gstreamer/plugins/nle/nleobject.h
Sjors Gielen 84f7f04a64 Handle changing playback rate
Before this patch, NLE and GES did not support NleOperations (respectively
GESEffects) that changed the speed/tempo/rate at which the source plays. For
example, the 'pitch' element can make audio play faster or slower. In GES 1.5.90
and before, an NleOperation containing the pitch element to change the rate (or
tempo) would cause a pipeline state change to PAUSED after that stack; that has
been fixed in 1.5.91 (see #755012 [0]). But even then, in 1.5.91 and later,
NleComposition would send segment events to its NleSources assuming that one
source second is equal to one pipeline second. The resulting early EOS event
(in the case of a source rate higher than 1.0) would cause it to switch stacks
too early, causing confusion in the timeline and spectacularly messed up
output.

This patch fixes that by searching for rate-changing elements in
GESTrackElements such as GESEffects. If such rate-changing elements are found,
their final effect on the playing rate is stored in the corresponding NleObject
as the 'media duration factor', named like this because the 'media duration',
or source duration, of an NleObject can be computed by multiplying the duration
with the media duration factor of that object and its parents (this is called
the 'recursive media duration factor'). For example, a 4-second NleSource with
an NleOperation with a media duration factor of 2.0 will have an 8-second media
duration, which means that for playing 4 seconds in the pipeline, the seek
event sent to it must span 8 seconds of media. (So, the 'duration' of an
NleObject or GES object always refers to its duration in the timeline, not the
media duration.)

To summarize:

* Rate-changing elements are registered in the GESEffectClass (pitch::tempo and
  pitch::rate are registered by default);
* GESTimelineElement is responsible for detecting rate-changing elements and
  computing the media_duration_factor;
* GESTrackElement is responsible for storing the media_duration_factor in
  NleObject;
* NleComposition is responsible for the recursive_media_duration_factor;
* The latter property finally fixes media time computations in NleObject.

NLE and GES tests are included.

[0] https://bugzilla.gnome.org/show_bug.cgi?id=755012

Differential Revision: https://phabricator.freedesktop.org/D276
2016-02-26 19:54:40 +01:00

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5.2 KiB
C

/* GStreamer
* Copyright (C) 2001 Wim Taymans <wim.taymans@gmail.com>
* 2004-2008 Edward Hervey <bilboed@bilboed.com>
*
* nleobject.h: Header for base NleObject
*
* 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.
*/
#ifndef __NLE_OBJECT_H__
#define __NLE_OBJECT_H__
#include <gst/gst.h>
#include "nletypes.h"
G_BEGIN_DECLS
#define NLE_TYPE_OBJECT \
(nle_object_get_type())
#define NLE_OBJECT(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),NLE_TYPE_OBJECT,NleObject))
#define NLE_OBJECT_CAST(obj) ((NleObject*) (obj))
#define NLE_OBJECT_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),NLE_TYPE_OBJECT,NleObjectClass))
#define NLE_OBJECT_GET_CLASS(obj) \
(G_TYPE_INSTANCE_GET_CLASS ((obj), NLE_TYPE_OBJECT, NleObjectClass))
#define NLE_IS_OBJECT(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),NLE_TYPE_OBJECT))
#define NLE_IS_OBJECT_CLASS(obj) \
(G_TYPE_CHECK_CLASS_TYPE((klass),NLE_TYPE_OBJECT))
#define NLE_OBJECT_SRC(obj) (((NleObject *) obj)->srcpad)
/**
* NleObjectFlags:
* @NLE_OBJECT_IS_SOURCE:
* @NLE_OBJECT_IS_OPERATION:
* @NLE_OBJECT_IS_EXPANDABLE: The #NleObject start/stop will extend accross the full composition.
* @NLE_OBJECT_LAST_FLAG:
*/
typedef enum
{
NLE_OBJECT_SOURCE = (GST_BIN_FLAG_LAST << 0),
NLE_OBJECT_OPERATION = (GST_BIN_FLAG_LAST << 1),
NLE_OBJECT_EXPANDABLE = (GST_BIN_FLAG_LAST << 2),
NLE_OBJECT_COMPOSITION = (GST_BIN_FLAG_LAST << 3),
/* padding */
NLE_OBJECT_LAST_FLAG = (GST_BIN_FLAG_LAST << 5)
} NleObjectFlags;
#define NLE_OBJECT_IS_SOURCE(obj) \
(GST_OBJECT_FLAG_IS_SET(obj, NLE_OBJECT_SOURCE))
#define NLE_OBJECT_IS_OPERATION(obj) \
(GST_OBJECT_FLAG_IS_SET(obj, NLE_OBJECT_OPERATION))
#define NLE_OBJECT_IS_EXPANDABLE(obj) \
(GST_OBJECT_FLAG_IS_SET(obj, NLE_OBJECT_EXPANDABLE))
#define NLE_OBJECT_IS_COMPOSITION(obj) \
(GST_OBJECT_FLAG_IS_SET(obj, NLE_OBJECT_COMPOSITION))
/* For internal usage only */
#define NLE_OBJECT_START(obj) (NLE_OBJECT_CAST (obj)->start)
#define NLE_OBJECT_STOP(obj) (NLE_OBJECT_CAST (obj)->stop)
#define NLE_OBJECT_DURATION(obj) (NLE_OBJECT_CAST (obj)->duration)
#define NLE_OBJECT_INPOINT(obj) (NLE_OBJECT_CAST (obj)->inpoint)
#define NLE_OBJECT_PRIORITY(obj) (NLE_OBJECT_CAST (obj)->priority)
#define NLE_OBJECT_ACTIVE(obj) (NLE_OBJECT_DURATION(obj) > 0 && NLE_OBJECT_CAST (obj)->active)
#define NLE_OBJECT_IS_COMMITING(obj) (NLE_OBJECT_CAST (obj)->commiting)
struct _NleObject
{
GstBin parent;
GstPad *srcpad;
/* Time positionning */
GstClockTime start;
GstClockTime inpoint;
GstClockTimeDiff duration;
/* Pending time positionning
* Should be == GST_CLOCK_TIME_NONE when nothing to do
*/
GstClockTime pending_start;
GstClockTime pending_inpoint;
GstClockTimeDiff pending_duration;
guint32 pending_priority;
gboolean pending_active;
gboolean commit_needed;
gboolean commiting; /* Set to TRUE during the commiting time only */
gboolean expandable;
/* read-only */
GstClockTime stop;
/* priority in parent */
guint32 priority;
/* active in parent */
gboolean active;
/* Filtering caps */
GstCaps *caps;
/* current segment seek <RO> */
gdouble segment_rate;
GstSeekFlags segment_flags;
gint64 segment_start;
gint64 segment_stop;
/* the rate at which this object speeds up or slows down media */
gdouble media_duration_factor;
/* the rate at which this object and all of its children speed up or slow
* down media */
gdouble recursive_media_duration_factor;
gboolean in_composition;
};
struct _NleObjectClass
{
GstBinClass parent_class;
/* Signal method handler */
gboolean (*commit_signal_handler) (NleObject * object, gboolean recurse);
/* virtual methods for subclasses */
gboolean (*prepare) (NleObject * object);
gboolean (*cleanup) (NleObject * object);
gboolean (*commit) (NleObject * object, gboolean recurse);
};
GType nle_object_get_type (void)G_GNUC_INTERNAL;
gboolean
nle_object_to_media_time (NleObject * object, GstClockTime otime,
GstClockTime * mtime) G_GNUC_INTERNAL;
gboolean
nle_media_to_object_time (NleObject * object, GstClockTime mtime,
GstClockTime * otime) G_GNUC_INTERNAL;
void
nle_object_set_caps (NleObject * object, const GstCaps * caps) G_GNUC_INTERNAL;
void
nle_object_set_commit_needed (NleObject *object) G_GNUC_INTERNAL;
gboolean
nle_object_commit (NleObject *object, gboolean recurse) G_GNUC_INTERNAL;
void
nle_object_reset (NleObject *object) G_GNUC_INTERNAL;
GstStateChangeReturn
nle_object_cleanup (NleObject * object) G_GNUC_INTERNAL;
void nle_object_seek_all_children (NleObject *object, GstEvent *seek_event) G_GNUC_INTERNAL;
G_END_DECLS
#endif /* __NLE_OBJECT_H__ */