/* GStreamer
 * Copyright (C) <2005> Wim Taymans <wim@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 <gst/rtp/gstrtpbuffer.h>

#include "gstrtph263ppay.h"

/* elementfactory information */
static const GstElementDetails gst_rtp_h263ppay_details =
GST_ELEMENT_DETAILS ("RTP packet payloader",
    "Codec/Payloader/Network",
    "Payload-encodes H263+ video in RTP packets (RFC 2429)",
    "Wim Taymans <wim@fluendo.com>");

static GstStaticPadTemplate gst_rtp_h263p_pay_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-h263, "
        "variant = (string) \"itu\", " "h263version = (string) \"h263p\"")
    );

static GstStaticPadTemplate gst_rtp_h263p_pay_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("application/x-rtp, "
        "media = (string) \"video\", "
        "payload = (int) [ 96, 127 ], "
        "clock-rate = (int) 90000, " "encoding-name = (string) \"H263-1998\"")
    );

static void gst_rtp_h263p_pay_class_init (GstRtpH263PPayClass * klass);
static void gst_rtp_h263p_pay_base_init (GstRtpH263PPayClass * klass);
static void gst_rtp_h263p_pay_init (GstRtpH263PPay * rtph263ppay);
static void gst_rtp_h263p_pay_finalize (GObject * object);

static gboolean gst_rtp_h263p_pay_setcaps (GstBaseRTPPayload * payload,
    GstCaps * caps);
static GstFlowReturn gst_rtp_h263p_pay_handle_buffer (GstBaseRTPPayload *
    payload, GstBuffer * buffer);

static GstBaseRTPPayloadClass *parent_class = NULL;

static GType
gst_rtp_h263p_pay_get_type (void)
{
  static GType rtph263ppay_type = 0;

  if (!rtph263ppay_type) {
    static const GTypeInfo rtph263ppay_info = {
      sizeof (GstRtpH263PPayClass),
      (GBaseInitFunc) gst_rtp_h263p_pay_base_init,
      NULL,
      (GClassInitFunc) gst_rtp_h263p_pay_class_init,
      NULL,
      NULL,
      sizeof (GstRtpH263PPay),
      0,
      (GInstanceInitFunc) gst_rtp_h263p_pay_init,
    };

    rtph263ppay_type =
        g_type_register_static (GST_TYPE_BASE_RTP_PAYLOAD, "GstRtpH263PPay",
        &rtph263ppay_info, 0);
  }
  return rtph263ppay_type;
}

static void
gst_rtp_h263p_pay_base_init (GstRtpH263PPayClass * klass)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_rtp_h263p_pay_src_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_rtp_h263p_pay_sink_template));

  gst_element_class_set_details (element_class, &gst_rtp_h263ppay_details);
}

static void
gst_rtp_h263p_pay_class_init (GstRtpH263PPayClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;
  GstBaseRTPPayloadClass *gstbasertppayload_class;

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

  parent_class = g_type_class_peek_parent (klass);

  gobject_class->finalize = gst_rtp_h263p_pay_finalize;

  gstbasertppayload_class->set_caps = gst_rtp_h263p_pay_setcaps;
  gstbasertppayload_class->handle_buffer = gst_rtp_h263p_pay_handle_buffer;
}

static void
gst_rtp_h263p_pay_init (GstRtpH263PPay * rtph263ppay)
{
  rtph263ppay->adapter = gst_adapter_new ();
}

static void
gst_rtp_h263p_pay_finalize (GObject * object)
{
  GstRtpH263PPay *rtph263ppay;

  rtph263ppay = GST_RTP_H263P_PAY (object);

  g_object_unref (rtph263ppay->adapter);
  rtph263ppay->adapter = NULL;

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

static gboolean
gst_rtp_h263p_pay_setcaps (GstBaseRTPPayload * payload, GstCaps * caps)
{
  gst_basertppayload_set_options (payload, "video", TRUE, "H263-1998", 90000);
  gst_basertppayload_set_outcaps (payload, NULL);

  return TRUE;
}


static GstFlowReturn
gst_rtp_h263p_pay_flush (GstRtpH263PPay * rtph263ppay)
{
  guint avail;
  GstBuffer *outbuf;
  GstFlowReturn ret;
  gboolean fragmented;

  avail = gst_adapter_available (rtph263ppay->adapter);
  if (avail == 0)
    return GST_FLOW_OK;

  fragmented = FALSE;

  /* This algorithm assumes the H263+ encoder sends complete frames in each
   * buffer */
  /* This algorithm implements the Follow-on packets method for packetization.
   * This assumes low packet loss network. A more resilient method would be to
   * separate large frames at synchronisation points (Segments) (See RFC 2429
   * section 6). It would be interesting to have a property such as network
   * quality to select between both packetization methods */
  /* TODO Add VRC supprt (See RFC 2429 section 4.2) */
  while (avail > 0) {
    guint towrite;
    guint8 *payload;
    guint8 *data;
    guint payload_len;
    gint header_len;

    /* for picture start frames (non-fragmented), we need to remove the first
     * two 0x00 bytes and set P=1 */
    header_len = (fragmented ? 2 : 0);

    towrite = MIN (avail, gst_rtp_buffer_calc_payload_len
        (GST_BASE_RTP_PAYLOAD_MTU (rtph263ppay) - header_len, 0, 0));

    payload_len = header_len + towrite;

    outbuf = gst_rtp_buffer_new_allocate (payload_len, 0, 0);
    /* last fragment gets the marker bit set */
    gst_rtp_buffer_set_marker (outbuf, avail > towrite ? 0 : 1);

    payload = gst_rtp_buffer_get_payload (outbuf);

    data = (guint8 *) gst_adapter_peek (rtph263ppay->adapter, towrite);
    memcpy (&payload[header_len], data, towrite);

    /*  0                   1
     *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     * |   RR    |P|V|   PLEN    |PEBIT|
     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     */
    payload[0] = fragmented ? 0x00 : 0x04;
    payload[1] = 0;

    GST_BUFFER_TIMESTAMP (outbuf) = rtph263ppay->first_ts;
    gst_adapter_flush (rtph263ppay->adapter, towrite);

    ret = gst_basertppayload_push (GST_BASE_RTP_PAYLOAD (rtph263ppay), outbuf);

    avail -= towrite;
    fragmented = TRUE;
  }

  return ret;
}

static GstFlowReturn
gst_rtp_h263p_pay_handle_buffer (GstBaseRTPPayload * payload,
    GstBuffer * buffer)
{
  GstRtpH263PPay *rtph263ppay;
  GstFlowReturn ret;
  guint size;

  rtph263ppay = GST_RTP_H263P_PAY (payload);

  size = GST_BUFFER_SIZE (buffer);
  rtph263ppay->first_ts = GST_BUFFER_TIMESTAMP (buffer);

  /* we always encode and flush a full picture */
  gst_adapter_push (rtph263ppay->adapter, buffer);
  ret = gst_rtp_h263p_pay_flush (rtph263ppay);

  return ret;
}

gboolean
gst_rtp_h263p_pay_plugin_init (GstPlugin * plugin)
{
  return gst_element_register (plugin, "rtph263ppay",
      GST_RANK_NONE, GST_TYPE_RTP_H263P_PAY);
}