mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-07-03 21:25:54 +00:00
94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
/* GStreamer RIST plugin
|
|
* Copyright (C) 2019 Net Insight AB
|
|
* Author: Nicolas Dufresne <nicolas.dufresne@collabora.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., 51 Franklin St, Fifth Floor,
|
|
* Boston, MA 02110-1301, USA.
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include "gstrist.h"
|
|
#include "gstroundrobin.h"
|
|
|
|
/*
|
|
* 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/.
|
|
*/
|
|
guint32
|
|
gst_rist_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;
|
|
}
|