2 * Copyright (C) 2005 Wim Taymans <wim@fluendo.com>
4 * gstsegment.c: GstSegment subsystem
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
23 #include "gst_private.h"
26 #include "gstsegment.h"
30 * @short_description: Structure describing the configured region of interest
32 * @see_also: #GstEvent
34 * This helper structure holds the relevant values for tracking the region of
35 * interest in a media file, called a segment.
37 * The structure can be used for two purposes:
39 * <listitem><para>performing seeks (handling seek events)</para></listitem>
40 * <listitem><para>tracking playback regions (handling newsegment events)</para></listitem>
43 * The segment is usually configured by the application with a seek event which
44 * is propagated upstream and eventually handled by an element that performs the seek.
46 * The configured segment is then propagated back downstream with a newsegment event.
47 * This information is then used to clip media to the segment boundaries.
49 * A segment structure is initialized with gst_segment_init(), which takes a #GstFormat
50 * that will be used as the format of the segment values. The segment will be configured
51 * with a start value of 0 and a stop/duration of -1, which is undefined. The default
52 * rate and applied_rate is 1.0.
54 * If the segment is used for managing seeks, the segment duration should be set with
55 * gst_segment_set_duration(). The public duration field contains the duration of the
56 * segment. When using the segment for seeking, the start and time members should
57 * normally be left to their default 0 value. The stop position is left to -1 unless
58 * explicitly configured to a different value after a seek event.
60 * The current position in the segment should be set with the gst_segment_set_last_stop().
61 * The public last_stop field contains the last set stop position in the segment.
63 * For elements that perform seeks, the current segment should be updated with the
64 * gst_segment_set_seek() and the values from the seek event. This method will update
65 * all the segment fields. The last_pos field will contain the new playback position.
66 * If the cur_type was different from GST_SEEK_TYPE_NONE, playback continues from
67 * the last_pos position, possibly with updated flags or rate.
69 * For elements that want to use #GstSegment to track the playback region, use
70 * gst_segment_set_newsegment() to update the segment fields with the information from
71 * the newsegment event. The gst_segment_clip() method can be used to check and clip
72 * the media data to the segment boundaries.
74 * For elements that want to synchronize to the pipeline clock, gst_segment_to_running_time()
75 * can be used to convert a timestamp to a value that can be used to synchronize
76 * to the clock. This function takes into account all accumulated segments as well as
77 * any rate or applied_rate conversions.
79 * For elements that need to perform operations on media data in stream_time,
80 * gst_segment_to_stream_time() can be used to convert a timestamp and the segment
81 * info to stream time (which is always between 0 and the duration of the stream).
83 * Last reviewed on 2006-05-03 (0.10.6)
87 gst_segment_copy (GstSegment * segment)
89 GstSegment *result = NULL;
92 result = gst_segment_new ();
93 memcpy (result, segment, sizeof (GstSegment));
99 gst_segment_get_type (void)
101 static GType gst_segment_type = 0;
103 if (G_UNLIKELY (gst_segment_type == 0)) {
104 gst_segment_type = g_boxed_type_register_static ("GstSegment",
105 (GBoxedCopyFunc) gst_segment_copy, (GBoxedFreeFunc) gst_segment_free);
108 return gst_segment_type;
114 * Allocate a new #GstSegment structure and initialize it using
115 * gst_segment_init().
117 * Returns: a new #GstSegment, free with gst_segment_free().
120 gst_segment_new (void)
124 result = g_new0 (GstSegment, 1);
125 gst_segment_init (result, GST_FORMAT_UNDEFINED);
132 * @segment: a #GstSegment
134 * Free the allocated segment @segment.
137 gst_segment_free (GstSegment * segment)
144 * @segment: a #GstSegment structure.
145 * @format: the format of the segment.
147 * The start/last_stop positions are set to 0 and the stop/duration
148 * fields are set to -1 (unknown). The default rate of 1.0 and no
151 * Initialize @segment to its default values.
154 gst_segment_init (GstSegment * segment, GstFormat format)
156 g_return_if_fail (segment != NULL);
159 segment->abs_rate = 1.0;
160 segment->applied_rate = 1.0;
161 segment->format = format;
167 segment->last_stop = 0;
168 segment->duration = -1;
172 * gst_segment_set_duration:
173 * @segment: a #GstSegment structure.
174 * @format: the format of the segment.
175 * @duration: the duration of the segment info or -1 if unknown.
177 * Set the duration of the segment to @duration. This function is mainly
178 * used by elements that perform seeking and know the total duration of the
181 * This field should be set to allow seeking requests relative to the
185 gst_segment_set_duration (GstSegment * segment, GstFormat format,
188 g_return_if_fail (segment != NULL);
190 if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))
191 segment->format = format;
193 g_return_if_fail (segment->format == format);
195 segment->duration = duration;
199 * gst_segment_set_last_stop:
200 * @segment: a #GstSegment structure.
201 * @format: the format of the segment.
202 * @position: the position
204 * Set the last observed stop position in the segment to @position.
206 * This field should be set to allow seeking requests relative to the
207 * current playing position.
210 gst_segment_set_last_stop (GstSegment * segment, GstFormat format,
213 g_return_if_fail (segment != NULL);
214 g_return_if_fail (position != -1);
216 if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))
217 segment->format = format;
219 g_return_if_fail (segment->format == format);
221 segment->last_stop = MAX (segment->start, position);
225 * gst_segment_set_seek:
226 * @segment: a #GstSegment structure.
227 * @rate: the rate of the segment.
228 * @format: the format of the segment.
229 * @flags: the seek flags for the segment
230 * @start_type: the seek method
231 * @start: the seek start value
232 * @stop_type: the seek method
233 * @stop: the seek stop value
234 * @update: boolean holding whether start or stop were updated.
236 * Update the segment structure with the field values of a seek event (see
237 * gst_event_new_seek()).
239 * After calling this method, the segment field last_stop and time will
240 * contain the requested new position in the segment. The new requested
241 * position in the segment depends on @rate and @start_type and @stop_type.
243 * For positive @rate, the new position in the segment is the new @segment
244 * start field when it was updated with a @start_type different from
245 * #GST_SEEK_TYPE_NONE. If no update was performed on @segment start position
246 * (#GST_SEEK_TYPE_NONE), @start is ignored and @segment last_stop is
249 * For negative @rate, the new position in the segment is the new @segment
250 * stop field when it was updated with a @stop_type different from
251 * #GST_SEEK_TYPE_NONE. If no stop was previously configured in the segment, the
252 * duration of the segment will be used to update the stop position.
253 * If no update was performed on @segment stop position (#GST_SEEK_TYPE_NONE),
254 * @stop is ignored and @segment last_stop is unmodified.
256 * The applied rate of the segment will be set to 1.0 by default.
257 * If the caller can apply a rate change, it should update @segment
258 * rate and applied_rate after calling this function.
261 gst_segment_set_seek (GstSegment * segment, gdouble rate,
262 GstFormat format, GstSeekFlags flags,
263 GstSeekType start_type, gint64 start,
264 GstSeekType stop_type, gint64 stop, gboolean * update)
266 gboolean update_stop, update_start;
268 g_return_if_fail (rate != 0.0);
269 g_return_if_fail (segment != NULL);
271 if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))
272 segment->format = format;
274 g_return_if_fail (segment->format == format);
276 update_stop = update_start = TRUE;
278 /* start is never invalid */
279 switch (start_type) {
280 case GST_SEEK_TYPE_NONE:
281 /* no update to segment */
282 start = segment->start;
283 update_start = FALSE;
285 case GST_SEEK_TYPE_SET:
286 /* start holds desired position, map -1 to the start */
290 case GST_SEEK_TYPE_CUR:
291 /* add start to currently configure segment */
292 start = segment->start + start;
294 case GST_SEEK_TYPE_END:
295 if (segment->duration != -1) {
296 /* add start to total length */
297 start = segment->duration + start;
299 /* no update if duration unknown */
300 start = segment->start;
301 update_start = FALSE;
305 /* bring in sane range */
306 if (segment->duration != -1)
307 start = CLAMP (start, 0, segment->duration);
309 start = MAX (start, 0);
311 /* stop can be -1 if we have not configured a stop. */
313 case GST_SEEK_TYPE_NONE:
314 stop = segment->stop;
317 case GST_SEEK_TYPE_SET:
318 /* stop holds required value */
320 case GST_SEEK_TYPE_CUR:
321 if (segment->stop != -1)
322 stop = segment->stop + stop;
326 case GST_SEEK_TYPE_END:
327 if (segment->duration != -1)
328 stop = segment->duration + stop;
330 stop = segment->stop;
336 /* if we have a valid stop time, make sure it is clipped */
338 if (segment->duration != -1)
339 stop = CLAMP (stop, 0, segment->duration);
341 stop = MAX (stop, 0);
344 /* we can't have stop before start */
346 g_return_if_fail (start <= stop);
348 segment->rate = rate;
349 segment->abs_rate = ABS (rate);
350 segment->applied_rate = 1.0;
351 segment->flags = flags;
352 segment->start = start;
353 if (update_start && rate > 0.0) {
354 segment->last_stop = start;
356 if (update_stop && rate < 0.0) {
358 segment->last_stop = stop;
360 if (segment->duration != -1)
361 segment->last_stop = segment->duration;
363 segment->last_stop = 0;
366 segment->time = start;
367 segment->stop = stop;
370 *update = update_start || update_stop;
374 * gst_segment_set_newsegment:
375 * @segment: a #GstSegment structure.
376 * @update: flag indicating a new segment is started or updated
377 * @rate: the rate of the segment.
378 * @format: the format of the segment.
379 * @start: the new start value
380 * @stop: the new stop value
381 * @time: the new stream time
383 * Update the segment structure with the field values of a new segment event and
384 * with a default applied_rate of 1.0.
389 gst_segment_set_newsegment (GstSegment * segment, gboolean update, gdouble rate,
390 GstFormat format, gint64 start, gint64 stop, gint64 time)
392 gst_segment_set_newsegment_full (segment, update, rate, 1.0, format, start,
397 * gst_segment_set_newsegment_full:
398 * @segment: a #GstSegment structure.
399 * @update: flag indicating a new segment is started or updated
400 * @rate: the rate of the segment.
401 * @applied_rate: the applied rate of the segment.
402 * @format: the format of the segment.
403 * @start: the new start value
404 * @stop: the new stop value
405 * @time: the new stream time
407 * Update the segment structure with the field values of a new segment event.
410 gst_segment_set_newsegment_full (GstSegment * segment, gboolean update,
411 gdouble rate, gdouble applied_rate, GstFormat format, gint64 start,
412 gint64 stop, gint64 time)
416 g_return_if_fail (rate != 0.0);
417 g_return_if_fail (applied_rate != 0.0);
418 g_return_if_fail (segment != NULL);
420 if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))
421 segment->format = format;
423 /* any other format with 0 also gives time 0, the other values are
424 * invalid in the format though. */
425 if (format != segment->format && start == 0) {
426 format = segment->format;
433 g_return_if_fail (segment->format == format);
436 /* an update to the current segment is done, elapsed time is
437 * difference between the old start and new start. */
438 if (start > segment->start)
439 duration = start - segment->start;
443 /* the new segment has to be aligned with the old segment.
444 * We first update the accumulated time of the previous
445 * segment. the accumulated time is used when syncing to the
448 if (segment->stop != -1) {
449 duration = segment->stop - segment->start;
450 } else if (segment->last_stop != -1) {
451 /* else use last seen timestamp as segment stop */
452 duration = segment->last_stop - segment->start;
454 /* else we don't know and throw a warning.. really, this should
455 * be fixed in the element. */
456 g_warning ("closing segment of unknown duration, assuming duration of 0");
460 /* use previous rate to calculate duration */
461 if (segment->abs_rate != 1.0)
462 duration /= segment->abs_rate;
464 /* accumulate duration */
465 segment->accum += duration;
467 /* then update the current segment */
468 segment->rate = rate;
469 segment->abs_rate = ABS (rate);
470 segment->applied_rate = applied_rate;
471 segment->start = start;
472 segment->last_stop = start;
473 segment->stop = stop;
474 segment->time = time;
478 * gst_segment_to_stream_time:
479 * @segment: a #GstSegment structure.
480 * @format: the format of the segment.
481 * @position: the position in the segment
483 * Translate @position to stream time using the currently configured
484 * segment. The @position value must be between @segment start and
487 * This function is typically used by elements that need to operate on
488 * the stream time of the buffers it receives, such as effect plugins.
489 * In those use cases, @position is typically the buffer timestamp or
490 * clock time that one wants to convert to the stream time.
491 * The stream time is always between 0 and the total duration of the
494 * Returns: the position in stream_time or -1 when an invalid position
498 gst_segment_to_stream_time (GstSegment * segment, GstFormat format,
502 gdouble abs_applied_rate;
504 g_return_val_if_fail (segment != NULL, -1);
506 /* format does not matter for -1 */
507 if (G_UNLIKELY (position == -1))
510 if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))
511 segment->format = format;
513 g_return_val_if_fail (segment->format == format, -1);
515 /* outside of the segment boundary stop */
516 if (G_UNLIKELY (segment->stop != -1 && position >= segment->stop))
519 /* before the segment boundary */
520 if (G_UNLIKELY (position < segment->start))
523 /* time must be known */
524 if (G_UNLIKELY (segment->time == -1))
527 /* bring to uncorrected position in segment */
528 result = position - segment->start;
530 abs_applied_rate = ABS (segment->applied_rate);
532 /* correct for applied rate if needed */
533 if (abs_applied_rate != 1.0)
534 result *= abs_applied_rate;
536 /* add or subtract from segment time based on applied rate */
537 if (segment->applied_rate > 0.0) {
538 /* correct for segment time */
539 result += segment->time;
541 /* correct for segment time, clamp at 0 */
542 if (segment->time > result)
543 result = segment->time - result;
552 * gst_segment_to_running_time:
553 * @segment: a #GstSegment structure.
554 * @format: the format of the segment.
555 * @position: the position in the segment
557 * Translate @position to the total running time using the currently configured
558 * and previously accumulated segments. Position is a value between @segment
559 * start and stop time.
561 * This function is typically used by elements that need to synchronize to the
562 * global clock in a pipeline. The runnning time is a constantly increasing value
563 * starting from 0. When gst_segment_init() is called, this value will reset to
566 * This function returns -1 if the position is outside of @segment start and stop.
568 * Returns: the position as the total running time or -1 when an invalid position
572 gst_segment_to_running_time (GstSegment * segment, GstFormat format,
577 g_return_val_if_fail (segment != NULL, -1);
579 if (G_UNLIKELY (position == -1))
582 if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))
583 segment->format = format;
584 else if (segment->accum)
585 g_return_val_if_fail (segment->format == format, -1);
587 /* before the segment boundary */
588 if (G_UNLIKELY (position < segment->start))
591 if (segment->rate > 0.0) {
592 /* outside of the segment boundary stop */
593 if (G_UNLIKELY (segment->stop != -1 && position >= segment->stop))
596 /* bring to uncorrected position in segment */
597 result = position - segment->start;
599 /* cannot continue if no stop position set or outside of
601 if (G_UNLIKELY (segment->stop == -1 || position >= segment->stop))
604 /* bring to uncorrected position in segment */
605 result = segment->stop - position;
608 /* scale based on the rate, avoid division by and conversion to
609 * float when not needed */
610 if (segment->abs_rate != 1.0)
611 result /= segment->abs_rate;
613 /* correct for accumulated segments */
614 result += segment->accum;
621 * @segment: a #GstSegment structure.
622 * @format: the format of the segment.
623 * @start: the start position in the segment
624 * @stop: the stop position in the segment
625 * @clip_start: the clipped start position in the segment
626 * @clip_stop: the clipped stop position in the segment
628 * Clip the given @start and @stop values to the segment boundaries given
629 * in @segment. @start and @stop are compared and clipped to @segment
630 * start and stop values.
632 * If the function returns FALSE, @start and @stop are known to fall
633 * outside of @segment and @clip_start and @clip_stop are not updated.
635 * When the function returns TRUE, @clip_start and @clip_stop will be
636 * updated. If @clip_start or @clip_stop are different from @start or @stop
637 * respectively, the region fell partially in the segment.
639 * Returns: TRUE if the given @start and @stop times fall partially or
640 * completely in @segment, FALSE if the values are completely outside
644 gst_segment_clip (GstSegment * segment, GstFormat format, gint64 start,
645 gint64 stop, gint64 * clip_start, gint64 * clip_stop)
647 g_return_val_if_fail (segment != NULL, FALSE);
649 if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))
650 segment->format = format;
652 g_return_val_if_fail (segment->format == format, FALSE);
654 /* if we have a stop position and a valid start and start is bigger,
655 * we're outside of the segment */
656 if (G_UNLIKELY (segment->stop != -1 && start != -1 && start >= segment->stop))
659 /* if a stop position is given and is before the segment start,
660 * we're outside of the segment */
661 if (G_UNLIKELY (stop != -1 && stop != start && stop <= segment->start))
668 *clip_start = MAX (start, segment->start);
673 *clip_stop = segment->stop;
674 else if (segment->stop == -1)
675 *clip_stop = MAX (-1, stop);
677 *clip_stop = MIN (stop, segment->stop);
679 if (segment->duration != -1)
680 *clip_stop = MIN (*clip_stop, segment->duration);