reconstruct (depayloaded) jpeg rtp packet

I want to write a simple function to re-combine / reconstruct/depayload rtp packets. For testing, I will just use an jpeg image, break it apart in RTP packets then try to recombine them.

The thing is, i am not too sure on how to do that. Can someone give me some direction ?

Here is the snipet code on rtp packet

/**
 * The same timestamp MUST appear in each fragment of a given frame.
 * The RTP marker bit MUST be set in the last packet of a frame.
 * @param[in] *udp The UDP socket to send the RTP packet over
 * @param[in] *Jpeg JPEG encoded image byte buffer
 * @param[in] JpegLen The length of the byte buffer
 * @param[in] m_SequenceNumber RTP sequence number
 * @param[in] m_Timestamp Timestamp of the image in usec
 * @param[in] m_offset 3 byte fragmentation offset for fragmented images
 * @param[in] marker_bit RTP marker bit
 * @param[in] w The width of the JPEG image
 * @param[in] h The height of the image
 * @param[in] format_code 0 for YUV422 and 1 for YUV421
 * @param[in] quality_code The JPEG encoding quality
 * @param[in] has_dri_header Whether we have an DRI header or not
 */
static void rtp_packet_send(
  struct UdpSocket *udp,
  uint8_t *Jpeg, int JpegLen,
  uint32_t m_SequenceNumber, uint32_t m_Timestamp,
  uint32_t m_offset, uint8_t marker_bit,
  int w, int h,
  uint8_t format_code, uint8_t quality_code,
  uint8_t has_dri_header)
{

#define KRtpHeaderSize 12           // size of the RTP header
#define KJpegHeaderSize 8           // size of the special JPEG payload header

  uint8_t     RtpBuf[2048];
  int         RtpPacketSize = JpegLen + KRtpHeaderSize + KJpegHeaderSize;

  memset(RtpBuf, 0x00, sizeof(RtpBuf));

  /*
   The RTP header has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |V=2|P|X|  CC   |M|     PT      |       sequence number         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           timestamp                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           synchronization source (SSRC) identifier            |
   +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
   |            contributing source (CSRC) identifiers             |
   |                             ....                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * */

  m_Timestamp *= 9 / 100; // convert timestamp to units of 1 / 90000 Hz
  // Prepare the 12 byte RTP header
  RtpBuf[0]  = 0x80;                               // RTP version
  RtpBuf[1]  = 0x1a + (marker_bit << 7);           // JPEG payload (26) and marker bit
  RtpBuf[2]  = m_SequenceNumber >> 8;
  RtpBuf[3]  = m_SequenceNumber & 0x0FF;           // each packet is counted with a sequence counter
  RtpBuf[4]  = (m_Timestamp & 0xFF000000) >> 24;   // each image gets a timestamp
  RtpBuf[5]  = (m_Timestamp & 0x00FF0000) >> 16;
  RtpBuf[6]  = (m_Timestamp & 0x0000FF00) >> 8;
  RtpBuf[7]  = (m_Timestamp & 0x000000FF);
  RtpBuf[8]  = 0x13;                               // 4 byte SSRC (sychronization source identifier)
  RtpBuf[9]  = 0xf9;                               // we just an arbitrary number here to keep it simple
  RtpBuf[10] = 0x7e;
  RtpBuf[11] = 0x67;

  /* JPEG header", are as follows:
   *
   * http://tools.ietf.org/html/rfc2435

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Type-specific |              Fragment Offset                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Type     |       Q       |     Width     |     Height    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   */

  // Prepare the 8 byte payload JPEG header
  RtpBuf[12] = 0x00;                               // type specific
  RtpBuf[13] = (m_offset & 0x00FF0000) >> 16;      // 3 byte fragmentation offset for fragmented images
  RtpBuf[14] = (m_offset & 0x0000FF00) >> 8;
  RtpBuf[15] = (m_offset & 0x000000FF);
  RtpBuf[16] = 0x00;                             // type: 0 422 or 1 421
  RtpBuf[17] = 60;                               // quality scale factor
  RtpBuf[16] = format_code;                      // type: 0 422 or 1 421
  if (has_dri_header) {
    RtpBuf[16] |= 0x40;  // DRI flag
  }
  RtpBuf[17] = quality_code;                     // quality scale factor
  RtpBuf[18] = w / 8;                            // width  / 8 -> 48 pixel
  RtpBuf[19] = h / 8;                            // height / 8 -> 32 pixel
  // append the JPEG scan data to the RTP buffer
  memcpy(&RtpBuf[20], Jpeg, JpegLen);

  //udp_socket_send_dontwait(udp, RtpBuf, RtpPacketSize);   // uncomment after done testing reconstruct rtp packet


};
struct JPEGDepay{
    int width;
    int height;
    int framerate;
    int framerate_denom;
    bool discontl;
};

the struct JPEGdepay is just there because i have no idea what to do next.