gstevent.c 38.6 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

Wim Taymans's avatar
Wim Taymans committed
88
GType _gst_event_type = 0;
89

90 91 92 93 94 95 96 97
typedef struct
{
  GstQOSType type;
  gdouble proportion;
  gint64 diff;
  GstClockTime timestamp;
} GstEventQOSData;

Wim Taymans's avatar
Wim Taymans committed
98 99 100 101 102
typedef struct
{
  GstEvent event;

  GstStructure *structure;
103 104 105 106 107

  union
  {
    GstEventQOSData qos;
  };
Wim Taymans's avatar
Wim Taymans committed
108 109
} GstEventImpl;

110 111
#define GST_EVENT_STRUCTURE(e)        (((GstEventImpl *)(e))->structure)
#define GST_EVENT_IMPL(e,data,field)  (((GstEventImpl *)(e))->data.field)
Wim Taymans's avatar
Wim Taymans committed
112

113 114
typedef struct
{
115 116
  const gint type;
  const gchar *name;
117 118 119 120 121 122 123 124
  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},
Wim Taymans's avatar
Wim Taymans committed
125
  {GST_EVENT_CAPS, "caps", 0},
Wim Taymans's avatar
Wim Taymans committed
126
  {GST_EVENT_SEGMENT, "segment", 0},
127
  {GST_EVENT_TAG, "tag", 0},
128
  {GST_EVENT_BUFFERSIZE, "buffersize", 0},
129
  {GST_EVENT_SINK_MESSAGE, "sink-message", 0},
130 131 132
  {GST_EVENT_QOS, "qos", 0},
  {GST_EVENT_SEEK, "seek", 0},
  {GST_EVENT_NAVIGATION, "navigation", 0},
133
  {GST_EVENT_LATENCY, "latency", 0},
Sebastian Dröge's avatar
Sebastian Dröge committed
134
  {GST_EVENT_STEP, "step", 0},
135
  {GST_EVENT_RECONFIGURE, "reconfigure", 0},
136 137 138
  {GST_EVENT_CUSTOM_UPSTREAM, "custom-upstream", 0},
  {GST_EVENT_CUSTOM_DOWNSTREAM, "custom-downstream", 0},
  {GST_EVENT_CUSTOM_DOWNSTREAM_OOB, "custom-downstream-oob", 0},
139 140 141
  {GST_EVENT_CUSTOM_BOTH, "custom-both", 0},
  {GST_EVENT_CUSTOM_BOTH_OOB, "custom-both-oob", 0},

142 143 144
  {0, NULL, 0}
};

145 146 147 148
void
_gst_event_initialize (void)
{
  gint i;
149

Wim Taymans's avatar
Wim Taymans committed
150 151
  _gst_event_type = gst_mini_object_register ("GstEvent");

152 153 154 155 156 157 158 159
  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
160 161 162 163 164 165
/**
 * 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
166
 * Returns: a reference to the static name of the event.
Stefan Kost's avatar
Stefan Kost committed
167
 */
168 169 170 171 172 173 174 175 176 177 178 179
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
180 181 182 183 184 185 186 187
/**
 * 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
 */
188 189 190 191 192 193 194 195 196 197 198 199
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;
}

200 201 202 203 204 205 206 207 208 209 210 211 212
/**
 * 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;

213
  ret = type & ((1 << GST_EVENT_STICKY_SHIFT) - 1);
214 215 216 217

  return ret;
}

218
static void
219
_gst_event_free (GstEvent * event)
220
{
Wim Taymans's avatar
Wim Taymans committed
221 222
  GstStructure *s;

223 224 225
  g_return_if_fail (event != NULL);
  g_return_if_fail (GST_IS_EVENT (event));

226
  GST_CAT_LOG (GST_CAT_EVENT, "freeing event %p type %s", event,
227
      GST_EVENT_TYPE_NAME (event));
Wim Taymans's avatar
Wim Taymans committed
228

Wim Taymans's avatar
Wim Taymans committed
229 230 231 232 233
  s = GST_EVENT_STRUCTURE (event);

  if (s) {
    gst_structure_set_parent_refcount (s, NULL);
    gst_structure_free (s);
234
  }
235

Wim Taymans's avatar
Wim Taymans committed
236
  g_slice_free1 (GST_MINI_OBJECT_SIZE (event), event);
237 238 239
}

static GstEvent *
240
_gst_event_copy (GstEventImpl * event)
241
{
Wim Taymans's avatar
Wim Taymans committed
242 243
  GstEventImpl *copy;
  GstStructure *s;
244

245 246 247
  copy = g_slice_dup (GstEventImpl, event);
  gst_mini_object_init (GST_MINI_OBJECT_CAST (copy), _gst_event_type,
      sizeof (GstEventImpl));
248

249
  GST_EVENT_TYPE (copy) = GST_EVENT_TYPE (event);
Wim Taymans's avatar
Wim Taymans committed
250
  GST_EVENT_TIMESTAMP (copy) = GST_EVENT_TIMESTAMP (event);
251
  GST_EVENT_SEQNUM (copy) = GST_EVENT_SEQNUM (event);
252

Wim Taymans's avatar
Wim Taymans committed
253 254 255
  s = GST_EVENT_STRUCTURE (event);
  if (s) {
    GST_EVENT_STRUCTURE (copy) = gst_structure_copy (s);
256 257
    gst_structure_set_parent_refcount (GST_EVENT_STRUCTURE (copy),
        &copy->event.mini_object.refcount);
258
  }
Wim Taymans's avatar
Wim Taymans committed
259
  return GST_EVENT_CAST (copy);
260 261
}

Wim Taymans's avatar
Wim Taymans committed
262
static void
Wim Taymans's avatar
Wim Taymans committed
263
gst_event_init (GstEventImpl * event, gsize size, GstEventType type)
Wim Taymans's avatar
Wim Taymans committed
264
{
Wim Taymans's avatar
Wim Taymans committed
265
  gst_mini_object_init (GST_MINI_OBJECT_CAST (event), _gst_event_type, size);
Wim Taymans's avatar
Wim Taymans committed
266

Wim Taymans's avatar
Wim Taymans committed
267 268
  event->event.mini_object.copy = (GstMiniObjectCopyFunction) _gst_event_copy;
  event->event.mini_object.free = (GstMiniObjectFreeFunction) _gst_event_free;
Wim Taymans's avatar
Wim Taymans committed
269 270 271 272 273 274

  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
275 276
static GstEvent *
gst_event_new (GstEventType type)
277
{
Wim Taymans's avatar
Wim Taymans committed
278
  GstEventImpl *event;
279

Wim Taymans's avatar
Wim Taymans committed
280
  event = g_slice_new0 (GstEventImpl);
281

Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
282 283
  GST_CAT_DEBUG (GST_CAT_EVENT, "creating new event %p %s %d", event,
      gst_event_type_get_name (type), type);
284

Wim Taymans's avatar
Wim Taymans committed
285
  gst_event_init (event, sizeof (GstEventImpl), type);
286

Wim Taymans's avatar
Wim Taymans committed
287
  return GST_EVENT_CAST (event);
288 289
}

290
/**
Wim Taymans's avatar
Wim Taymans committed
291
 * gst_event_new_custom:
292
 * @type: The type of the new event
293 294
 * @structure: (transfer full): the structure for the event. The event will
 *     take ownership of the structure.
295
 *
Wim Taymans's avatar
Wim Taymans committed
296 297 298
 * 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.
299
 *
Wim Taymans's avatar
Wim Taymans committed
300 301 302 303 304 305 306
 * 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.
 *
307
 * Returns: (transfer full): the new custom event.
308
 */
309
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
310
gst_event_new_custom (GstEventType type, GstStructure * structure)
311 312 313
{
  GstEvent *event;

314
  /* structure must not have a parent */
Wim Taymans's avatar
Wim Taymans committed
315 316
  event = gst_event_new (type);
  if (structure) {
Wim Taymans's avatar
Wim Taymans committed
317 318 319 320
    if (!gst_structure_set_parent_refcount (structure,
            &event->mini_object.refcount))
      goto had_parent;

Wim Taymans's avatar
Wim Taymans committed
321
    GST_EVENT_STRUCTURE (event) = structure;
Wim Taymans's avatar
Wim Taymans committed
322
  }
323
  return event;
Wim Taymans's avatar
Wim Taymans committed
324 325 326 327 328 329 330 331

  /* ERRORS */
had_parent:
  {
    gst_event_unref (event);
    g_warning ("structure is already owned by another object");
    return NULL;
  }
332 333
}

334
/**
Wim Taymans's avatar
Wim Taymans committed
335 336
 * gst_event_get_structure:
 * @event: The #GstEvent.
337
 *
Wim Taymans's avatar
Wim Taymans committed
338
 * Access the structure of the event.
339
 *
Wim Taymans's avatar
Wim Taymans committed
340 341 342 343 344
 * 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.
345
 */
Wim Taymans's avatar
Wim Taymans committed
346 347
const GstStructure *
gst_event_get_structure (GstEvent * event)
348
{
Wim Taymans's avatar
Wim Taymans committed
349
  g_return_val_if_fail (GST_IS_EVENT (event), NULL);
350

351
  return GST_EVENT_STRUCTURE (event);
Wim Taymans's avatar
Wim Taymans committed
352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374
}

/**
 * gst_event_writable_structure:
 * @event: The #GstEvent.
 *
 * Get a writable version of the structure.
 *
 * 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.
 * This function checks if @event is writable and will never return NULL.
 *
 * MT safe.
 */
GstStructure *
gst_event_writable_structure (GstEvent * event)
{
  GstStructure *structure;

  g_return_val_if_fail (GST_IS_EVENT (event), NULL);
  g_return_val_if_fail (gst_event_is_writable (event), NULL);

375
  structure = GST_EVENT_STRUCTURE (event);
Wim Taymans's avatar
Wim Taymans committed
376

377
  if (structure == NULL) {
Wim Taymans's avatar
Wim Taymans committed
378
    structure =
379 380 381 382 383
        gst_structure_id_empty_new (gst_event_type_to_quark (GST_EVENT_TYPE
            (event)));
    gst_structure_set_parent_refcount (structure, &event->mini_object.refcount);
    GST_EVENT_STRUCTURE (event) = structure;
  }
Wim Taymans's avatar
Wim Taymans committed
384
  return structure;
385
}
386

387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403
/**
 * 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);

Wim Taymans's avatar
Wim Taymans committed
404
  if (GST_EVENT_STRUCTURE (event) == NULL)
405 406
    return FALSE;

Wim Taymans's avatar
Wim Taymans committed
407
  return gst_structure_has_name (GST_EVENT_STRUCTURE (event), name);
408 409
}

410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463
/**
 * 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;
}

464 465 466 467
/* 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
468
/**
Wim Taymans's avatar
Wim Taymans committed
469 470
 * gst_event_new_flush_start:
 *
471
 * Allocate a new flush start event. The flush start event can be sent
Wim Taymans's avatar
Wim Taymans committed
472
 * upstream and downstream and travels out-of-bounds with the dataflow.
473 474 475 476 477
 *
 * 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
478
 * on a flushing pad will return %FALSE immediately.
Wim Taymans's avatar
Wim Taymans committed
479
 *
480 481
 * 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
482
 *
483 484
 * 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
485
 *
486
 * Returns: (transfer full): a new flush start event.
Wim Taymans's avatar
Wim Taymans committed
487
 */
488
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
489
gst_event_new_flush_start (void)
490
{
Wim Taymans's avatar
Wim Taymans committed
491
  return gst_event_new (GST_EVENT_FLUSH_START);
492 493
}

494
/**
Wim Taymans's avatar
Wim Taymans committed
495 496
 * gst_event_new_flush_stop:
 *
497
 * Allocate a new flush stop event. The flush stop event can be sent
Thiago Santos's avatar
Thiago Santos committed
498
 * upstream and downstream and travels serialized with the dataflow.
499
 * It is typically sent after sending a FLUSH_START event to make the
Wim Taymans's avatar
Wim Taymans committed
500
 * pads accept data again.
501
 *
Wim Taymans's avatar
Wim Taymans committed
502 503
 * Elements can process this event synchronized with the dataflow since
 * the preceeding FLUSH_START event stopped the dataflow.
504
 *
Wim Taymans's avatar
Wim Taymans committed
505 506 507
 * This event is typically generated to complete a seek and to resume
 * dataflow.
 *
508
 * Returns: (transfer full): a new flush stop event.
509
 */
510
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
511
gst_event_new_flush_stop (void)
512
{
Wim Taymans's avatar
Wim Taymans committed
513
  return gst_event_new (GST_EVENT_FLUSH_STOP);
514 515
}

Wim Taymans's avatar
Wim Taymans committed
516
/**
Wim Taymans's avatar
Wim Taymans committed
517
 * gst_event_new_eos:
Wim Taymans's avatar
Wim Taymans committed
518
 *
Wim Taymans's avatar
Wim Taymans committed
519 520
 * Create a new EOS event. The eos event can only travel downstream
 * synchronized with the buffer flow. Elements that receive the EOS
521 522
 * 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
523
 *
Jan Schmidt's avatar
Jan Schmidt committed
524
 * The EOS event will travel down to the sink elements in the pipeline
525
 * which will then post the #GST_MESSAGE_EOS on the bus after they have
Jan Schmidt's avatar
Jan Schmidt committed
526
 * finished playing any buffered data.
Wim Taymans's avatar
Wim Taymans committed
527
 *
528
 * When all sinks have posted an EOS message, an EOS message is
Wim Taymans's avatar
Wim Taymans committed
529 530
 * forwarded to the application.
 *
Wim Taymans's avatar
Wim Taymans committed
531
 * The EOS event itself will not cause any state transitions of the pipeline.
Stefan Kost's avatar
Stefan Kost committed
532
 *
533
 * Returns: (transfer full): the new EOS event.
Wim Taymans's avatar
Wim Taymans committed
534
 */
Wim Taymans's avatar
Wim Taymans committed
535 536
GstEvent *
gst_event_new_eos (void)
537
{
Wim Taymans's avatar
Wim Taymans committed
538
  return gst_event_new (GST_EVENT_EOS);
539 540
}

Wim Taymans's avatar
Wim Taymans committed
541 542 543 544 545
/**
 * gst_event_new_caps:
 * @caps: a #GstCaps
 *
 * Create a new CAPS event for @caps. The caps event can only travel downstream
Wim Taymans's avatar
Wim Taymans committed
546
 * synchronized with the buffer flow and contains the format of the buffers
Wim Taymans's avatar
Wim Taymans committed
547 548 549 550 551 552 553 554 555
 * that will follow after the event.
 *
 * Returns: (transfer full): the new CAPS event.
 */
GstEvent *
gst_event_new_caps (GstCaps * caps)
{
  GstEvent *event;

Wim Taymans's avatar
Wim Taymans committed
556 557
  g_return_val_if_fail (caps != NULL, NULL);
  g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
558

Wim Taymans's avatar
Wim Taymans committed
559 560
  GST_CAT_INFO (GST_CAT_EVENT, "creating caps event %" GST_PTR_FORMAT, caps);

561
  event = gst_event_new_custom (GST_EVENT_CAPS,
Wim Taymans's avatar
Wim Taymans committed
562 563 564 565 566 567 568 569 570 571 572
      gst_structure_id_new (GST_QUARK (EVENT_CAPS),
          GST_QUARK (CAPS), GST_TYPE_CAPS, caps, NULL));

  return event;
}

/**
 * gst_event_parse_caps:
 * @event: The event to parse
 * @caps: (out): A pointer to the caps
 *
573 574
 * Get the caps from @event. The caps remains valid as long as @event remains
 * valid.
Wim Taymans's avatar
Wim Taymans committed
575 576 577 578
 */
void
gst_event_parse_caps (GstEvent * event, GstCaps ** caps)
{
Wim Taymans's avatar
Wim Taymans committed
579 580
  GstStructure *structure;

Wim Taymans's avatar
Wim Taymans committed
581 582 583
  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_CAPS);

Wim Taymans's avatar
Wim Taymans committed
584
  structure = GST_EVENT_STRUCTURE (event);
Wim Taymans's avatar
Wim Taymans committed
585 586 587 588
  if (G_LIKELY (caps))
    *caps =
        g_value_get_boxed (gst_structure_id_get_value (structure,
            GST_QUARK (CAPS)));
Wim Taymans's avatar
Wim Taymans committed
589 590
}

591
/**
Wim Taymans's avatar
Wim Taymans committed
592 593
 * gst_event_new_segment:
 * @segment: a #GstSegment
594
 *
Wim Taymans's avatar
Wim Taymans committed
595 596 597
 * Create a new SEGMENT event for @segment. The segment event can only travel
 * downstream synchronized with the buffer flow and contains timing information
 * and playback properties for the buffers that will follow.
Wim Taymans's avatar
Wim Taymans committed
598 599
 *
 * The newsegment event marks the range of buffers to be processed. All
600
 * data not within the segment range is not to be processed. This can be
601
 * used intelligently by plugins to apply more efficient methods of skipping
602 603
 * unneeded data. The valid range is expressed with the @start and @stop
 * values.
604
 *
605
 * The time value of the segment is used in conjunction with the start
Wim Taymans's avatar
Wim Taymans committed
606 607 608
 * value to convert the buffer timestamps into the stream time. This is
 * usually done in sinks to report the current stream_time.
 * @time represents the stream_time of a buffer carrying a timestamp of
609
 * @start. @time cannot be -1.
610
 *
611
 * @start cannot be -1, @stop can be -1. If there
Wim Taymans's avatar
Wim Taymans committed
612
 * is a valid @stop given, it must be greater or equal the @start, including
613
 * when the indicated playback @rate is < 0.
614 615
 *
 * The @applied_rate value provides information about any rate adjustment that
Wim Taymans's avatar
Wim Taymans committed
616 617 618 619 620
 * 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
621
 * with @rate of 1.0 and @applied_rate of 2.0
622
 *
Wim Taymans's avatar
Wim Taymans committed
623 624
 * After a newsegment event, the buffer stream time is calculated with:
 *
625
 *   time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)
Wim Taymans's avatar
Wim Taymans committed
626
 *
Wim Taymans's avatar
Wim Taymans committed
627
 * Returns: (transfer full): the new SEGMENT event.
628
 */
629
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
630
gst_event_new_segment (GstSegment * segment)
631
{
632 633
  GstEvent *event;

Wim Taymans's avatar
Wim Taymans committed
634
  g_return_val_if_fail (segment != NULL, NULL);
635

Wim Taymans's avatar
Wim Taymans committed
636 637 638 639 640 641
  GST_CAT_INFO (GST_CAT_EVENT, "creating segment event %" GST_PTR_FORMAT,
      segment);

  event = gst_event_new_custom (GST_EVENT_SEGMENT,
      gst_structure_id_new (GST_QUARK (EVENT_SEGMENT),
          GST_QUARK (SEGMENT), GST_TYPE_SEGMENT, segment, NULL));
642 643

  return event;
Wim Taymans's avatar
Wim Taymans committed
644
}
645

Wim Taymans's avatar
Wim Taymans committed
646
/**
Wim Taymans's avatar
Wim Taymans committed
647 648 649 650 651 652 653 654
 * gst_event_get_segment:
 * @event: The event
 *
 * Get the segment from @event. The segment remains valid as long as @event remains
 * valid.
 *
 * Returns: the #GstSegment. The segment stays valid for as long as @event is
 * valid.
Wim Taymans's avatar
Wim Taymans committed
655
 */
Wim Taymans's avatar
Wim Taymans committed
656 657
const GstSegment *
gst_event_get_segment (GstEvent * event)
Wim Taymans's avatar
Wim Taymans committed
658
{
Wim Taymans's avatar
Wim Taymans committed
659 660
  GstStructure *structure;
  GstSegment *segment;
661

Wim Taymans's avatar
Wim Taymans committed
662 663
  g_return_val_if_fail (GST_IS_EVENT (event), NULL);
  g_return_val_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT, NULL);
Wim Taymans's avatar
Wim Taymans committed
664

Wim Taymans's avatar
Wim Taymans committed
665
  structure = GST_EVENT_STRUCTURE (event);
Wim Taymans's avatar
Wim Taymans committed
666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689
  segment = g_value_get_boxed (gst_structure_id_get_value (structure,
          GST_QUARK (SEGMENT)));

  return segment;
}

/**
 * gst_event_parse_segment:
 * @event: The event to parse
 * @segment: a #GstSegment
 *
 * Copy the segment values from @event into @segment.
 */
void
gst_event_parse_segment (GstEvent * event, GstSegment * segment)
{
  const GstSegment *src;

  g_return_if_fail (segment != NULL);

  src = gst_event_get_segment (event);
  g_return_if_fail (src != NULL);

  gst_segment_copy_into (src, segment);
Wim Taymans's avatar
Wim Taymans committed
690
}
691

692 693
/**
 * gst_event_new_tag:
694 695
 * @taglist: (transfer full): metadata list. The event will take ownership
 *     of the taglist.
696 697
 *
 * Generates a metadata tag event from the given @taglist.
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
698
 *
699
 * Returns: (transfer full): a new #GstEvent
700
 */
Wim Taymans's avatar
Wim Taymans committed
701 702 703 704
GstEvent *
gst_event_new_tag (GstTagList * taglist)
{
  g_return_val_if_fail (taglist != NULL, NULL);
705

Wim Taymans's avatar
Wim Taymans committed
706
  return gst_event_new_custom (GST_EVENT_TAG, (GstStructure *) taglist);
707 708
}

709 710 711
/**
 * gst_event_parse_tag:
 * @event: a tag event
712
 * @taglist: (out) (transfer none): pointer to metadata list
713 714
 *
 * Parses a tag @event and stores the results in the given @taglist location.
715 716 717
 * 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.
718
 */
Wim Taymans's avatar
Wim Taymans committed
719 720 721 722 723
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);
724

Wim Taymans's avatar
Wim Taymans committed
725
  if (taglist)
Wim Taymans's avatar
Wim Taymans committed
726
    *taglist = (GstTagList *) GST_EVENT_STRUCTURE (event);
Wim Taymans's avatar
Wim Taymans committed
727 728
}

729 730
/* buffersize event */
/**
731
 * gst_event_new_buffer_size:
Stefan Kost's avatar
Stefan Kost committed
732 733 734 735
 * @format: buffer format
 * @minsize: minimum buffer size
 * @maxsize: maximum buffer size
 * @async: thread behavior
736 737 738 739
 *
 * Create a new buffersize event. The event is sent downstream and notifies
 * elements that they should provide a buffer of the specified dimensions.
 *
740
 * When the @async flag is set, a thread boundary is prefered.
741
 *
742
 * Returns: (transfer full): a new #GstEvent
743 744
 */
GstEvent *
745
gst_event_new_buffer_size (GstFormat format, gint64 minsize,
746 747
    gint64 maxsize, gboolean async)
{
748 749 750
  GstEvent *event;
  GstStructure *structure;

751
  GST_CAT_INFO (GST_CAT_EVENT,
752 753
      "creating buffersize format %s, minsize %" G_GINT64_FORMAT
      ", maxsize %" G_GINT64_FORMAT ", async %d", gst_format_get_name (format),
754
      minsize, maxsize, async);
755

756
  structure = gst_structure_id_new (GST_QUARK (EVENT_BUFFER_SIZE),
757 758 759 760 761 762 763
      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;
764 765
}

Stefan Kost's avatar
Stefan Kost committed
766
/**
767
 * gst_event_parse_buffer_size:
Stefan Kost's avatar
Stefan Kost committed
768
 * @event: The event to query
Johan Dahlin's avatar
Johan Dahlin committed
769 770 771 772
 * @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
773 774 775
 *
 * Get the format, minsize, maxsize and async-flag in the buffersize event.
 */
776
void
777
gst_event_parse_buffer_size (GstEvent * event, GstFormat * format,
778 779 780 781 782 783
    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);
784

Wim Taymans's avatar
Wim Taymans committed
785
  structure = GST_EVENT_STRUCTURE (event);
786
  if (format)
787 788 789
    *format =
        g_value_get_enum (gst_structure_id_get_value (structure,
            GST_QUARK (FORMAT)));
790 791
  if (minsize)
    *minsize =
792 793
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (MINSIZE)));
794 795
  if (maxsize)
    *maxsize =
796 797
        g_value_get_int64 (gst_structure_id_get_value (structure,
            GST_QUARK (MAXSIZE)));
798
  if (async)
799 800 801
    *async =
        g_value_get_boolean (gst_structure_id_get_value (structure,
            GST_QUARK (ASYNC)));
802 803
}

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

862 863 864
  /* diff must be positive or timestamp + diff must be positive */
  g_return_val_if_fail (diff >= 0 || -diff <= timestamp, NULL);

865
  GST_CAT_INFO (GST_CAT_EVENT,
Wim Taymans's avatar
Wim Taymans committed
866 867
      "creating qos type %d, proportion %lf, diff %" G_GINT64_FORMAT
      ", timestamp %" GST_TIME_FORMAT, type, proportion,
868
      diff, GST_TIME_ARGS (timestamp));
869

870 871 872 873 874 875
  event = gst_event_new (GST_EVENT_QOS);

  GST_EVENT_IMPL (event, qos, type) = type;
  GST_EVENT_IMPL (event, qos, proportion) = proportion;
  GST_EVENT_IMPL (event, qos, diff) = diff;
  GST_EVENT_IMPL (event, qos, timestamp) = timestamp;
876 877

  return event;
Wim Taymans's avatar
Wim Taymans committed
878
}
879

Wim Taymans's avatar
Wim Taymans committed
880 881 882
/**
 * gst_event_parse_qos:
 * @event: The event to query
Wim Taymans's avatar
Wim Taymans committed
883 884 885 886 887 888
 * @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
Wim Taymans's avatar
Wim Taymans committed
889
 * gst_event_new_qos() for more information about the different QoS values.
Wim Taymans's avatar
Wim Taymans committed
890 891
 */
void
Wim Taymans's avatar
Wim Taymans committed
892
gst_event_parse_qos (GstEvent * event, GstQOSType * type,
Wim Taymans's avatar
Wim Taymans committed
893
    gdouble * proportion, GstClockTimeDiff * diff, GstClockTime * timestamp)
Wim Taymans's avatar
Wim Taymans committed
894 895 896
{
  g_return_if_fail (GST_IS_EVENT (event));
  g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_QOS);
897

Wim Taymans's avatar
Wim Taymans committed
898
  if (type)
899
    *type = GST_EVENT_IMPL (event, qos, type);
Wim Taymans's avatar
Wim Taymans committed
900
  if (proportion)
901
    *proportion = GST_EVENT_IMPL (event, qos, proportion);
Wim Taymans's avatar
Wim Taymans committed
902
  if (diff)
903
    *diff = GST_EVENT_IMPL (event, qos, diff);
Wim Taymans's avatar
Wim Taymans committed
904
  if (timestamp)
905
    *timestamp = GST_EVENT_IMPL (event, qos, timestamp);
906
}
907 908

/**
Wim Taymans's avatar
Wim Taymans committed
909 910 911
 * 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
912
 * @flags: The optional seek flags
913 914
 * @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
915 916 917 918 919
 * @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.
 *
920 921 922
 * 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.
923
 *
Wim Taymans's avatar
Wim Taymans committed
924 925
 * 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
926 927 928
 * rate is not allowed and should be accomplished instead by PAUSING the
 * pipeline.
 *
929 930 931
 * 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. 
932
 *
933
 * @start_type and @stop_type specify how to adjust the currently configured 
934 935 936
 * 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.
937
 *
938
 * When the rate is positive and @start has been updated, playback will start
939 940 941 942 943
 * 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.
944 945 946 947
 *
 * 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
948
 * #GST_SEEK_TYPE_SET to the desired position. 
949
 *
950
 * Returns: (transfer full): a new seek event.
951 952
 */
GstEvent *
Wim Taymans's avatar
Wim Taymans committed
953
gst_event_new_seek (gdouble rate, GstFormat format, GstSeekFlags flags,
954
    GstSeekType start_type, gint64 start, GstSeekType stop_type, gint64 stop)
955
{
956 957 958
  GstEvent *event;
  GstStructure *structure;

959 960
  g_return_val_if_fail (rate != 0.0, NULL);

961 962 963
  if (format == GST_FORMAT_TIME) {
    GST_CAT_INFO (GST_CAT_EVENT,
        "creating seek rate %lf, format TIME, flags %d, "
964
        "start_type %d, start %" GST_TIME_FORMAT ", "
965
        "stop_type %d, stop %" GST_TIME_FORMAT,
966
        rate, flags, start_type, GST_TIME_ARGS (start),
967 968 969
        stop_type, GST_TIME_ARGS (stop));
  } else {
    GST_CAT_INFO (GST_CAT_EVENT,
970
        "creating seek rate %lf, format %s, flags %d, "
971
        "start_type %d, start %" G_GINT64_FORMAT ", "
972
        "stop_type %d, stop %" G_GINT64_FORMAT,
973 974
        rate, gst_format_get_name (format), flags, start_type, start, stop_type,
        stop);
975 976
  }

977
  structure = gst_structure_id_new (GST_QUARK (EVENT_SEEK),
978 979 980 981 982 983 984 985 986 987
      GST_QUARK (RATE), G_TYPE_DOUBLE, rate,
      GST_QUARK (FORMAT), GST_TYPE_FORMAT, format,
      GST_QUARK (FLAGS), GST_TYPE_SEEK_FLAGS, flags,
      GST_QUARK (CUR_TYPE), GST_TYPE_SEEK_TYPE, start_type,
      GST_QUARK (CUR), G_TYPE_INT64, start,
      GST_QUARK (STOP_TYPE), GST_TYPE_SEEK_TYPE, stop_type,
      GST_QUARK (STOP), G_TYPE_INT64, stop, NULL);
  event = gst_event_new_custom (GST_EVENT_SEEK, structure);

  return event;
Wim Taymans's avatar
Wim Taymans committed
988
}