Message

Messages are implemented as a subclass of gstreamer.MiniObject with a generic gstreamer.Structure as the content. This allows for writing custom messages without requiring an API change while allowing a wide range of different types of messages.

Messages are posted by objects in the pipeline and are passed to the application using the gstreamer.Bus

The basic use pattern of posting a message on a gstreamer.Bus is as follows:

gst_bus_post (bus, [gstreamer.Message.Message.newEos|Message.newEos]);

A gstreamer.Element usually posts messages on the bus provided by the parent container using Element.postMessage.

class Message {
bool ownedRef;
}

Constructors

this
this(GstMessage* gstMessage, bool ownedRef = false)

Sets our main struct and passes it to the parent class.

this
this(ObjectGst src, Structure structure)

Create a new application-typed message. GStreamer will never create these messages; they are a gift from us to you. Enjoy.

this
this(ObjectGst src, GstClockTime runningTime)

The message is posted when elements completed an ASYNC state change. running_time contains the time of the desired running_time when this elements goes to PLAYING. A value of GST_CLOCK_TIME_NONE for running_time means that the element has no clock interaction and thus doesn't care about the running_time of the pipeline.

this
this(ObjectGst src, int percent)

Create a new buffering message. This message can be posted by an element that needs to buffer data before it can continue processing. percent should be a value between 0 and 100. A value of 100 means that the buffering completed.

this
this(ObjectGst src, Clock clock)

Create a clock lost message. This message is posted whenever the clock is not valid anymore.

this
this(ObjectGst src, Clock clock, bool ready)

Create a clock provide message. This message is posted whenever an element is ready to provide a clock or lost its ability to provide a clock (maybe because it paused or became EOS).

this
this(GstMessageType type, ObjectGst src, Structure structure)

Create a new custom-typed message. This can be used for anything not handled by other message-specific functions to pass a message to the app. The structure field can be NULL.

this
this(ObjectGst src, Context context)

This message is posted when an element has a new local gstreamer.Context

this
this(ObjectGst src, string contextType)

This message is posted when an element needs a specific gstreamer.Context

this
this(ObjectGst src, GstProgressType type, string code, string text)

Progress messages are posted by elements when they use an asynchronous task to perform actions triggered by a state change.

this
this(ObjectGst src, string propertyName, Value val)
this
this(ObjectGst src, bool live, ulong runningTime, ulong streamTime, ulong timestamp, ulong duration)

A QOS message is posted on the bus whenever an element decides to drop a buffer because of QoS reasons or whenever it changes its processing strategy because of QoS reasons (quality adjustments such as processing at lower accuracy).

this
this(ObjectGst src, string location, TagList tagList, Structure entryStruct)

Creates a new redirect message and adds a new entry to it. Redirect messages are posted when an element detects that the actual data has to be retrieved from a different location. This is useful if such a redirection cannot be handled inside a source element, for example when HTTP 302/303 redirects return a non-HTTP URL.

this
this(ObjectGst src, GstState state)

This message can be posted by elements when they want to have their state changed. A typical use case would be an audio server that wants to pause the pipeline because a higher priority stream is being played.

this
this(ObjectGst src, GstState oldstate, GstState newstate, GstState pending)

Create a state change message. This message is posted whenever an element changed its state.

this
this(ObjectGst src, GstFormat format, ulong amount, double rate, bool flush, bool intermediate, ulong duration, bool eos)

This message is posted by elements when they complete a part, when intermediate set to TRUE, or a complete step operation.

this
this(ObjectGst src, bool active, GstFormat format, ulong amount, double rate, bool flush, bool intermediate)

This message is posted by elements when they accept or activate a new step event for amount in format.

this
this(ObjectGst src)

Create a new stream_start message. This message is generated and posted in the sink elements of a GstBin. The bin will only forward the STREAM_START message to the application if all sinks have posted an STREAM_START message.

this
this(ObjectGst src, GstStreamStatusType type, Element owner)

Create a new stream status message. This message is posted when a streaming thread is created/destroyed or when the state changed.

this
this(ObjectGst src, GstStructureChangeType type, Element owner, bool busy)

Create a new structure change message. This message is posted when the structure of a pipeline is in the process of being changed, for example when pads are linked or unlinked.

this
this(ObjectGst src, TagList tagList)

Create a new tag message. The message will take ownership of the tag list. The message is posted by elements that discovered a new taglist.

this
this(ObjectGst src, Toc toc, bool updated)

Create a new TOC message. The message is posted by elements that discovered or updated a TOC.

Members

Functions

addRedirectEntry
void addRedirectEntry(string location, TagList tagList, Structure entryStruct)

Creates and appends a new entry.

getMessageStruct
GstMessage* getMessageStruct(bool transferOwnership = false)

Get the main Gtk struct

getNumRedirectEntries
size_t getNumRedirectEntries()
getSeqnum
uint getSeqnum()

Retrieve the sequence number of a message.

getStreamStatusObject
Value getStreamStatusObject()

Extracts the object managing the streaming thread from message.

getStruct
void* getStruct()

the main Gtk struct as a void*

getStructure
Structure getStructure()

Access the structure of the message.

hasName
bool hasName(string name)

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

parseAsyncDone
void parseAsyncDone(out GstClockTime runningTime)

Extract the running_time from the async_done message.

parseBuffering
void parseBuffering(out int percent)

Extracts the buffering percent from the GstMessage. see also Message.newBuffering.

parseBufferingStats
void parseBufferingStats(out GstBufferingMode mode, out int avgIn, out int avgOut, out long bufferingLeft)

Extracts the buffering stats values from message.

parseClockLost
void parseClockLost(out Clock clock)

Extracts the lost clock from the GstMessage. The clock object returned remains valid until the message is freed.

parseClockProvide
void parseClockProvide(out Clock clock, out bool ready)

Extracts the clock and ready flag from the GstMessage. The clock object returned remains valid until the message is freed.

parseContextType
bool parseContextType(out string contextType)

Parse a context type from an existing GST_MESSAGE_NEED_CONTEXT message.

parseDeviceAdded
void parseDeviceAdded(out Device device)

Parses a device-added message. The device-added message is produced by gstreamer.DeviceProvider or a gstreamer.DeviceMonitor It announces the appearance of monitored devices.

parseDeviceRemoved
void parseDeviceRemoved(out Device device)

Parses a device-removed message. The device-removed message is produced by gstreamer.DeviceProvider or a gstreamer.DeviceMonitor It announces the disappearance of monitored devices.

parseError
void parseError(out ErrorG gerror, out string dbg)

Extracts the GError and debug string from the GstMessage. The values returned in the output arguments are copies; the caller must free them when done.

parseErrorDetails
void parseErrorDetails(out Structure structure)

Returns the optional details structure, may be NULL if none. The returned structure must not be freed.

parseGroupId
bool parseGroupId(out uint groupId)

Extract the group from the STREAM_START message.

parseHaveContext
void parseHaveContext(out Context context)

Extract the context from the HAVE_CONTEXT message.

parseInfo
void parseInfo(out ErrorG gerror, out string dbg)

Extracts the GError and debug string from the GstMessage. The values returned in the output arguments are copies; the caller must free them when done.

parseInfoDetails
void parseInfoDetails(out Structure structure)

Returns the optional details structure, may be NULL if none The returned structure must not be freed.

parseNewClock
void parseNewClock(out Clock clock)

Extracts the new clock from the GstMessage. The clock object returned remains valid until the message is freed.

parseProgress
void parseProgress(out GstProgressType type, out string code, out string text)

Parses the progress type, code and text.

parsePropertyNotify
void parsePropertyNotify(out ObjectGst object, out string propertyName, out Value propertyValue)

Parses a property-notify message. These will be posted on the bus only when set up with Element.addPropertyNotifyWatch or Element.addPropertyDeepNotifyWatch.

parseQos
void parseQos(out bool live, out ulong runningTime, out ulong streamTime, out ulong timestamp, out ulong duration)

Extract the timestamps and live status from the QoS message.

parseQosStats
void parseQosStats(out GstFormat format, out ulong processed, out ulong dropped)

Extract the QoS stats representing the history of the current continuous pipeline playback period.

parseQosValues
void parseQosValues(out long jitter, out double proportion, out int quality)

Extract the QoS values that have been calculated/analysed from the QoS data

parseRedirectEntry
void parseRedirectEntry(size_t entryIndex, out string location, out TagList tagList, out Structure entryStruct)

Parses the location and/or structure from the entry with the given index. The index must be between 0 and Message.getNumRedirectEntries - 1. Returned pointers are valid for as long as this message exists.

parseRequestState
void parseRequestState(out GstState state)

Extract the requested state from the request_state message.

parseResetTime
void parseResetTime(out GstClockTime runningTime)

Extract the running-time from the RESET_TIME message.

parseSegmentDone
void parseSegmentDone(out GstFormat format, out long position)

Extracts the position and format from the segment done message.

parseSegmentStart
void parseSegmentStart(out GstFormat format, out long position)

Extracts the position and format from the segment start message.

parseStateChanged
void parseStateChanged(out GstState oldstate, out GstState newstate, out GstState pending)

Extracts the old and new states from the GstMessage.

parseStepDone
void parseStepDone(out GstFormat format, out ulong amount, out double rate, out bool flush, out bool intermediate, out ulong duration, out bool eos)

Extract the values the step_done message.

parseStepStart
void parseStepStart(out bool active, out GstFormat format, out ulong amount, out double rate, out bool flush, out bool intermediate)

Extract the values from step_start message.

parseStreamCollection
void parseStreamCollection(out StreamCollection collection)

Parses a stream-collection message.

parseStreamStatus
void parseStreamStatus(out GstStreamStatusType type, out Element owner)

Extracts the stream status type and owner the GstMessage. The returned owner remains valid for as long as the reference to message is valid and should thus not be unreffed.

parseStreamsSelected
void parseStreamsSelected(out StreamCollection collection)

Parses a streams-selected message.

parseStructureChange
void parseStructureChange(out GstStructureChangeType type, out Element owner, out bool busy)

Extracts the change type and completion status from the GstMessage.

parseTag
void parseTag(out TagList tagList)

Extracts the tag list from the GstMessage. The tag list returned in the output argument is a copy; the caller must free it when done.

parseToc
void parseToc(out Toc toc, out bool updated)

Extract the TOC from the gstreamer.Message The TOC returned in the output argument is a copy; the caller must free it with Toc.unref when done.

parseWarning
void parseWarning(out ErrorG gerror, out string dbg)

Extracts the GError and debug string from the GstMessage. The values returned in the output arguments are copies; the caller must free them when done.

parseWarningDetails
void parseWarningDetails(out Structure structure)

Returns the optional details structure, may be NULL if none The returned structure must not be freed.

setBufferingStats
void setBufferingStats(GstBufferingMode mode, int avgIn, int avgOut, long bufferingLeft)

Configures the buffering stats values in message.

setGroupId
void setGroupId(uint groupId)

Sets the group id on the stream-start message.

setQosStats
void setQosStats(GstFormat format, ulong processed, ulong dropped)

Set the QoS stats representing the history of the current continuous pipeline playback period.

setQosValues
void setQosValues(long jitter, double proportion, int quality)

Set the QoS values that have been calculated/analysed from the QoS data

setSeqnum
void setSeqnum(uint seqnum)

Set the sequence number of a message.

setStreamStatusObject
void setStreamStatusObject(Value object)

Configures the object handling the streaming thread. This is usually a GstTask object but other objects might be added in the future.

src
ObjectGst src()

Get the src (the element that originated the message) of the message.

streamsSelectedAdd
void streamsSelectedAdd(Stream stream)

Adds the stream to the message.

streamsSelectedGetSize
uint streamsSelectedGetSize()

Returns the number of streams contained in the message.

streamsSelectedGetStream
Stream streamsSelectedGetStream(uint idx)

Retrieves the gstreamer.Stream with index index from the message.

type
GstMessageType type()

Get the type of the message.

writableStructure
Structure writableStructure()

Get a writable version of the structure.

Static functions

getType
GType getType()
newAsyncDone
Message newAsyncDone(ObjectGst src, GstClockTime runningTime)

The message is posted when elements completed an ASYNC state change. running_time contains the time of the desired running_time when this elements goes to PLAYING. A value of GST_CLOCK_TIME_NONE for running_time means that the element has no clock interaction and thus doesn't care about the running_time of the pipeline.

newAsyncStart
Message newAsyncStart(ObjectGst src)

This message is posted by elements when they start an ASYNC state change.

newDeviceAdded
Message newDeviceAdded(ObjectGst src, Device device)

Creates a new device-added message. The device-added message is produced by gstreamer.DeviceProvider or a gstreamer.DeviceMonitor They announce the appearance of monitored devices.

newDeviceRemoved
Message newDeviceRemoved(ObjectGst src, Device device)

Creates a new device-removed message. The device-removed message is produced by gstreamer.DeviceProvider or a gstreamer.DeviceMonitor They announce the disappearance of monitored devices.

newDurationChanged
Message newDurationChanged(ObjectGst src)

Create a new duration changed message. This message is posted by elements that know the duration of a stream when the duration changes. This message is received by bins and is used to calculate the total duration of a pipeline. Elements may post a duration message with a duration of GST_CLOCK_TIME_NONE to indicate that the duration has changed and the cached duration should be discarded. The new duration can then be retrieved via a query.

newEOS
Message newEOS(ObjectGst src)

Create a new eos message. This message is generated and posted in the sink elements of a GstBin. The bin will only forward the EOS message to the application if all sinks have posted an EOS message. MT safe.

newElement
Message newElement(ObjectGst src, Structure structure)

Create a new element-specific message. This is meant as a generic way of allowing one-way communication from an element to an application, for example "the firewire cable was unplugged". The format of the message should be documented in the element's documentation. The structure field can be NULL. MT safe.

newError
Message newError(ObjectGst src, ErrorG error, string dbug)

Create a new error message. The message will copy error and debug. This message is posted by element when a fatal event occured. The pipeline will probably (partially) stop. The application receiving this message should stop the pipeline. MT safe.

newErrorWithDetails
Message newErrorWithDetails(ObjectGst src, ErrorG error, string dbg, Structure details)

Create a new error message. The message will copy error and debug. This message is posted by element when a fatal event occurred. The pipeline will probably (partially) stop. The application receiving this message should stop the pipeline.

newInfo
Message newInfo(ObjectGst src, ErrorG error, string dbug)

Create a new info message. The message will make copies of error and debug. MT safe. Since 0.10.12

newInfoWithDetails
Message newInfoWithDetails(ObjectGst src, ErrorG error, string dbg, Structure details)

Create a new info message. The message will make copies of error and debug.

newLatency
Message newLatency(ObjectGst src)

This message can be posted by elements when their latency requirements have changed.

newNewClock
Message newNewClock(ObjectGst src, Clock clock)

Create a new clock message. This message is posted whenever the pipeline selectes a new clock for the pipeline. MT safe.

newSegmentDone
Message newSegmentDone(ObjectGst src, GstFormat format, long position)

Create a new segment done message. This message is posted by elements that finish playback of a segment as a result of a segment seek. This message is received by the application after all elements that posted a segment_start have posted the segment_done. MT safe.

newSegmentStart
Message newSegmentStart(ObjectGst src, GstFormat format, long position)

Create a new segment message. This message is posted by elements that start playback of a segment as a result of a segment seek. This message is not received by the application but is used for maintenance reasons in container elements. MT safe.

newStateDirty
Message newStateDirty(ObjectGst src)

Create a state dirty message. This message is posted whenever an element changed its state asynchronously and is used internally to update the states of container objects. MT safe.

newStreamCollection
Message newStreamCollection(ObjectGst src, StreamCollection collection)

Creates a new stream-collection message. The message is used to announce new gstreamer.StreamCollection

newStreamsSelected
Message newStreamsSelected(ObjectGst src, StreamCollection collection)

Creates a new steams-selected message. The message is used to announce that an array of streams has been selected. This is generally in response to a GST_EVENT_SELECT_STREAMS event, or when an element (such as decodebin3) makes an initial selection of streams.

newWarning
Message newWarning(ObjectGst src, ErrorG error, string dbug)

Create a new warning message. The message will make copies of error and debug. MT safe.

newWarningWithDetails
Message newWarningWithDetails(ObjectGst src, ErrorG error, string dbg, Structure details)

Create a new warning message. The message will make copies of error and debug.

typeGetName
string typeGetName(GstMessageType type)

Get a printable name for the given message type. Do not modify or free.

typeToQuark
GQuark typeToQuark(GstMessageType type)

Get the unique quark for the given message type.

Variables

gstMessage
GstMessage* gstMessage;

the main Gtk struct

Meta