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595254f21b
This element can be configured to add jitter and/or drift to incoming buffers' PTS, DTS, or both. Amplitude and average of jitter and drift are configurable. https://bugzilla.gnome.org/show_bug.cgi?id=787358
387 lines
12 KiB
C
387 lines
12 KiB
C
/*
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* GStreamer
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* Copyright (C) 2017 Vivia Nikolaidou <vivia@ahiru.eu>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/**
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* SECTION:element-jitterer
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* @title: jitterer
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*
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* Adds jitter and/or drift to a buffer's PTS and/or DTS. Amplitude and
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* average of jitter and drift are configurable.
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*
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* ## Example launch line
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* |[
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* gst-launch-1.0 videotestsrc ! jitterer drift-average=100 drift-amplitude=10 ! autovideosink
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* ]|
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "gstjitterer.h"
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#define GST_CAT_DEFAULT gst_jitterer_debug
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GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
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enum
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{
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PROP_0,
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PROP_JITTER_AMPL,
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PROP_JITTER_AVG,
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PROP_DRIFT_AMPL,
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PROP_DRIFT_AVG,
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PROP_CHANGE_PTS,
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PROP_CHANGE_DTS
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};
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static void gst_jitterer_set_property (GObject * object, guint prop_id,
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const GValue * value, GParamSpec * pspec);
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static void gst_jitterer_get_property (GObject * object, guint prop_id,
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GValue * value, GParamSpec * pspec);
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static void gst_jitterer_finalize (GObject * object);
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static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
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GST_PAD_SINK,
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GST_PAD_ALWAYS,
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GST_STATIC_CAPS_ANY);
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static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
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GST_PAD_SRC,
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GST_PAD_ALWAYS,
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GST_STATIC_CAPS_ANY);
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#define parent_class gst_jitterer_parent_class
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G_DEFINE_TYPE (GstJitterer, gst_jitterer, GST_TYPE_ELEMENT);
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static GstFlowReturn gst_jitterer_sink_chain (GstPad * pad,
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GstObject * parent, GstBuffer * inbuf);
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static gboolean gst_jitterer_sink_event (GstPad * pad, GstObject * parent,
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GstEvent * event);
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static void
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gst_jitterer_class_init (GstJittererClass * klass)
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{
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GstElementClass *gstelement_class;
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GObjectClass *object_class = G_OBJECT_CLASS (klass);
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GST_DEBUG_CATEGORY_INIT (gst_jitterer_debug, "jitterer", 0,
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"Add jitter and/or drift to buffers");
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gstelement_class = (GstElementClass *) klass;
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gst_element_class_set_static_metadata (gstelement_class,
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"Jitterer", "Generic", "Add jitter and/or drift to buffers",
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"Vivia Nikolaidou <vivia@ahiru.eu>");
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gst_element_class_add_static_pad_template (gstelement_class, &src_template);
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gst_element_class_add_static_pad_template (gstelement_class, &sink_template);
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/* define virtual function pointers */
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object_class->set_property = gst_jitterer_set_property;
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object_class->get_property = gst_jitterer_get_property;
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object_class->finalize = gst_jitterer_finalize;
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/* define properties */
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g_object_class_install_property (object_class, PROP_JITTER_AMPL,
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g_param_spec_uint64 ("jitter-amplitude", "Jitter amplitude",
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"Amplitude of the jitter to apply",
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0, G_MAXINT64 / 2, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (object_class, PROP_JITTER_AVG,
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g_param_spec_int64 ("jitter-average", "Jitter average",
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"Average of the jitter to apply",
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-G_MAXINT64 / 2, G_MAXINT64 / 2, 0,
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G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (object_class, PROP_DRIFT_AMPL,
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g_param_spec_uint64 ("drift-amplitude", "Drift amplitude",
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"Amplitude of the drift to apply",
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0, G_MAXINT64 / 2, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (object_class, PROP_DRIFT_AVG,
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g_param_spec_int64 ("drift-average", "Drift average",
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"Average of the drift to apply",
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-G_MAXINT64 / 2, G_MAXINT64 / 2, 0,
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G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (object_class, PROP_CHANGE_PTS,
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g_param_spec_boolean ("change-pts", "Change PTS",
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"Whether to change the PTS of incoming buffers",
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TRUE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (object_class, PROP_CHANGE_DTS,
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g_param_spec_boolean ("change-dts", "Change DTS",
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"Whether to change the DTS of incoming buffers",
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TRUE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
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}
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static void
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gst_jitterer_init (GstJitterer * self)
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{
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self->sinkpad = gst_pad_new_from_static_template (&sink_template, "sink");
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gst_pad_set_chain_function (self->sinkpad,
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GST_DEBUG_FUNCPTR (gst_jitterer_sink_chain));
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gst_pad_set_event_function (self->sinkpad,
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GST_DEBUG_FUNCPTR (gst_jitterer_sink_event));
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GST_PAD_SET_PROXY_ALLOCATION (self->sinkpad);
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GST_PAD_SET_PROXY_CAPS (self->sinkpad);
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GST_PAD_SET_PROXY_SCHEDULING (self->sinkpad);
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gst_element_add_pad (GST_ELEMENT (self), self->sinkpad);
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self->srcpad = gst_pad_new_from_static_template (&src_template, "src");
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gst_pad_use_fixed_caps (self->srcpad);
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GST_PAD_SET_PROXY_ALLOCATION (self->srcpad);
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GST_PAD_SET_PROXY_CAPS (self->srcpad);
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GST_PAD_SET_PROXY_SCHEDULING (self->srcpad);
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gst_element_add_pad (GST_ELEMENT (self), self->srcpad);
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self->jitter_ampl = 0;
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self->jitter_avg = 0;
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self->drift_ampl = 0;
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self->drift_avg = 0;
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self->change_pts = TRUE;
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self->change_dts = TRUE;
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self->prev_pts = GST_CLOCK_TIME_NONE;
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self->dts_drift_so_far = 0;
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self->pts_drift_so_far = 0;
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self->rand = g_rand_new ();
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}
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static void
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gst_jitterer_finalize (GObject * object)
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{
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GstJitterer *self = GST_JITTERER (object);
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g_rand_free (self->rand);
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G_OBJECT_CLASS (parent_class)->finalize (object);
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}
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static void
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gst_jitterer_set_property (GObject * object, guint prop_id,
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const GValue * value, GParamSpec * pspec)
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{
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GstJitterer *self = GST_JITTERER (object);
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switch (prop_id) {
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case PROP_JITTER_AMPL:
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self->jitter_ampl = g_value_get_uint64 (value);
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break;
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case PROP_JITTER_AVG:
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self->jitter_avg = g_value_get_int64 (value);
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break;
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case PROP_DRIFT_AMPL:
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self->drift_ampl = g_value_get_uint64 (value);
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break;
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case PROP_DRIFT_AVG:
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self->drift_avg = g_value_get_int64 (value);
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break;
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case PROP_CHANGE_PTS:
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self->change_pts = g_value_get_boolean (value);
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break;
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case PROP_CHANGE_DTS:
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self->change_dts = g_value_get_boolean (value);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static void
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gst_jitterer_get_property (GObject * object, guint prop_id, GValue * value,
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GParamSpec * pspec)
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{
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GstJitterer *self = GST_JITTERER (object);
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switch (prop_id) {
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case PROP_JITTER_AMPL:
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g_value_set_uint64 (value, self->jitter_ampl);
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break;
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case PROP_JITTER_AVG:
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g_value_set_int64 (value, self->jitter_avg);
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break;
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case PROP_DRIFT_AMPL:
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g_value_set_uint64 (value, self->drift_ampl);
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break;
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case PROP_DRIFT_AVG:
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g_value_set_int64 (value, self->drift_avg);
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break;
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case PROP_CHANGE_PTS:
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g_value_set_boolean (value, self->change_pts);
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break;
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case PROP_CHANGE_DTS:
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g_value_set_boolean (value, self->change_dts);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static gint64
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gst_jitterer_rand_uint64_range (GRand * rand, gint64 min, gint64 max)
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{
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gint64 dist;
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g_assert (max > min);
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dist = max - min;
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if (G_LIKELY (dist < G_MAXINT32)) {
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return g_rand_int_range (rand, 0, dist) + min;
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} else {
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/* This code is based on g_rand_int_range source */
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gint64 ret = max + 1;
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/* maxvalue is set to the predecessor of the greatest
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* multiple of dist less or equal 2^64.
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*/
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guint64 maxvalue;
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if (dist <= 0x8000000000000000u) { /* 2^63 */
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/* maxvalue = 2^64 - 1 - (2^64 % dist) */
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guint64 leftover = (0x8000000000000000u % dist) * 2;
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if (leftover >= dist)
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leftover -= dist;
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maxvalue = 0xffffffffffffffffu - leftover;
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} else {
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maxvalue = dist - 1;
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}
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do {
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gint32 highrand, lowrand;
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highrand = g_rand_int (rand);
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lowrand = g_rand_int (rand);
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ret = ((((gint64) highrand) << 32) | lowrand);
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} while (ret > maxvalue);
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ret %= dist;
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return ret;
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}
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}
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static gboolean
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gst_jitterer_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
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{
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GstJitterer *self = GST_JITTERER (parent);
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switch (GST_EVENT_TYPE (event)) {
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case GST_EVENT_SEGMENT:
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case GST_EVENT_FLUSH_STOP:
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self->prev_pts = GST_CLOCK_TIME_NONE;
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break;
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default:
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break;
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}
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return gst_pad_event_default (pad, parent, event);
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}
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static GstFlowReturn
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gst_jitterer_sink_chain (GstPad * pad, GstObject * parent, GstBuffer * inbuf)
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{
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GstJitterer *self = GST_JITTERER (parent);
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if (self->jitter_ampl > 0) {
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gint64 min, max;
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gint64 jitter;
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min = self->jitter_avg - self->jitter_ampl / 2;
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max = self->jitter_avg + self->jitter_ampl / 2;
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if (self->change_pts && GST_BUFFER_PTS (inbuf) != GST_CLOCK_TIME_NONE) {
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jitter = gst_jitterer_rand_uint64_range (self->rand, min, max);
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if (GST_BUFFER_PTS (inbuf) + jitter > 0)
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GST_BUFFER_PTS (inbuf) = GST_BUFFER_PTS (inbuf) + jitter;
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}
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if (self->change_dts && GST_BUFFER_DTS (inbuf) != GST_CLOCK_TIME_NONE) {
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jitter = gst_jitterer_rand_uint64_range (self->rand, min, max);
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if (GST_BUFFER_DTS (inbuf) + jitter > 0)
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GST_BUFFER_DTS (inbuf) = GST_BUFFER_DTS (inbuf) + jitter;
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}
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} else {
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if (self->change_pts && GST_BUFFER_PTS (inbuf) != GST_CLOCK_TIME_NONE)
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GST_BUFFER_PTS (inbuf) = GST_BUFFER_PTS (inbuf) + self->jitter_avg;
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if (self->change_dts && GST_BUFFER_DTS (inbuf) != GST_CLOCK_TIME_NONE)
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GST_BUFFER_DTS (inbuf) = GST_BUFFER_DTS (inbuf) + self->jitter_avg;
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}
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if (self->prev_pts != GST_CLOCK_TIME_NONE) {
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GstClockTimeDiff drift_avg_per_frame;
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GstClockTime pts_diff = GST_BUFFER_PTS (inbuf) - self->prev_pts;
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if (self->drift_avg == 0) {
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drift_avg_per_frame = 0;
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} else if (self->drift_avg > 0) {
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drift_avg_per_frame =
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gst_util_uint64_scale (self->drift_avg, pts_diff, GST_SECOND);
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} else {
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drift_avg_per_frame =
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-gst_util_uint64_scale (-self->drift_avg, pts_diff, GST_SECOND);
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}
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if (self->drift_ampl > 0) {
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gint min, max;
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GstClockTime drift_ampl_per_frame;
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drift_ampl_per_frame =
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gst_util_uint64_scale (self->drift_ampl, pts_diff, GST_SECOND);
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min = drift_avg_per_frame - drift_ampl_per_frame / 2;
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max = drift_avg_per_frame + drift_ampl_per_frame / 2;
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if (self->change_pts && GST_BUFFER_PTS (inbuf) != GST_CLOCK_TIME_NONE) {
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/* FIXME: if (min == max) means the amplitude is too small, make a
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* probabilistic +1 or -1 instead */
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if (min == max)
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self->pts_drift_so_far += drift_avg_per_frame;
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else
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self->pts_drift_so_far +=
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gst_jitterer_rand_uint64_range (self->rand, min, max);
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if (GST_BUFFER_PTS (inbuf) + self->pts_drift_so_far > 0)
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GST_BUFFER_PTS (inbuf) =
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GST_BUFFER_PTS (inbuf) + self->pts_drift_so_far;
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}
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if (self->change_dts && GST_BUFFER_DTS (inbuf) != GST_CLOCK_TIME_NONE) {
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if (min == max)
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self->pts_drift_so_far += drift_avg_per_frame;
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else
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self->dts_drift_so_far +=
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gst_jitterer_rand_uint64_range (self->rand, min, max);
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if (GST_BUFFER_DTS (inbuf) + self->dts_drift_so_far > 0)
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GST_BUFFER_DTS (inbuf) =
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GST_BUFFER_DTS (inbuf) + self->dts_drift_so_far;
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}
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} else {
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if (self->change_pts && GST_BUFFER_PTS (inbuf) != GST_CLOCK_TIME_NONE) {
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self->pts_drift_so_far += drift_avg_per_frame;
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GST_BUFFER_PTS (inbuf) =
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GST_BUFFER_PTS (inbuf) + self->pts_drift_so_far;
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}
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if (self->change_dts && GST_BUFFER_DTS (inbuf) != GST_CLOCK_TIME_NONE) {
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self->dts_drift_so_far += drift_avg_per_frame;
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GST_BUFFER_DTS (inbuf) =
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GST_BUFFER_DTS (inbuf) + self->dts_drift_so_far;
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}
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}
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}
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self->prev_pts = GST_BUFFER_PTS (inbuf);
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return gst_pad_push (self->srcpad, inbuf);
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}
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