Sets our main struct and passes it to the parent class
Constructs a new custom query object. Use gst_query_unref() when done with it. Free-function: gst_query_unref
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. Free-function: gst_query_unref
Constructs a new query object for querying the caps. The CAPS query should return the allowable caps for a pad in the context of the element's state, its link to other elements, and the devices or files it has opened. These caps must be a subset of the pad template caps. In the NULL state with no links, the CAPS query should ideally return the same caps as the pad template. In rare circumstances, an object property can affect the caps returned by the CAPS query, but this is discouraged. For most filters, the caps returned by CAPS query is directly affected by the allowed caps on other pads. For demuxers and decoders, the caps returned by the srcpad's getcaps function is directly related to the stream data. Again, the CAPS query should return the most specific caps it reasonably can, since this helps with autoplugging. The filter is used to restrict the result caps, only the caps matching filter should be returned from the CAPS query. Specifying a filter might greatly reduce the amount of processing an element needs to do. Free-function: gst_query_unref
Constructs a new query object for querying the buffering status of a stream. Free-function: gst_query_unref
Constructs a new query object for querying the allocation properties. Free-function: gst_query_unref
Constructs a new query object for querying the pipeline-local context. Free-function: gst_query_unref Since 1.2
Add api with params as one of the supported metadata API to query.
Add allocator and its params as a supported memory allocator.
Set the pool parameters in query.
Set the buffering-ranges array field in query. The current last start position of the array should be inferior to start.
Add mode as aone of the supported scheduling modes to query.
Copies the given query using the copy function of the parent GstStructure. Free-function: gst_query_unref
Increases the refcount of the given query by one.
Check if query has metadata api set. When this function returns TRUE, index will contain the index where the requested API and the flags can be found.
Retrieve the number of values currently stored in the meta API array of the query's structure.
Retrieve the number of values currently stored in the allocator params array of the query's structure. If no memory allocator is specified, the downstream element can handle the default memory allocator. The first memory allocator in the query should be generic and allow mapping to system memory, all following allocators should be ordered by preference with the preferred one first.
Retrieve the number of values currently stored in the pool array of the query's structure.
Retrieve the number of values currently stored in the buffered-ranges array of the query's structure.
Retrieve the number of values currently stored in the scheduling mode array of the query's structure.
the main Gtk struct as a void*
Get the structure of a query.
Check if query has scheduling mode set. Note When checking if upstream supports pull mode, it is usually not enough to just check for GST_PAD_MODE_PULL with this function, you also want to check whether the scheduling flags returned by gst_query_parse_scheduling() have the seeking flag set (meaning random access is supported, not only sequential pulls).
Check if query has scheduling mode set and flags is set in query scheduling flags.
Get the caps from query. The caps remains valid as long as query remains valid.
Parse the result from query and store in result.
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.
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.
Parse an available query, writing the format into format, and other results into the passed parameters, if the respective parameters are non-NULL
Extracts the buffering stats values from query.
Get the filter from the caps query. The caps remains valid as long as query remains valid.
Get the caps result from query. The caps remains valid as long as query remains valid.
Get the context from the context query. The context remains valid as long as query remains valid. Since 1.2
Parse a context type from an existing GST_QUERY_CONTEXT query. Since 1.2
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.
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.
Parse a latency query answer.
Parse the number of formats in the formats query.
Parse an available query and get the metadata API at index of the metadata API array.
Parse an available query and get the alloctor and its params at index of the allocator array.
Get the pool parameters in query. Unref pool with gst_object_unref() when it's not needed any more.
Parse an available query and get the start and stop values stored at the index of the buffered ranges array.
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.
Parse an available query and get the scheduling mode at index of the scheduling modes array.
Parse a position query, writing the format into format, and the position into cur, if the respective parameters are non-NULL.
Set the scheduling properties.
Parse a seeking query, writing the format into format, and other results into the passed parameters, if the respective parameters are non-NULL
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. See gst_query_set_segment() for an explanation of the function arguments.
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.
Remove the metadata API at index of the metadata API array.
Remove the allocation param at index of the allocation param array. Since 1.2
Remove the allocation pool at index of the allocation pool array. Since 1.2
Set result as the result for the query.
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.
Set the available query result fields in query.
Configures the buffering stats values in query.
Set the caps result in query.
Answer a context query by setting the requested context. Since 1.2
Answer a convert query by setting the requested values.
Answer a duration query by setting the requested value in the given format.
Set the formats query result fields in query. The number of formats passed in the formats array must be equal to n_formats.
Answer a latency query by setting the requested values in the given format.
Parse an available query and get the alloctor and its params at index of the allocator array.
Set the pool parameters in query.
Answer a position query by setting the requested value in the given format.
Set the scheduling properties.
Set the seeking query result fields in query.
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. start_value and stop_value will respectively contain the configured playback range start and stop values expressed in format. The values are always between 0 and the duration of the media and start_value <= stop_value. rate will contain the playback rate. For negative rates, playback will actually happen from stop_value to start_value.
Answer a URI query by setting the requested URI.
Decreases the refcount of the query. If the refcount reaches 0, the query will be freed.
Get the structure of a query. This method should be called with a writable query so that the returned structure is guranteed to be writable.
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.
Modifies a pointer to a GstQuery to point to a different GstQuery. The modification is done atomically (so this is useful for ensuring thread safety in some cases), and the reference counts are updated appropriately (the old query is unreffed, the new one is reffed). Either new_query or the GstQuery pointed to by old_query may be NULL.
Gets the GstQueryTypeFlags associated with type.
Get a printable name for the given query type. Do not modify or free.
Get the unique quark for the given query type.
the main Gtk struct
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:
Last reviewed on 2012-03-29 (0.11.3)