gstreamer/gst/gstsegment.h
Jan Schmidt f3756af07b segment: Add new skip flags for clarifying trick mode playback.
Add GST_SEEK_FLAG_TRICKMODE_KEY_UNITS and
GST_SEEK_FLAG_TRICKMODE_NO_AUDIO, and rename GST_SEEK_FLAG_SKIP
to GST_SEEK_FLAG_TRICKMODE (with backwards compat define).

Do the same for the corresponding SEGMENT flags.

https://bugzilla.gnome.org/show_bug.cgi?id=735666
2015-01-27 01:51:58 +11:00

237 lines
10 KiB
C

/* GStreamer
* Copyright (C) 2005 Wim Taymans <wim@fluendo.com>
*
* gstsegment.h: Header for GstSegment subsystem
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef __GST_SEGMENT_H__
#define __GST_SEGMENT_H__
#include <gst/gstformat.h>
G_BEGIN_DECLS
#define GST_TYPE_SEGMENT (gst_segment_get_type())
typedef struct _GstSegment GstSegment;
/**
* GstSeekType:
* @GST_SEEK_TYPE_NONE: no change in position is required
* @GST_SEEK_TYPE_SET: absolute position is requested
* @GST_SEEK_TYPE_END: relative position to duration is requested
*
* The different types of seek events. When constructing a seek event with
* gst_event_new_seek() or when doing gst_segment_do_seek ().
*/
typedef enum {
/* one of these */
GST_SEEK_TYPE_NONE = 0,
GST_SEEK_TYPE_SET = 1,
GST_SEEK_TYPE_END = 2
} GstSeekType;
/**
* GstSeekFlags:
* @GST_SEEK_FLAG_NONE: no flag
* @GST_SEEK_FLAG_FLUSH: flush pipeline
* @GST_SEEK_FLAG_ACCURATE: accurate position is requested, this might
* be considerably slower for some formats.
* @GST_SEEK_FLAG_KEY_UNIT: seek to the nearest keyframe. This might be
* faster but less accurate.
* @GST_SEEK_FLAG_SEGMENT: perform a segment seek.
* @GST_SEEK_FLAG_TRICKMODE: when doing fast forward or fast reverse playback, allow
* elements to skip frames instead of generating all
* frames. (Since: 1.6)
* @GST_SEEK_FLAG_SNAP_BEFORE: go to a location before the requested position,
* if KEY_UNIT this means the keyframe at or before the
* requested position the one at or before the seek target.
* @GST_SEEK_FLAG_SNAP_AFTER: go to a location after the requested position,
* if KEY_UNIT this means the keyframe at of after the
* requested position.
* @GST_SEEK_FLAG_SNAP_NEAREST: go to a position near the requested position,
* if KEY_UNIT this means the keyframe closest to the
* requested position, if both keyframes are at an equal
* distance, behaves like SNAP_BEFORE.
* @GST_SEEK_FLAG_TRICKMODE_KEY_UNITS: when doing fast forward or fast reverse
* playback, request that elements only decode keyframes
* and skip all other content, for formats that have
* keyframes. (Since: 1.6)
* @GST_SEEK_FLAG_TRICKMODE_NO_AUDIO: when doing fast forward or fast reverse
* playback, request that audio decoder elements skip
* decoding and output only gap events or silence. (Since: 1.6)
* @GST_SEEK_FLAG_SKIP: Deprecated backward compatibility flag, replaced
* by @GST_SEEK_FLAG_TRICKMODE
*
* Flags to be used with gst_element_seek() or gst_event_new_seek(). All flags
* can be used together.
*
* A non flushing seek might take some time to perform as the currently
* playing data in the pipeline will not be cleared.
*
* An accurate seek might be slower for formats that don't have any indexes
* or timestamp markers in the stream. Specifying this flag might require a
* complete scan of the file in those cases.
*
* When performing a segment seek: after the playback of the segment completes,
* no EOS will be emitted by the element that performed the seek, but a
* #GST_MESSAGE_SEGMENT_DONE message will be posted on the bus by the element.
* When this message is posted, it is possible to send a new seek event to
* continue playback. With this seek method it is possible to perform seamless
* looping or simple linear editing.
*
* When doing fast forward (rate > 1.0) or fast reverse (rate < -1.0) trickmode
* playback, the @GST_SEEK_FLAG_TRICKMODE flag can be used to instruct decoders
* and demuxers to adjust the playback rate by skipping frames. This can improve
* performance and decrease CPU usage because not all frames need to be decoded.
*
* Beyond that, the @GST_SEEK_FLAG_TRICKMODE_KEY_UNITS flag can be used to
* request that decoders skip all frames except key units, and
* @GST_SEEK_FLAG_TRICKMODE_NO_AUDIO flags can be used to request that audio
* decoders do no decoding at all, and simple output silence.
*
* The @GST_SEEK_FLAG_SNAP_BEFORE flag can be used to snap to the previous
* relevant location, and the @GST_SEEK_FLAG_SNAP_AFTER flag can be used to
* select the next relevant location. If KEY_UNIT is specified, the relevant
* location is a keyframe. If both flags are specified, the nearest of these
* locations will be selected. If none are specified, the implementation is
* free to select whichever it wants.
* The before and after here are in running time, so when playing backwards,
* the next location refers to the one that will played in next, and not the
* one that is located after in the actual source stream.
*
* Also see part-seeking.txt in the GStreamer design documentation for more
* details on the meaning of these flags and the behaviour expected of
* elements that handle them.
*/
typedef enum {
GST_SEEK_FLAG_NONE = 0,
GST_SEEK_FLAG_FLUSH = (1 << 0),
GST_SEEK_FLAG_ACCURATE = (1 << 1),
GST_SEEK_FLAG_KEY_UNIT = (1 << 2),
GST_SEEK_FLAG_SEGMENT = (1 << 3),
GST_SEEK_FLAG_TRICKMODE = (1 << 4),
/* FIXME 2.0: Remove _SKIP flag,
* which was kept for backward compat when _TRICKMODE was added */
GST_SEEK_FLAG_SKIP = (1 << 4),
GST_SEEK_FLAG_SNAP_BEFORE = (1 << 5),
GST_SEEK_FLAG_SNAP_AFTER = (1 << 6),
GST_SEEK_FLAG_SNAP_NEAREST = GST_SEEK_FLAG_SNAP_BEFORE | GST_SEEK_FLAG_SNAP_AFTER,
/* Careful to restart next flag with 1<<7 here */
GST_SEEK_FLAG_TRICKMODE_KEY_UNITS = (1 << 7),
GST_SEEK_FLAG_TRICKMODE_NO_AUDIO = (1 << 8),
} GstSeekFlags;
/**
* GstSegmentFlags:
* @GST_SEGMENT_FLAG_NONE: no flags
* @GST_SEGMENT_FLAG_RESET: reset the pipeline running_time to the segment
* running_time
* @GST_SEGMENT_FLAG_TRICKMODE: perform skip playback (Since: 1.6)
* @GST_SEGMENT_FLAG_SEGMENT: send SEGMENT_DONE instead of EOS
* @GST_SEGMENT_FLAG_TRICKMODE_KEY_UNITS: Decode only keyframes, where
* possible (Since: 1.6)
* @GST_SEGMENT_FLAG_TRICKMODE_NO_AUDIO: Do not decode any audio, where
* possible (Since: 1.6)
* @GST_SEGMENT_FLAG_SKIP: Deprecated backward compatibility flag, replaced
* by @GST_SEGMENT_FLAG_TRICKMODE
*
* Flags for the GstSegment structure. Currently mapped to the corresponding
* values of the seek flags.
*/
/* Note: update gst_segment_do_seek() when adding new flags here */
typedef enum { /*< flags >*/
GST_SEGMENT_FLAG_NONE = GST_SEEK_FLAG_NONE,
GST_SEGMENT_FLAG_RESET = GST_SEEK_FLAG_FLUSH,
GST_SEGMENT_FLAG_TRICKMODE = GST_SEEK_FLAG_TRICKMODE,
/* FIXME 2.0: Remove _SKIP flag,
* which was kept for backward compat when _TRICKMODE was added */
GST_SEGMENT_FLAG_SKIP = GST_SEEK_FLAG_TRICKMODE,
GST_SEGMENT_FLAG_SEGMENT = GST_SEEK_FLAG_SEGMENT,
GST_SEGMENT_FLAG_TRICKMODE_KEY_UNITS = GST_SEEK_FLAG_TRICKMODE_KEY_UNITS,
GST_SEGMENT_FLAG_TRICKMODE_NO_AUDIO = GST_SEEK_FLAG_TRICKMODE_NO_AUDIO
} GstSegmentFlags;
/**
* GstSegment:
* @flags: flags for this segment
* @rate: the rate of the segment
* @applied_rate: the already applied rate to the segment
* @format: the format of the segment values
* @base: the base of the segment
* @offset: the offset to apply to @start or @stop
* @start: the start of the segment
* @stop: the stop of the segment
* @time: the stream time of the segment
* @position: the position in the segment
* @duration: the duration of the segment
*
* A helper structure that holds the configured region of
* interest in a media file.
*/
struct _GstSegment {
/*< public >*/
GstSegmentFlags flags;
gdouble rate;
gdouble applied_rate;
GstFormat format;
guint64 base;
guint64 offset;
guint64 start;
guint64 stop;
guint64 time;
guint64 position;
guint64 duration;
/* < private > */
gpointer _gst_reserved[GST_PADDING];
};
GType gst_segment_get_type (void);
GstSegment * gst_segment_new (void) G_GNUC_MALLOC;
GstSegment * gst_segment_copy (const GstSegment *segment) G_GNUC_MALLOC;
void gst_segment_copy_into (const GstSegment *src, GstSegment *dest);
void gst_segment_free (GstSegment *segment);
void gst_segment_init (GstSegment *segment, GstFormat format);
guint64 gst_segment_to_stream_time (const GstSegment *segment, GstFormat format, guint64 position);
guint64 gst_segment_to_running_time (const GstSegment *segment, GstFormat format, guint64 position);
guint64 gst_segment_to_position (const GstSegment *segment, GstFormat format, guint64 running_time);
gboolean gst_segment_set_running_time (GstSegment *segment, GstFormat format, guint64 running_time);
gboolean gst_segment_offset_running_time (GstSegment *segment, GstFormat format, gint64 offset);
gboolean gst_segment_clip (const GstSegment *segment, GstFormat format, guint64 start,
guint64 stop, guint64 *clip_start, guint64 *clip_stop);
gboolean gst_segment_do_seek (GstSegment * segment, gdouble rate,
GstFormat format, GstSeekFlags flags,
GstSeekType start_type, guint64 start,
GstSeekType stop_type, guint64 stop, gboolean * update);
G_END_DECLS
#endif /* __GST_SEGMENT_H__ */