Query

Queries can be performed on pads (gst_pad_query()) and elements (gst_element_query()). Please note that some queries might need a running pipeline to work.

Queries can be created using the gst_query_new_*() functions. Query values can be set using gst_query_set_*(), and parsed using gst_query_parse_*() helpers.

The following example shows how to query the duration of a pipeline: |[<!-- language="C" --> GstQuery *query; gboolean res; query = gst_query_new_duration (GST_FORMAT_TIME); res = gst_element_query (pipeline, query); if (res) { gint64 duration; gst_query_parse_duration (query, NULL, &amp;duration); g_print ("duration = %"GST_TIME_FORMAT, GST_TIME_ARGS (duration)); } else { g_print ("duration query failed..."); } gst_query_unref (query); ]|

class Query {}

Constructors

this
this(GstQuery* gstQuery, bool ownedRef)

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

this
this(Caps caps, bool needPool)

Constructs a new query object for querying the allocation properties.

this
this(GstFormat format)

Constructs a new query object for querying the buffering status of a stream.

this
this(Caps filter)

Constructs a new query object for querying the caps.

this
this(string contextType)

Constructs a new query object for querying the pipeline-local context.

this
this(GstFormat srcFormat, long value, GstFormat destFormat)

Constructs a new convert query object. Use gst_query_unref() when done with it. A convert query is used to ask for a conversion between one format and another.

this
this(GstQueryType type, Structure structure)

Constructs a new custom query object. Use gst_query_unref() when done with it.

Members

Functions

addAllocationMeta
void addAllocationMeta(GType api, Structure params)

Add @api with @params as one of the supported metadata API to @query.

addAllocationParam
void addAllocationParam(Allocator allocator, AllocationParams params)

Add @allocator and its @params as a supported memory allocator.

addAllocationPool
void addAllocationPool(BufferPool pool, uint size, uint minBuffers, uint maxBuffers)

Set the pool parameters in @query.

addBufferingRange
bool addBufferingRange(long start, long stop)

Set the buffering-ranges array field in @query. The current last start position of the array should be inferior to @start.

addSchedulingMode
void addSchedulingMode(GstPadMode mode)

Add @mode as one of the supported scheduling modes to @query.

findAllocationMeta
bool findAllocationMeta(GType api, uint index)

Check if @query has metadata @api set. When this function returns %TRUE, @index will contain the index where the requested API and the parameters can be found.

getNAllocationMetas
uint getNAllocationMetas()

Retrieve the number of values currently stored in the meta API array of the query's structure.

getNAllocationParams
uint getNAllocationParams()

Retrieve the number of values currently stored in the allocator params array of the query's structure.

getNAllocationPools
uint getNAllocationPools()

Retrieve the number of values currently stored in the pool array of the query's structure.

getNBufferingRanges
uint getNBufferingRanges()

Retrieve the number of values currently stored in the buffered-ranges array of the query's structure.

getNSchedulingModes
uint getNSchedulingModes()

Retrieve the number of values currently stored in the scheduling mode array of the query's structure.

getQueryStruct
GstQuery* getQueryStruct(bool transferOwnership)

Get the main Gtk struct

getStruct
void* getStruct()

the main Gtk struct as a void*

getStructure
Structure getStructure()

Get the structure of a query.

hasSchedulingMode
bool hasSchedulingMode(GstPadMode mode)

Check if @query has scheduling mode set.

hasSchedulingModeWithFlags
bool hasSchedulingModeWithFlags(GstPadMode mode, GstSchedulingFlags flags)

Check if @query has scheduling mode set and @flags is set in query scheduling flags.

parseAcceptCaps
void parseAcceptCaps(Caps caps)

Get the caps from @query. The caps remains valid as long as @query remains valid.

parseAcceptCapsResult
void parseAcceptCapsResult(bool result)

Parse the result from @query and store in @result.

parseAllocation
void parseAllocation(Caps caps, bool needPool)

Parse an allocation query, writing the requested caps in @caps and whether a pool is needed in @need_pool, if the respective parameters are non-%NULL.

parseBufferingPercent
void parseBufferingPercent(bool busy, int percent)

Get the percentage of buffered data. This is a value between 0 and 100. The @busy indicator is %TRUE when the buffering is in progress.

parseBufferingRange
void parseBufferingRange(GstFormat format, long start, long stop, long estimatedTotal)

Parse an available query, writing the format into @format, and other results into the passed parameters, if the respective parameters are non-%NULL

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

Extracts the buffering stats values from @query.

parseCaps
void parseCaps(Caps filter)

Get the filter from the caps @query. The caps remains valid as long as @query remains valid.

parseCapsResult
void parseCapsResult(Caps caps)

Get the caps result from @query. The caps remains valid as long as @query remains valid.

parseContext
void parseContext(Context context)

Get the context from the context @query. The context remains valid as long as @query remains valid.

parseContextType
bool parseContextType(string contextType)

Parse a context type from an existing GST_QUERY_CONTEXT query.

parseConvert
void parseConvert(GstFormat srcFormat, long srcValue, GstFormat destFormat, long destValue)

Parse a convert query answer. Any of @src_format, @src_value, @dest_format, and @dest_value may be %NULL, in which case that value is omitted.

parseDuration
void parseDuration(GstFormat format, long duration)

Parse a duration query answer. Write the format of the duration into @format, and the value into @duration, if the respective variables are non-%NULL.

parseLatency
void parseLatency(bool live, GstClockTime minLatency, GstClockTime maxLatency)

Parse a latency query answer.

parseNFormats
void parseNFormats(uint nFormats)

Parse the number of formats in the formats @query.

parseNthAllocationMeta
GType parseNthAllocationMeta(uint index, Structure params)

Parse an available query and get the metadata API at @index of the metadata API array.

parseNthAllocationParam
void parseNthAllocationParam(uint index, Allocator allocator, AllocationParams params)

Parse an available query and get the allocator and its params at @index of the allocator array.

parseNthAllocationPool
void parseNthAllocationPool(uint index, BufferPool pool, uint size, uint minBuffers, uint maxBuffers)

Get the pool parameters in @query.

parseNthBufferingRange
bool parseNthBufferingRange(uint index, long start, long stop)

Parse an available query and get the start and stop values stored at the @index of the buffered ranges array.

parseNthFormat
void parseNthFormat(uint nth, GstFormat format)

Parse the format query and retrieve the @nth format from it into @format. If the list contains less elements than @nth, @format will be set to GST_FORMAT_UNDEFINED.

parseNthSchedulingMode
GstPadMode parseNthSchedulingMode(uint index)

Parse an available query and get the scheduling mode at @index of the scheduling modes array.

parsePosition
void parsePosition(GstFormat format, long cur)

Parse a position query, writing the format into @format, and the position into @cur, if the respective parameters are non-%NULL.

parseScheduling
void parseScheduling(GstSchedulingFlags flags, int minsize, int maxsize, int alig)

Set the scheduling properties.

parseSeeking
void parseSeeking(GstFormat format, bool seekable, long segmentStart, long segmentEnd)

Parse a seeking query, writing the format into @format, and other results into the passed parameters, if the respective parameters are non-%NULL

parseSegment
void parseSegment(double rate, GstFormat format, long startValue, long stopValue)

Parse a segment query answer. Any of @rate, @format, @start_value, and @stop_value may be %NULL, which will cause this value to be omitted.

parseUri
void parseUri(string uri)

Parse an URI query, writing the URI into @uri as a newly allocated string, if the respective parameters are non-%NULL. Free the string with g_free() after usage.

parseUriRedirection
void parseUriRedirection(string uri)

Parse an URI query, writing the URI into @uri as a newly allocated string, if the respective parameters are non-%NULL. Free the string with g_free() after usage.

parseUriRedirectionPermanent
void parseUriRedirectionPermanent(bool permanent)

Parse an URI query, and set @permanent to %TRUE if there is a redirection and it should be considered permanent. If a redirection is permanent, applications should update their internal storage of the URI, otherwise they should make all future requests to the original URI.

removeNthAllocationMeta
void removeNthAllocationMeta(uint index)

Remove the metadata API at @index of the metadata API array.

removeNthAllocationParam
void removeNthAllocationParam(uint index)

Remove the allocation param at @index of the allocation param array.

removeNthAllocationPool
void removeNthAllocationPool(uint index)

Remove the allocation pool at @index of the allocation pool array.

setAcceptCapsResult
void setAcceptCapsResult(bool result)

Set @result as the result for the @query.

setBufferingPercent
void setBufferingPercent(bool busy, int percent)

Set the percentage of buffered data. This is a value between 0 and 100. The @busy indicator is %TRUE when the buffering is in progress.

setBufferingRange
void setBufferingRange(GstFormat format, long start, long stop, long estimatedTotal)

Set the available query result fields in @query.

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

Configures the buffering stats values in @query.

setCapsResult
void setCapsResult(Caps caps)

Set the @caps result in @query.

setContext
void setContext(Context context)

Answer a context query by setting the requested context.

setConvert
void setConvert(GstFormat srcFormat, long srcValue, GstFormat destFormat, long destValue)

Answer a convert query by setting the requested values.

setDuration
void setDuration(GstFormat format, long duration)

Answer a duration query by setting the requested value in the given format.

setFormatsv
void setFormatsv(GstFormat[] formats)

Set the formats query result fields in @query. The number of formats passed in the @formats array must be equal to @n_formats.

setLatency
void setLatency(bool live, GstClockTime minLatency, GstClockTime maxLatency)

Answer a latency query by setting the requested values in the given format.

setNthAllocationParam
void setNthAllocationParam(uint index, Allocator allocator, AllocationParams params)

Parse an available query and get the allocator and its params at @index of the allocator array.

setNthAllocationPool
void setNthAllocationPool(uint index, BufferPool pool, uint size, uint minBuffers, uint maxBuffers)

Set the pool parameters in @query.

setPosition
void setPosition(GstFormat format, long cur)

Answer a position query by setting the requested value in the given format.

setScheduling
void setScheduling(GstSchedulingFlags flags, int minsize, int maxsize, int alig)

Set the scheduling properties.

setSeeking
void setSeeking(GstFormat format, bool seekable, long segmentStart, long segmentEnd)

Set the seeking query result fields in @query.

setSegment
void setSegment(double rate, GstFormat format, long startValue, long stopValue)

Answer a segment query by setting the requested values. The normal playback segment of a pipeline is 0 to duration at the default rate of 1.0. If a seek was performed on the pipeline to play a different segment, this query will return the range specified in the last seek.

setUri
void setUri(string uri)

Answer a URI query by setting the requested URI.

setUriRedirection
void setUriRedirection(string uri)

Answer a URI query by setting the requested URI redirection.

setUriRedirectionPermanent
void setUriRedirectionPermanent(bool permanent)

Answer a URI query by setting the requested URI redirection to permanent or not.

writableStructure
Structure writableStructure()

Get the structure of a query. This method should be called with a writable @query so that the returned structure is guaranteed to be writable.

Static functions

getType
GType getType()
newAcceptCaps
Query newAcceptCaps(Caps caps)

Constructs a new query object for querying if caps are accepted. Free-function: gst_query_unref

newDrain
Query newDrain()

Constructs a new query object for querying the drain state. Free-function: gst_query_unref

newDuration
Query newDuration(GstFormat format)

Constructs a new stream duration query object to query in the given format. Use gst_query_unref() when done with it. A duration query will give the total length of the stream.

newFormats
Query newFormats()

Constructs a new query object for querying formats of the stream.

newLatency
Query newLatency()

Constructs a new latency query object. Use gst_query_unref() when done with it. A latency query is usually performed by sinks to compensate for additional latency introduced by elements in the pipeline. Free-function: gst_query_unref

newPosition
Query newPosition(GstFormat format)

Constructs a new query stream position query object. Use gst_query_unref() when done with it. A position query is used to query the current position of playback in the streams, in some format.

newScheduling
Query newScheduling()

Constructs a new query object for querying the scheduling properties. Free-function: gst_query_unref

newSeeking
Query newSeeking(GstFormat format)

Constructs a new query object for querying seeking properties of the stream.

newSegment
Query newSegment(GstFormat format)

Constructs a new segment query object. Use gst_query_unref() when done with it. A segment query is used to discover information about the currently configured segment for playback.

newUri
Query newUri()

Constructs a new query URI query object. Use gst_query_unref() when done with it. An URI query is used to query the current URI that is used by the source or sink. Free-function: gst_query_unref

typeGetFlags
GstQueryTypeFlags typeGetFlags(GstQueryType type)

Gets the #GstQueryTypeFlags associated with @type.

typeGetName
string typeGetName(GstQueryType type)

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

typeToQuark
GQuark typeToQuark(GstQueryType type)

Get the unique quark for the given query type.

Variables

gstQuery
GstQuery* gstQuery;

the main Gtk struct

ownedRef
bool ownedRef;
Undocumented in source.

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