gstevent.c 41.3 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
static GType _gst_event_type = 0;
89

90 91
typedef struct
{
92 93
  const gint type;
  const gchar *name;
94 95 96 97 98 99 100 101 102 103
  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},
104
  {GST_EVENT_BUFFERSIZE, "buffersize", 0},
105
  {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
106 107 108
  {GST_EVENT_QOS, "qos", 0},
  {GST_EVENT_SEEK, "seek", 0},
  {GST_EVENT_NAVIGATION, "navigation", 0},
109
  {GST_EVENT_LATENCY, "latency", 0},
Sebastian Dröge's avatar
Sebastian Dröge committed
110
  {GST_EVENT_STEP, "step", 0},
111 112 113
  {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
  {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
  {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
114 115 116
  {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
  {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},

117 118 119
  {0, NULL, 0}
};

120 121 122 123
void
_gst_event_initialize (void)
{
  gint i;
124 125

  gst_event_get_type ();
126 127 128 129 130 131 132 133
  g_type_class_ref (gst_seek_flags_get_type ());
  g_type_class_ref (gst_seek_type_get_type ());

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

Stefan Kost's avatar
Stefan Kost committed
134 135 136 137 138 139
/**
 * 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
140
 * Returns: a reference to the static name of the event.
Stefan Kost's avatar
Stefan Kost committed
141
 */
142 143 144 145 146 147 148 149 150 151 152 153
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
154 155 156 157 158 159 160 161
/**
 * 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
 */
162 163 164 165 166 167 168 169 170 171 172 173
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;
}

174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191
/**
 * 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;
}

192 193
GType
gst_event_get_type (void)
Wim Taymans's avatar
Wim Taymans committed
194
{
195 196 197 198
  if (G_UNLIKELY (_gst_event_type == 0)) {
    _gst_event_type = gst_mini_object_register ("GstEvent");
  }
  return _gst_event_type;
Wim Taymans's avatar
Wim Taymans committed
199 200
}

201
static void
202
_gst_event_free (GstEvent * event)
203
{
204 205 206
  g_return_if_fail (event != NULL);
  g_return_if_fail (GST_IS_EVENT (event));

207
  GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
208
      GST_EVENT_TYPE_NAME (event));
Wim Taymans's avatar
Wim Taymans committed
209

210 211
  if (GST_EVENT_SRC (event)) {
    gst_object_unref (GST_EVENT_SRC (event));
212
    GST_EVENT_SRC (event) = NULL;
213
  }
Wim Taymans's avatar
Wim Taymans committed
214 215 216
  if (event->structure) {
    gst_structure_set_parent_refcount (event->structure, NULL);
    gst_structure_free (event->structure);
217
  }
218

Wim Taymans's avatar
Wim Taymans committed
219
  g_slice_free1 (GST_MINI_OBJECT_SIZE (event), event);
220 221
}

Wim Taymans's avatar
Wim Taymans committed
222
static void gst_event_init (GstEvent * event, gsize size, GstEventType type);
Wim Taymans's avatar
Wim Taymans committed
223

224 225 226 227 228
static GstEvent *
_gst_event_copy (GstEvent * event)
{
  GstEvent *copy;

229 230
  copy = g_slice_new0 (GstEvent);

Wim Taymans's avatar
Wim Taymans committed
231
  gst_event_init (copy, sizeof (GstEvent), GST_EVENT_TYPE (event));
232

Wim Taymans's avatar
Wim Taymans committed
233
  GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
234
  GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
235

Wim Taymans's avatar
Wim Taymans committed
236 237 238 239 240 241
  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,
242
        &copy->mini_object.refcount);
243 244
  }
  return copy;
245 246
}

Wim Taymans's avatar
Wim Taymans committed
247
static void
Wim Taymans's avatar
Wim Taymans committed
248
gst_event_init (GstEvent * event, gsize size, GstEventType type)
Wim Taymans's avatar
Wim Taymans committed
249
{
Wim Taymans's avatar
Wim Taymans committed
250
  gst_mini_object_init (GST_MINI_OBJECT_CAST (event), _gst_event_type, size);
Wim Taymans's avatar
Wim Taymans committed
251 252 253 254 255 256 257 258 259

  event->mini_object.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
  event->mini_object.free = (GstMiniObjectFreeFunction) _gst_event_free;

  GST_EVENT_TYPE (event) = type;
  GST_EVENT_TIMESTAMP (event) = GST_CLOCK_TIME_NONE;
  GST_EVENT_SEQNUM (event) = gst_util_seqnum_next ();
}

Wim Taymans's avatar
Wim Taymans committed
260 261
static GstEvent *
gst_event_new (GstEventType type)
262
{
Wim Taymans's avatar
Wim Taymans committed
263
  GstEvent *event;
264

265
  event = g_slice_new0 (GstEvent);
266

Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
267 268
  GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
      gst_event_type_get_name (type), type);
269

Wim Taymans's avatar
Wim Taymans committed
270
  gst_event_init (event, sizeof (GstEvent), type);
271

Wim Taymans's avatar
Wim Taymans committed
272
  return event;
273 274
}

275
/**
Wim Taymans's avatar
Wim Taymans committed
276
 * gst_event_new_custom:
277
 * @type: The type of the new event
278 279
 * @structure: (transfer full): the structure for the event. The event will
 *     take ownership of the structure.
280
 *
Wim Taymans's avatar
Wim Taymans committed
281 282 283
 * 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.
284
 *
Wim Taymans's avatar
Wim Taymans committed
285 286 287 288 289 290 291
 * 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.
 *
292
 * Returns: (transfer full): the new custom event.
293
 */
294
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
295
gst_event_new_custom (GstEventType type, GstStructure * structure)
296 297 298
{
  GstEvent *event;

299 300 301 302
  /* 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
303 304 305 306 307
  event = gst_event_new (type);
  if (structure) {
    gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
    event->structure = structure;
  }
308
  return event;
309 310
}

311
/**
Wim Taymans's avatar
Wim Taymans committed
312 313
 * gst_event_get_structure:
 * @event: The #GstEvent.
314
 *
Wim Taymans's avatar
Wim Taymans committed
315
 * Access the structure of the event.
316
 *
Wim Taymans's avatar
Wim Taymans committed
317 318 319 320 321
 * 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.
322
 */
Wim Taymans's avatar
Wim Taymans committed
323 324
const GstStructure *
gst_event_get_structure (GstEvent * event)
325
{
Wim Taymans's avatar
Wim Taymans committed
326
  g_return_val_if_fail (GST_IS_EVENT (event), NULL);
327

Wim Taymans's avatar
Wim Taymans committed
328
  return event->structure;
329
}
330

331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353
/**
 * 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);
}

354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407
/**
 * 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;
}

408 409 410 411
/* 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
412
/**
Wim Taymans's avatar
Wim Taymans committed
413 414
 * gst_event_new_flush_start:
 *
415
 * Allocate a new flush start event. The flush start event can be sent
Wim Taymans's avatar
Wim Taymans committed
416
 * upstream and downstream and travels out-of-bounds with the dataflow.
417 418 419 420 421
 *
 * 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
422
 * on a flushing pad will return %FALSE immediately.
Wim Taymans's avatar
Wim Taymans committed
423
 *
424 425
 * 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
426
 *
427 428
 * 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
429
 *
430
 * Returns: (transfer full): a new flush start event.
Wim Taymans's avatar
Wim Taymans committed
431
 */
432
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
433
gst_event_new_flush_start (void)
434
{
Wim Taymans's avatar
Wim Taymans committed
435
  return gst_event_new (GST_EVENT_FLUSH_START);
436 437
}

438
/**
Wim Taymans's avatar
Wim Taymans committed
439 440
 * gst_event_new_flush_stop:
 *
441
 * Allocate a new flush stop event. The flush stop event can be sent
Thiago Santos's avatar
Thiago Santos committed
442
 * upstream and downstream and travels serialized with the dataflow.
443
 * It is typically sent after sending a FLUSH_START event to make the
Wim Taymans's avatar
Wim Taymans committed
444
 * pads accept data again.
445
 *
Wim Taymans's avatar
Wim Taymans committed
446 447
 * Elements can process this event synchronized with the dataflow since
 * the preceeding FLUSH_START event stopped the dataflow.
448
 *
Wim Taymans's avatar
Wim Taymans committed
449 450 451
 * This event is typically generated to complete a seek and to resume
 * dataflow.
 *
452
 * Returns: (transfer full): a new flush stop event.
453
 */
454
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
455
gst_event_new_flush_stop (void)
456
{
Wim Taymans's avatar
Wim Taymans committed
457
  return gst_event_new (GST_EVENT_FLUSH_STOP);
458 459
}

Wim Taymans's avatar
Wim Taymans committed
460
/**
Wim Taymans's avatar
Wim Taymans committed
461
 * gst_event_new_eos:
Wim Taymans's avatar
Wim Taymans committed
462
 *
Wim Taymans's avatar
Wim Taymans committed
463 464
 * Create a new EOS event. The eos event can only travel downstream
 * synchronized with the buffer flow. Elements that receive the EOS
465 466
 * 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
467
 *
Jan Schmidt's avatar
Jan Schmidt committed
468
 * The EOS event will travel down to the sink elements in the pipeline
469
 * which will then post the #GST_MESSAGE_EOS on the bus after they have
Jan Schmidt's avatar
Jan Schmidt committed
470
 * finished playing any buffered data.
Wim Taymans's avatar
Wim Taymans committed
471
 *
472
 * When all sinks have posted an EOS message, an EOS message is
Wim Taymans's avatar
Wim Taymans committed
473 474
 * forwarded to the application.
 *
Wim Taymans's avatar
Wim Taymans committed
475
 * The EOS event itself will not cause any state transitions of the pipeline.
Stefan Kost's avatar
Stefan Kost committed
476
 *
477
 * Returns: (transfer full): the new EOS event.
Wim Taymans's avatar
Wim Taymans committed
478
 */
Wim Taymans's avatar
Wim Taymans committed
479 480
GstEvent *
gst_event_new_eos (void)
481
{
Wim Taymans's avatar
Wim Taymans committed
482
  return gst_event_new (GST_EVENT_EOS);
483 484
}

485
/**
486
 * gst_event_new_new_segment:
487
 * @update: is this segment an update to a previous one
Wim Taymans's avatar
Wim Taymans committed
488 489
 * @rate: a new rate for playback
 * @format: The format of the segment values
490 491 492
 * @start: the start value of the segment
 * @stop: the stop value of the segment
 * @position: stream position
Wim Taymans's avatar
Wim Taymans committed
493
 *
494 495 496 497
 * 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
498
 *
499
 * Returns: (transfer full): a new newsegment event.
500 501 502 503 504 505 506 507 508 509 510 511
 */
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
512 513 514 515 516 517
 * @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
518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544
 *
 * 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
545 546
 *
 * The newsegment event marks the range of buffers to be processed. All
547
 * data not within the segment range is not to be processed. This can be
548
 * used intelligently by plugins to apply more efficient methods of skipping
549 550
 * unneeded data. The valid range is expressed with the @start and @stop
 * values.
551
 *
552 553 554 555 556
 * 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.
557
 *
558
 * @start cannot be -1, @stop can be -1. If there
559
 * is a valid @stop given, it must be greater or equal the @start, including 
560
 * when the indicated playback @rate is < 0.
561 562 563 564 565 566 567 568
 *
 * 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
569
 *
Wim Taymans's avatar
Wim Taymans committed
570 571
 * After a newsegment event, the buffer stream time is calculated with:
 *
572
 *   position + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
Wim Taymans's avatar
Wim Taymans committed
573
 *
574
 * Returns: (transfer full): a new newsegment event.
575 576
 *
 * Since: 0.10.6
577
 */
578
GstEvent *
579 580 581
gst_event_new_new_segment_full (gboolean update, gdouble rate,
    gdouble applied_rate, GstFormat format, gint64 start, gint64 stop,
    gint64 position)
582
{
583 584 585
  GstEvent *event;
  GstStructure *structure;

586
  g_return_val_if_fail (rate != 0.0, NULL);
587
  g_return_val_if_fail (applied_rate != 0.0, NULL);
588

589 590
  if (format == GST_FORMAT_TIME) {
    GST_CAT_INFO (GST_CAT_EVENT,
591
        "creating newsegment update %d, rate %lf, format GST_FORMAT_TIME, "
592
        "start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
593 594 595
        ", position %" GST_TIME_FORMAT,
        update, rate, GST_TIME_ARGS (start),
        GST_TIME_ARGS (stop), GST_TIME_ARGS (position));
596 597
  } else {
    GST_CAT_INFO (GST_CAT_EVENT,
598
        "creating newsegment update %d, rate %lf, format %s, "
599
        "start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", position %"
600 601
        G_GINT64_FORMAT, update, rate, gst_format_get_name (format), start,
        stop, position);
602
  }
603

604 605 606 607
  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);
608

609
  structure = gst_structure_id_new (GST_QUARK (EVENT_NEWSEGMENT),
610 611 612 613 614 615 616 617 618 619
      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
620
}
621

Wim Taymans's avatar
Wim Taymans committed
622
/**
623
 * gst_event_parse_new_segment_full:
Wim Taymans's avatar
Wim Taymans committed
624
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
625 626 627 628 629 630 631
 * @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
632
 *
633 634 635 636 637
 * 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
638 639
 */
void
640 641 642
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
643 644
{
  const GstStructure *structure;
645

Wim Taymans's avatar
Wim Taymans committed
646 647 648
  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT);

649
  structure = event->structure;
650
  if (G_LIKELY (update))
651
    *update =
652 653
        g_value_get_boolean (gst_structure_id_get_value (structure,
            GST_QUARK (UPDATE)));
654
  if (G_LIKELY (rate))
655 656 657
    *rate =
        g_value_get_double (gst_structure_id_get_value (structure,
            GST_QUARK (RATE)));
658 659
  if (G_LIKELY (applied_rate))
    *applied_rate =
660 661
        g_value_get_double (gst_structure_id_get_value (structure,
            GST_QUARK (APPLIED_RATE)));
662
  if (G_LIKELY (format))
663 664 665
    *format =
        g_value_get_enum (gst_structure_id_get_value (structure,
            GST_QUARK (FORMAT)));
666
  if (G_LIKELY (start))
667 668 669
    *start =
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (START)));
670
  if (G_LIKELY (stop))
671 672 673
    *stop =
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (STOP)));
674
  if (G_LIKELY (position))
675
    *position =
676 677
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (POSITION)));
Wim Taymans's avatar
Wim Taymans committed
678
}
679

680 681
/**
 * gst_event_new_tag:
682 683
 * @taglist: (transfer full): metadata list. The event will take ownership
 *     of the taglist.
684 685
 *
 * Generates a metadata tag event from the given @taglist.
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
686
 *
687
 * Returns: (transfer full): a new #GstEvent
688
 */
Wim Taymans's avatar
Wim Taymans committed
689 690 691 692
GstEvent *
gst_event_new_tag (GstTagList * taglist)
{
  g_return_val_if_fail (taglist != NULL, NULL);
693

Wim Taymans's avatar
Wim Taymans committed
694
  return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
695 696
}

697 698 699
/**
 * gst_event_parse_tag:
 * @event: a tag event
700
 * @taglist: (out) (transfer none): pointer to metadata list
701 702
 *
 * Parses a tag @event and stores the results in the given @taglist location.
703 704 705
 * 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.
706
 */
Wim Taymans's avatar
Wim Taymans committed
707 708 709 710 711
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);
712

Wim Taymans's avatar
Wim Taymans committed
713 714 715 716
  if (taglist)
    *taglist = (GstTagList *) event->structure;
}

717 718
/* buffersize event */
/**
719
 * gst_event_new_buffer_size:
Stefan Kost's avatar
Stefan Kost committed
720 721 722 723
 * @format: buffer format
 * @minsize: minimum buffer size
 * @maxsize: maximum buffer size
 * @async: thread behavior
724 725 726 727
 *
 * Create a new buffersize event. The event is sent downstream and notifies
 * elements that they should provide a buffer of the specified dimensions.
 *
728
 * When the @async flag is set, a thread boundary is prefered.
729
 *
730
 * Returns: (transfer full): a new #GstEvent
731 732
 */
GstEvent *
733
gst_event_new_buffer_size (GstFormat format, gint64 minsize,
734 735
    gint64 maxsize, gboolean async)
{
736 737 738
  GstEvent *event;
  GstStructure *structure;

739
  GST_CAT_INFO (GST_CAT_EVENT,
740 741
      "creating buffersize format %s, minsize %" G_GINT64_FORMAT
      ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
742
      minsize, maxsize, async);
743

744
  structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
745 746 747 748 749 750 751
      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;
752 753
}

Stefan Kost's avatar
Stefan Kost committed
754
/**
755
 * gst_event_parse_buffer_size:
Stefan Kost's avatar
Stefan Kost committed
756
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
757 758 759 760
 * @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
761 762 763
 *
 * Get the format, minsize, maxsize and async-flag in the buffersize event.
 */
764
void
765
gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
766 767 768 769 770 771
    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);
772

773
  structure = event->structure;
774
  if (format)
775 776 777
    *format =
        g_value_get_enum (gst_structure_id_get_value (structure,
            GST_QUARK (FORMAT)));
778 779
  if (minsize)
    *minsize =
780 781
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (MINSIZE)));
782 783
  if (maxsize)
    *maxsize =
784 785
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (MAXSIZE)));
786
  if (async)
787 788 789
    *async =
        g_value_get_boolean (gst_structure_id_get_value (structure,
            GST_QUARK (ASYNC)));
790 791
}

792
/**
Wim Taymans's avatar
Wim Taymans committed
793 794 795 796 797
 * 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
798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825
 * 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
826 827 828
 * 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
829 830 831 832 833 834 835 836 837 838
 * 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.
839 840 841 842 843 844 845 846 847 848 849 850 851 852
 *
 * @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
853 854
 * indicates how late the buffer with @timestamp was. When throttling is
 * enabled, @diff will be set to the requested throttling interval.
855
 *
856
 * @timestamp is the timestamp of the last buffer that cause the element
857 858
 * to generate the QOS event. It is expressed in running time and thus an ever
 * increasing value.
859 860
 *
 * The upstream element can use the @diff and @timestamp values to decide
861 862
 * whether to process more buffers. For possitive @diff, all buffers with
 * timestamp <= @timestamp + @diff will certainly arrive late in the sink
863 864
 * as well. A (negative) @diff value so that @timestamp + @diff would yield a
 * result smaller than 0 is not allowed.
865 866 867
 *
 * 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
868
 *
869
 * Returns: (transfer full): a new QOS event.
Wim Taymans's avatar
Wim Taymans committed
870 871
 *
 * Since: 0.10.33
872
 */
873
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
874 875
gst_event_new_qos_full (GstQOSType type, gdouble proportion,
    GstClockTimeDiff diff, GstClockTime timestamp)
876
{
877 878 879
  GstEvent *event;
  GstStructure *structure;

880 881 882
  /* diff must be positive or timestamp + diff must be positive */
  g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);

883
  GST_CAT_INFO (GST_CAT_EVENT,
Wim Taymans's avatar
Wim Taymans committed
884 885
      "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
      ", timestamp %" GST_TIME_FORMAT, type, proportion,
886
      diff, GST_TIME_ARGS (timestamp));
887

888
  structure = gst_structure_id_new (GST_QUARK (EVENT_QOS),
Wim Taymans's avatar
Wim Taymans committed
889
      GST_QUARK (TYPE), GST_TYPE_QOS_TYPE, type,
890 891 892 893 894 895
      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
896
}
897

Wim Taymans's avatar
Wim Taymans committed
898 899 900
/**
 * gst_event_parse_qos:
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
901 902 903
 * @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
904
 *
905 906
 * 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
907 908 909 910
 */
void
gst_event_parse_qos (GstEvent * event, gdouble * proportion,
    GstClockTimeDiff * diff, GstClockTime * timestamp)
Wim Taymans's avatar
Wim Taymans committed
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930
{
  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
931 932
{
  const GstStructure *structure;
933

Wim Taymans's avatar
Wim Taymans committed
934 935
  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
936

937
  structure = event->structure;
Wim Taymans's avatar
Wim Taymans committed
938 939 940 941
  if (type)
    *type =
        g_value_get_enum (gst_structure_id_get_value (structure,
            GST_QUARK (TYPE)));
Wim Taymans's avatar
Wim Taymans committed
942 943
  if (proportion)
    *proportion =
944 945
        g_value_get_double (gst_structure_id_get_value (structure,
            GST_QUARK (PROPORTION)));
Wim Taymans's avatar
Wim Taymans committed
946
  if (diff)
947 948 949
    *diff =
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (DIFF)));
Wim Taymans's avatar
Wim Taymans committed
950 951
  if (timestamp)
    *timestamp =
952 953
        g_value_get_uint64 (gst_structure_id_get_value (structure,
            GST_QUARK (TIMESTAMP)));
954
}
955 956

/**
Wim Taymans's avatar
Wim Taymans committed
957 958 959
 * 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
960
 * @flags: The optional seek flags
961 962
 * @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
963 964 965 966 967
 * @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.
 *
968 969 970
 * 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.
971
 *
Wim Taymans's avatar
Wim Taymans committed
972 973
 * 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
974 975 976
 * rate is not allowed and should be accomplished instead by PAUSING the
 * pipeline.
 *
977 978 979
 * 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. 
980
 *
981
 * @start_type and @stop_type specify how to adjust the currently configured 
982 983 984
 * 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.
985
 *
986
 * When the rate is positive and @start has been updated, playback will start
987 988 989 990 991
 * 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.
992 993 994 995
 *
 * 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
996
 * #GST_SEEK_TYPE_SET to the desired position. 
997
 *
998
 * Returns: (transfer full): a new seek event.
999 1000
 */
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
1001
gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
1002
    GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
1003
{
1004 1005 1006
  GstEvent *event;
  GstStructure *structure;

1007 1008
  g_return_val_if_fail (rate != 0.0, NULL);

1009 1010 1011
  if (format == GST_FORMAT_TIME) {
    GST_CAT_INFO (GST_CAT_EVENT,
        "creating seek rate %lf, format TIME, flags %d, "
1012
        "start_type %d, start %" GST_TIME_FORMAT ", "
1013
        "stop_type %d, stop %" GST_TIME_FORMAT,
1014
        rate, flags, start_type, GST_TIME_ARGS (start),
1015 1016 1017
        stop_type, GST_TIME_ARGS (stop));
  } else {
    GST_CAT_INFO (GST_CAT_EVENT,
1018
        "creating seek rate %lf, format %s, flags %d, "
1019
        "start_type %d, start %" G_GINT64_FORMAT ", "
Wim Taymans's avatar