gstclock.c 41.4 KB
Newer Older
1 2 3
/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
4
 *                    2004 Wim Taymans <wim@fluendo.com>
5 6
 *
 * gstclock.c: Clock subsystem for maintaining time sync
Wim Taymans's avatar
Wim Taymans committed
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 26
/**
 * SECTION:gstclock
 * @short_description: Abstract class for global clocks
Wim Taymans's avatar
Wim Taymans committed
27
 * @see_also: #GstSystemClock, #GstPipeline
28
 *
Wim Taymans's avatar
Wim Taymans committed
29
 * GStreamer uses a global clock to synchronize the plugins in a pipeline.
30
 * Different clock implementations are possible by implementing this abstract
31
 * base class or, more conveniently, by subclassing #GstSystemClock.
32
 *
Wim Taymans's avatar
Wim Taymans committed
33
 * The #GstClock returns a monotonically increasing time with the method
Wim Taymans's avatar
Wim Taymans committed
34 35
 * gst_clock_get_time(). Its accuracy and base time depend on the specific
 * clock implementation but time is always expressed in nanoseconds. Since the
Wim Taymans's avatar
Wim Taymans committed
36
 * baseline of the clock is undefined, the clock time returned is not
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
37
 * meaningful in itself, what matters are the deltas between two clock times.
Wim Taymans's avatar
Wim Taymans committed
38
 * The time returned by a clock is called the absolute time.
Wim Taymans's avatar
Wim Taymans committed
39
 *
40
 * The pipeline uses the clock to calculate the running time. Usually all
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
41
 * renderers synchronize to the global clock using the buffer timestamps, the
Wim Taymans's avatar
Wim Taymans committed
42
 * newsegment events and the element's base time, see #GstPipeline.
Wim Taymans's avatar
Wim Taymans committed
43
 *
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
44 45
 * A clock implementation can support periodic and single shot clock
 * notifications both synchronous and asynchronous.
Wim Taymans's avatar
Wim Taymans committed
46 47
 *
 * One first needs to create a #GstClockID for the periodic or single shot
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
48 49
 * notification using gst_clock_new_single_shot_id() or
 * gst_clock_new_periodic_id().
Wim Taymans's avatar
Wim Taymans committed
50 51 52
 *
 * To perform a blocking wait for the specific time of the #GstClockID use the
 * gst_clock_id_wait(). To receive a callback when the specific time is reached
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
53 54
 * in the clock use gst_clock_id_wait_async(). Both these calls can be
 * interrupted with the gst_clock_id_unschedule() call. If the blocking wait is
Stefan Kost's avatar
Stefan Kost committed
55
 * unscheduled a return value of #GST_CLOCK_UNSCHEDULED is returned.
Wim Taymans's avatar
Wim Taymans committed
56
 *
57
 * Periodic callbacks scheduled async will be repeatedly called automatically
Wim Taymans's avatar
Wim Taymans committed
58
 * until it is unscheduled. To schedule a sync periodic callback,
59
 * gst_clock_id_wait() should be called repeatedly.
60
 *
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
61 62
 * The async callbacks can happen from any thread, either provided by the core
 * or from a streaming thread. The application should be prepared for this.
Wim Taymans's avatar
Wim Taymans committed
63 64
 *
 * A #GstClockID that has been unscheduled cannot be used again for any wait
Wim Taymans's avatar
Wim Taymans committed
65
 * operation, a new #GstClockID should be created and the old unscheduled one
66
 * should be destroyed with gst_clock_id_unref().
Wim Taymans's avatar
Wim Taymans committed
67
 *
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
68 69
 * It is possible to perform a blocking wait on the same #GstClockID from
 * multiple threads. However, registering the same #GstClockID for multiple
Wim Taymans's avatar
Wim Taymans committed
70 71
 * async notifications is not possible, the callback will only be called for
 * the thread registering the entry last.
Wim Taymans's avatar
Wim Taymans committed
72
 *
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
73 74 75 76
 * None of the wait operations unref the #GstClockID, the owner is responsible
 * for unreffing the ids itself. This holds for both periodic and single shot
 * notifications. The reason being that the owner of the #GstClockID has to
 * keep a handle to the #GstClockID to unblock the wait on FLUSHING events or
Wim Taymans's avatar
Wim Taymans committed
77 78
 * state changes and if the entry would be unreffed automatically, the handle 
 * might become invalid without any notification.
Wim Taymans's avatar
Wim Taymans committed
79
 *
80
 * These clock operations do not operate on the running time, so the callbacks
Wim Taymans's avatar
Wim Taymans committed
81 82 83 84
 * will also occur when not in PLAYING state as if the clock just keeps on
 * running. Some clocks however do not progress when the element that provided
 * the clock is not PLAYING.
 *
85
 * When a clock has the #GST_CLOCK_FLAG_CAN_SET_MASTER flag set, it can be
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
86
 * slaved to another #GstClock with the gst_clock_set_master(). The clock will
87
 * then automatically be synchronized to this master clock by repeatedly
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
88
 * sampling the master clock and the slave clock and recalibrating the slave
Kjartan Maraas's avatar
Kjartan Maraas committed
89
 * clock with gst_clock_set_calibration(). This feature is mostly useful for
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
90 91 92
 * plugins that have an internal clock but must operate with another clock
 * selected by the #GstPipeline.  They can track the offset and rate difference
 * of their internal clock relative to the master clock by using the
Wim Taymans's avatar
Wim Taymans committed
93 94
 * gst_clock_get_calibration() function. 
 *
Stefan Kost's avatar
Stefan Kost committed
95 96 97 98 99 100
 * The master/slave synchronisation can be tuned with the #GstClock:timeout,
 * #GstClock:window-size and #GstClock:window-threshold properties.
 * The #GstClock:timeout property defines the interval to sample the master
 * clock and run the calibration functions. #GstClock:window-size defines the
 * number of samples to use when calibrating and #GstClock:window-threshold
 * defines the minimum number of samples before the calibration is performed.
Wim Taymans's avatar
Wim Taymans committed
101
 *
102
 * Last reviewed on 2009-05-21 (0.10.24)
103
 */
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
104

105 106

#include "gst_private.h"
107
#include <time.h>
108

109
#include "gstclock.h"
110
#include "gstinfo.h"
111
#include "gstutils.h"
Wim Taymans's avatar
Wim Taymans committed
112

Wim Taymans's avatar
Wim Taymans committed
113
#ifndef GST_DISABLE_TRACE
Wim Taymans's avatar
Wim Taymans committed
114
/* #define GST_WITH_ALLOC_TRACE */
Wim Taymans's avatar
Wim Taymans committed
115 116 117
#include "gsttrace.h"
static GstAllocTrace *_gst_clock_entry_trace;
#endif
Wim Taymans's avatar
Wim Taymans committed
118

119 120
/* #define DEBUGGING_ENABLED */

Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
121 122 123 124
#define DEFAULT_STATS                   FALSE
#define DEFAULT_WINDOW_SIZE             32
#define DEFAULT_WINDOW_THRESHOLD        4
#define DEFAULT_TIMEOUT                 GST_SECOND / 10
125

126 127
enum
{
128 129 130 131 132
  PROP_0,
  PROP_STATS,
  PROP_WINDOW_SIZE,
  PROP_WINDOW_THRESHOLD,
  PROP_TIMEOUT
133 134
};

135 136 137 138 139 140 141 142
struct _GstClockPrivate
{
  gint pre_count;
  gint post_count;
};

/* seqlocks */
#define read_seqbegin(clock)                                   \
143
  g_atomic_int_get (&clock->ABI.priv->post_count);
144 145 146 147 148

static inline gboolean
read_seqretry (GstClock * clock, gint seq)
{
  /* no retry if the seqnum did not change */
149
  if (G_LIKELY (seq == g_atomic_int_get (&clock->ABI.priv->pre_count)))
150 151 152 153 154 155 156 157 158 159 160
    return FALSE;

  /* wait for the writer to finish and retry */
  GST_OBJECT_LOCK (clock);
  GST_OBJECT_UNLOCK (clock);
  return TRUE;
}

#define write_seqlock(clock)                      \
G_STMT_START {                                    \
  GST_OBJECT_LOCK (clock);                        \
161
  g_atomic_int_inc (&clock->ABI.priv->pre_count);     \
162 163 164 165
} G_STMT_END;

#define write_sequnlock(clock)                    \
G_STMT_START {                                    \
166
  g_atomic_int_inc (&clock->ABI.priv->post_count);    \
167 168 169
  GST_OBJECT_UNLOCK (clock);                      \
} G_STMT_END;

170 171
static void gst_clock_class_init (GstClockClass * klass);
static void gst_clock_init (GstClock * clock);
172
static void gst_clock_dispose (GObject * object);
Wim Taymans's avatar
Wim Taymans committed
173
static void gst_clock_finalize (GObject * object);
Wim Taymans's avatar
Wim Taymans committed
174

175 176 177 178 179
static void gst_clock_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_clock_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static void gst_clock_update_stats (GstClock * clock);
180

181

182
static GstObjectClass *parent_class = NULL;
183

184 185
/* static guint gst_clock_signals[LAST_SIGNAL] = { 0 }; */

Wim Taymans's avatar
Wim Taymans committed
186
static GstClockID
187 188
gst_clock_entry_new (GstClock * clock, GstClockTime time,
    GstClockTime interval, GstClockEntryType type)
189 190
{
  GstClockEntry *entry;
191

192
  entry = g_slice_new (GstClockEntry);
Wim Taymans's avatar
Wim Taymans committed
193
#ifndef GST_DISABLE_TRACE
Wim Taymans's avatar
Wim Taymans committed
194
  gst_alloc_trace_new (_gst_clock_entry_trace, entry);
Wim Taymans's avatar
Wim Taymans committed
195
#endif
196 197
  GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock,
      "created entry %p, time %" GST_TIME_FORMAT, entry, GST_TIME_ARGS (time));
198

199
  entry->refcount = 1;
200
  entry->clock = clock;
201
  entry->type = type;
202
  entry->time = time;
203
  entry->interval = interval;
204
  entry->status = GST_CLOCK_OK;
205 206
  entry->func = NULL;
  entry->user_data = NULL;
207

208 209
  return (GstClockID) entry;
}
210

211 212
/**
 * gst_clock_id_ref:
Wim Taymans's avatar
Wim Taymans committed
213
 * @id: The #GstClockID to ref
214
 *
Wim Taymans's avatar
Wim Taymans committed
215
 * Increase the refcount of given @id.
216 217 218 219 220 221 222 223 224 225
 *
 * Returns: The same #GstClockID with increased refcount.
 *
 * MT safe.
 */
GstClockID
gst_clock_id_ref (GstClockID id)
{
  g_return_val_if_fail (id != NULL, NULL);

226
  g_atomic_int_inc (&((GstClockEntry *) id)->refcount);
227 228 229 230 231 232 233 234 235 236 237 238 239 240

  return id;
}

static void
_gst_clock_id_free (GstClockID id)
{
  g_return_if_fail (id != NULL);

  GST_CAT_DEBUG (GST_CAT_CLOCK, "freed entry %p", id);

#ifndef GST_DISABLE_TRACE
  gst_alloc_trace_free (_gst_clock_entry_trace, id);
#endif
241
  g_slice_free (GstClockEntry, id);
242 243 244 245
}

/**
 * gst_clock_id_unref:
Wim Taymans's avatar
Wim Taymans committed
246
 * @id: The #GstClockID to unref
247
 *
Wim Taymans's avatar
Wim Taymans committed
248
 * Unref given @id. When the refcount reaches 0 the
249 250 251 252 253 254 255 256 257 258 259
 * #GstClockID will be freed.
 *
 * MT safe.
 */
void
gst_clock_id_unref (GstClockID id)
{
  gint zero;

  g_return_if_fail (id != NULL);

260
  zero = g_atomic_int_dec_and_test (&((GstClockEntry *) id)->refcount);
261 262 263 264 265 266
  /* if we ended up with the refcount at zero, free the id */
  if (zero) {
    _gst_clock_id_free (id);
  }
}

267 268
/**
 * gst_clock_new_single_shot_id
Wim Taymans's avatar
Wim Taymans committed
269
 * @clock: The #GstClockID to get a single shot notification from
270 271
 * @time: the requested time
 *
Wim Taymans's avatar
Wim Taymans committed
272
 * Get a #GstClockID from @clock to trigger a single shot
273 274
 * notification at the requested time. The single shot id should be
 * unreffed after usage.
275
 *
Wim Taymans's avatar
Wim Taymans committed
276
 * Returns: A #GstClockID that can be used to request the time notification.
277 278
 *
 * MT safe.
279 280
 */
GstClockID
281
gst_clock_new_single_shot_id (GstClock * clock, GstClockTime time)
282
{
283 284
  g_return_val_if_fail (GST_IS_CLOCK (clock), NULL);

285 286
  return gst_clock_entry_new (clock,
      time, GST_CLOCK_TIME_NONE, GST_CLOCK_ENTRY_SINGLE);
287 288 289
}

/**
Wim Taymans's avatar
Wim Taymans committed
290
 * gst_clock_new_periodic_id
Wim Taymans's avatar
Wim Taymans committed
291
 * @clock: The #GstClockID to get a periodic notification id from
292 293 294
 * @start_time: the requested start time
 * @interval: the requested interval
 *
Wim Taymans's avatar
Wim Taymans committed
295
 * Get an ID from @clock to trigger a periodic notification.
296 297
 * The periodic notifications will start at time @start_time and
 * will then be fired with the given @interval. @id should be unreffed
298
 * after usage.
299
 *
Wim Taymans's avatar
Wim Taymans committed
300
 * Returns: A #GstClockID that can be used to request the time notification.
301 302
 *
 * MT safe.
303 304
 */
GstClockID
305 306
gst_clock_new_periodic_id (GstClock * clock, GstClockTime start_time,
    GstClockTime interval)
307
{
308
  g_return_val_if_fail (GST_IS_CLOCK (clock), NULL);
309
  g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (start_time), NULL);
310
  g_return_val_if_fail (interval != 0, NULL);
311
  g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (interval), NULL);
312

313 314
  return gst_clock_entry_new (clock,
      start_time, interval, GST_CLOCK_ENTRY_PERIODIC);
315 316
}

317 318
/**
 * gst_clock_id_compare_func
Wim Taymans's avatar
Wim Taymans committed
319 320
 * @id1: A #GstClockID
 * @id2: A #GstClockID to compare with
321
 *
Wim Taymans's avatar
Wim Taymans committed
322
 * Compares the two #GstClockID instances. This function can be used
323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
 * as a GCompareFunc when sorting ids.
 *
 * Returns: negative value if a < b; zero if a = b; positive value if a > b
 *
 * MT safe.
 */
gint
gst_clock_id_compare_func (gconstpointer id1, gconstpointer id2)
{
  GstClockEntry *entry1, *entry2;

  entry1 = (GstClockEntry *) id1;
  entry2 = (GstClockEntry *) id2;

  if (GST_CLOCK_ENTRY_TIME (entry1) > GST_CLOCK_ENTRY_TIME (entry2)) {
    return 1;
  }
  if (GST_CLOCK_ENTRY_TIME (entry1) < GST_CLOCK_ENTRY_TIME (entry2)) {
    return -1;
  }
Wim Taymans's avatar
Wim Taymans committed
343
  return 0;
344 345
}

346 347
/**
 * gst_clock_id_get_time
Wim Taymans's avatar
Wim Taymans committed
348
 * @id: The #GstClockID to query
349 350 351
 *
 * Get the time of the clock ID
 *
352 353 354
 * Returns: the time of the given clock id.
 *
 * MT safe.
355 356 357 358 359 360
 */
GstClockTime
gst_clock_id_get_time (GstClockID id)
{
  g_return_val_if_fail (id != NULL, GST_CLOCK_TIME_NONE);

361
  return GST_CLOCK_ENTRY_TIME ((GstClockEntry *) id);
362 363 364 365
}

/**
 * gst_clock_id_wait
Wim Taymans's avatar
Wim Taymans committed
366
 * @id: The #GstClockID to wait on
367
 * @jitter: A pointer that will contain the jitter, can be %NULL.
Wim Taymans's avatar
Wim Taymans committed
368 369 370 371 372 373
 *
 * Perform a blocking wait on @id. 
 * @id should have been created with gst_clock_new_single_shot_id()
 * or gst_clock_new_periodic_id() and should not have been unscheduled
 * with a call to gst_clock_id_unschedule(). 
 *
374
 * If the @jitter argument is not %NULL and this function returns #GST_CLOCK_OK
Wim Taymans's avatar
Wim Taymans committed
375 376
 * or #GST_CLOCK_EARLY, it will contain the difference
 * against the clock and the time of @id when this method was
377 378
 * called. 
 * Positive values indicate how late @id was relative to the clock
379
 * (in which case this function will return #GST_CLOCK_EARLY). 
380
 * Negative values indicate how much time was spent waiting on the clock 
381
 * before this function returned.
Wim Taymans's avatar
Wim Taymans committed
382 383 384 385 386
 *
 * Returns: the result of the blocking wait. #GST_CLOCK_EARLY will be returned
 * if the current clock time is past the time of @id, #GST_CLOCK_OK if 
 * @id was scheduled in time. #GST_CLOCK_UNSCHEDULED if @id was 
 * unscheduled with gst_clock_id_unschedule().
387 388
 *
 * MT safe.
389 390
 */
GstClockReturn
391
gst_clock_id_wait (GstClockID id, GstClockTimeDiff * jitter)
392 393
{
  GstClockEntry *entry;
394
  GstClock *clock;
395
  GstClockReturn res;
396
  GstClockTime requested;
Wim Taymans's avatar
Wim Taymans committed
397
  GstClockClass *cclass;
398

399
  g_return_val_if_fail (id != NULL, GST_CLOCK_ERROR);
400

401 402
  entry = (GstClockEntry *) id;
  requested = GST_CLOCK_ENTRY_TIME (entry);
403

404 405
  clock = GST_CLOCK_ENTRY_CLOCK (entry);

Wim Taymans's avatar
Wim Taymans committed
406
  /* can't sync on invalid times */
407 408 409
  if (G_UNLIKELY (!GST_CLOCK_TIME_IS_VALID (requested)))
    goto invalid_time;

Wim Taymans's avatar
Wim Taymans committed
410
  cclass = GST_CLOCK_GET_CLASS (clock);
411

Wim Taymans's avatar
Wim Taymans committed
412 413
  GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock, "waiting on clock entry %p", id);

414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433
  /* if we have a wait_jitter function, use that */
  if (G_LIKELY (cclass->wait_jitter)) {
    res = cclass->wait_jitter (clock, entry, jitter);
  } else {
    /* check if we have a simple _wait function otherwise. The function without
     * the jitter arg is less optimal as we need to do an additional _get_time()
     * which is not atomic with the _wait() and a typical _wait() function does
     * yet another _get_time() anyway. */
    if (G_UNLIKELY (cclass->wait == NULL))
      goto not_supported;

    if (jitter) {
      GstClockTime now = gst_clock_get_time (clock);

      /* jitter is the diff against the clock when this entry is scheduled. Negative
       * values mean that the entry was in time, a positive value means that the
       * entry was too late. */
      *jitter = GST_CLOCK_DIFF (requested, now);
    }
    res = cclass->wait (clock, entry);
Wim Taymans's avatar
Wim Taymans committed
434 435 436 437 438
  }

  GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock,
      "done waiting entry %p, res: %d", id, res);

439 440
  if (entry->type == GST_CLOCK_ENTRY_PERIODIC)
    entry->time = requested + entry->interval;
Wim Taymans's avatar
Wim Taymans committed
441

442
  if (G_UNLIKELY (clock->stats))
Wim Taymans's avatar
Wim Taymans committed
443 444
    gst_clock_update_stats (clock);

445
  return res;
446 447 448 449

  /* ERRORS */
invalid_time:
  {
450 451
    GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock,
        "invalid time requested, returning _BADTIME");
452 453
    return GST_CLOCK_BADTIME;
  }
Wim Taymans's avatar
Wim Taymans committed
454 455 456 457 458
not_supported:
  {
    GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock, "clock wait is not supported");
    return GST_CLOCK_UNSUPPORTED;
  }
459 460 461
}

/**
Wim Taymans's avatar
Wim Taymans committed
462 463
 * gst_clock_id_wait_async:
 * @id: a #GstClockID to wait on
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
464
 * @func: The callback function
465
 * @user_data: User data passed in the callback
466
 *
Wim Taymans's avatar
Wim Taymans committed
467 468
 * Register a callback on the given #GstClockID @id with the given
 * function and user_data. When passing a #GstClockID with an invalid
469
 * time to this function, the callback will be called immediately
470
 * with  a time set to GST_CLOCK_TIME_NONE. The callback will
Wim Taymans's avatar
Wim Taymans committed
471
 * be called when the time of @id has been reached.
472
 *
473 474 475
 * The callback @func can be invoked from any thread, either provided by the
 * core or from a streaming thread. The application should be prepared for this.
 *
476
 * Returns: the result of the non blocking wait.
477 478
 *
 * MT safe.
479 480 481
 */
GstClockReturn
gst_clock_id_wait_async (GstClockID id,
482
    GstClockCallback func, gpointer user_data)
483 484 485
{
  GstClockEntry *entry;
  GstClock *clock;
486
  GstClockReturn res;
Wim Taymans's avatar
Wim Taymans committed
487
  GstClockClass *cclass;
488
  GstClockTime requested;
489

490
  g_return_val_if_fail (id != NULL, GST_CLOCK_ERROR);
491
  g_return_val_if_fail (func != NULL, GST_CLOCK_ERROR);
492 493

  entry = (GstClockEntry *) id;
494 495
  requested = GST_CLOCK_ENTRY_TIME (entry);
  clock = GST_CLOCK_ENTRY_CLOCK (entry);
496

Wim Taymans's avatar
Wim Taymans committed
497
  /* can't sync on invalid times */
498 499 500
  if (G_UNLIKELY (!GST_CLOCK_TIME_IS_VALID (requested)))
    goto invalid_time;

Wim Taymans's avatar
Wim Taymans committed
501 502
  cclass = GST_CLOCK_GET_CLASS (clock);

Wim Taymans's avatar
Wim Taymans committed
503 504 505 506 507 508 509
  if (G_UNLIKELY (cclass->wait_async == NULL))
    goto not_supported;

  entry->func = func;
  entry->user_data = user_data;

  res = cclass->wait_async (clock, entry);
Wim Taymans's avatar
Wim Taymans committed
510

511 512
  return res;

513 514 515 516
  /* ERRORS */
invalid_time:
  {
    (func) (clock, GST_CLOCK_TIME_NONE, id, user_data);
517 518
    GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock,
        "invalid time requested, returning _BADTIME");
519 520
    return GST_CLOCK_BADTIME;
  }
Wim Taymans's avatar
Wim Taymans committed
521 522 523 524 525
not_supported:
  {
    GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock, "clock wait is not supported");
    return GST_CLOCK_UNSUPPORTED;
  }
526 527
}

528
/**
Wim Taymans's avatar
Wim Taymans committed
529 530
 * gst_clock_id_unschedule:
 * @id: The id to unschedule
531
 *
Wim Taymans's avatar
Wim Taymans committed
532
 * Cancel an outstanding request with @id. This can either
533
 * be an outstanding async notification or a pending sync notification.
Wim Taymans's avatar
Wim Taymans committed
534 535
 * After this call, @id cannot be used anymore to receive sync or
 * async notifications, you need to create a new #GstClockID.
536 537
 *
 * MT safe.
538 539 540 541 542 543
 */
void
gst_clock_id_unschedule (GstClockID id)
{
  GstClockEntry *entry;
  GstClock *clock;
Wim Taymans's avatar
Wim Taymans committed
544
  GstClockClass *cclass;
545

546 547 548 549
  g_return_if_fail (id != NULL);

  entry = (GstClockEntry *) id;
  clock = entry->clock;
550

Wim Taymans's avatar
Wim Taymans committed
551 552
  cclass = GST_CLOCK_GET_CLASS (clock);

Wim Taymans's avatar
Wim Taymans committed
553
  if (G_LIKELY (cclass->unschedule))
Wim Taymans's avatar
Wim Taymans committed
554
    cclass->unschedule (clock, entry);
555 556
}

557 558 559 560

/**
 * GstClock abstract base class implementation
 */
561
G_DEFINE_TYPE (GstClock, gst_clock, GST_TYPE_OBJECT);
562

563
static void
564
gst_clock_class_init (GstClockClass * klass)
565
{
566
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
567

568
  parent_class = g_type_class_peek_parent (klass);
569

Wim Taymans's avatar
Wim Taymans committed
570
#ifndef GST_DISABLE_TRACE
571 572
  _gst_clock_entry_trace =
      gst_alloc_trace_register (GST_CLOCK_ENTRY_TRACE_NAME);
Wim Taymans's avatar
Wim Taymans committed
573
#endif
574

575
  gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_clock_dispose);
Wim Taymans's avatar
Wim Taymans committed
576
  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_clock_finalize);
577 578 579
  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_clock_set_property);
  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_clock_get_property);

580
  g_object_class_install_property (gobject_class, PROP_STATS,
581 582
      g_param_spec_boolean ("stats", "Stats",
          "Enable clock stats (unimplemented)", DEFAULT_STATS,
583
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
584
  g_object_class_install_property (gobject_class, PROP_WINDOW_SIZE,
585 586
      g_param_spec_int ("window-size", "Window size",
          "The size of the window used to calculate rate and offset", 2, 1024,
587
          DEFAULT_WINDOW_SIZE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
588 589
  g_object_class_install_property (gobject_class, PROP_WINDOW_THRESHOLD,
      g_param_spec_int ("window-threshold", "Window threshold",
590
          "The threshold to start calculating rate and offset", 2, 1024,
591 592
          DEFAULT_WINDOW_THRESHOLD,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
593
  g_object_class_install_property (gobject_class, PROP_TIMEOUT,
594 595
      g_param_spec_uint64 ("timeout", "Timeout",
          "The amount of time, in nanoseconds, to sample master and slave clocks",
596 597
          0, G_MAXUINT64, DEFAULT_TIMEOUT,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
598 599

  g_type_class_add_private (klass, sizeof (GstClockPrivate));
Wim Taymans's avatar
Wim Taymans committed
600 601
}

602
static void
603
gst_clock_init (GstClock * clock)
Wim Taymans's avatar
Wim Taymans committed
604
{
605 606
  clock->last_time = 0;
  clock->entries = NULL;
607
  clock->entries_changed = g_cond_new ();
608
  clock->stats = FALSE;
609

610
  clock->ABI.priv =
611 612
      G_TYPE_INSTANCE_GET_PRIVATE (clock, GST_TYPE_CLOCK, GstClockPrivate);

613 614
  clock->internal_calibration = 0;
  clock->external_calibration = 0;
615 616 617 618
  clock->rate_numerator = 1;
  clock->rate_denominator = 1;

  clock->slave_lock = g_mutex_new ();
619 620
  clock->window_size = DEFAULT_WINDOW_SIZE;
  clock->window_threshold = DEFAULT_WINDOW_THRESHOLD;
Wim Taymans's avatar
Wim Taymans committed
621
  clock->filling = TRUE;
622 623 624
  clock->time_index = 0;
  clock->timeout = DEFAULT_TIMEOUT;
  clock->times = g_new0 (GstClockTime, 4 * clock->window_size);
Wim Taymans's avatar
Wim Taymans committed
625 626
}

627 628 629 630
static void
gst_clock_dispose (GObject * object)
{
  GstClock *clock = GST_CLOCK (object);
631
  GstClock **master_p;
632 633

  GST_OBJECT_LOCK (clock);
634 635
  master_p = &clock->master;
  gst_object_replace ((GstObject **) master_p, NULL);
636 637 638 639 640
  GST_OBJECT_UNLOCK (clock);

  G_OBJECT_CLASS (parent_class)->dispose (object);
}

Wim Taymans's avatar
Wim Taymans committed
641
static void
Wim Taymans's avatar
Wim Taymans committed
642
gst_clock_finalize (GObject * object)
Wim Taymans's avatar
Wim Taymans committed
643 644 645
{
  GstClock *clock = GST_CLOCK (object);

646
  GST_CLOCK_SLAVE_LOCK (clock);
647 648 649 650 651 652 653
  if (clock->clockid) {
    gst_clock_id_unschedule (clock->clockid);
    gst_clock_id_unref (clock->clockid);
    clock->clockid = NULL;
  }
  g_free (clock->times);
  clock->times = NULL;
654
  GST_CLOCK_SLAVE_UNLOCK (clock);
655

656
  g_cond_free (clock->entries_changed);
657 658
  g_mutex_free (clock->slave_lock);

Wim Taymans's avatar
Wim Taymans committed
659
  G_OBJECT_CLASS (parent_class)->finalize (object);
Wim Taymans's avatar
Wim Taymans committed
660 661
}

Wim Taymans's avatar
Wim Taymans committed
662
/**
663
 * gst_clock_set_resolution
664
 * @clock: a #GstClock
665
 * @resolution: The resolution to set
Wim Taymans's avatar
Wim Taymans committed
666
 *
667 668 669 670 671
 * Set the accuracy of the clock. Some clocks have the possibility to operate
 * with different accuracy at the expense of more resource usage. There is
 * normally no need to change the default resolution of a clock. The resolution
 * of a clock can only be changed if the clock has the
 * #GST_CLOCK_FLAG_CAN_SET_RESOLUTION flag set.
672 673
 *
 * Returns: the new resolution of the clock.
Wim Taymans's avatar
Wim Taymans committed
674
 */
675 676
GstClockTime
gst_clock_set_resolution (GstClock * clock, GstClockTime resolution)
Wim Taymans's avatar
Wim Taymans committed
677
{
Wim Taymans's avatar
Wim Taymans committed
678 679
  GstClockClass *cclass;

680 681
  g_return_val_if_fail (GST_IS_CLOCK (clock), 0);
  g_return_val_if_fail (resolution != 0, 0);
682

Wim Taymans's avatar
Wim Taymans committed
683 684 685
  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->change_resolution)
686
    clock->resolution =
687
        cclass->change_resolution (clock, clock->resolution, resolution);
688

689 690
  return clock->resolution;
}
691

692 693
/**
 * gst_clock_get_resolution
694
 * @clock: a #GstClock
695
 *
696 697
 * Get the accuracy of the clock. The accuracy of the clock is the granularity
 * of the values returned by gst_clock_get_time().
698
 *
699
 * Returns: the resolution of the clock in units of #GstClockTime.
700 701
 *
 * MT safe.
702
 */
703
GstClockTime
704
gst_clock_get_resolution (GstClock * clock)
705
{
Wim Taymans's avatar
Wim Taymans committed
706 707
  GstClockClass *cclass;

708
  g_return_val_if_fail (GST_IS_CLOCK (clock), 0);
709

Wim Taymans's avatar
Wim Taymans committed
710 711 712 713
  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->get_resolution)
    return cclass->get_resolution (clock);
714

715
  return 1;
Wim Taymans's avatar
Wim Taymans committed
716 717
}

Wim Taymans's avatar
Wim Taymans committed
718
/**
719 720 721
 * gst_clock_adjust_unlocked
 * @clock: a #GstClock to use
 * @internal: a clock time
Wim Taymans's avatar
Wim Taymans committed
722
 *
723
 * Converts the given @internal clock time to the external time, adjusting for the
724 725
 * rate and reference time set with gst_clock_set_calibration() and making sure
 * that the returned time is increasing. This function should be called with the
726
 * clock's OBJECT_LOCK held and is mainly used by clock subclasses.
Wim Taymans's avatar
Wim Taymans committed
727
 *
728
 * This function is the reverse of gst_clock_unadjust_unlocked().
729
 *
730
 * Returns: the converted time of the clock.
731
 */
732 733
GstClockTime
gst_clock_adjust_unlocked (GstClock * clock, GstClockTime internal)
734
{
735 736 737 738 739 740 741 742 743
  GstClockTime ret, cinternal, cexternal, cnum, cdenom;

  /* get calibration values for readability */
  cinternal = clock->internal_calibration;
  cexternal = clock->external_calibration;
  cnum = clock->rate_numerator;
  cdenom = clock->rate_denominator;

  /* avoid divide by 0 */
744
  if (G_UNLIKELY (cdenom == 0))
745 746 747 748 749
    cnum = cdenom = 1;

  /* The formula is (internal - cinternal) * cnum / cdenom + cexternal
   *
   * Since we do math on unsigned 64-bit ints we have to special case for
750
   * internal < cinternal to get the sign right. this case is not very common,
751 752 753
   * though.
   */
  if (G_LIKELY (internal >= cinternal)) {
754 755
    ret = internal - cinternal;
    ret = gst_util_uint64_scale (ret, cnum, cdenom);
756 757
    ret += cexternal;
  } else {
758 759
    ret = cinternal - internal;
    ret = gst_util_uint64_scale (ret, cnum, cdenom);
760
    /* clamp to 0 */
761
    if (G_LIKELY (cexternal > ret))
762 763 764 765
      ret = cexternal - ret;
    else
      ret = 0;
  }
766 767 768 769 770

  /* make sure the time is increasing */
  clock->last_time = MAX (ret, clock->last_time);

  return clock->last_time;
771 772
}

773 774 775 776 777 778 779 780 781 782
/**
 * gst_clock_unadjust_unlocked
 * @clock: a #GstClock to use
 * @external: an external clock time
 *
 * Converts the given @external clock time to the internal time of @clock,
 * using the rate and reference time set with gst_clock_set_calibration().
 * This function should be called with the clock's OBJECT_LOCK held and
 * is mainly used by clock subclasses.
 *
783
 * This function is the reverse of gst_clock_adjust_unlocked().
784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800
 *
 * Returns: the internal time of the clock corresponding to @external.
 *
 * Since: 0.10.13
 */
GstClockTime
gst_clock_unadjust_unlocked (GstClock * clock, GstClockTime external)
{
  GstClockTime ret, cinternal, cexternal, cnum, cdenom;

  /* get calibration values for readability */
  cinternal = clock->internal_calibration;
  cexternal = clock->external_calibration;
  cnum = clock->rate_numerator;
  cdenom = clock->rate_denominator;

  /* avoid divide by 0 */
801
  if (G_UNLIKELY (cnum == 0))
802 803 804
    cnum = cdenom = 1;

  /* The formula is (external - cexternal) * cdenom / cnum + cinternal */
805 806 807
  if (G_LIKELY (external >= cexternal)) {
    ret = external - cexternal;
    ret = gst_util_uint64_scale (ret, cdenom, cnum);
808 809
    ret += cinternal;
  } else {
810 811 812
    ret = cexternal - external;
    ret = gst_util_uint64_scale (ret, cdenom, cnum);
    if (G_LIKELY (cinternal > ret))
813 814 815 816 817 818 819
      ret = cinternal - ret;
    else
      ret = 0;
  }
  return ret;
}

Wim Taymans's avatar
Wim Taymans committed
820
/**
821
 * gst_clock_get_internal_time
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
822
 * @clock: a #GstClock to query
Wim Taymans's avatar
Wim Taymans committed
823
 *
824 825
 * Gets the current internal time of the given clock. The time is returned
 * unadjusted for the offset and the rate.
826
 *
827
 * Returns: the internal time of the clock. Or GST_CLOCK_TIME_NONE when
828
 * given invalid input.
829 830
 *
 * MT safe.
Wim Taymans's avatar
Wim Taymans committed
831
 */
832
GstClockTime
833
gst_clock_get_internal_time (GstClock * clock)
834
{
835
  GstClockTime ret;
836
  GstClockClass *cclass;
837

838
  g_return_val_if_fail (GST_IS_CLOCK (clock), GST_CLOCK_TIME_NONE);
839

840
  cclass = GST_CLOCK_GET_CLASS (clock);
Wim Taymans's avatar
Wim Taymans committed
841

Wim Taymans's avatar
Wim Taymans committed
842 843 844 845 846
  if (G_UNLIKELY (cclass->get_internal_time == NULL))
    goto not_supported;

  ret = cclass->get_internal_time (clock);

847
  GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock, "internal time %" GST_TIME_FORMAT,
848
      GST_TIME_ARGS (ret));
849

850
  return ret;
Wim Taymans's avatar
Wim Taymans committed
851 852 853 854 855 856 857 858

  /* ERRORS */
not_supported:
  {
    GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock,
        "internal time not supported, return 0");
    return G_GINT64_CONSTANT (0);
  }
859 860 861 862 863 864 865 866 867 868 869
}

/**
 * gst_clock_get_time
 * @clock: a #GstClock to query
 *
 * Gets the current time of the given clock. The time is always
 * monotonically increasing and adjusted according to the current
 * offset and rate.
 *
 * Returns: the time of the clock. Or GST_CLOCK_TIME_NONE when
870
 * given invalid input.
871 872 873 874 875 876 877
 *
 * MT safe.
 */
GstClockTime
gst_clock_get_time (GstClock * clock)
{
  GstClockTime ret;
878
  gint seq;
879 880 881

  g_return_val_if_fail (GST_IS_CLOCK (clock), GST_CLOCK_TIME_NONE);

882 883 884 885
  do {
    /* reget the internal time when we retry to get the most current
     * timevalue */
    ret = gst_clock_get_internal_time (clock);
886

887 888 889 890
    seq = read_seqbegin (clock);
    /* this will scale for rate and offset */
    ret = gst_clock_adjust_unlocked (clock, ret);
  } while (read_seqretry (clock, seq));
891

892
  GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock, "adjusted time %" GST_TIME_FORMAT,
893
      GST_TIME_ARGS (ret));
894

895
  return ret;
896 897
}

898 899 900 901 902
/**
 * gst_clock_set_calibration
 * @clock: a #GstClock to calibrate
 * @internal: a reference internal time
 * @external: a reference external time
903 904 905
 * @rate_num: the numerator of the rate of the clock relative to its
 *            internal time 
 * @rate_denom: the denominator of the rate of the clock
906
 *
907 908
 * Adjusts the rate and time of @clock. A rate of 1/1 is the normal speed of
 * the clock. Values bigger than 1/1 make the clock go faster.
909 910 911 912 913
 *
 * @internal and @external are calibration parameters that arrange that