The GstRTPBuffer helper functions makes it easy to parse and create regular GstBuffer objects that contain RTP payloads. These buffers are typically of 'application/x-rtp' GstCaps.

GST_RTP_VERSION

#define GST_RTP_VERSION 2

The supported RTP version 2.

gst_rtp_buffer_allocate_data ()

void                gst_rtp_buffer_allocate_data        (GstBuffer *buffer,
                                                         guint payload_len,
                                                         guint8 pad_len,
                                                         guint8 csrc_count);

Allocate enough data in buffer to hold an RTP packet with csrc_count CSRCs, a payload length of payload_len and padding of pad_len. buffer must be writable and all previous memory in buffer will be freed. If pad_len is >0, the padding bit will be set. All other RTP header fields will be set to 0/FALSE.

gst_rtp_buffer_new_take_data ()

GstBuffer *         gst_rtp_buffer_new_take_data        (gpointer data,
                                                         gsize len);

Create a new buffer and set the data and size of the buffer to data and len respectively. data will be freed when the buffer is unreffed, so this function transfers ownership of data to the new buffer.

gst_rtp_buffer_new_copy_data ()

GstBuffer *         gst_rtp_buffer_new_copy_data        (gpointer data,
                                                         gsize len);

Create a new buffer and set the data to a copy of len bytes of data and the size to len. The data will be freed when the buffer is freed.

gst_rtp_buffer_new_allocate ()

GstBuffer *         gst_rtp_buffer_new_allocate         (guint payload_len,
                                                         guint8 pad_len,
                                                         guint8 csrc_count);

Allocate a new GstBuffer with enough data to hold an RTP packet with csrc_count CSRCs, a payload length of payload_len and padding of pad_len. All other RTP header fields will be set to 0/FALSE.

gst_rtp_buffer_new_allocate_len ()

GstBuffer *         gst_rtp_buffer_new_allocate_len     (guint packet_len,
                                                         guint8 pad_len,
                                                         guint8 csrc_count);

Create a new GstBuffer that can hold an RTP packet that is exactly packet_len long. The length of the payload depends on pad_len and csrc_count and can be calculated with gst_rtp_buffer_calc_payload_len(). All RTP header fields will be set to 0/FALSE.

struct GstRTPBuffer

struct GstRTPBuffer {
  GstBuffer   *buffer;
  guint        state;
  gpointer     data[4];
  gsize        size[4];
  GstMapInfo   map[4];
};

Data structure that points to an RTP packet. The size of the structure is made public to allow stack allocations.

GST_RTP_BUFFER_INIT

#define             GST_RTP_BUFFER_INIT

gst_rtp_buffer_map ()

gboolean            gst_rtp_buffer_map                  (GstBuffer *buffer,
                                                         GstMapFlags flags,
                                                         GstRTPBuffer *rtp);

Map the contents of buffer into rtp.

gst_rtp_buffer_unmap ()

void                gst_rtp_buffer_unmap                (GstRTPBuffer *rtp);

Unmap rtp previously mapped with gst_rtp_buffer_map().

gst_rtp_buffer_calc_header_len ()

guint               gst_rtp_buffer_calc_header_len      (guint8 csrc_count);

Calculate the header length of an RTP packet with csrc_count CSRC entries. An RTP packet can have at most 15 CSRC entries.

gst_rtp_buffer_calc_packet_len ()

guint               gst_rtp_buffer_calc_packet_len      (guint payload_len,
                                                         guint8 pad_len,
                                                         guint8 csrc_count);

Calculate the total length of an RTP packet with a payload size of payload_len, a padding of pad_len and a csrc_count CSRC entries.

gst_rtp_buffer_calc_payload_len ()

guint               gst_rtp_buffer_calc_payload_len     (guint packet_len,
                                                         guint8 pad_len,
                                                         guint8 csrc_count);

Calculate the length of the payload of an RTP packet with size packet_len, a padding of pad_len and a csrc_count CSRC entries.

gst_rtp_buffer_set_packet_len ()

void                gst_rtp_buffer_set_packet_len       (GstRTPBuffer *rtp,
                                                         guint len);

Set the total rtp size to len. The data in the buffer will be made larger if needed. Any padding will be removed from the packet.

gst_rtp_buffer_get_packet_len ()

guint               gst_rtp_buffer_get_packet_len       (GstRTPBuffer *rtp);

Return the total length of the packet in buffer.

gst_rtp_buffer_get_header_len ()

guint               gst_rtp_buffer_get_header_len       (GstRTPBuffer *rtp);

Return the total length of the header in buffer. This include the length of the fixed header, the CSRC list and the extension header.

gst_rtp_buffer_get_version ()

guint8              gst_rtp_buffer_get_version          (GstRTPBuffer *rtp);

Get the version number of the RTP packet in buffer.

gst_rtp_buffer_set_version ()

void                gst_rtp_buffer_set_version          (GstRTPBuffer *rtp,
                                                         guint8 version);

Set the version of the RTP packet in buffer to version.

gst_rtp_buffer_get_padding ()

gboolean            gst_rtp_buffer_get_padding          (GstRTPBuffer *rtp);

Check if the padding bit is set on the RTP packet in buffer.

gst_rtp_buffer_set_padding ()

void                gst_rtp_buffer_set_padding          (GstRTPBuffer *rtp,
                                                         gboolean padding);

Set the padding bit on the RTP packet in buffer to padding.

gst_rtp_buffer_pad_to ()

void                gst_rtp_buffer_pad_to               (GstRTPBuffer *rtp,
                                                         guint len);

Set the amount of padding in the RTP packet in buffer to len. If len is 0, the padding is removed.

NOTE: This function does not work correctly.

gst_rtp_buffer_get_extension ()

gboolean            gst_rtp_buffer_get_extension        (GstRTPBuffer *rtp);

Check if the extension bit is set on the RTP packet in buffer.

gst_rtp_buffer_set_extension ()

void                gst_rtp_buffer_set_extension        (GstRTPBuffer *rtp,
                                                         gboolean extension);

Set the extension bit on the RTP packet in buffer to extension.

gst_rtp_buffer_get_extension_data ()

gboolean            gst_rtp_buffer_get_extension_data   (GstRTPBuffer *rtp,
                                                         guint16 *bits,
                                                         gpointer *data,
                                                         guint *wordlen);

Get the extension data. bits will contain the extension 16 bits of custom data. data will point to the data in the extension and wordlen will contain the length of data in 32 bits words.

If buffer did not contain an extension, this function will return FALSE with bits, data and wordlen unchanged.

gst_rtp_buffer_get_ssrc ()

guint32             gst_rtp_buffer_get_ssrc             (GstRTPBuffer *rtp);

Get the SSRC of the RTP packet in buffer.

gst_rtp_buffer_set_ssrc ()

void                gst_rtp_buffer_set_ssrc             (GstRTPBuffer *rtp,
                                                         guint32 ssrc);

Set the SSRC on the RTP packet in buffer to ssrc.

gst_rtp_buffer_get_csrc_count ()

guint8              gst_rtp_buffer_get_csrc_count       (GstRTPBuffer *rtp);

Get the CSRC count of the RTP packet in buffer.

gst_rtp_buffer_get_csrc ()

guint32             gst_rtp_buffer_get_csrc             (GstRTPBuffer *rtp,
                                                         guint8 idx);

Get the CSRC at index idx in buffer.

gst_rtp_buffer_set_csrc ()

void                gst_rtp_buffer_set_csrc             (GstRTPBuffer *rtp,
                                                         guint8 idx,
                                                         guint32 csrc);

Modify the CSRC at index idx in buffer to csrc.

gst_rtp_buffer_get_marker ()

gboolean            gst_rtp_buffer_get_marker           (GstRTPBuffer *rtp);

Check if the marker bit is set on the RTP packet in buffer.

gst_rtp_buffer_set_marker ()

void                gst_rtp_buffer_set_marker           (GstRTPBuffer *rtp,
                                                         gboolean marker);

Set the marker bit on the RTP packet in buffer to marker.

gst_rtp_buffer_get_payload_type ()

guint8              gst_rtp_buffer_get_payload_type     (GstRTPBuffer *rtp);

Get the payload type of the RTP packet in buffer.

gst_rtp_buffer_set_payload_type ()

void                gst_rtp_buffer_set_payload_type     (GstRTPBuffer *rtp,
                                                         guint8 payload_type);

Set the payload type of the RTP packet in buffer to payload_type.

gst_rtp_buffer_get_seq ()

guint16             gst_rtp_buffer_get_seq              (GstRTPBuffer *rtp);

Get the sequence number of the RTP packet in buffer.

gst_rtp_buffer_set_seq ()

void                gst_rtp_buffer_set_seq              (GstRTPBuffer *rtp,
                                                         guint16 seq);

Set the sequence number of the RTP packet in buffer to seq.

gst_rtp_buffer_get_timestamp ()

guint32             gst_rtp_buffer_get_timestamp        (GstRTPBuffer *rtp);

Get the timestamp of the RTP packet in buffer.

gst_rtp_buffer_set_timestamp ()

void                gst_rtp_buffer_set_timestamp        (GstRTPBuffer *rtp,
                                                         guint32 timestamp);

Set the timestamp of the RTP packet in buffer to timestamp.

gst_rtp_buffer_get_payload_buffer ()

GstBuffer *         gst_rtp_buffer_get_payload_buffer   (GstRTPBuffer *rtp);

Create a buffer of the payload of the RTP packet in buffer. This function will internally create a subbuffer of buffer so that a memcpy can be avoided.

gst_rtp_buffer_get_payload_subbuffer ()

GstBuffer *         gst_rtp_buffer_get_payload_subbuffer
                                                        (GstRTPBuffer *rtp,
                                                         guint offset,
                                                         guint len);

Create a subbuffer of the payload of the RTP packet in buffer. offset bytes are skipped in the payload and the subbuffer will be of size len. If len is -1 the total payload starting from offset if subbuffered.

gst_rtp_buffer_get_payload_len ()

guint               gst_rtp_buffer_get_payload_len      (GstRTPBuffer *rtp);

Get the length of the payload of the RTP packet in buffer.

gst_rtp_buffer_get_payload ()

gpointer            gst_rtp_buffer_get_payload          (GstRTPBuffer *rtp);

Get a pointer to the payload data in buffer. This pointer is valid as long as a reference to buffer is held.

gst_rtp_buffer_default_clock_rate ()

guint32             gst_rtp_buffer_default_clock_rate   (guint8 payload_type);

Get the default clock-rate for the static payload type payload_type.

gst_rtp_buffer_compare_seqnum ()

gint                gst_rtp_buffer_compare_seqnum       (guint16 seqnum1,
                                                         guint16 seqnum2);

Compare two sequence numbers, taking care of wraparounds. This function returns the difference between seqnum1 and seqnum2.

gst_rtp_buffer_ext_timestamp ()

guint64             gst_rtp_buffer_ext_timestamp        (guint64 *exttimestamp,
                                                         guint32 timestamp);

Update the exttimestamp field with timestamp. For the first call of the method, exttimestamp should point to a location with a value of -1.

This function makes sure that the returned value is a constantly increasing value even in the case where there is a timestamp wraparound.

gst_rtp_buffer_set_extension_data ()

gboolean            gst_rtp_buffer_set_extension_data   (GstRTPBuffer *rtp,
                                                         guint16 bits,
                                                         guint16 length);

Set the extension bit of the rtp buffer and fill in the bits and length of the extension header. If the existing extension data is not large enough, it will be made larger.

gst_rtp_buffer_get_extension_onebyte_header ()

gboolean            gst_rtp_buffer_get_extension_onebyte_header
                                                        (GstRTPBuffer *rtp,
                                                         guint8 id,
                                                         guint nth,
                                                         gpointer *data,
                                                         guint *size);

Parses RFC 5285 style header extensions with a one byte header. It will return the nth extension with the requested id.

gst_rtp_buffer_get_extension_twobytes_header ()

gboolean            gst_rtp_buffer_get_extension_twobytes_header
                                                        (GstRTPBuffer *rtp,
                                                         guint8 *appbits,
                                                         guint8 id,
                                                         guint nth,
                                                         gpointer *data,
                                                         guint *size);

Parses RFC 5285 style header extensions with a two bytes header. It will return the nth extension with the requested id.

gst_rtp_buffer_add_extension_onebyte_header ()

gboolean            gst_rtp_buffer_add_extension_onebyte_header
                                                        (GstRTPBuffer *rtp,
                                                         guint8 id,
                                                         gpointer data,
                                                         guint size);

Adds a RFC 5285 header extension with a one byte header to the end of the RTP header. If there is already a RFC 5285 header extension with a one byte header, the new extension will be appended. It will not work if there is already a header extension that does not follow the mecanism described in RFC 5285 or if there is a header extension with a two bytes header as described in RFC 5285. In that case, use gst_rtp_buffer_add_extension_twobytes_header()

gst_rtp_buffer_add_extension_twobytes_header ()

gboolean            gst_rtp_buffer_add_extension_twobytes_header
                                                        (GstRTPBuffer *rtp,
                                                         guint8 appbits,
                                                         guint8 id,
                                                         gpointer data,
                                                         guint size);

Adds a RFC 5285 header extension with a two bytes header to the end of the RTP header. If there is already a RFC 5285 header extension with a two bytes header, the new extension will be appended. It will not work if there is already a header extension that does not follow the mecanism described in RFC 5285 or if there is a header extension with a one byte header as described in RFC 5285. In that case, use gst_rtp_buffer_add_extension_onebyte_header()