rist: Insert RTP seqnum extension header

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1153>
This commit is contained in:
Olivier Crête 2019-07-23 17:26:16 -04:00 committed by Olivier Crête
parent 005bd960ee
commit fa5d206c2c

View file

@ -77,19 +77,89 @@ struct _GstRistRtpExt
GstPad *srcpad, *sinkpad;
gboolean drop_null;
gboolean seqnumext;
gboolean add_seqnumext;
guint32 extseqnum;
};
G_DEFINE_TYPE_WITH_CODE (GstRistRtpExt, gst_rist_rtp_ext, GST_TYPE_ELEMENT,
GST_DEBUG_CATEGORY_INIT (gst_rist_rtp_ext_debug, "ristrtpext", 0,
"RIST RTP Extension"));
/*
* rtp_ext_seq:
* @extseq: (inout): a previous extended seqs
* @seq: a new seq
*
* Update the @extseq field with the extended seq of @seq
* For the first call of the method, @extseq should point to a location
* with a value of -1.
*
* This function is able to handle both forward and backward seqs taking
* into account:
* - seq wraparound making sure that the returned value is properly increased.
* - seq unwraparound making sure that the returned value is properly decreased.
*
* Returns: The extended seq of @seq or 0 if the result can't go anywhere backwards.
*
* NOTE: This is a calque of gst_rtp_buffer_ext_timestamp() but with
* s/32/16/ and s/64/32/ and s/0xffffffff/0xffff/ and s/timestamp/seqnum/.
*/
static guint32
rtp_ext_seq (guint32 * extseqnum, guint16 seqnum)
{
guint32 result, ext;
g_return_val_if_fail (extseqnum != NULL, -1);
ext = *extseqnum;
if (ext == -1) {
result = seqnum;
} else {
/* pick wraparound counter from previous seqnum and add to new seqnum */
result = seqnum + (ext & ~(0xffff));
/* check for seqnum wraparound */
if (result < ext) {
guint32 diff = ext - result;
if (diff > G_MAXINT16) {
/* seqnum went backwards more than allowed, we wrap around and get
* updated extended seqnum. */
result += (1 << 16);
}
} else {
guint32 diff = result - ext;
if (diff > G_MAXINT16) {
if (result < (1 << 16)) {
GST_WARNING
("Cannot unwrap, any wrapping took place yet. Returning 0 without updating extended seqnum.");
return 0;
} else {
/* seqnum went forwards more than allowed, we unwrap around and get
* updated extended seqnum. */
result -= (1 << 16);
/* We don't want the extended seqnum storage to go back, ever */
return result;
}
}
}
}
*extseqnum = result;
return result;
}
static GstFlowReturn
gst_rist_rtp_ext_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
{
GstRistRtpExt *self = GST_RIST_RTP_EXT (parent);
GstRTPBuffer rtp = GST_RTP_BUFFER_INIT;
guint16 seqnumext_val = 0;
gboolean drop_null = self->drop_null;
gboolean ts_packet_size = 0;
guint ts_packet_count = 0;
@ -97,7 +167,7 @@ gst_rist_rtp_ext_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
guint8 npd_bits = 0;
gboolean num_packets_deleted = 0;
if (!self->drop_null && !self->seqnumext)
if (!self->drop_null && !self->add_seqnumext)
return gst_pad_push (self->srcpad, buffer);
if (self->drop_null) {
@ -180,14 +250,21 @@ gst_rist_rtp_ext_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
bits |= (npd_bits & 0x7F);
gst_rtp_buffer_set_extension (&rtp, TRUE);
gst_rtp_buffer_set_extension_data (&rtp, bits, self->seqnumext ? 1 : 0);
gst_rtp_buffer_set_extension_data (&rtp, bits, self->add_seqnumext ? 1 : 0);
if (self->seqnumext) {
if (self->add_seqnumext) {
guint8 *data;
guint wordlen;
guint16 seqnum = gst_rtp_buffer_get_seq (&rtp);
guint32 extseqnum;
if (GST_BUFFER_IS_DISCONT (buffer))
self->extseqnum = -1;
extseqnum = rtp_ext_seq (&self->extseqnum, seqnum);
gst_rtp_buffer_get_extension_data (&rtp, &bits, (void **) &data, &wordlen);
GST_WRITE_UINT16_BE (data, seqnumext_val);
GST_WRITE_UINT16_BE (data, (extseqnum >> 16));
data[2] = data[3] = 0;
}
@ -212,6 +289,8 @@ error_mapped:
static void
gst_rist_rtp_ext_init (GstRistRtpExt * self)
{
self->extseqnum = -1;
self->sinkpad = gst_pad_new_from_static_template (&sink_templ,
sink_templ.name_template);
self->srcpad = gst_pad_new_from_static_template (&src_templ,
@ -236,7 +315,7 @@ gst_rist_rtp_ext_get_property (GObject * object, guint prop_id,
g_value_set_boolean (value, self->drop_null);
break;
case PROP_SEQUENCE_NUMBER_EXTENSION:
g_value_set_boolean (value, self->seqnumext);
g_value_set_boolean (value, self->add_seqnumext);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@ -255,7 +334,7 @@ gst_rist_rtp_ext_set_property (GObject * object, guint prop_id,
self->drop_null = g_value_get_boolean (value);
break;
case PROP_SEQUENCE_NUMBER_EXTENSION:
self->seqnumext = g_value_get_boolean (value);
self->add_seqnumext = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);