Copyright | Will Thompson Iñaki García Etxebarria and Jonas Platte |
---|---|
License | LGPL-2.1 |
Maintainer | Iñaki García Etxebarria (inaki@blueleaf.cc) |
Safe Haskell | None |
Language | Haskell2010 |
- Exported types
- Methods
- copySegment
- getRunningTimeOffset
- getSeqnum
- getStructure
- hasName
- newBufferSize
- newCaps
- newCustom
- newEos
- newFlushStart
- newFlushStop
- newGap
- newLatency
- newNavigation
- newProtection
- newQos
- newReconfigure
- newSeek
- newSegment
- newSegmentDone
- newSelectStreams
- newSinkMessage
- newStep
- newStreamCollection
- newStreamGroupDone
- newStreamStart
- newTag
- newToc
- newTocSelect
- parseBufferSize
- parseCaps
- parseFlushStop
- parseGap
- parseGroupId
- parseLatency
- parseProtection
- parseQos
- parseSeek
- parseSeekTrickmodeInterval
- parseSegment
- parseSegmentDone
- parseSelectStreams
- parseSinkMessage
- parseStep
- parseStream
- parseStreamCollection
- parseStreamFlags
- parseStreamGroupDone
- parseStreamStart
- parseTag
- parseToc
- parseTocSelect
- setGroupId
- setRunningTimeOffset
- setSeekTrickmodeInterval
- setSeqnum
- setStream
- setStreamFlags
- writableStructure
- Properties
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"); ...
Synopsis
- newtype Event = Event (ManagedPtr Event)
- newZeroEvent :: MonadIO m => m Event
- noEvent :: Maybe Event
- eventCopySegment :: (HasCallStack, MonadIO m) => Event -> Segment -> m ()
- eventGetRunningTimeOffset :: (HasCallStack, MonadIO m) => Event -> m Int64
- eventGetSeqnum :: (HasCallStack, MonadIO m) => Event -> m Word32
- eventGetStructure :: (HasCallStack, MonadIO m) => Event -> m (Maybe Structure)
- eventHasName :: (HasCallStack, MonadIO m) => Event -> Text -> m Bool
- eventNewBufferSize :: (HasCallStack, MonadIO m) => Format -> Int64 -> Int64 -> Bool -> m Event
- eventNewCaps :: (HasCallStack, MonadIO m) => Caps -> m (Maybe Event)
- eventNewCustom :: (HasCallStack, MonadIO m) => EventType -> Structure -> m (Maybe Event)
- eventNewEos :: (HasCallStack, MonadIO m) => m Event
- eventNewFlushStart :: (HasCallStack, MonadIO m) => m Event
- eventNewFlushStop :: (HasCallStack, MonadIO m) => Bool -> m Event
- eventNewGap :: (HasCallStack, MonadIO m) => Word64 -> Word64 -> m Event
- eventNewLatency :: (HasCallStack, MonadIO m) => Word64 -> m Event
- eventNewNavigation :: (HasCallStack, MonadIO m) => Structure -> m Event
- eventNewProtection :: (HasCallStack, MonadIO m) => Text -> Buffer -> Text -> m Event
- eventNewQos :: (HasCallStack, MonadIO m) => QOSType -> Double -> Int64 -> Word64 -> m (Maybe Event)
- eventNewReconfigure :: (HasCallStack, MonadIO m) => m Event
- eventNewSeek :: (HasCallStack, MonadIO m) => Double -> Format -> [SeekFlags] -> SeekType -> Int64 -> SeekType -> Int64 -> m (Maybe Event)
- eventNewSegment :: (HasCallStack, MonadIO m) => Segment -> m (Maybe Event)
- eventNewSegmentDone :: (HasCallStack, MonadIO m) => Format -> Int64 -> m Event
- eventNewSelectStreams :: (HasCallStack, MonadIO m) => [Text] -> m Event
- eventNewSinkMessage :: (HasCallStack, MonadIO m) => Text -> Message -> m Event
- eventNewStep :: (HasCallStack, MonadIO m) => Format -> Word64 -> Double -> Bool -> Bool -> m (Maybe Event)
- eventNewStreamCollection :: (HasCallStack, MonadIO m, IsStreamCollection a) => a -> m Event
- eventNewStreamGroupDone :: (HasCallStack, MonadIO m) => Word32 -> m Event
- eventNewStreamStart :: (HasCallStack, MonadIO m) => Text -> m Event
- eventNewTag :: (HasCallStack, MonadIO m) => TagList -> m Event
- eventNewToc :: (HasCallStack, MonadIO m) => Toc -> Bool -> m Event
- eventNewTocSelect :: (HasCallStack, MonadIO m) => Text -> m Event
- eventParseBufferSize :: (HasCallStack, MonadIO m) => Event -> m (Format, Int64, Int64, Bool)
- eventParseCaps :: (HasCallStack, MonadIO m) => Event -> m Caps
- eventParseFlushStop :: (HasCallStack, MonadIO m) => Event -> m Bool
- eventParseGap :: (HasCallStack, MonadIO m) => Event -> m (Word64, Word64)
- eventParseGroupId :: (HasCallStack, MonadIO m) => Event -> m (Bool, Word32)
- eventParseLatency :: (HasCallStack, MonadIO m) => Event -> m Word64
- eventParseProtection :: (HasCallStack, MonadIO m) => Event -> m (Text, Buffer, Maybe Text)
- eventParseQos :: (HasCallStack, MonadIO m) => Event -> m (QOSType, Double, Int64, Word64)
- eventParseSeek :: (HasCallStack, MonadIO m) => Event -> m (Double, Format, [SeekFlags], SeekType, Int64, SeekType, Int64)
- eventParseSeekTrickmodeInterval :: (HasCallStack, MonadIO m) => Event -> m Word64
- eventParseSegment :: (HasCallStack, MonadIO m) => Event -> m Segment
- eventParseSegmentDone :: (HasCallStack, MonadIO m) => Event -> m (Format, Int64)
- eventParseSelectStreams :: (HasCallStack, MonadIO m) => Event -> m [Text]
- eventParseSinkMessage :: (HasCallStack, MonadIO m) => Event -> m Message
- eventParseStep :: (HasCallStack, MonadIO m) => Event -> m (Format, Word64, Double, Bool, Bool)
- eventParseStream :: (HasCallStack, MonadIO m) => Event -> m Stream
- eventParseStreamCollection :: (HasCallStack, MonadIO m) => Event -> m StreamCollection
- eventParseStreamFlags :: (HasCallStack, MonadIO m) => Event -> m [StreamFlags]
- eventParseStreamGroupDone :: (HasCallStack, MonadIO m) => Event -> m Word32
- eventParseStreamStart :: (HasCallStack, MonadIO m) => Event -> m Text
- eventParseTag :: (HasCallStack, MonadIO m) => Event -> m TagList
- eventParseToc :: (HasCallStack, MonadIO m) => Event -> m (Toc, Bool)
- eventParseTocSelect :: (HasCallStack, MonadIO m) => Event -> m Text
- eventSetGroupId :: (HasCallStack, MonadIO m) => Event -> Word32 -> m ()
- eventSetRunningTimeOffset :: (HasCallStack, MonadIO m) => Event -> Int64 -> m ()
- eventSetSeekTrickmodeInterval :: (HasCallStack, MonadIO m) => Event -> Word64 -> m ()
- eventSetSeqnum :: (HasCallStack, MonadIO m) => Event -> Word32 -> m ()
- eventSetStream :: (HasCallStack, MonadIO m, IsStream a) => Event -> a -> m ()
- eventSetStreamFlags :: (HasCallStack, MonadIO m) => Event -> [StreamFlags] -> m ()
- eventWritableStructure :: (HasCallStack, MonadIO m) => Event -> m Structure
- getEventMiniObject :: MonadIO m => Event -> m MiniObject
- getEventSeqnum :: MonadIO m => Event -> m Word32
- setEventSeqnum :: MonadIO m => Event -> Word32 -> m ()
- getEventTimestamp :: MonadIO m => Event -> m Word64
- setEventTimestamp :: MonadIO m => Event -> Word64 -> m ()
- getEventType :: MonadIO m => Event -> m EventType
- setEventType :: MonadIO m => Event -> EventType -> m ()
Exported types
Memory-managed wrapper type.
Instances
BoxedObject Event Source # | |
tag ~ AttrSet => Constructible Event tag Source # | |
Defined in GI.Gst.Structs.Event |
Methods
copySegment
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> Segment |
|
-> m () |
Parses a segment event
and copies the Segment
into the location
given by segment
.
getRunningTimeOffset
eventGetRunningTimeOffset Source #
:: (HasCallStack, MonadIO m) | |
=> 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
:: (HasCallStack, MonadIO m) | |
=> 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
:: (HasCallStack, MonadIO m) | |
=> 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
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> Text |
|
-> m Bool | Returns: |
Checks if event
has the given name
. This function is usually used to
check the name of a custom event.
newBufferSize
:: (HasCallStack, MonadIO m) | |
=> Format |
|
-> Int64 |
|
-> Int64 |
|
-> Bool |
|
-> m Event | Returns: a new |
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
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
:: (HasCallStack, MonadIO m) | |
=> EventType |
|
-> Structure |
|
-> m (Maybe 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
:: (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
:: (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
:: (HasCallStack, MonadIO m) | |
=> Bool |
|
-> 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
:: (HasCallStack, MonadIO m) | |
=> Word64 |
|
-> Word64 |
|
-> 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.
newLatency
:: (HasCallStack, MonadIO m) | |
=> Word64 |
|
-> m Event | Returns: a new |
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
:: (HasCallStack, MonadIO m) | |
=> Structure |
|
-> m Event | Returns: a new |
Create a new navigation event from the given description.
newProtection
:: (HasCallStack, MonadIO m) | |
=> Text |
|
-> Buffer |
|
-> Text |
|
-> m Event | Returns: a |
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
:: (HasCallStack, MonadIO m) | |
=> QOSType |
|
-> Double |
|
-> Int64 |
|
-> Word64 |
|
-> m (Maybe 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
:: (HasCallStack, MonadIO m) | |
=> m Event | Returns: a new |
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
:: (HasCallStack, MonadIO m) | |
=> Double |
|
-> Format |
|
-> [SeekFlags] |
|
-> SeekType |
|
-> Int64 |
|
-> SeekType |
|
-> Int64 |
|
-> m (Maybe 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
:: (HasCallStack, MonadIO m) | |
=> Segment |
|
-> m (Maybe 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
:: (HasCallStack, MonadIO m) | |
=> Format |
|
-> Int64 |
|
-> m Event | Returns: a new |
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 Source #
:: (HasCallStack, MonadIO m) | |
=> [Text] |
|
-> m Event | Returns: a new select-streams event or |
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
:: (HasCallStack, MonadIO m) | |
=> Text |
|
-> Message |
|
-> m Event | Returns: a new |
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
:: (HasCallStack, MonadIO m) | |
=> Format |
|
-> Word64 |
|
-> Double |
|
-> Bool |
|
-> Bool |
|
-> m (Maybe Event) | Returns: a new |
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 Source #
:: (HasCallStack, MonadIO m, IsStreamCollection a) | |
=> a |
|
-> 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 Source #
:: (HasCallStack, MonadIO m) | |
=> Word32 |
|
-> 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
:: (HasCallStack, MonadIO m) | |
=> Text |
|
-> 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
:: (HasCallStack, MonadIO m) | |
=> TagList |
|
-> m Event | Returns: a new |
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
:: (HasCallStack, MonadIO m) | |
=> Toc |
|
-> Bool |
|
-> m Event | Returns: a new |
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
:: (HasCallStack, MonadIO m) | |
=> Text |
|
-> m Event | Returns: a new |
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
Get the format, minsize, maxsize and async-flag in the buffersize event.
parseCaps
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m Caps |
Get the caps from event
. The caps remains valid as long as event
remains
valid.
parseFlushStop
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m Bool |
Parse the FLUSH_STOP event and retrieve the resetTime
member.
parseGap
Extract timestamp and duration from a new GAP event.
parseGroupId
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m (Bool, Word32) | Returns: |
No description available in the introspection data.
Since: 1.2
parseLatency
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m Word64 |
Get the latency in the latency event.
parseProtection
:: (HasCallStack, MonadIO m) | |
=> 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
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> 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
:: (HasCallStack, MonadIO m) | |
=> 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 Source #
Retrieve the trickmode interval that may have been set on a
seek event with eventSetSeekTrickmodeInterval
.
Since: 1.16
parseSegment
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> 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 Source #
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m (Format, Int64) |
Extracts the position and format from the segment done message.
parseSelectStreams
eventParseSelectStreams Source #
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m [Text] |
Parse the SELECT_STREAMS event and retrieve the contained streams.
Since: 1.10
parseSinkMessage
eventParseSinkMessage Source #
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m Message |
Parse the sink-message event. Unref msg
after usage.
parseStep
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m (Format, Word64, Double, Bool, Bool) |
Parse the step event.
parseStream
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m Stream |
Parse a stream-start event
and extract the Stream
from it.
Since: 1.10
parseStreamCollection
eventParseStreamCollection Source #
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m StreamCollection |
Retrieve new StreamCollection
from STREAM_COLLECTION event event
.
Since: 1.10
parseStreamFlags
eventParseStreamFlags Source #
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m [StreamFlags] |
No description available in the introspection data.
Since: 1.2
parseStreamGroupDone
eventParseStreamGroupDone Source #
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m Word32 |
Parse a stream-group-done event
and store the result in the given
groupId
location.
Since: 1.10
parseStreamStart
eventParseStreamStart Source #
:: (HasCallStack, MonadIO m) | |
=> 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
:: (HasCallStack, MonadIO m) | |
=> 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
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m (Toc, Bool) |
Parse a TOC event
and store the results in the given toc
and updated
locations.
parseTocSelect
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> m Text |
Parse a TOC select event
and store the results in the given uid
location.
setGroupId
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> Word32 |
|
-> 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 Source #
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> Int64 |
|
-> 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 () Source #
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
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> Word32 |
|
-> 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
:: (HasCallStack, MonadIO m, IsStream a) | |
=> Event |
|
-> a |
|
-> m () |
Set the stream
on the stream-start event
Since: 1.10
setStreamFlags
:: (HasCallStack, MonadIO m) | |
=> Event |
|
-> [StreamFlags] |
|
-> m () |
No description available in the introspection data.
Since: 1.2
writableStructure
eventWritableStructure Source #
:: (HasCallStack, MonadIO m) | |
=> 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 checks if MT safe. |
Get a writable version of the structure.
Properties
miniObject
the parent structure
getEventMiniObject :: MonadIO m => Event -> m MiniObject Source #
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 Source #
Get the value of the “seqnum
” field.
When overloading is enabled, this is equivalent to
get
event #seqnum
setEventSeqnum :: MonadIO m => Event -> Word32 -> m () Source #
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 Source #
Get the value of the “timestamp
” field.
When overloading is enabled, this is equivalent to
get
event #timestamp
setEventTimestamp :: MonadIO m => Event -> Word64 -> m () Source #
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 Source #
Get the value of the “type
” field.
When overloading is enabled, this is equivalent to
get
event #type
setEventType :: MonadIO m => Event -> EventType -> m () Source #
Set the value of the “type
” field.
When overloading is enabled, this is equivalent to
set
event [ #type:=
value ]