gstevent.c 41.4 KB
Newer Older
1 2 3
/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wim.taymans@chello.be>
4
 *                    2005 Wim Taymans <wim@fluendo.com>
5
 *
6
 * gstevent.c: GstEvent subsystem
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
 *
 * 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., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
23

24 25
/**
 * SECTION:gstevent
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
26 27
 * @short_description: Structure describing events that are passed up and down
 *                     a pipeline
28 29
 * @see_also: #GstPad, #GstElement
 *
Wim Taymans's avatar
Wim Taymans committed
30
 * The event class provides factory methods to construct events for sending
Stefan Kost's avatar
Stefan Kost committed
31
 * and functions to query (parse) received events.
32
 *
33 34
 * Events are usually created with gst_event_new_*() which takes event-type
 * specific parameters as arguments.
35 36
 * To send an event application will usually use gst_element_send_event() and
 * elements will use gst_pad_send_event() or gst_pad_push_event().
37 38 39
 * The event should be unreffed with gst_event_unref() if it has not been sent.
 *
 * Events that have been received can be parsed with their respective 
40
 * gst_event_parse_*() functions. It is valid to pass %NULL for unwanted details.
41
 *
Wim Taymans's avatar
Wim Taymans committed
42 43 44 45
 * Events are passed between elements in parallel to the data stream. Some events
 * are serialized with buffers, others are not. Some events only travel downstream,
 * others only upstream. Some events can travel both upstream and downstream. 
 * 
46 47 48
 * The events are used to signal special conditions in the datastream such as
 * EOS (end of stream) or the start of a new stream-segment.
 * Events are also used to flush the pipeline of any pending data.
Wim Taymans's avatar
Wim Taymans committed
49
 *
50 51 52 53
 * Most of the event API is used inside plugins. Applications usually only 
 * construct and use seek events. 
 * To do that gst_event_new_seek() is used to create a seek event. It takes
 * the needed parameters to specity seeking time and mode.
Wim Taymans's avatar
Wim Taymans committed
54 55 56 57 58 59 60 61 62 63
 * <example>
 * <title>performing a seek on a pipeline</title>
 *   <programlisting>
 *   GstEvent *event;
 *   gboolean result;
 *   ...
 *   // construct a seek event to play the media from second 2 to 5, flush
 *   // the pipeline to decrease latency.
 *   event = gst_event_new_seek (1.0, 
 *      GST_FORMAT_TIME, 
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
64 65 66
 *      GST_SEEK_FLAG_FLUSH,
 *      GST_SEEK_TYPE_SET, 2 * GST_SECOND,
 *      GST_SEEK_TYPE_SET, 5 * GST_SECOND);
Wim Taymans's avatar
Wim Taymans committed
67 68 69 70 71 72 73
 *   ...
 *   result = gst_element_send_event (pipeline, event);
 *   if (!result)
 *     g_warning ("seek failed");
 *   ...
 *   </programlisting>
 * </example>
Wim Taymans's avatar
Wim Taymans committed
74
 *
75
 * Last reviewed on 2006-09-6 (0.10.10)
76
 */
Wim Taymans's avatar
Wim Taymans committed
77

78

79
#include "gst_private.h"
80
#include <string.h>             /* memcpy */
81 82

#include "gstinfo.h"
83
#include "gstevent.h"
Wim Taymans's avatar
Wim Taymans committed
84
#include "gstenumtypes.h"
85
#include "gstutils.h"
86
#include "gstquark.h"
Benjamin Otte's avatar
Benjamin Otte committed
87

88 89
#define GST_EVENT_SEQNUM(e) ((GstEvent*)e)->abidata.seqnum

90 91
static void gst_event_finalize (GstEvent * event);
static GstEvent *_gst_event_copy (GstEvent * event);
92

93 94
static GstMiniObjectClass *parent_class = NULL;

95 96 97
void
_gst_event_initialize (void)
{
98 99 100
  g_type_class_ref (gst_event_get_type ());
  g_type_class_ref (gst_seek_flags_get_type ());
  g_type_class_ref (gst_seek_type_get_type ());
101 102
}

103 104
typedef struct
{
105 106
  const gint type;
  const gchar *name;
107 108 109 110 111 112 113 114 115 116
  GQuark quark;
} GstEventQuarks;

static GstEventQuarks event_quarks[] = {
  {GST_EVENT_UNKNOWN, "unknown", 0},
  {GST_EVENT_FLUSH_START, "flush-start", 0},
  {GST_EVENT_FLUSH_STOP, "flush-stop", 0},
  {GST_EVENT_EOS, "eos", 0},
  {GST_EVENT_NEWSEGMENT, "newsegment", 0},
  {GST_EVENT_TAG, "tag", 0},
117
  {GST_EVENT_BUFFERSIZE, "buffersize", 0},
118
  {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
119 120 121
  {GST_EVENT_QOS, "qos", 0},
  {GST_EVENT_SEEK, "seek", 0},
  {GST_EVENT_NAVIGATION, "navigation", 0},
122
  {GST_EVENT_LATENCY, "latency", 0},
Sebastian Dröge's avatar
Sebastian Dröge committed
123
  {GST_EVENT_STEP, "step", 0},
124 125 126
  {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
  {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
  {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
127 128 129
  {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
  {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},

130 131 132
  {0, NULL, 0}
};

Stefan Kost's avatar
Stefan Kost committed
133 134 135 136 137 138
/**
 * gst_event_type_get_name:
 * @type: the event type
 *
 * Get a printable name for the given event type. Do not modify or free.
 *
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
139
 * Returns: a reference to the static name of the event.
Stefan Kost's avatar
Stefan Kost committed
140
 */
141 142 143 144 145 146 147 148 149 150 151 152
const gchar *
gst_event_type_get_name (GstEventType type)
{
  gint i;

  for (i = 0; event_quarks[i].name; i++) {
    if (type == event_quarks[i].type)
      return event_quarks[i].name;
  }
  return "unknown";
}

Stefan Kost's avatar
Stefan Kost committed
153 154 155 156 157 158 159 160
/**
 * gst_event_type_to_quark:
 * @type: the event type
 *
 * Get the unique quark for the given event type.
 *
 * Returns: the quark associated with the event type
 */
161 162 163 164 165 166 167 168 169 170 171 172
GQuark
gst_event_type_to_quark (GstEventType type)
{
  gint i;

  for (i = 0; event_quarks[i].name; i++) {
    if (type == event_quarks[i].type)
      return event_quarks[i].quark;
  }
  return 0;
}

173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190
/**
 * gst_event_type_get_flags:
 * @type: a #GstEventType
 *
 * Gets the #GstEventTypeFlags associated with @type.
 *
 * Returns: a #GstEventTypeFlags.
 */
GstEventTypeFlags
gst_event_type_get_flags (GstEventType type)
{
  GstEventTypeFlags ret;

  ret = type & ((1 << GST_EVENT_TYPE_SHIFT) - 1);

  return ret;
}

191 192 193 194 195 196 197
#define _do_init \
{ \
  gint i; \
  \
  for (i = 0; event_quarks[i].name; i++) { \
    event_quarks[i].quark = g_quark_from_static_string (event_quarks[i].name); \
  } \
198 199
}

200 201
G_DEFINE_TYPE_WITH_CODE (GstEvent, gst_event, GST_TYPE_MINI_OBJECT, _do_init);

202
static void
203
gst_event_class_init (GstEventClass * klass)
Wim Taymans's avatar
Wim Taymans committed
204
{
205
  parent_class = g_type_class_peek_parent (klass);
Wim Taymans's avatar
Wim Taymans committed
206

207 208
  klass->mini_object_class.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
  klass->mini_object_class.finalize =
209 210
      (GstMiniObjectFinalizeFunction) gst_event_finalize;
}
Wim Taymans's avatar
Wim Taymans committed
211

212
static void
213
gst_event_init (GstEvent * event)
214 215
{
  GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
Wim Taymans's avatar
Wim Taymans committed
216 217
}

218
static void
219
gst_event_finalize (GstEvent * event)
220
{
221 222 223
  g_return_if_fail (event != NULL);
  g_return_if_fail (GST_IS_EVENT (event));

224
  GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
225
      GST_EVENT_TYPE_NAME (event));
Wim Taymans's avatar
Wim Taymans committed
226

227 228
  if (GST_EVENT_SRC (event)) {
    gst_object_unref (GST_EVENT_SRC (event));
229
    GST_EVENT_SRC (event) = NULL;
230
  }
Wim Taymans's avatar
Wim Taymans committed
231 232 233
  if (event->structure) {
    gst_structure_set_parent_refcount (event->structure, NULL);
    gst_structure_free (event->structure);
234
  }
235

236
/*   GST_MINI_OBJECT_CLASS (parent_class)->finalize (GST_MINI_OBJECT (event)); */
237 238 239 240 241 242 243
}

static GstEvent *
_gst_event_copy (GstEvent * event)
{
  GstEvent *copy;

Wim Taymans's avatar
Wim Taymans committed
244
  copy = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
245

Wim Taymans's avatar
Wim Taymans committed
246 247
  GST_EVENT_TYPE (copy) = GST_EVENT_TYPE (event);
  GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
248
  GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
249

Wim Taymans's avatar
Wim Taymans committed
250 251 252 253 254 255
  if (GST_EVENT_SRC (event)) {
    GST_EVENT_SRC (copy) = gst_object_ref (GST_EVENT_SRC (event));
  }
  if (event->structure) {
    copy->structure = gst_structure_copy (event->structure);
    gst_structure_set_parent_refcount (copy->structure,
256
        &copy->mini_object.refcount);
257 258
  }
  return copy;
259 260
}

Wim Taymans's avatar
Wim Taymans committed
261 262
static GstEvent *
gst_event_new (GstEventType type)
263
{
Wim Taymans's avatar
Wim Taymans committed
264
  GstEvent *event;
265

Wim Taymans's avatar
Wim Taymans committed
266
  event = (GstEvent *) gst_mini_object_new (GST_TYPE_EVENT);
267

Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
268 269
  GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
      gst_event_type_get_name (type), type);
270

Wim Taymans's avatar
Wim Taymans committed
271 272 273
  event->type = type;
  event->src = NULL;
  event->structure = NULL;
274
  GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
275

Wim Taymans's avatar
Wim Taymans committed
276
  return event;
277 278
}

279
/**
Wim Taymans's avatar
Wim Taymans committed
280
 * gst_event_new_custom:
281
 * @type: The type of the new event
282 283
 * @structure: (transfer full): the structure for the event. The event will
 *     take ownership of the structure.
284
 *
Wim Taymans's avatar
Wim Taymans committed
285 286 287
 * Create a new custom-typed event. This can be used for anything not
 * handled by other event-specific functions to pass an event to another
 * element.
288
 *
Wim Taymans's avatar
Wim Taymans committed
289 290 291 292 293 294 295
 * Make sure to allocate an event type with the #GST_EVENT_MAKE_TYPE macro,
 * assigning a free number and filling in the correct direction and
 * serialization flags.
 *
 * New custom events can also be created by subclassing the event type if
 * needed.
 *
296
 * Returns: (transfer full): the new custom event.
297
 */
298
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
299
gst_event_new_custom (GstEventType type, GstStructure * structure)
300 301 302
{
  GstEvent *event;

303 304 305 306
  /* structure must not have a parent */
  if (structure)
    g_return_val_if_fail (structure->parent_refcount == NULL, NULL);

Wim Taymans's avatar
Wim Taymans committed
307 308 309 310 311
  event = gst_event_new (type);
  if (structure) {
    gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
    event->structure = structure;
  }
312
  return event;
313 314
}

315
/**
Wim Taymans's avatar
Wim Taymans committed
316 317
 * gst_event_get_structure:
 * @event: The #GstEvent.
318
 *
Wim Taymans's avatar
Wim Taymans committed
319
 * Access the structure of the event.
320
 *
Wim Taymans's avatar
Wim Taymans committed
321 322 323 324 325
 * Returns: The structure of the event. The structure is still
 * owned by the event, which means that you should not free it and
 * that the pointer becomes invalid when you free the event.
 *
 * MT safe.
326
 */
Wim Taymans's avatar
Wim Taymans committed
327 328
const GstStructure *
gst_event_get_structure (GstEvent * event)
329
{
Wim Taymans's avatar
Wim Taymans committed
330
  g_return_val_if_fail (GST_IS_EVENT (event), NULL);
331

Wim Taymans's avatar
Wim Taymans committed
332
  return event->structure;
333
}
334

335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357
/**
 * gst_event_has_name:
 * @event: The #GstEvent.
 * @name: name to check
 *
 * Checks if @event has the given @name. This function is usually used to
 * check the name of a custom event.
 *
 * Returns: %TRUE if @name matches the name of the event structure.
 *
 * Since: 0.10.20
 */
gboolean
gst_event_has_name (GstEvent * event, const gchar * name)
{
  g_return_val_if_fail (GST_IS_EVENT (event), FALSE);

  if (event->structure == NULL)
    return FALSE;

  return gst_structure_has_name (event->structure, name);
}

358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411
/**
 * gst_event_get_seqnum:
 * @event: A #GstEvent.
 *
 * Retrieve the sequence number of a event.
 *
 * Events have ever-incrementing sequence numbers, which may also be set
 * explicitly via gst_event_set_seqnum(). Sequence numbers are typically used to
 * indicate that a event corresponds to some other set of events or messages,
 * for example an EOS event corresponding to a SEEK event. It is considered good
 * practice to make this correspondence when possible, though it is not
 * required.
 *
 * Note that events and messages share the same sequence number incrementor;
 * two events or messages will never not have the same sequence number unless
 * that correspondence was made explicitly.
 *
 * Returns: The event's sequence number.
 *
 * MT safe.
 *
 * Since: 0.10.22
 */
guint32
gst_event_get_seqnum (GstEvent * event)
{
  g_return_val_if_fail (GST_IS_EVENT (event), -1);

  return GST_EVENT_SEQNUM (event);
}

/**
 * gst_event_set_seqnum:
 * @event: A #GstEvent.
 * @seqnum: A sequence number.
 *
 * Set the sequence number of a event.
 *
 * This function might be called by the creator of a event to indicate that the
 * event relates to other events or messages. See gst_event_get_seqnum() for
 * more information.
 *
 * MT safe.
 *
 * Since: 0.10.22
 */
void
gst_event_set_seqnum (GstEvent * event, guint32 seqnum)
{
  g_return_if_fail (GST_IS_EVENT (event));

  GST_EVENT_SEQNUM (event) = seqnum;
}

412 413 414 415
/* FIXME 0.11: It would be nice to have flush events
 * that don't reset the running time in the sinks
 */

Wim Taymans's avatar
Wim Taymans committed
416
/**
Wim Taymans's avatar
Wim Taymans committed
417 418
 * gst_event_new_flush_start:
 *
419
 * Allocate a new flush start event. The flush start event can be sent
Wim Taymans's avatar
Wim Taymans committed
420
 * upstream and downstream and travels out-of-bounds with the dataflow.
421 422 423 424 425
 *
 * It marks pads as being flushing and will make them return
 * #GST_FLOW_WRONG_STATE when used for data flow with gst_pad_push(),
 * gst_pad_chain(), gst_pad_alloc_buffer(), gst_pad_get_range() and
 * gst_pad_pull_range(). Any event (except a #GST_EVENT_FLUSH_STOP) received
426
 * on a flushing pad will return %FALSE immediately.
Wim Taymans's avatar
Wim Taymans committed
427
 *
428 429
 * Elements should unlock any blocking functions and exit their streaming
 * functions as fast as possible when this event is received.
Wim Taymans's avatar
Wim Taymans committed
430
 *
431 432
 * This event is typically generated after a seek to flush out all queued data
 * in the pipeline so that the new media is played as soon as possible.
Wim Taymans's avatar
Wim Taymans committed
433
 *
434
 * Returns: (transfer full): a new flush start event.
Wim Taymans's avatar
Wim Taymans committed
435
 */
436
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
437
gst_event_new_flush_start (void)
438
{
Wim Taymans's avatar
Wim Taymans committed
439
  return gst_event_new (GST_EVENT_FLUSH_START);
440 441
}

442
/**
Wim Taymans's avatar
Wim Taymans committed
443 444
 * gst_event_new_flush_stop:
 *
445
 * Allocate a new flush stop event. The flush stop event can be sent
Thiago Santos's avatar
Thiago Santos committed
446
 * upstream and downstream and travels serialized with the dataflow.
447
 * It is typically sent after sending a FLUSH_START event to make the
Wim Taymans's avatar
Wim Taymans committed
448
 * pads accept data again.
449
 *
Wim Taymans's avatar
Wim Taymans committed
450 451
 * Elements can process this event synchronized with the dataflow since
 * the preceeding FLUSH_START event stopped the dataflow.
452
 *
Wim Taymans's avatar
Wim Taymans committed
453 454 455
 * This event is typically generated to complete a seek and to resume
 * dataflow.
 *
456
 * Returns: (transfer full): a new flush stop event.
457
 */
458
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
459
gst_event_new_flush_stop (void)
460
{
Wim Taymans's avatar
Wim Taymans committed
461
  return gst_event_new (GST_EVENT_FLUSH_STOP);
462 463
}

Wim Taymans's avatar
Wim Taymans committed
464
/**
Wim Taymans's avatar
Wim Taymans committed
465
 * gst_event_new_eos:
Wim Taymans's avatar
Wim Taymans committed
466
 *
Wim Taymans's avatar
Wim Taymans committed
467 468
 * Create a new EOS event. The eos event can only travel downstream
 * synchronized with the buffer flow. Elements that receive the EOS
469 470
 * event on a pad can return #GST_FLOW_UNEXPECTED as a #GstFlowReturn
 * when data after the EOS event arrives.
Wim Taymans's avatar
Wim Taymans committed
471
 *
Jan Schmidt's avatar
Jan Schmidt committed
472
 * The EOS event will travel down to the sink elements in the pipeline
473
 * which will then post the #GST_MESSAGE_EOS on the bus after they have
Jan Schmidt's avatar
Jan Schmidt committed
474
 * finished playing any buffered data.
Wim Taymans's avatar
Wim Taymans committed
475
 *
476
 * When all sinks have posted an EOS message, an EOS message is
Wim Taymans's avatar
Wim Taymans committed
477 478
 * forwarded to the application.
 *
Wim Taymans's avatar
Wim Taymans committed
479
 * The EOS event itself will not cause any state transitions of the pipeline.
Stefan Kost's avatar
Stefan Kost committed
480
 *
481
 * Returns: (transfer full): the new EOS event.
Wim Taymans's avatar
Wim Taymans committed
482
 */
Wim Taymans's avatar
Wim Taymans committed
483 484
GstEvent *
gst_event_new_eos (void)
485
{
Wim Taymans's avatar
Wim Taymans committed
486
  return gst_event_new (GST_EVENT_EOS);
487 488
}

489
/**
490
 * gst_event_new_new_segment:
491
 * @update: is this segment an update to a previous one
Wim Taymans's avatar
Wim Taymans committed
492 493
 * @rate: a new rate for playback
 * @format: The format of the segment values
494 495 496
 * @start: the start value of the segment
 * @stop: the stop value of the segment
 * @position: stream position
Wim Taymans's avatar
Wim Taymans committed
497
 *
498 499 500 501
 * Allocate a new newsegment event with the given format/values tripplets
 *
 * This method calls gst_event_new_new_segment_full() passing a default
 * value of 1.0 for applied_rate
Tim-Philipp Müller's avatar
Tim-Philipp Müller committed
502
 *
503
 * Returns: (transfer full): a new newsegment event.
504 505 506 507 508 509 510 511 512 513 514 515
 */
GstEvent *
gst_event_new_new_segment (gboolean update, gdouble rate, GstFormat format,
    gint64 start, gint64 stop, gint64 position)
{
  return gst_event_new_new_segment_full (update, rate, 1.0, format, start,
      stop, position);
}

/**
 * gst_event_parse_new_segment:
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
516 517 518 519 520 521
 * @update: (out): A pointer to the update flag of the segment
 * @rate: (out): A pointer to the rate of the segment
 * @format: (out): A pointer to the format of the newsegment values
 * @start: (out): A pointer to store the start value in
 * @stop: (out): A pointer to store the stop value in
 * @position: (out): A pointer to store the stream time in
522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548
 *
 * Get the update flag, rate, format, start, stop and position in the 
 * newsegment event. In general, gst_event_parse_new_segment_full() should
 * be used instead of this, to also retrieve the applied_rate value of the
 * segment. See gst_event_new_new_segment_full() for a full description 
 * of the newsegment event.
 */
void
gst_event_parse_new_segment (GstEvent * event, gboolean * update,
    gdouble * rate, GstFormat * format, gint64 * start,
    gint64 * stop, gint64 * position)
{
  gst_event_parse_new_segment_full (event, update, rate, NULL, format, start,
      stop, position);
}

/**
 * gst_event_new_new_segment_full:
 * @update: Whether this segment is an update to a previous one
 * @rate: A new rate for playback
 * @applied_rate: The rate factor which has already been applied
 * @format: The format of the segment values
 * @start: The start value of the segment
 * @stop: The stop value of the segment
 * @position: stream position
 *
 * Allocate a new newsegment event with the given format/values triplets.
Wim Taymans's avatar
Wim Taymans committed
549 550
 *
 * The newsegment event marks the range of buffers to be processed. All
551
 * data not within the segment range is not to be processed. This can be
552
 * used intelligently by plugins to apply more efficient methods of skipping
553 554
 * unneeded data. The valid range is expressed with the @start and @stop
 * values.
555
 *
556 557 558 559 560
 * The position value of the segment is used in conjunction with the start
 * value to convert the buffer timestamps into the stream time. This is 
 * usually done in sinks to report the current stream_time. 
 * @position represents the stream_time of a buffer carrying a timestamp of 
 * @start. @position cannot be -1.
561
 *
562
 * @start cannot be -1, @stop can be -1. If there
563
 * is a valid @stop given, it must be greater or equal the @start, including 
564
 * when the indicated playback @rate is < 0.
565 566 567 568 569 570 571 572
 *
 * The @applied_rate value provides information about any rate adjustment that
 * has already been made to the timestamps and content on the buffers of the 
 * stream. (@rate * @applied_rate) should always equal the rate that has been 
 * requested for playback. For example, if an element has an input segment 
 * with intended playback @rate of 2.0 and applied_rate of 1.0, it can adjust 
 * incoming timestamps and buffer content by half and output a newsegment event 
 * with @rate of 1.0 and @applied_rate of 2.0
573
 *
Wim Taymans's avatar
Wim Taymans committed
574 575
 * After a newsegment event, the buffer stream time is calculated with:
 *
576
 *   position + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
Wim Taymans's avatar
Wim Taymans committed
577
 *
578
 * Returns: (transfer full): a new newsegment event.
579 580
 *
 * Since: 0.10.6
581
 */
582
GstEvent *
583 584 585
gst_event_new_new_segment_full (gboolean update, gdouble rate,
    gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
    gint64 position)
586
{
587 588 589
  GstEvent *event;
  GstStructure *structure;

590
  g_return_val_if_fail (rate != 0.0, NULL);
591
  g_return_val_if_fail (applied_rate != 0.0, NULL);
592

593 594
  if (format == GST_FORMAT_TIME) {
    GST_CAT_INFO (GST_CAT_EVENT,
595
        "creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
596
        "start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
597 598 599
        ", position %" GST_TIME_FORMAT,
        update, rate, GST_TIME_ARGS (start),
        GST_TIME_ARGS (stop), GST_TIME_ARGS (position));
600 601
  } else {
    GST_CAT_INFO (GST_CAT_EVENT,
602
        "creating newsegment update %d, rate %lf, format %s, "
603
        "start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", position %"
604 605
        G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
        stop, position);
606
  }
607

608 609 610 611
  g_return_val_if_fail (position != -1, NULL);
  g_return_val_if_fail (start != -1, NULL);
  if (stop != -1)
    g_return_val_if_fail (start <= stop, NULL);
612

613
  structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
614 615 616 617 618 619 620 621 622 623
      GST_QUARK (UPDATE), G_TYPE_BOOLEAN, update,
      GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
      GST_QUARK (APPLIED_RATE), G_TYPE_DOUBLE, applied_rate,
      GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
      GST_QUARK (START), G_TYPE_INT64, start,
      GST_QUARK (STOP), G_TYPE_INT64, stop,
      GST_QUARK (POSITION), G_TYPE_INT64, position, NULL);
  event = gst_event_new_custom (GST_EVENT_NEWSEGMENT, structure);

  return event;
Wim Taymans's avatar
Wim Taymans committed
624
}
625

Wim Taymans's avatar
Wim Taymans committed
626
/**
627
 * gst_event_parse_new_segment_full:
Wim Taymans's avatar
Wim Taymans committed
628
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
629 630 631 632 633 634 635
 * @update: (out): A pointer to the update flag of the segment
 * @rate: (out): A pointer to the rate of the segment
 * @applied_rate: (out): A pointer to the applied_rate of the segment
 * @format: (out): A pointer to the format of the newsegment values
 * @start: (out): A pointer to store the start value in
 * @stop: (out): A pointer to store the stop value in
 * @position: (out): A pointer to store the stream time in
Wim Taymans's avatar
Wim Taymans committed
636
 *
637 638 639 640 641
 * Get the update, rate, applied_rate, format, start, stop and 
 * position in the newsegment event. See gst_event_new_new_segment_full() 
 * for a full description of the newsegment event.
 *
 * Since: 0.10.6
Wim Taymans's avatar
Wim Taymans committed
642 643
 */
void
644 645 646
gst_event_parse_new_segment_full (GstEvent * event, gboolean * update,
    gdouble * rate, gdouble * applied_rate, GstFormat * format,
    gint64 * start, gint64 * stop, gint64 * position)
Wim Taymans's avatar
Wim Taymans committed
647 648
{
  const GstStructure *structure;
649

Wim Taymans's avatar
Wim Taymans committed
650 651 652
  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);

653
  structure = event->structure;
654
  if (G_LIKELY (update))
655
    *update =
656 657
        g_value_get_boolean (gst_structure_id_get_value (structure,
            GST_QUARK (UPDATE)));
658
  if (G_LIKELY (rate))
659 660 661
    *rate =
        g_value_get_double (gst_structure_id_get_value (structure,
            GST_QUARK (RATE)));
662 663
  if (G_LIKELY (applied_rate))
    *applied_rate =
664 665
        g_value_get_double (gst_structure_id_get_value (structure,
            GST_QUARK (APPLIED_RATE)));
666
  if (G_LIKELY (format))
667 668 669
    *format =
        g_value_get_enum (gst_structure_id_get_value (structure,
            GST_QUARK (FORMAT)));
670
  if (G_LIKELY (start))
671 672 673
    *start =
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (START)));
674
  if (G_LIKELY (stop))
675 676 677
    *stop =
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (STOP)));
678
  if (G_LIKELY (position))
679
    *position =
680 681
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (POSITION)));
Wim Taymans's avatar
Wim Taymans committed
682
}
683

684 685
/**
 * gst_event_new_tag:
686 687
 * @taglist: (transfer full): metadata list. The event will take ownership
 *     of the taglist.
688 689
 *
 * Generates a metadata tag event from the given @taglist.
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
690
 *
691
 * Returns: (transfer full): a new #GstEvent
692
 */
Wim Taymans's avatar
Wim Taymans committed
693 694 695 696
GstEvent *
gst_event_new_tag (GstTagList * taglist)
{
  g_return_val_if_fail (taglist != NULL, NULL);
697

Wim Taymans's avatar
Wim Taymans committed
698
  return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
699 700
}

701 702 703
/**
 * gst_event_parse_tag:
 * @event: a tag event
704
 * @taglist: (out) (transfer none): pointer to metadata list
705 706
 *
 * Parses a tag @event and stores the results in the given @taglist location.
707 708 709
 * No reference to the taglist will be returned, it remains valid only until
 * the @event is freed. Don't modify or free the taglist, make a copy if you
 * want to modify it or store it for later use.
710
 */
Wim Taymans's avatar
Wim Taymans committed
711 712 713 714 715
void
gst_event_parse_tag (GstEvent * event, GstTagList ** taglist)
{
  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_TAG);
716

Wim Taymans's avatar
Wim Taymans committed
717 718 719 720
  if (taglist)
    *taglist = (GstTagList *) event->structure;
}

721 722
/* buffersize event */
/**
723
 * gst_event_new_buffer_size:
Stefan Kost's avatar
Stefan Kost committed
724 725 726 727
 * @format: buffer format
 * @minsize: minimum buffer size
 * @maxsize: maximum buffer size
 * @async: thread behavior
728 729 730 731
 *
 * Create a new buffersize event. The event is sent downstream and notifies
 * elements that they should provide a buffer of the specified dimensions.
 *
732
 * When the @async flag is set, a thread boundary is prefered.
733
 *
734
 * Returns: (transfer full): a new #GstEvent
735 736
 */
GstEvent *
737
gst_event_new_buffer_size (GstFormat format, gint64 minsize,
738 739
    gint64 maxsize, gboolean async)
{
740 741 742
  GstEvent *event;
  GstStructure *structure;

743
  GST_CAT_INFO (GST_CAT_EVENT,
744 745
      "creating buffersize format %s, minsize %" G_GINT64_FORMAT
      ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
746
      minsize, maxsize, async);
747

748
  structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
749 750 751 752 753 754 755
      GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
      GST_QUARK (MINSIZE), G_TYPE_INT64, minsize,
      GST_QUARK (MAXSIZE), G_TYPE_INT64, maxsize,
      GST_QUARK (ASYNC), G_TYPE_BOOLEAN, async, NULL);
  event = gst_event_new_custom (GST_EVENT_BUFFERSIZE, structure);

  return event;
756 757
}

Stefan Kost's avatar
Stefan Kost committed
758
/**
759
 * gst_event_parse_buffer_size:
Stefan Kost's avatar
Stefan Kost committed
760
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
761 762 763 764
 * @format: (out): A pointer to store the format in
 * @minsize: (out): A pointer to store the minsize in
 * @maxsize: (out): A pointer to store the maxsize in
 * @async: (out): A pointer to store the async-flag in
Stefan Kost's avatar
Stefan Kost committed
765 766 767
 *
 * Get the format, minsize, maxsize and async-flag in the buffersize event.
 */
768
void
769
gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
770 771 772 773 774 775
    gint64 * minsize, gint64 * maxsize, gboolean * async)
{
  const GstStructure *structure;

  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_BUFFERSIZE);
776

777
  structure = event->structure;
778
  if (format)
779 780 781
    *format =
        g_value_get_enum (gst_structure_id_get_value (structure,
            GST_QUARK (FORMAT)));
782 783
  if (minsize)
    *minsize =
784 785
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (MINSIZE)));
786 787
  if (maxsize)
    *maxsize =
788 789
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (MAXSIZE)));
790
  if (async)
791 792 793
    *async =
        g_value_get_boolean (gst_structure_id_get_value (structure,
            GST_QUARK (ASYNC)));
794 795
}

796
/**
Wim Taymans's avatar
Wim Taymans committed
797 798 799 800 801
 * gst_event_new_qos:
 * @proportion: the proportion of the qos message
 * @diff: The time difference of the last Clock sync
 * @timestamp: The timestamp of the buffer
 *
Wim Taymans's avatar
Wim Taymans committed
802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829
 * Allocate a new qos event with the given values. This function calls
 * gst_event_new_qos_full() with the type set to #GST_QOS_TYPE_OVERFLOW
 * when diff is negative (buffers are in time) and #GST_QOS_TYPE_UNDERFLOW
 * when @diff is positive (buffers are late).
 *
 * Returns: (transfer full): a new QOS event.
 */
GstEvent *
gst_event_new_qos (gdouble proportion, GstClockTimeDiff diff,
    GstClockTime timestamp)
{
  GstQOSType type;

  if (diff <= 0)
    type = GST_QOS_TYPE_OVERFLOW;
  else
    type = GST_QOS_TYPE_UNDERFLOW;

  return gst_event_new_qos_full (type, proportion, diff, timestamp);
}

/**
 * gst_event_new_qos_full:
 * @type: the QoS type
 * @proportion: the proportion of the qos message
 * @diff: The time difference of the last Clock sync
 * @timestamp: The timestamp of the buffer
 *
Wim Taymans's avatar
Wim Taymans committed
830 831 832
 * Allocate a new qos event with the given values.
 * The QOS event is generated in an element that wants an upstream
 * element to either reduce or increase its rate because of
Wim Taymans's avatar
Wim Taymans committed
833 834 835 836 837 838 839 840 841 842
 * high/low CPU load or other resource usage such as network performance or
 * throttling. Typically sinks generate these events for each buffer
 * they receive.
 *
 * @type indicates the reason for the QoS event. #GST_QOS_TYPE_OVERFLOW is
 * used when a buffer arrived in time or when the sink cannot keep up with
 * the upstream datarate. #GST_QOS_TYPE_UNDERFLOW is when the sink is not
 * receiving buffers fast enough and thus has to drop late buffers. 
 * #GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited
 * by the application, for example to reduce power consumption.
843 844 845 846 847 848 849 850 851 852 853 854 855 856
 *
 * @proportion indicates the real-time performance of the streaming in the
 * element that generated the QoS event (usually the sink). The value is
 * generally computed based on more long term statistics about the streams
 * timestamps compared to the clock.
 * A value < 1.0 indicates that the upstream element is producing data faster
 * than real-time. A value > 1.0 indicates that the upstream element is not
 * producing data fast enough. 1.0 is the ideal @proportion value. The
 * proportion value can safely be used to lower or increase the quality of
 * the element.
 *
 * @diff is the difference against the clock in running time of the last
 * buffer that caused the element to generate the QOS event. A negative value
 * means that the buffer with @timestamp arrived in time. A positive value
Wim Taymans's avatar
Wim Taymans committed
857 858
 * indicates how late the buffer with @timestamp was. When throttling is
 * enabled, @diff will be set to the requested throttling interval.
859
 *
860
 * @timestamp is the timestamp of the last buffer that cause the element
861 862
 * to generate the QOS event. It is expressed in running time and thus an ever
 * increasing value.
863 864
 *
 * The upstream element can use the @diff and @timestamp values to decide
865 866
 * whether to process more buffers. For possitive @diff, all buffers with
 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
867 868
 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
 * result smaller than 0 is not allowed.
869 870 871
 *
 * The application can use general event probes to intercept the QoS
 * event and implement custom application specific QoS handling.
Wim Taymans's avatar
Wim Taymans committed
872
 *
873
 * Returns: (transfer full): a new QOS event.
Wim Taymans's avatar
Wim Taymans committed
874 875
 *
 * Since: 0.10.33
876
 */
877
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
878 879
gst_event_new_qos_full (GstQOSType type, gdouble proportion,
    GstClockTimeDiff diff, GstClockTime timestamp)
880
{
881 882 883
  GstEvent *event;
  GstStructure *structure;

884 885 886
  /* diff must be positive or timestamp + diff must be positive */
  g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);

887
  GST_CAT_INFO (GST_CAT_EVENT,
Wim Taymans's avatar
Wim Taymans committed
888 889
      "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
      ", timestamp %" GST_TIME_FORMAT, type, proportion,
890
      diff, GST_TIME_ARGS (timestamp));
891

892
  structure = gst_structure_id_new (GST_QUARK (EVENT_QOS),
Wim Taymans's avatar
Wim Taymans committed
893
      GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
894 895 896 897 898 899
      GST_QUARK (PROPORTION), G_TYPE_DOUBLE, proportion,
      GST_QUARK (DIFF), G_TYPE_INT64, diff,
      GST_QUARK (TIMESTAMP), G_TYPE_UINT64, timestamp, NULL);
  event = gst_event_new_custom (GST_EVENT_QOS, structure);

  return event;
Wim Taymans's avatar
Wim Taymans committed
900
}
901

Wim Taymans's avatar
Wim Taymans committed
902 903 904
/**
 * gst_event_parse_qos:
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
905 906 907
 * @proportion: (out): A pointer to store the proportion in
 * @diff: (out): A pointer to store the diff in
 * @timestamp: (out): A pointer to store the timestamp in
Wim Taymans's avatar
Wim Taymans committed
908
 *
909 910
 * Get the proportion, diff and timestamp in the qos event. See
 * gst_event_new_qos() for more information about the different QoS values.
Wim Taymans's avatar
Wim Taymans committed
911 912 913 914
 */
void
gst_event_parse_qos (GstEvent * event, gdouble * proportion,
    GstClockTimeDiff * diff, GstClockTime * timestamp)
Wim Taymans's avatar
Wim Taymans committed
915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934
{
  gst_event_parse_qos_full (event, NULL, proportion, diff, timestamp);
}

/**
 * gst_event_parse_qos_full:
 * @event: The event to query
 * @type: (out): A pointer to store the QoS type in
 * @proportion: (out): A pointer to store the proportion in
 * @diff: (out): A pointer to store the diff in
 * @timestamp: (out): A pointer to store the timestamp in
 *
 * Get the type, proportion, diff and timestamp in the qos event. See
 * gst_event_new_qos_full() for more information about the different QoS values.
 *
 * Since: 0.10.33
 */
void
gst_event_parse_qos_full (GstEvent * event, GstQOSType * type,
    gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
Wim Taymans's avatar
Wim Taymans committed
935 936
{
  const GstStructure *structure;
937

Wim Taymans's avatar
Wim Taymans committed
938 939
  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
940

941
  structure = event->structure;
Wim Taymans's avatar
Wim Taymans committed
942 943 944 945
  if (type)
    *type =
        g_value_get_enum (gst_structure_id_get_value (structure,
            GST_QUARK (TYPE)));
Wim Taymans's avatar
Wim Taymans committed
946 947
  if (proportion)
    *proportion =
948 949
        g_value_get_double (gst_structure_id_get_value (structure,
            GST_QUARK (PROPORTION)));
Wim Taymans's avatar
Wim Taymans committed
950
  if (diff)
951 952 953
    *diff =
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (DIFF)));
Wim Taymans's avatar
Wim Taymans committed
954 955
  if (timestamp)
    *timestamp =
956 957
        g_value_get_uint64 (gst_structure_id_get_value (structure,
            GST_QUARK (TIMESTAMP)));
958
}
959 960

/**
Wim Taymans's avatar
Wim Taymans committed
961 962 963
 * gst_event_new_seek:
 * @rate: The new playback rate
 * @format: The format of the seek values
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
964
 * @flags: The optional seek flags
965 966
 * @start_type: The type and flags for the new start position
 * @start: The value of the new start position
Wim Taymans's avatar
Wim Taymans committed
967 968 969 970 971
 * @stop_type: The type and flags for the new stop position
 * @stop: The value of the new stop position
 *
 * Allocate a new seek event with the given parameters.
 *
972 973 974
 * The seek event configures playback of the pipeline between @start to @stop
 * at the speed given in @rate, also called a playback segment.
 * The @start and @stop values are expressed in @format.
975
 *
Wim Taymans's avatar
Wim Taymans committed
976 977
 * A @rate of 1.0 means normal playback rate, 2.0 means double speed.
 * Negatives values means backwards playback. A value of 0.0 for the
978 979 980
 * rate is not allowed and should be accomplished instead by PAUSING the
 * pipeline.
 *
981 982 983
 * A pipeline has a default playback segment configured with a start
 * position of 0, a stop position of -1 and a rate of 1.0. The currently
 * configured playback segment can be queried with #GST_QUERY_SEGMENT. 
984
 *
985
 * @start_type and @stop_type specify how to adjust the currently configured 
986 987 988
 * start and stop fields in playback segment. Adjustments can be made relative
 * or absolute to the last configured values. A type of #GST_SEEK_TYPE_NONE
 * means that the position should not be updated.
989
 *
990
 * When the rate is positive and @start has been updated, playback will start
991 992 993 994 995
 * from the newly configured start position. 
 *
 * For negative rates, playback will start from the newly configured stop
 * position (if any). If the stop position if updated, it must be different from
 * -1 for negative rates.
996 997 998 999
 *
 * It is not possible to seek relative to the current playback position, to do
 * this, PAUSE the pipeline, query the current playback position with
 * #GST_QUERY_POSITION and update the playback segment current position with a
1000
 * #GST_SEEK_TYPE_SET to the desired position. 
1001
 *
1002
 * Returns: (transfer full): a new seek event.
1003 1004
 */
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
1005
gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1006
    GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1007
{
1008 1009 1010
  GstEvent *event;
  GstStructure *structure;

1011 1012
  g_return_val_if_fail (rate != 0.0, NULL);

1013 1014 1015
  if (format == GST_FORMAT_TIME) {
    GST_CAT_INFO (GST_CAT_EVENT,
        "creating seek rate %lf, format TIME, flags %d, "
1016
        "start_type %d, start %" GST_TIME_FORMAT ", "