GI.Gst.Structs.Event

The event class provides factory methods to construct events for sending and functions to query (parse) received events.

Events are usually created with gst_event_new_*() which takes event-type specific parameters as arguments. To send an event application will usually use elementSendEvent and elements will use padSendEvent or padPushEvent. The event should be unreffed with gst_event_unref() if it has not been sent.

Events that have been received can be parsed with their respective gst_event_parse_*() functions. It is valid to pass Nothing for unwanted details.

Events are passed between elements in parallel to the data stream. Some events are serialized with buffers, others are not. Some events only travel downstream, others only upstream. Some events can travel both upstream and downstream.

The events are used to signal special conditions in the datastream such as EOS (end of stream) or the start of a new stream-segment. Events are also used to flush the pipeline of any pending data.

Most of the event API is used inside plugins. Applications usually only construct and use seek events. To do that eventNewSeek is used to create a seek event. It takes the needed parameters to specify seeking time and mode.

C code

 GstEvent *event;
 gboolean result;
 ...
 // construct a seek event to play the media from second 2 to 5, flush
 // the pipeline to decrease latency.
 event = gst_event_new_seek (1.0,
    GST_FORMAT_TIME,
    GST_SEEK_FLAG_FLUSH,
    GST_SEEK_TYPE_SET, 2 * GST_SECOND,
    GST_SEEK_TYPE_SET, 5 * GST_SECOND);
 ...
 result = gst_element_send_event (pipeline, event);
 if (!result)
   g_warning ("seek failed");
 ...

Exported types

newtype Event

Memory-managed wrapper type.

Constructors

Event (ManagedPtr Event)

Instances

Eq Event

Defined in GI.Gst.Structs.Event

Methods

(==) :: Event -> Event -> Bool

(/=) :: Event -> Event -> Bool

GBoxed Event

Defined in GI.Gst.Structs.Event

ManagedPtrNewtype Event

Defined in GI.Gst.Structs.Event

Methods

toManagedPtr :: Event -> ManagedPtr Event

TypedObject Event

Defined in GI.Gst.Structs.Event

Methods

glibType :: IO GType

HasParentTypes Event

Defined in GI.Gst.Structs.Event

tag ~ 'AttrSet => Constructible Event tag

Defined in GI.Gst.Structs.Event

Methods

new :: MonadIO m => (ManagedPtr Event -> Event) -> [AttrOp Event tag] -> m Event

IsGValue (Maybe Event)

Convert Event to and from GValue. See toGValue and fromGValue.

Defined in GI.Gst.Structs.Event

Methods

gvalueGType_ :: IO GType

gvalueSet_ :: Ptr GValue -> Maybe Event -> IO ()

gvalueGet_ :: Ptr GValue -> IO (Maybe Event)

type ParentTypes Event

Defined in GI.Gst.Structs.Event

type ParentTypes Event = '[] :: [Type]

newZeroEvent :: MonadIO m => m Event

Construct a Event struct initialized to zero.

Methods

Click to display all available methods, including inherited ones

Methods

copySegment, hasName, hasNameId, parseBufferSize, parseCaps, parseFlushStop, parseGap, parseGapFlags, parseGroupId, parseInstantRateChange, parseInstantRateSyncTime, parseLatency, parseProtection, parseQos, parseSeek, parseSeekTrickmodeInterval, parseSegment, parseSegmentDone, parseSelectStreams, parseSinkMessage, parseStep, parseStream, parseStreamCollection, parseStreamFlags, parseStreamGroupDone, parseStreamStart, parseTag, parseToc, parseTocSelect, writableStructure.

Getters

getRunningTimeOffset, getSeqnum, getStructure.

Setters

setGapFlags, setGroupId, setRunningTimeOffset, setSeekTrickmodeInterval, setSeqnum, setStream, setStreamFlags.

copySegment

eventCopySegment

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to parse

-> Segment

segment: a pointer to a Segment

-> m ()

Parses a segment event and copies the Segment into the location given by segment.

getRunningTimeOffset

eventGetRunningTimeOffset

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: A Event.

-> m Int64

Returns: The event's running time offset

MT safe.

Retrieve the accumulated running time offset of the event.

Events passing through GstPads that have a running time offset set via padSetOffset will get their offset adjusted according to the pad's offset.

If the event contains any information that related to the running time, this information will need to be updated before usage with this offset.

Since: 1.4

getSeqnum

eventGetSeqnum

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: A Event.

-> m Word32

Returns: The event's sequence number.

MT safe.

Retrieve the sequence number of a event.

Events have ever-incrementing sequence numbers, which may also be set explicitly via eventSetSeqnum. Sequence numbers are typically used to indicate that a event corresponds to some other set of events or messages, for example an EOS event corresponding to a SEEK event. It is considered good practice to make this correspondence when possible, though it is not required.

Note that events and messages share the same sequence number incrementor; two events or messages will never have the same sequence number unless that correspondence was made explicitly.

getStructure

eventGetStructure

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The Event.

-> m (Maybe Structure)

Returns: The structure of the event. The structure is still owned by the event, which means that you should not free it and that the pointer becomes invalid when you free the event.

MT safe.

Access the structure of the event.

hasName

eventHasName

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The Event.

-> Text

name: name to check

-> m Bool

Returns: True if name matches the name of the event structure.

Checks if event has the given name. This function is usually used to check the name of a custom event.

hasNameId

eventHasNameId

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The Event.

-> Word32

name: name to check as a GQuark

-> m Bool

Returns: True if name matches the name of the event structure.

Checks if event has the given name. This function is usually used to check the name of a custom event.

Since: 1.18

newBufferSize

eventNewBufferSize

Arguments

:: (HasCallStack, MonadIO m)

=> Format

format: buffer format

-> Int64

minsize: minimum buffer size

-> Int64

maxsize: maximum buffer size

-> Bool

async: thread behavior

-> m Event

Returns: a new Event

Create a new buffersize event. The event is sent downstream and notifies elements that they should provide a buffer of the specified dimensions.

When the async flag is set, a thread boundary is preferred.

newCaps

eventNewCaps

Arguments

:: (HasCallStack, MonadIO m)

=> Caps

caps: a Caps

-> m Event

Returns: the new CAPS event.

Create a new CAPS event for caps. The caps event can only travel downstream synchronized with the buffer flow and contains the format of the buffers that will follow after the event.

newCustom

eventNewCustom

Arguments

:: (HasCallStack, MonadIO m)

=> EventType

type: The type of the new event

-> Structure

structure: the structure for the event. The event will take ownership of the structure.

-> m Event

Returns: the new custom event.

Create a new custom-typed event. This can be used for anything not handled by other event-specific functions to pass an event to another element.

Make sure to allocate an event type with the GST_EVENT_MAKE_TYPE macro, assigning a free number and filling in the correct direction and serialization flags.

New custom events can also be created by subclassing the event type if needed.

newEos

eventNewEos

Arguments

:: (HasCallStack, MonadIO m)

=> m Event

Returns: the new EOS event.

Create a new EOS event. The eos event can only travel downstream synchronized with the buffer flow. Elements that receive the EOS event on a pad can return GST_FLOW_EOS as a FlowReturn when data after the EOS event arrives.

The EOS event will travel down to the sink elements in the pipeline which will then post the GST_MESSAGE_EOS on the bus after they have finished playing any buffered data.

When all sinks have posted an EOS message, an EOS message is forwarded to the application.

The EOS event itself will not cause any state transitions of the pipeline.

newFlushStart

eventNewFlushStart

Arguments

:: (HasCallStack, MonadIO m)

=> m Event

Returns: a new flush start event.

Allocate a new flush start event. The flush start event can be sent upstream and downstream and travels out-of-bounds with the dataflow.

It marks pads as being flushing and will make them return GST_FLOW_FLUSHING when used for data flow with padPush, padChain, padGetRange and padPullRange. Any event (except a GST_EVENT_FLUSH_STOP) received on a flushing pad will return False immediately.

Elements should unlock any blocking functions and exit their streaming functions as fast as possible when this event is received.

This event is typically generated after a seek to flush out all queued data in the pipeline so that the new media is played as soon as possible.

newFlushStop

eventNewFlushStop

Arguments

:: (HasCallStack, MonadIO m)

=> Bool

resetTime: if time should be reset

-> m Event

Returns: a new flush stop event.

Allocate a new flush stop event. The flush stop event can be sent upstream and downstream and travels serialized with the dataflow. It is typically sent after sending a FLUSH_START event to make the pads accept data again.

Elements can process this event synchronized with the dataflow since the preceding FLUSH_START event stopped the dataflow.

This event is typically generated to complete a seek and to resume dataflow.

newGap

eventNewGap

Arguments

:: (HasCallStack, MonadIO m)

=> Word64

timestamp: the start time (pts) of the gap

-> Word64

duration: the duration of the gap

-> m Event

Returns: the new GAP event.

Create a new GAP event. A gap event can be thought of as conceptually equivalent to a buffer to signal that there is no data for a certain amount of time. This is useful to signal a gap to downstream elements which may wait for data, such as muxers or mixers or overlays, especially for sparse streams such as subtitle streams.

newInstantRateChange

eventNewInstantRateChange

Arguments

:: (HasCallStack, MonadIO m)

=> Double

rateMultiplier: the multiplier to be applied to the playback rate

-> [SegmentFlags]

newFlags: A new subset of segment flags to replace in segments

-> m Event

Returns: the new instant-rate-change event.

Create a new instant-rate-change event. This event is sent by seek handlers (e.g. demuxers) when receiving a seek with the SeekFlagsInstantRateChange and signals to downstream elements that the playback rate in the existing segment should be immediately multiplied by the rateMultiplier factor.

The flags provided replace any flags in the existing segment, for the flags within the SEGMENT_INSTANT_FLAGS set. Other GstSegmentFlags are ignored and not transferred in the event.

Since: 1.18

newInstantRateSyncTime

eventNewInstantRateSyncTime

Arguments

:: (HasCallStack, MonadIO m)

=> Double

rateMultiplier: the new playback rate multiplier to be applied

-> Word64

runningTime: Running time when the rate change should be applied

-> Word64

upstreamRunningTime: The upstream-centric running-time when the rate change should be applied.

-> m Event

Returns: the new instant-rate-sync-time event.

Create a new instant-rate-sync-time event. This event is sent by the pipeline to notify elements handling the instant-rate-change event about the running-time when the new rate should be applied. The running time may be in the past when elements handle this event, which can lead to switching artifacts. The magnitude of those depends on the exact timing of event delivery to each element and the magnitude of the change in playback rate being applied.

The runningTime and upstreamRunningTime are the same if this is the first instant-rate adjustment, but will differ for later ones to compensate for the accumulated offset due to playing at a rate different to the one indicated in the playback segments.

Since: 1.18

newLatency

eventNewLatency

Arguments

:: (HasCallStack, MonadIO m)

=> Word64

latency: the new latency value

-> m Event

Returns: a new Event

Create a new latency event. The event is sent upstream from the sinks and notifies elements that they should add an additional latency to the running time before synchronising against the clock.

The latency is mostly used in live sinks and is always expressed in the time format.

newNavigation

eventNewNavigation

Arguments

:: (HasCallStack, MonadIO m)

=> Structure

structure: description of the event. The event will take ownership of the structure. See GstNavigation for more specific constructors.

-> m Event

Returns: a new Event

Create a new navigation event from the given description.

newProtection

eventNewProtection

Arguments

:: (HasCallStack, MonadIO m)

=> Text

systemId: a string holding a UUID that uniquely identifies a protection system.

-> Buffer

data: a Buffer holding protection system specific information. The reference count of the buffer will be incremented by one.

-> Text

origin: a string indicating where the protection information carried in the event was extracted from. The allowed values of this string will depend upon the protection scheme.

-> m Event

Returns: a GST_EVENT_PROTECTION event.

Creates a new event containing information specific to a particular protection system (uniquely identified by systemId), by which that protection system can acquire key(s) to decrypt a protected stream.

In order for a decryption element to decrypt media protected using a specific system, it first needs all the protection system specific information necessary to acquire the decryption key(s) for that stream. The functions defined here enable this information to be passed in events from elements that extract it (e.g., ISOBMFF demuxers, MPEG DASH demuxers) to protection decrypter elements that use it.

Events containing protection system specific information are created using gst_event_new_protection, and they can be parsed by downstream elements using gst_event_parse_protection.

In Common Encryption, protection system specific information may be located within ISOBMFF files, both in movie (moov) boxes and movie fragment (moof) boxes; it may also be contained in ContentProtection elements within MPEG DASH MPDs. The events created by gst_event_new_protection contain data identifying from which of these locations the encapsulated protection system specific information originated. This origin information is required as some protection systems use different encodings depending upon where the information originates.

The events returned by eventNewProtection are implemented in such a way as to ensure that the most recently-pushed protection info event of a particular origin and systemId will be stuck to the output pad of the sending element.

Since: 1.6

newQos

eventNewQos

Arguments

:: (HasCallStack, MonadIO m)

=> QOSType

type: the QoS type

-> Double

proportion: the proportion of the qos message

-> Int64

diff: The time difference of the last Clock sync

-> Word64

timestamp: The timestamp of the buffer

-> m Event

Returns: a new QOS event.

Allocate a new qos event with the given values. The QOS event is generated in an element that wants an upstream element to either reduce or increase its rate because of high/low CPU load or other resource usage such as network performance or throttling. Typically sinks generate these events for each buffer they receive.

type indicates the reason for the QoS event. GST_QOS_TYPE_OVERFLOW is used when a buffer arrived in time or when the sink cannot keep up with the upstream datarate. GST_QOS_TYPE_UNDERFLOW is when the sink is not receiving buffers fast enough and thus has to drop late buffers. GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited by the application, for example to reduce power consumption.

proportion indicates the real-time performance of the streaming in the element that generated the QoS event (usually the sink). The value is generally computed based on more long term statistics about the streams timestamps compared to the clock. A value < 1.0 indicates that the upstream element is producing data faster than real-time. A value > 1.0 indicates that the upstream element is not producing data fast enough. 1.0 is the ideal proportion value. The proportion value can safely be used to lower or increase the quality of the element.

diff is the difference against the clock in running time of the last buffer that caused the element to generate the QOS event. A negative value means that the buffer with timestamp arrived in time. A positive value indicates how late the buffer with timestamp was. When throttling is enabled, diff will be set to the requested throttling interval.

timestamp is the timestamp of the last buffer that cause the element to generate the QOS event. It is expressed in running time and thus an ever increasing value.

The upstream element can use the diff and timestamp values to decide whether to process more buffers. For positive diff, all buffers with timestamp <= timestamp + diff will certainly arrive late in the sink as well. A (negative) diff value so that timestamp + diff would yield a result smaller than 0 is not allowed.

The application can use general event probes to intercept the QoS event and implement custom application specific QoS handling.

newReconfigure

eventNewReconfigure

Arguments

:: (HasCallStack, MonadIO m)

=> m Event

Returns: a new Event

Create a new reconfigure event. The purpose of the reconfigure event is to travel upstream and make elements renegotiate their caps or reconfigure their buffer pools. This is useful when changing properties on elements or changing the topology of the pipeline.

newSeek

eventNewSeek

Arguments

:: (HasCallStack, MonadIO m)

=> Double

rate: The new playback rate

-> Format

format: The format of the seek values

-> [SeekFlags]

flags: The optional seek flags

-> SeekType

startType: The type and flags for the new start position

-> Int64

start: The value of the new start position

-> SeekType

stopType: The type and flags for the new stop position

-> Int64

stop: The value of the new stop position

-> m Event

Returns: a new seek event.

Allocate a new seek event with the given parameters.

The seek event configures playback of the pipeline between start to stop at the speed given in rate, also called a playback segment. The start and stop values are expressed in format.

A rate of 1.0 means normal playback rate, 2.0 means double speed. Negatives values means backwards playback. A value of 0.0 for the rate is not allowed and should be accomplished instead by PAUSING the pipeline.

A pipeline has a default playback segment configured with a start position of 0, a stop position of -1 and a rate of 1.0. The currently configured playback segment can be queried with GST_QUERY_SEGMENT.

startType and stopType specify how to adjust the currently configured start and stop fields in playback segment. Adjustments can be made relative or absolute to the last configured values. A type of GST_SEEK_TYPE_NONE means that the position should not be updated.

When the rate is positive and start has been updated, playback will start from the newly configured start position.

For negative rates, playback will start from the newly configured stop position (if any). If the stop position is updated, it must be different from -1 (CLOCK_TIME_NONE) for negative rates.

It is not possible to seek relative to the current playback position, to do this, PAUSE the pipeline, query the current playback position with GST_QUERY_POSITION and update the playback segment current position with a GST_SEEK_TYPE_SET to the desired position.

newSegment

eventNewSegment

Arguments

:: (HasCallStack, MonadIO m)

=> Segment

segment: a Segment

-> m Event

Returns: the new SEGMENT event.

Create a new SEGMENT event for segment. The segment event can only travel downstream synchronized with the buffer flow and contains timing information and playback properties for the buffers that will follow.

The segment event marks the range of buffers to be processed. All data not within the segment range is not to be processed. This can be used intelligently by plugins to apply more efficient methods of skipping unneeded data. The valid range is expressed with the start and stop values.

The time value of the segment is used in conjunction with the start value to convert the buffer timestamps into the stream time. This is usually done in sinks to report the current stream_time. time represents the stream_time of a buffer carrying a timestamp of start. time cannot be -1.

start cannot be -1, stop can be -1. If there is a valid stop given, it must be greater or equal the start, including when the indicated playback rate is < 0.

The appliedRate value provides information about any rate adjustment that has already been made to the timestamps and content on the buffers of the stream. (rate * appliedRate) should always equal the rate that has been requested for playback. For example, if an element has an input segment with intended playback rate of 2.0 and applied_rate of 1.0, it can adjust incoming timestamps and buffer content by half and output a segment event with rate of 1.0 and appliedRate of 2.0

After a segment event, the buffer stream time is calculated with:

time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)

newSegmentDone

eventNewSegmentDone

Arguments

:: (HasCallStack, MonadIO m)

=> Format

format: The format of the position being done

-> Int64

position: The position of the segment being done

-> m Event

Returns: a new Event

Create a new segment-done event. This event is sent by elements that finish playback of a segment as a result of a segment seek.

newSelectStreams

eventNewSelectStreams

Arguments

:: (HasCallStack, MonadIO m)

=> [Text]

streams: the list of streams to activate

-> m Event

Returns: a new select-streams event.

Allocate a new select-streams event.

The select-streams event requests the specified streams to be activated.

The list of streams corresponds to the "Stream ID" of each stream to be activated. Those ID can be obtained via the Stream objects present in GST_EVENT_STREAM_START, GST_EVENT_STREAM_COLLECTION or GST_MESSAGE_STREAM_COLLECTION.

Note: The list of streams can not be empty.

Since: 1.10

newSinkMessage

eventNewSinkMessage

Arguments

:: (HasCallStack, MonadIO m)

=> Text

name: a name for the event

-> Message

msg: the Message to be posted

-> m Event

Returns: a new Event

Create a new sink-message event. The purpose of the sink-message event is to instruct a sink to post the message contained in the event synchronized with the stream.

name is used to store multiple sticky events on one pad.

newStep

eventNewStep

Arguments

:: (HasCallStack, MonadIO m)

=> Format

format: the format of amount

-> Word64

amount: the amount of data to step

-> Double

rate: the step rate

-> Bool

flush: flushing steps

-> Bool

intermediate: intermediate steps

-> m Event

Returns: a new Event

Create a new step event. The purpose of the step event is to instruct a sink to skip amount (expressed in format) of media. It can be used to implement stepping through the video frame by frame or for doing fast trick modes.

A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate = 0.0 or first reverse the direction of playback using a seek event to get the same effect as rate < 0.0.

The flush flag will clear any pending data in the pipeline before starting the step operation.

The intermediate flag instructs the pipeline that this step operation is part of a larger step operation.

newStreamCollection

eventNewStreamCollection

Arguments

:: (HasCallStack, MonadIO m, IsStreamCollection a)

=> a

collection: Active collection for this data flow

-> m Event

Returns: the new STREAM_COLLECTION event.

Create a new STREAM_COLLECTION event. The stream collection event can only travel downstream synchronized with the buffer flow.

Source elements, demuxers and other elements that manage collections of streams and post StreamCollection messages on the bus also send this event downstream on each pad involved in the collection, so that activation of a new collection can be tracked through the downstream data flow.

Since: 1.10

newStreamGroupDone

eventNewStreamGroupDone

Arguments

:: (HasCallStack, MonadIO m)

=> Word32

groupId: the group id of the stream group which is ending

-> m Event

Returns: the new stream-group-done event.

Create a new Stream Group Done event. The stream-group-done event can only travel downstream synchronized with the buffer flow. Elements that receive the event on a pad should handle it mostly like EOS, and emit any data or pending buffers that would depend on more data arriving and unblock, since there won't be any more data.

This event is followed by EOS at some point in the future, and is generally used when switching pads - to unblock downstream so that new pads can be exposed before sending EOS on the existing pads.

Since: 1.10

newStreamStart

eventNewStreamStart

Arguments

:: (HasCallStack, MonadIO m)

=> Text

streamId: Identifier for this stream

-> m Event

Returns: the new STREAM_START event.

Create a new STREAM_START event. The stream start event can only travel downstream synchronized with the buffer flow. It is expected to be the first event that is sent for a new stream.

Source elements, demuxers and other elements that create new streams are supposed to send this event as the first event of a new stream. It should not be sent after a flushing seek or in similar situations and is used to mark the beginning of a new logical stream. Elements combining multiple streams must ensure that this event is only forwarded downstream once and not for every single input stream.

The streamId should be a unique string that consists of the upstream stream-id, / as separator and a unique stream-id for this specific stream. A new stream-id should only be created for a stream if the upstream stream is split into (potentially) multiple new streams, e.g. in a demuxer, but not for every single element in the pipeline. padCreateStreamId or gst_pad_create_stream_id_printf() can be used to create a stream-id. There are no particular semantics for the stream-id, though it should be deterministic (to support stream matching) and it might be used to order streams (besides any information conveyed by stream flags).

newTag

eventNewTag

Arguments

:: (HasCallStack, MonadIO m)

=> TagList

taglist: metadata list. The event will take ownership of the taglist.

-> m Event

Returns: a new Event

Generates a metadata tag event from the given taglist.

The scope of the taglist specifies if the taglist applies to the complete medium or only to this specific stream. As the tag event is a sticky event, elements should merge tags received from upstream with a given scope with their own tags with the same scope and create a new tag event from it.

newToc

eventNewToc

Arguments

:: (HasCallStack, MonadIO m)

=> Toc

toc: Toc structure.

-> Bool

updated: whether toc was updated or not.

-> m Event

Returns: a new Event.

Generate a TOC event from the given toc. The purpose of the TOC event is to inform elements that some kind of the TOC was found.

newTocSelect

eventNewTocSelect

Arguments

:: (HasCallStack, MonadIO m)

=> Text

uid: UID in the TOC to start playback from.

-> m Event

Returns: a new Event.

Generate a TOC select event with the given uid. The purpose of the TOC select event is to start playback based on the TOC's entry with the given uid.

parseBufferSize

eventParseBufferSize

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to query

-> m (Format, Int64, Int64, Bool)

Get the format, minsize, maxsize and async-flag in the buffersize event.

parseCaps

eventParseCaps

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to parse

-> m Caps

Get the caps from event. The caps remains valid as long as event remains valid.

parseFlushStop

eventParseFlushStop

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to parse

-> m Bool

Parse the FLUSH_STOP event and retrieve the resetTime member.

parseGap

eventParseGap

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event of type GST_EVENT_GAP

-> m (Word64, Word64)

Extract timestamp and duration from a new GAP event.

parseGapFlags

eventParseGapFlags

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event of type GST_EVENT_GAP

-> m [GapFlags]

Retrieve the gap flags that may have been set on a gap event with eventSetGapFlags.

Since: 1.20

parseGroupId

eventParseGroupId

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-start event

-> m (Bool, Word32)

Returns: True if a group id was set on the event and could be parsed, False otherwise.

No description available in the introspection data.

Since: 1.2

parseInstantRateChange

eventParseInstantRateChange

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event of type GST_EVENT_INSTANT_RATE_CHANGE

-> m (Double, [SegmentFlags])

Extract rate and flags from an instant-rate-change event.

Since: 1.18

parseInstantRateSyncTime

eventParseInstantRateSyncTime

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event of type GST_EVENT_INSTANT_RATE_CHANGE

-> m (Double, Word64, Word64)

Extract the rate multiplier and running times from an instant-rate-sync-time event.

Since: 1.18

parseLatency

eventParseLatency

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to query

-> m Word64

Get the latency in the latency event.

parseProtection

eventParseProtection

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a GST_EVENT_PROTECTION event.

-> m (Text, Buffer, Maybe Text)

Parses an event containing protection system specific information and stores the results in systemId, data and origin. The data stored in systemId, origin and data are valid until event is released.

Since: 1.6

parseQos

eventParseQos

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to query

-> m (QOSType, Double, Int64, Word64)

Get the type, proportion, diff and timestamp in the qos event. See eventNewQos for more information about the different QoS values.

timestamp will be adjusted for any pad offsets of pads it was passing through.

parseSeek

eventParseSeek

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a seek event

-> m (Double, Format, [SeekFlags], SeekType, Int64, SeekType, Int64)

Parses a seek event and stores the results in the given result locations.

parseSeekTrickmodeInterval

eventParseSeekTrickmodeInterval :: (HasCallStack, MonadIO m) => Event -> m Word64

Retrieve the trickmode interval that may have been set on a seek event with eventSetSeekTrickmodeInterval.

Since: 1.16

parseSegment

eventParseSegment

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to parse

-> m Segment

Parses a segment event and stores the result in the given segment location. segment remains valid only until the event is freed. Don't modify the segment and make a copy if you want to modify it or store it for later use.

parseSegmentDone

eventParseSegmentDone

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: A valid Event of type GST_EVENT_SEGMENT_DONE.

-> m (Format, Int64)

Extracts the position and format from the segment done message.

parseSelectStreams

eventParseSelectStreams

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to parse

-> m [Text]

Parse the SELECT_STREAMS event and retrieve the contained streams.

Since: 1.10

parseSinkMessage

eventParseSinkMessage

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to query

-> m Message

Parse the sink-message event. Unref msg after usage.

parseStep

eventParseStep

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: The event to query

-> m (Format, Word64, Double, Bool, Bool)

Parse the step event.

parseStream

eventParseStream

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-start event

-> m Stream

Parse a stream-start event and extract the Stream from it.

Since: 1.10

parseStreamCollection

eventParseStreamCollection

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-collection event

-> m StreamCollection

Retrieve new StreamCollection from STREAM_COLLECTION event event.

Since: 1.10

parseStreamFlags

eventParseStreamFlags

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-start event

-> m [StreamFlags]

No description available in the introspection data.

Since: 1.2

parseStreamGroupDone

eventParseStreamGroupDone

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-group-done event.

-> m Word32

Parse a stream-group-done event and store the result in the given groupId location.

Since: 1.10

parseStreamStart

eventParseStreamStart

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-start event.

-> m Text

Parse a stream-id event and store the result in the given streamId location. The string stored in streamId must not be modified and will remain valid only until event gets freed. Make a copy if you want to modify it or store it for later use.

parseTag

eventParseTag

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a tag event

-> m TagList

Parses a tag event and stores the results in the given taglist location. No reference to the taglist will be returned, it remains valid only until the event is freed. Don't modify or free the taglist, make a copy if you want to modify it or store it for later use.

parseToc

eventParseToc

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a TOC event.

-> m (Toc, Bool)

Parse a TOC event and store the results in the given toc and updated locations.

parseTocSelect

eventParseTocSelect

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a TOC select event.

-> m Text

Parse a TOC select event and store the results in the given uid location.

setGapFlags

eventSetGapFlags

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event of type GST_EVENT_GAP

-> [GapFlags]

flags: a GapFlags

-> m ()

Sets flags on event to give additional information about the reason for the GST_EVENT_GAP.

Since: 1.20

setGroupId

eventSetGroupId

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-start event

-> Word32

groupId: the group id to set

-> m ()

All streams that have the same group id are supposed to be played together, i.e. all streams inside a container file should have the same group id but different stream ids. The group id should change each time the stream is started, resulting in different group ids each time a file is played for example.

Use utilGroupIdNext to get a new group id.

Since: 1.2

setRunningTimeOffset

eventSetRunningTimeOffset

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: A Event.

-> Int64

offset: A the new running time offset

-> m ()

Set the running time offset of a event. See eventGetRunningTimeOffset for more information.

MT safe.

Since: 1.4

setSeekTrickmodeInterval

eventSetSeekTrickmodeInterval :: (HasCallStack, MonadIO m) => Event -> Word64 -> m ()

Sets a trickmode interval on a (writable) seek event. Elements that support TRICKMODE_KEY_UNITS seeks SHOULD use this as the minimal interval between each frame they may output.

Since: 1.16

setSeqnum

eventSetSeqnum

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: A Event.

-> Word32

seqnum: A sequence number.

-> m ()

Set the sequence number of a event.

This function might be called by the creator of a event to indicate that the event relates to other events or messages. See eventGetSeqnum for more information.

MT safe.

setStream

eventSetStream

Arguments

:: (HasCallStack, MonadIO m, IsStream a)

=> Event

event: a stream-start event

-> a

stream: the stream object to set

-> m ()

Set the stream on the stream-start event

Since: 1.10

setStreamFlags

eventSetStreamFlags

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a stream-start event

-> [StreamFlags]

flags: the stream flags to set

-> m ()

No description available in the introspection data.

Since: 1.2

writableStructure

eventWritableStructure

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: A writable Event.

-> m Structure

Returns: The structure of the event. The structure is still owned by the event, which means that you should not free it and that the pointer becomes invalid when you free the event. This function ensures that event is writable, and if so, will never return Nothing.

MT safe.

Get a writable version of the structure.

Properties

miniObject

the parent structure

getEventMiniObject :: MonadIO m => Event -> m MiniObject

Get the value of the “mini_object” field. When overloading is enabled, this is equivalent to

get event #miniObject

seqnum

the sequence number of the event

getEventSeqnum :: MonadIO m => Event -> m Word32

Get the value of the “seqnum” field. When overloading is enabled, this is equivalent to

get event #seqnum

setEventSeqnum :: MonadIO m => Event -> Word32 -> m ()

Set the value of the “seqnum” field. When overloading is enabled, this is equivalent to

set event [ #seqnum := value ]

timestamp

the timestamp of the event

getEventTimestamp :: MonadIO m => Event -> m Word64

Get the value of the “timestamp” field. When overloading is enabled, this is equivalent to

get event #timestamp

setEventTimestamp :: MonadIO m => Event -> Word64 -> m ()

Set the value of the “timestamp” field. When overloading is enabled, this is equivalent to

set event [ #timestamp := value ]

type

the EventType of the event

getEventType :: MonadIO m => Event -> m EventType

Get the value of the “type” field. When overloading is enabled, this is equivalent to

get event #type

setEventType :: MonadIO m => Event -> EventType -> m ()

Set the value of the “type” field. When overloading is enabled, this is equivalent to

set event [ #type := value ]