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., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
22 #include "gst_private.h"
27 #include "gstsegment.h"
31 * @short_description: Structure describing the configured region of interest
33 * @see_also: #GstEvent
35 * This helper structure holds the relevant values for tracking the region of
36 * interest in a media file, called a segment.
38 * The structure can be used for two purposes:
40 * <listitem><para>performing seeks (handling seek events)</para></listitem>
41 * <listitem><para>tracking playback regions (handling newsegment events)</para></listitem>
44 * The segment is usually configured by the application with a seek event which
45 * is propagated upstream and eventually handled by an element that performs the seek.
47 * The configured segment is then propagated back downstream with a newsegment event.
48 * This information is then used to clip media to the segment boundaries.
50 * A segment structure is initialized with gst_segment_init(), which takes a #GstFormat
51 * that will be used as the format of the segment values. The segment will be configured
52 * with a start value of 0 and a stop/duration of -1, which is undefined. The default
53 * rate and applied_rate is 1.0.
55 * The public duration field contains the duration of the segment. When using
56 * the segment for seeking, the start and time members should normally be left
57 * to their default 0 value. The stop position is left to -1 unless explicitly
58 * configured to a different value after a seek event.
60 * The current position in the segment should be set by changing the position
61 * member in the structure.
63 * For elements that perform seeks, the current segment should be updated with the
64 * gst_segment_do_seek() and the values from the seek event. This method will update
65 * all the segment fields. The position field will contain the new playback position.
66 * If the start_type was different from GST_SEEK_TYPE_NONE, playback continues from
67 * the position position, possibly with updated flags or rate.
69 * For elements that want to use #GstSegment to track the playback region,
70 * update the segment fields with the information from the newsegment event.
71 * 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 the base 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).
86 * @segment: (transfer none): a #GstSegment
88 * Create a copy of given @segment.
90 * Free-function: gst_segment_free
92 * Returns: (transfer full): a new #GstSegment, free with gst_segment_free().
95 gst_segment_copy (const GstSegment * segment)
97 GstSegment *result = NULL;
100 result = (GstSegment *) g_slice_copy (sizeof (GstSegment), segment);
106 * gst_segment_copy_into:
107 * @src: (transfer none): a #GstSegment
108 * @dest: (transfer none): a #GstSegment
110 * Copy the contents of @src into @dest.
113 gst_segment_copy_into (const GstSegment * src, GstSegment * dest)
115 memcpy (dest, src, sizeof (GstSegment));
118 G_DEFINE_BOXED_TYPE (GstSegment, gst_segment,
119 (GBoxedCopyFunc) gst_segment_copy, (GBoxedFreeFunc) gst_segment_free);
124 * Allocate a new #GstSegment structure and initialize it using
125 * gst_segment_init().
127 * Free-function: gst_segment_free
129 * Returns: (transfer full): a new #GstSegment, free with gst_segment_free().
132 gst_segment_new (void)
136 result = g_slice_new0 (GstSegment);
137 gst_segment_init (result, GST_FORMAT_UNDEFINED);
144 * @segment: (in) (transfer full): a #GstSegment
146 * Free the allocated segment @segment.
149 gst_segment_free (GstSegment * segment)
151 g_slice_free (GstSegment, segment);
156 * @segment: a #GstSegment structure.
157 * @format: the format of the segment.
159 * The start/position fields are set to 0 and the stop/duration
160 * fields are set to -1 (unknown). The default rate of 1.0 and no
163 * Initialize @segment to its default values.
166 gst_segment_init (GstSegment * segment, GstFormat format)
168 g_return_if_fail (segment != NULL);
170 segment->flags = GST_SEGMENT_FLAG_NONE;
172 segment->applied_rate = 1.0;
173 segment->format = format;
179 segment->position = 0;
180 segment->duration = -1;
184 * gst_segment_do_seek:
185 * @segment: a #GstSegment structure.
186 * @rate: the rate of the segment.
187 * @format: the format of the segment.
188 * @flags: the segment flags for the segment
189 * @start_type: the seek method
190 * @start: the seek start value
191 * @stop_type: the seek method
192 * @stop: the seek stop value
193 * @update: boolean holding whether position was updated.
195 * Update the segment structure with the field values of a seek event (see
196 * gst_event_new_seek()).
198 * After calling this method, the segment field position and time will
199 * contain the requested new position in the segment. The new requested
200 * position in the segment depends on @rate and @start_type and @stop_type.
202 * For positive @rate, the new position in the segment is the new @segment
203 * start field when it was updated with a @start_type different from
204 * #GST_SEEK_TYPE_NONE. If no update was performed on @segment start position
205 * (#GST_SEEK_TYPE_NONE), @start is ignored and @segment position is
208 * For negative @rate, the new position in the segment is the new @segment
209 * stop field when it was updated with a @stop_type different from
210 * #GST_SEEK_TYPE_NONE. If no stop was previously configured in the segment, the
211 * duration of the segment will be used to update the stop position.
212 * If no update was performed on @segment stop position (#GST_SEEK_TYPE_NONE),
213 * @stop is ignored and @segment position is unmodified.
215 * The applied rate of the segment will be set to 1.0 by default.
216 * If the caller can apply a rate change, it should update @segment
217 * rate and applied_rate after calling this function.
219 * @update will be set to %TRUE if a seek should be performed to the segment
220 * position field. This field can be %FALSE if, for example, only the @rate
221 * has been changed but not the playback position.
223 * Returns: %TRUE if the seek could be performed.
226 gst_segment_do_seek (GstSegment * segment, gdouble rate,
227 GstFormat format, GstSeekFlags flags,
228 GstSeekType start_type, guint64 start,
229 GstSeekType stop_type, guint64 stop, gboolean * update)
231 gboolean update_stop, update_start;
232 guint64 position, base;
234 g_return_val_if_fail (rate != 0.0, FALSE);
235 g_return_val_if_fail (segment != NULL, FALSE);
236 g_return_val_if_fail (segment->format == format, FALSE);
238 update_start = update_stop = TRUE;
240 position = segment->position;
242 /* segment->start is never invalid */
243 switch (start_type) {
244 case GST_SEEK_TYPE_NONE:
245 /* no update to segment, take previous start */
246 start = segment->start;
247 update_start = FALSE;
249 case GST_SEEK_TYPE_SET:
250 /* start holds desired position, map -1 to the start */
254 case GST_SEEK_TYPE_END:
255 if (segment->duration != -1) {
256 /* add start to total length */
257 start = segment->duration + start;
259 /* no update if duration unknown */
260 start = segment->start;
261 update_start = FALSE;
265 /* bring in sane range */
266 if (segment->duration != -1)
267 start = MIN (start, segment->duration);
269 start = MAX ((gint64) start, 0);
271 /* stop can be -1 if we have not configured a stop. */
273 case GST_SEEK_TYPE_NONE:
274 stop = segment->stop;
277 case GST_SEEK_TYPE_SET:
278 /* stop holds required value */
280 case GST_SEEK_TYPE_END:
281 if (segment->duration != -1) {
282 stop = segment->duration + stop;
284 stop = segment->stop;
290 /* if we have a valid stop time, make sure it is clipped */
292 if (segment->duration != -1)
293 stop = CLAMP ((gint64) stop, 0, (gint64) segment->duration);
295 stop = MAX ((gint64) stop, 0);
298 /* we can't have stop before start */
301 GST_WARNING ("segment update failed: start(%" G_GUINT64_FORMAT
302 ") > stop(%" G_GUINT64_FORMAT ")", start, stop);
303 g_return_val_if_fail (start <= stop, FALSE);
308 if (flags & GST_SEEK_FLAG_FLUSH) {
309 /* flush resets the running_time */
312 /* make sure the position is inside the segment start/stop */
313 position = CLAMP (position, segment->start, segment->stop);
315 /* remember the elapsed time */
316 base = gst_segment_to_running_time (segment, format, position);
317 GST_DEBUG ("updated segment.base: %" G_GUINT64_FORMAT, base);
320 if (update_start && rate > 0.0) {
323 if (update_stop && rate < 0.0) {
327 if (segment->duration != -1)
328 position = segment->duration;
334 /* set update arg to reflect update of position */
336 *update = position != segment->position;
338 /* update new values */
339 /* be explicit about our GstSeekFlag -> GstSegmentFlag conversion */
340 segment->flags = GST_SEGMENT_FLAG_NONE;
341 if ((flags & GST_SEEK_FLAG_FLUSH) != 0)
342 segment->flags |= GST_SEGMENT_FLAG_RESET;
343 if ((flags & GST_SEEK_FLAG_TRICKMODE) != 0)
344 segment->flags |= GST_SEGMENT_FLAG_TRICKMODE;
345 if ((flags & GST_SEEK_FLAG_SEGMENT) != 0)
346 segment->flags |= GST_SEGMENT_FLAG_SEGMENT;
347 if ((flags & GST_SEEK_FLAG_TRICKMODE_KEY_UNITS) != 0)
348 segment->flags |= GST_SEGMENT_FLAG_TRICKMODE_KEY_UNITS;
349 if ((flags & GST_SEEK_FLAG_TRICKMODE_NO_AUDIO) != 0)
350 segment->flags |= GST_SEGMENT_FLAG_TRICKMODE_NO_AUDIO;
352 segment->rate = rate;
353 segment->applied_rate = 1.0;
355 segment->base = base;
357 segment->offset = position - start;
360 segment->offset = stop - position;
361 else if (segment->duration != -1)
362 segment->offset = segment->duration - position;
367 segment->start = start;
368 segment->stop = stop;
369 segment->time = start;
370 segment->position = position;
372 GST_INFO ("segment updated: %" GST_SEGMENT_FORMAT, segment);
378 * gst_segment_to_stream_time:
379 * @segment: a #GstSegment structure.
380 * @format: the format of the segment.
381 * @position: the position in the segment
383 * Translate @position to stream time using the currently configured
384 * segment. The @position value must be between @segment start and
387 * This function is typically used by elements that need to operate on
388 * the stream time of the buffers it receives, such as effect plugins.
389 * In those use cases, @position is typically the buffer timestamp or
390 * clock time that one wants to convert to the stream time.
391 * The stream time is always between 0 and the total duration of the
394 * Returns: the position in stream_time or -1 when an invalid position
398 gst_segment_to_stream_time (const GstSegment * segment, GstFormat format,
401 guint64 stream_time, start, stop, time;
402 gdouble abs_applied_rate;
404 /* format does not matter for -1 */
405 if (G_UNLIKELY (position == -1))
408 g_return_val_if_fail (segment != NULL, -1);
409 g_return_val_if_fail (segment->format == format, -1);
411 stop = segment->stop;
413 /* outside of the segment boundary stop */
414 if (G_UNLIKELY (stop != -1 && position > stop))
417 start = segment->start;
419 /* before the segment boundary */
420 if (G_UNLIKELY (position < start))
423 time = segment->time;
425 /* time must be known */
426 if (G_UNLIKELY (time == -1))
429 abs_applied_rate = ABS (segment->applied_rate);
431 /* add or subtract from segment time based on applied rate */
432 if (G_LIKELY (segment->applied_rate > 0.0)) {
433 if (G_UNLIKELY (position < start))
435 /* bring to uncorrected position in segment */
436 stream_time = position - start;
437 /* correct for applied rate if needed */
438 if (G_UNLIKELY (abs_applied_rate != 1.0))
439 stream_time *= abs_applied_rate;
440 /* correct for segment time */
443 /* correct for segment time, clamp at 0. Streams with a negative
444 * applied_rate have timestamps between start and stop, as usual, but have
445 * the time member starting high and going backwards. */
446 if (G_UNLIKELY (position > stop))
448 stream_time = stop - position;
449 if (G_UNLIKELY (abs_applied_rate != 1.0))
450 stream_time *= abs_applied_rate;
458 * gst_segment_to_running_time_full:
459 * @segment: a #GstSegment structure.
460 * @format: the format of the segment.
461 * @position: the position in the segment
462 * @running_time: result running-time
464 * Translate @position to the total running time using the currently configured
465 * segment. Compared to gst_segment_to_running_time() this function can return
466 * negative running-time.
468 * This function is typically used by elements that need to synchronize buffers
469 * against the clock or eachother.
471 * @position can be any value and the result of this function for values outside
472 * of the segment is extrapolated.
474 * When 1 is returned, @position resulted in a positive running-time returned
477 * When this function returns -1, the returned @running_time should be negated
478 * to get the real negative running time.
480 * Returns: a 1 or -1 on success, 0 on failure.
485 gst_segment_to_running_time_full (const GstSegment * segment, GstFormat format,
486 guint64 position, guint64 * running_time)
490 guint64 start, stop, offset;
493 if (G_UNLIKELY (position == -1)) {
494 GST_DEBUG ("invalid position (-1)");
498 g_return_val_if_fail (segment != NULL, 0);
499 g_return_val_if_fail (segment->format == format, 0);
501 offset = segment->offset;
503 if (G_LIKELY (segment->rate > 0.0)) {
504 start = segment->start + offset;
506 /* bring to uncorrected position in segment */
507 if (position < start) {
509 result = start - position;
512 result = position - start;
516 stop = segment->stop;
518 /* cannot continue if no stop position set or invalid offset */
519 g_return_val_if_fail (stop != -1, 0);
520 g_return_val_if_fail (stop >= offset, 0);
524 /* bring to uncorrected position in segment */
525 if (position > stop) {
527 result = position - stop;
530 result = stop - position;
536 /* scale based on the rate, avoid division by and conversion to
537 * float when not needed */
538 abs_rate = ABS (segment->rate);
539 if (G_UNLIKELY (abs_rate != 1.0))
542 /* correct for base of the segment */
544 /* positive, add base */
545 *running_time = result + segment->base;
546 else if (segment->base >= result) {
547 /* negative and base is bigger, subtract from base and we have a
548 * positive value again */
549 *running_time = segment->base - result;
552 /* negative and base is smaller, subtract base and remainder is
554 *running_time = result - segment->base;
568 * gst_segment_to_running_time:
569 * @segment: a #GstSegment structure.
570 * @format: the format of the segment.
571 * @position: the position in the segment
573 * Translate @position to the total running time using the currently configured
574 * segment. Position is a value between @segment start and stop time.
576 * This function is typically used by elements that need to synchronize to the
577 * global clock in a pipeline. The running time is a constantly increasing value
578 * starting from 0. When gst_segment_init() is called, this value will reset to
581 * This function returns -1 if the position is outside of @segment start and stop.
583 * Returns: the position as the total running time or -1 when an invalid position
587 gst_segment_to_running_time (const GstSegment * segment, GstFormat format,
592 g_return_val_if_fail (segment != NULL, -1);
593 g_return_val_if_fail (segment->format == format, -1);
595 /* before the segment boundary */
596 if (G_UNLIKELY (position < segment->start)) {
597 GST_DEBUG ("position(%" G_GUINT64_FORMAT ") < start(%" G_GUINT64_FORMAT
598 ")", position, segment->start);
601 /* after the segment boundary */
602 if (G_UNLIKELY (segment->stop != -1 && position > segment->stop)) {
603 GST_DEBUG ("position(%" G_GUINT64_FORMAT ") > stop(%" G_GUINT64_FORMAT
604 ")", position, segment->stop);
608 if (gst_segment_to_running_time_full (segment, format, position,
617 * @segment: a #GstSegment structure.
618 * @format: the format of the segment.
619 * @start: the start position in the segment
620 * @stop: the stop position in the segment
621 * @clip_start: (out) (allow-none): the clipped start position in the segment
622 * @clip_stop: (out) (allow-none): the clipped stop position in the segment
624 * Clip the given @start and @stop values to the segment boundaries given
625 * in @segment. @start and @stop are compared and clipped to @segment
626 * start and stop values.
628 * If the function returns %FALSE, @start and @stop are known to fall
629 * outside of @segment and @clip_start and @clip_stop are not updated.
631 * When the function returns %TRUE, @clip_start and @clip_stop will be
632 * updated. If @clip_start or @clip_stop are different from @start or @stop
633 * respectively, the region fell partially in the segment.
635 * Note that when @stop is -1, @clip_stop will be set to the end of the
636 * segment. Depending on the use case, this may or may not be what you want.
638 * Returns: %TRUE if the given @start and @stop times fall partially or
639 * completely in @segment, %FALSE if the values are completely outside
643 gst_segment_clip (const GstSegment * segment, GstFormat format, guint64 start,
644 guint64 stop, guint64 * clip_start, guint64 * clip_stop)
646 g_return_val_if_fail (segment != NULL, FALSE);
647 g_return_val_if_fail (segment->format == format, FALSE);
649 /* if we have a stop position and a valid start and start is bigger,
650 * we're outside of the segment */
651 if (G_UNLIKELY (segment->stop != -1 && start != -1 && start >= segment->stop))
654 /* if a stop position is given and is before the segment start,
655 * we're outside of the segment. Special case is were start
656 * and stop are equal to the segment start. In that case we
657 * are inside the segment. */
658 if (G_UNLIKELY (stop != -1 && (stop < segment->start || (start != stop
659 && stop == segment->start))))
666 *clip_start = MAX (start, segment->start);
671 *clip_stop = segment->stop;
672 else if (segment->stop == -1)
675 *clip_stop = MIN (stop, segment->stop);
682 * gst_segment_to_position:
683 * @segment: a #GstSegment structure.
684 * @format: the format of the segment.
685 * @running_time: the running_time in the segment
687 * Convert @running_time into a position in the segment so that
688 * gst_segment_to_running_time() with that position returns @running_time.
690 * Returns: the position in the segment for @running_time. This function returns
691 * -1 when @running_time is -1 or when it is not inside @segment.
694 gst_segment_to_position (const GstSegment * segment, GstFormat format,
695 guint64 running_time)
698 guint64 start, stop, base;
701 if (G_UNLIKELY (running_time == -1))
704 g_return_val_if_fail (segment != NULL, -1);
705 g_return_val_if_fail (segment->format == format, FALSE);
707 base = segment->base;
709 /* this running_time was for a previous segment */
710 if (running_time < base)
713 /* start by subtracting the base time */
714 result = running_time - base;
716 /* move into the segment at the right rate */
717 abs_rate = ABS (segment->rate);
718 if (G_UNLIKELY (abs_rate != 1.0))
719 result = ceil (result * abs_rate);
721 start = segment->start;
722 stop = segment->stop;
724 if (G_LIKELY (segment->rate > 0.0)) {
725 /* bring to corrected position in segment */
726 result += start + segment->offset;
728 /* outside of the segment boundary stop */
729 if (G_UNLIKELY (stop != -1 && result > stop))
732 /* cannot continue if no stop position set or outside of
734 if (G_UNLIKELY (stop == -1 || result + start > stop))
737 /* bring to corrected position in segment */
738 result = stop - result - segment->offset;
744 * gst_segment_set_running_time:
745 * @segment: a #GstSegment structure.
746 * @format: the format of the segment.
747 * @running_time: the running_time in the segment
749 * Adjust the start/stop and base values of @segment such that the next valid
750 * buffer will be one with @running_time.
752 * Returns: %TRUE if the segment could be updated successfully. If %FALSE is
753 * returned, @running_time is -1 or not in @segment.
756 gst_segment_set_running_time (GstSegment * segment, GstFormat format,
757 guint64 running_time)
762 /* start by bringing the running_time into the segment position */
763 position = gst_segment_to_position (segment, format, running_time);
765 /* we must have a valid position now */
766 if (G_UNLIKELY (position == -1))
769 start = segment->start;
770 stop = segment->stop;
772 if (G_LIKELY (segment->rate > 0.0)) {
773 /* update the start and time values */
776 /* reverse, update stop */
779 /* and base time is exactly the running time */
780 segment->time = gst_segment_to_stream_time (segment, format, start);
781 segment->start = start;
782 segment->stop = stop;
783 segment->base = running_time;
789 * gst_segment_offset_running_time:
790 * @segment: a #GstSegment structure.
791 * @format: the format of the segment.
792 * @offset: the offset to apply in the segment
794 * Adjust the values in @segment so that @offset is applied to all
795 * future running-time calculations.
799 * Returns: %TRUE if the segment could be updated successfully. If %FALSE is
800 * returned, @offset is not in @segment.
803 gst_segment_offset_running_time (GstSegment * segment, GstFormat format,
806 g_return_val_if_fail (segment != NULL, FALSE);
807 g_return_val_if_fail (segment->format == format, FALSE);
813 /* positive offset, we can simply apply to the base time */
814 segment->base += offset;
817 /* negative offset, first try to subtract from base */
818 if (segment->base > offset) {
819 segment->base -= offset;
823 /* subtract all from segment.base, remainder in offset */
824 offset -= segment->base;
826 position = gst_segment_to_position (segment, format, offset);
830 segment->offset = position - segment->start;
837 * gst_segment_is_equal:
838 * @s0: a #GstSegment structure.
839 * @s1: a #GstSegment structure.
841 * Checks for two segments being equal. Equality here is defined
842 * as perfect equality, including floating point values.
846 * Returns: %TRUE if the segments are equal, %FALSE otherwise.
849 gst_segment_is_equal (const GstSegment * s0, const GstSegment * s1)
851 if (s0->flags != s1->flags)
853 if (s0->rate != s1->rate)
855 if (s0->applied_rate != s1->applied_rate)
857 if (s0->format != s1->format)
859 if (s0->base != s1->base)
861 if (s0->offset != s1->offset)
863 if (s0->start != s1->start)
865 if (s0->stop != s1->stop)
867 if (s0->time != s1->time)
869 if (s0->position != s1->position)
871 if (s0->duration != s1->duration)