Package org.freedesktop.gstreamer.gst

Enum Class SeekFlags

java.lang.Object

java.lang.Enum<SeekFlags>

org.freedesktop.gstreamer.gst.SeekFlags

All Implemented Interfaces:

Enumeration, Serializable, Comparable<SeekFlags>, Constable

@Generated("io.github.jwharm.JavaGI")
public enum SeekFlags
extends Enum<SeekFlags>
implements Enumeration

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 MessageType.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 only changing the playback rate and not the direction, the INSTANT_RATE_CHANGE flag can be used for a non-flushing seek to signal that the rate change should be applied immediately. This requires special support in the seek handlers (e.g. demuxers) and any elements synchronizing to the clock, and in general can't work in all cases (for example UDP streaming where the delivery rate is controlled by a remote server). The instant-rate-change mode supports changing the trickmode-related GST_SEEK_ flags, but can't be used in conjunction with other seek flags that affect the new playback position - as the playback position will not be changing.

When doing fast forward (rate > 1.0) or fast reverse (rate < -1.0) trickmode playback, the 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 TRICKMODE_KEY_UNITS flag can be used to request that decoders skip all frames except key units, and TRICKMODE_NO_AUDIO flags can be used to request that audio decoders do no decoding at all, and simple output silence.

The SNAP_BEFORE flag can be used to snap to the previous relevant location, and the 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.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
ACCURATE	accurate position is requested, this might be considerably slower for some formats.
FLUSH	flush pipeline
INSTANT_RATE_CHANGE	Signals that a rate change should be applied immediately.
KEY_UNIT	seek to the nearest keyframe.
NONE	no flag
SEGMENT	perform a segment seek.
SNAP_AFTER	go to a location after the requested position, if KEY_UNIT this means the keyframe at of after the requested position.
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.
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.
TRICKMODE	when doing fast forward or fast reverse playback, allow elements to skip frames instead of generating all frames.
TRICKMODE_FORWARD_PREDICTED	When doing fast forward or fast reverse playback, request that elements only decode keyframes and forward predicted frames and skip all other content (for example B-Frames), for formats that have keyframes and forward predicted frames.
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.
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.

Field Summary

Fields

Modifier and Type	Field	Description
static final SeekFlags	SKIP	Deprecated backward compatibility flag, replaced by TRICKMODE

Method Summary

Modifier and Type	Method	Description
static Type	getType()	Get the GType of the SeekFlags class
int	getValue()	Get the numeric value of this enum
static SeekFlags	of(int value)	Create a new SeekFlags for the provided value
static SeekFlags	valueOf(String name)	Returns the enum constant of this class with the specified name.
static SeekFlags[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

NONE

public static final SeekFlags NONE

no flag

FLUSH

public static final SeekFlags FLUSH

flush pipeline

ACCURATE

public static final SeekFlags ACCURATE

accurate position is requested, this might be considerably slower for some formats.

KEY_UNIT

public static final SeekFlags KEY_UNIT

seek to the nearest keyframe. This might be faster but less accurate.

SEGMENT

public static final SeekFlags SEGMENT

perform a segment seek.

TRICKMODE

public static final SeekFlags TRICKMODE

when doing fast forward or fast reverse playback, allow elements to skip frames instead of generating all frames. (Since: 1.6)

SNAP_BEFORE

public static final SeekFlags 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.

SNAP_AFTER

public static final SeekFlags SNAP_AFTER

go to a location after the requested position, if KEY_UNIT this means the keyframe at of after the requested position.

SNAP_NEAREST

public static final SeekFlags 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.

TRICKMODE_KEY_UNITS

public static final SeekFlags 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)

TRICKMODE_NO_AUDIO

public static final SeekFlags 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)

TRICKMODE_FORWARD_PREDICTED

public static final SeekFlags TRICKMODE_FORWARD_PREDICTED

When doing fast forward or fast reverse playback, request that elements only decode keyframes and forward predicted frames and skip all other content (for example B-Frames), for formats that have keyframes and forward predicted frames. (Since: 1.18)

INSTANT_RATE_CHANGE

public static final SeekFlags INSTANT_RATE_CHANGE

Signals that a rate change should be applied immediately. Only valid if start/stop position are GST_CLOCK_TIME_NONE, the playback direction does not change and the seek is not flushing. (Since: 1.18)

Field Details

SKIP

public static final SeekFlags SKIP

Deprecated backward compatibility flag, replaced by TRICKMODE

Method Details

values

public static SeekFlags[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static SeekFlags valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null

of

public static SeekFlags of(int value)

Create a new SeekFlags for the provided value

Parameters:

value - the bitfield value

Returns:

the bitfield for the provided value

getValue

public int getValue()

Get the numeric value of this enum

Specified by:

getValue in interface Enumeration

Returns:

the enum value

getType

public static Type getType()

Get the GType of the SeekFlags class

Returns:

the GType