gstreamer/ext/dash/gstdashdemux.h
Alex Ashley 95c705ae8f dashdemux: add support for UTCTiming elements for clock drift compensation
Unless the DASH client can compensate for the difference between its
clock and the clock used by the server, the client might request
fragments that either not yet on the server or fragments that have
already been expired from the server. This is an issue because these
requests can propagate all the way back to the origin

ISO/IEC 23009-1:2014/Amd 1 [PDAM1] defines a new UTCTiming element to allow
a DASH client to track the clock used by the server generating the
DASH stream. Multiple UTCTiming elements might be present, to indicate
support for multiple methods of UTC time gathering. Each element can
contain a white space separated list of URLs that can be contacted
to discover the UTC time from the server's perspective.

This commit provides parsing of UTCTiming elements, unit tests of this
parsing and a function to poll a time server. This function
supports the following methods:
    urn:mpeg:dash:utc:ntp:2014
    urn:mpeg:dash:utc:http-xsdate:2014
    urn:mpeg:dash:utc:http-iso:2014
    urn:mpeg:dash:utc:http-ntp:2014

The manifest update task is used to poll the clock time server,
to save having to create a new thread.

When choosing the starting fragment number and when waiting for a
fragment to become available, the difference between the server's idea
of UTC and the client's idea of UTC is taken into account. For example,
if the server's time is behind the client's idea of UTC, we wait for
longer before requesting a fragment

[PDAM1]: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=66068

dashdemux: support NTP time servers in UTCTiming elements

Use the gst_ntp_clock to support the use of an NTP server.

https://bugzilla.gnome.org/show_bug.cgi?id=752413
2015-08-14 06:47:20 -03:00

113 lines
3.1 KiB
C

/*
* DASH demux plugin for GStreamer
*
* gstdashdemux.h
*
* Copyright (C) 2012 Orange
* Authors:
* David Corvoysier <david.corvoysier@orange.com>
* Hamid Zakari <hamid.zakari@gmail.com>
*
* Copyright (C) 2013 Smart TV Alliance
* Author: Thiago Sousa Santos <thiago.sousa.santos@collabora.com>, Collabora Ltd.
*
* 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 2.1 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library (COPYING); if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifndef __GST_DASH_DEMUX_H__
#define __GST_DASH_DEMUX_H__
#include <gst/gst.h>
#include <gst/adaptivedemux/gstadaptivedemux.h>
#include <gst/base/gstadapter.h>
#include <gst/base/gstdataqueue.h>
#include "gstmpdparser.h"
#include "gstisoff.h"
#include <gst/uridownloader/gsturidownloader.h>
G_BEGIN_DECLS
#define GST_TYPE_DASH_DEMUX \
(gst_dash_demux_get_type())
#define GST_DASH_DEMUX(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_DASH_DEMUX,GstDashDemux))
#define GST_DASH_DEMUX_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_DASH_DEMUX,GstDashDemuxClass))
#define GST_IS_DASH_DEMUX(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_DASH_DEMUX))
#define GST_IS_DASH_DEMUX_CLASS(klass) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_DASH_DEMUX))
#define GST_DASH_DEMUX_CAST(obj) \
((GstDashDemux *)obj)
typedef struct _GstDashDemuxClockDrift GstDashDemuxClockDrift;
typedef struct _GstDashDemuxStream GstDashDemuxStream;
typedef struct _GstDashDemux GstDashDemux;
typedef struct _GstDashDemuxClass GstDashDemuxClass;
struct _GstDashDemuxStream
{
GstAdaptiveDemuxStream parent;
gint index;
GstActiveStream *active_stream;
GstMediaFragmentInfo current_fragment;
/* index parsing */
GstSidxParser sidx_parser;
gsize sidx_current_remaining;
gint sidx_index;
gint64 sidx_base_offset;
GstClockTime pending_seek_ts;
};
/**
* GstDashDemux:
*
* Opaque #GstDashDemux data structure.
*/
struct _GstDashDemux
{
GstAdaptiveDemux parent;
GSList *next_periods;
GstMpdClient *client; /* MPD client */
GMutex client_lock;
GstDashDemuxClockDrift *clock_drift;
gboolean end_of_period;
gboolean end_of_manifest;
/* Properties */
GstClockTime max_buffering_time; /* Maximum buffering time accumulated during playback */
guint64 max_bitrate; /* max of bitrate supported by target decoder */
gint n_audio_streams;
gint n_video_streams;
};
struct _GstDashDemuxClass
{
GstAdaptiveDemuxClass parent_class;
};
GType gst_dash_demux_get_type (void);
G_END_DECLS
#endif /* __GST_DASH_DEMUX_H__ */