gstreamer/subprojects/gst-plugins-bad/ext/avtp/gstavtpvfdepaybase.c

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/*
* GStreamer AVTP Plugin
* Copyright (c) 2021, Fastree3D
* Adrian Fiergolski <Adrian.Fiergolski@fastree3d.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
#include <avtp.h>
#include "gstavtpvfdepaybase.h"
GST_DEBUG_CATEGORY_STATIC (avtpvfdepaybase_debug);
#define GST_CAT_DEFAULT avtpvfdepaybase_debug
static GstStateChangeReturn gst_avtp_vf_depay_change_state (GstElement *
element, GstStateChange transition);
#define gst_avtp_vf_depay_base_parent_class parent_class
G_DEFINE_TYPE_EXTENDED (GstAvtpVfDepayBase, gst_avtp_vf_depay_base,
GST_TYPE_AVTP_BASE_DEPAYLOAD, G_TYPE_FLAG_ABSTRACT, {
});
static void
gst_avtp_vf_depay_base_class_init (GstAvtpVfDepayBaseClass * klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
element_class->change_state =
GST_DEBUG_FUNCPTR (gst_avtp_vf_depay_change_state);
klass->depay_push_caps = NULL;
GST_DEBUG_CATEGORY_INIT (avtpvfdepaybase_debug, "avtpvfdepaybase",
0, "debug category for avtpvfdepay element");
}
static void
gst_avtp_vf_depay_base_init (GstAvtpVfDepayBase * avtpvfdepaybase)
{
avtpvfdepaybase->out_buffer = NULL;
}
static GstStateChangeReturn
gst_avtp_vf_depay_change_state (GstElement * element, GstStateChange transition)
{
GstAvtpVfDepayBase *avtpvfdepaybase = GST_AVTP_VF_DEPAY_BASE (element);
GstStateChangeReturn ret;
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
if (ret == GST_STATE_CHANGE_FAILURE) {
return ret;
}
if (transition == GST_STATE_CHANGE_READY_TO_NULL) {
if (avtpvfdepaybase->out_buffer) {
gst_buffer_unref (avtpvfdepaybase->out_buffer);
avtpvfdepaybase->out_buffer = NULL;
}
}
return ret;
}
GstFlowReturn
gst_avtp_vf_depay_base_push (GstAvtpVfDepayBase * avtpvfdepaybase)
{
GstAvtpBaseDepayload *avtpbasedepayload =
GST_AVTP_BASE_DEPAYLOAD (avtpvfdepaybase);
GstFlowReturn ret;
if (G_UNLIKELY (!gst_pad_has_current_caps (avtpbasedepayload->srcpad))) {
guint64 pts_m;
guint32 dts, pts;
if (gst_debug_category_get_threshold (GST_CAT_DEFAULT) >= GST_LEVEL_DEBUG) {
GstClock *clock =
gst_element_get_clock (GST_ELEMENT_CAST (avtpvfdepaybase));
if (clock == NULL) {
GST_DEBUG_OBJECT (avtpvfdepaybase,
"Sending initial CAPS and SEGMENT, no pipeline time.");
} else {
GST_DEBUG_OBJECT (avtpvfdepaybase,
"Sending initial CAPS and SEGMENT, pipeline time: %"
GST_TIME_FORMAT, GST_TIME_ARGS (gst_clock_get_time (clock)));
}
}
g_assert (GST_AVTP_VF_DEPAY_BASE_GET_CLASS
(avtpvfdepaybase)->depay_push_caps != NULL);
if (!GST_AVTP_VF_DEPAY_BASE_GET_CLASS (avtpvfdepaybase)->depay_push_caps
(avtpvfdepaybase)) {
GST_ELEMENT_ERROR (avtpvfdepaybase, CORE, CAPS, (NULL), (NULL));
return GST_FLOW_ERROR;
}
if (!gst_avtp_base_depayload_push_segment_event (avtpbasedepayload,
GST_BUFFER_PTS (avtpvfdepaybase->out_buffer))) {
GST_ELEMENT_ERROR (avtpvfdepaybase, CORE, EVENT,
("Could not send SEGMENT event"), (NULL));
}
/* Now that we sent our segment starting on the first Presentation
* time available, `avtpbasedepayload->prev_ptime` saves that value,
* to be a reference for calculating future buffer timestamps from
* the AVTP timestamps.
*
* However, decode timestamps can be smaller than presentation
* timestamps. So we can't use `avtpbasedepayload->prev_time` as
* reference to calculate them. Instead, here, we calculate the
* first decode timestamp and save it on `avtpvfdepaybase->prev_ptime`.
*
* The method used to calculate the "absolute" decode timestamp (DTS)
* from presentation timestamp is as follows:
*
* DTS = dts > pts ? (PTSm - 1) | dts : PTSm | dts
*
* Where:
* dts: 32 bits gPTP decode timestamp
* pts: 32 bits gPTP presentation timestamp
* PTSm: 32 most signifactive bits of the "absolute" presentation
* timestamp
*
* This allow us to handle cases where the pts ends up being smaller
* than dts due pts falling after an AVTP timestamp wrapping.
*/
pts = GST_BUFFER_PTS (avtpvfdepaybase->out_buffer);
dts = GST_BUFFER_DTS (avtpvfdepaybase->out_buffer);
pts_m = avtpbasedepayload->prev_ptime & 0xFFFFFFFF00000000ULL;
avtpbasedepayload->prev_ptime = dts > pts ? (pts_m -=
(1ULL << 32)) | dts : pts_m | dts;
GST_DEBUG_OBJECT (avtpvfdepaybase, "prev_ptime set to %" GST_TIME_FORMAT,
GST_TIME_ARGS (avtpbasedepayload->prev_ptime));
}
/* At this point, we're sure segment was sent, so we can properly calc
* buffer timestamps */
GST_DEBUG_OBJECT (avtpvfdepaybase, "Converting %" GST_TIME_FORMAT " to PTS",
GST_TIME_ARGS (GST_BUFFER_PTS (avtpvfdepaybase->out_buffer)));
GST_BUFFER_PTS (avtpvfdepaybase->out_buffer) =
gst_avtp_base_depayload_tstamp_to_ptime (avtpbasedepayload, GST_BUFFER_PTS
(avtpvfdepaybase->out_buffer), avtpbasedepayload->prev_ptime);
GST_DEBUG_OBJECT (avtpvfdepaybase, "Converting %" GST_TIME_FORMAT " to DTS",
GST_TIME_ARGS (GST_BUFFER_DTS (avtpvfdepaybase->out_buffer)));
GST_BUFFER_DTS (avtpvfdepaybase->out_buffer) =
gst_avtp_base_depayload_tstamp_to_ptime (avtpbasedepayload, GST_BUFFER_DTS
(avtpvfdepaybase->out_buffer), avtpbasedepayload->prev_ptime);
/* Use DTS as prev_ptime as it is smaller or equal to PTS, so that
* next calculations of PTS/DTS won't wrap too early */
avtpbasedepayload->prev_ptime = GST_BUFFER_DTS (avtpvfdepaybase->out_buffer);
ret = gst_pad_push (GST_AVTP_BASE_DEPAYLOAD (avtpvfdepaybase)->srcpad,
avtpvfdepaybase->out_buffer);
avtpvfdepaybase->out_buffer = NULL;
return ret;
}