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rist: Factor our seqnum extension code

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Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1153>
This commit is contained in:
Olivier Crête 2019-07-26 16:49:51 -04:00 committed by Olivier Crête
parent 1342e4ba43
commit efd78bb8d8
3 changed files with 70 additions and 69 deletions
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2
gst/rist/gstrist.h
View file

@ -72,4 +72,6 @@ typedef struct {
} GstRistRtpDeextClass;
GType gst_rist_rtp_deext_get_type (void);
guint32 gst_rist_rtp_ext_seq (guint32 * extseqnum, guint16 seqnum);
#endif

67
gst/rist/gstristplugin.c
View file

@ -25,6 +25,73 @@
#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;
}
static gboolean
plugin_init (GstPlugin * plugin)
{

70
gst/rist/gstristrtpext.c
View file

@ -87,74 +87,6 @@ G_DEFINE_TYPE_WITH_CODE (GstRistRtpExt, gst_rist_rtp_ext, GST_TYPE_ELEMENT,
"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)
{
@ -261,7 +193,7 @@ gst_rist_rtp_ext_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
if (GST_BUFFER_IS_DISCONT (buffer))
self->extseqnum = -1;
extseqnum = rtp_ext_seq (&self->extseqnum, seqnum);
extseqnum = gst_rist_rtp_ext_seq (&self->extseqnum, seqnum);
gst_rtp_buffer_get_extension_data (&rtp, &bits, (void **) &data, &wordlen);
GST_WRITE_UINT16_BE (data, (extseqnum >> 16));