

  GST_DEBUG_OBJECT (mux, "Pad %" GST_PTR_FORMAT " being released", pad);

  /* Get the MpegTsPadData out of the pad */
  GST_OBJECT_LOCK (pad);
  pad_data = (MpegTsPadData *) gst_pad_get_element_private (pad);
  if (G_LIKELY (pad_data)) {
    /* Free codec data reference if any */
    if (pad_data->codec_data) {
      GST_DEBUG_OBJECT (element, "releasing codec_data reference");
      gst_buffer_unref (pad_data->codec_data);
      pad_data->codec_data = NULL;
    }
  }
  GST_OBJECT_UNLOCK (pad);

  gst_collect_pads_remove_pad (mux->collect, pad);
}

static gboolean
new_packet_cb (guint8 * data, guint len, void *user_data, gint64 new_pcr)
{
  /* Called when the TsMux has prepared a packet for output. Return FALSE
   * on error */
  MpegTsMux *mux = (MpegTsMux *) user_data;
  GstBuffer *buf, *out_buf;
  GstFlowReturn ret;
  gfloat current_ts;
  gint64 m2ts_pcr, pcr_bytes, chunk_bytes;
  gint8 *temp_ptr;
  gint64 ts_rate;

  if (mux->m2ts_mode == TRUE) {
    /* Enters when the m2ts-mode is set true */
    buf = gst_buffer_new_and_alloc (M2TS_PACKET_LENGTH);
    if (G_UNLIKELY (buf == NULL)) {
      mux->last_flow_ret = GST_FLOW_ERROR;
      return FALSE;
    }
    /* copies the ts data of 188 bytes to the m2ts buffer at an offset 
       of 4 bytes of timestamp  */
    memcpy (GST_BUFFER_DATA (buf) + 4, data, len);

    if (new_pcr >= 0) {
      /*when there is a pcr value in ts data */
      pcr_bytes = 0;
      if (mux->first_pcr) {
        /*Incase of first pcr */
        /*writing the 4  byte timestamp value */
        GST_WRITE_UINT32_BE (GST_BUFFER_DATA (buf), new_pcr);

        GST_LOG_OBJECT (mux, "Outputting a packet of length %d",
            M2TS_PACKET_LENGTH);
        ret = gst_pad_push (mux->srcpad, buf);
        if (G_UNLIKELY (ret != GST_FLOW_OK)) {
          mux->last_flow_ret = ret;
          return FALSE;
        }
        mux->first_pcr = FALSE;
        mux->previous_pcr = new_pcr;
        pcr_bytes = M2TS_PACKET_LENGTH;
      }
      chunk_bytes = gst_adapter_available (mux->adapter);

      if (G_UNLIKELY (chunk_bytes)) {
        /* calculate rate based on latest and previous pcr values */
        ts_rate = ((chunk_bytes * STANDARD_TIME_CLOCK) / (new_pcr -
                mux->previous_pcr));
        while (1) {
          /*loop till all the accumulated ts packets are transformed to 
             m2ts packets and pushed */
          current_ts = ((gfloat) mux->previous_pcr / STANDARD_TIME_CLOCK) +
              ((gfloat) pcr_bytes / ts_rate);
          m2ts_pcr = (((gint64) (STANDARD_TIME_CLOCK * current_ts / 300) &
                  TWO_POW_33_MINUS1) * 300) + ((gint64) (STANDARD_TIME_CLOCK *
                  current_ts) % 300);
          temp_ptr = (gint8 *) & m2ts_pcr;

          out_buf = gst_adapter_take_buffer (mux->adapter, M2TS_PACKET_LENGTH);
          if (G_UNLIKELY (!out_buf))
            break;

          /*writing the 4  byte timestamp value */
          GST_WRITE_UINT32_BE (GST_BUFFER_DATA (out_buf), m2ts_pcr);

          GST_LOG_OBJECT (mux, "Outputting a packet of length %d",
              M2TS_PACKET_LENGTH);
          ret = gst_pad_push (mux->srcpad, out_buf);
          if (G_UNLIKELY (ret != GST_FLOW_OK)) {
            mux->last_flow_ret = ret;
            return FALSE;
          }
          pcr_bytes += M2TS_PACKET_LENGTH;
        }
        mux->previous_pcr = m2ts_pcr;
      }
    } else
      /* If theres no pcr in current ts packet then push the packet 
         to an adapter, which is used to create m2ts packets */
      gst_adapter_push (mux->adapter, buf);
  } else {
    /* In case of Normal Ts packets */
    GST_LOG_OBJECT (mux, "Outputting a packet of length %d", len);
    buf = gst_buffer_new_and_alloc (len);
    if (G_UNLIKELY (buf == NULL)) {
      mux->last_flow_ret = GST_FLOW_ERROR;
      return FALSE;
    }

    memcpy (GST_BUFFER_DATA (buf), data, len);
    GST_BUFFER_TIMESTAMP (buf) = mux->last_ts;
    ret = gst_pad_push (mux->srcpad, buf);
    if (G_UNLIKELY (ret != GST_FLOW_OK)) {
      mux->last_flow_ret = ret;
      return FALSE;
    }
  }

  return TRUE;
}

static gboolean
mpegtsdemux_prepare_srcpad (MpegTsMux * mux)
{
  GstEvent *new_seg =
      gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_BYTES, 0, -1, 0);
  GstCaps *caps = gst_caps_new_simple ("video/mpegts",
      "systemstream", G_TYPE_BOOLEAN, TRUE,
      "packetsize", G_TYPE_INT,
      (mux->m2ts_mode ? M2TS_PACKET_LENGTH : NORMAL_TS_PACKET_LENGTH),
      NULL);

//      gst_static_pad_template_get_caps (&mpegtsmux_src_factory);

  /* Set caps on src pad from our template and push new segment */
  gst_pad_set_caps (mux->srcpad, caps);

  if (!gst_pad_push_event (mux->srcpad, new_seg)) {
    GST_WARNING_OBJECT (mux, "New segment event was not handled");
    return FALSE;
  }

  return TRUE;
}

static GstStateChangeReturn
mpegtsmux_change_state (GstElement * element, GstStateChange transition)
{
  MpegTsMux *mux = GST_MPEG_TSMUX (element);
  GstStateChangeReturn ret;

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

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

  switch (transition) {
    default:
      break;
  }

  return ret;
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  if (!gst_element_register (plugin, "mpegtsmux", GST_RANK_PRIMARY,
          mpegtsmux_get_type ()))
    return FALSE;

  GST_DEBUG_CATEGORY_INIT (mpegtsmux_debug, "mpegtsmux", 0,
      "MPEG Transport Stream muxer");

  return TRUE;
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR, GST_VERSION_MINOR,
    "mpegtsmux", "MPEG-TS muxer",
    plugin_init, VERSION, "LGPL", GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN);