Crate gstreamer[][src]


pub use ffi;
pub use glib;
pub use paste;
pub use crate::message::Message;
pub use crate::message::MessageErrorDomain;
pub use crate::message::MessageRef;
pub use crate::message::MessageView;
pub use crate::structure::Structure;
pub use crate::structure::StructureRef;
pub use crate::caps::Caps;
pub use crate::caps::CapsRef;
pub use crate::tags::tag_exists;
pub use crate::tags::tag_get_description;
pub use crate::tags::tag_get_flag;
pub use crate::tags::tag_get_nick;
pub use crate::tags::tag_get_type;
pub use crate::tags::Tag;
pub use crate::tags::TagList;
pub use crate::tags::TagListRef;
pub use crate::meta::MetaSeqnum;
pub use crate::meta::ReferenceTimestampMeta;
pub use crate::meta::Meta;
pub use crate::meta::MetaAPI;
pub use crate::meta::MetaRef;
pub use crate::meta::MetaRefMut;
pub use crate::meta::ParentBufferMeta;
pub use crate::meta::ProtectionMeta;
pub use crate::buffer::Buffer;
pub use crate::buffer::BufferMap;
pub use crate::buffer::BufferRef;
pub use crate::buffer::MappedBuffer;
pub use crate::buffer::BUFFER_COPY_ALL;
pub use crate::buffer::BUFFER_COPY_METADATA;
pub use crate::memory::MappedMemory;
pub use crate::memory::Memory;
pub use crate::memory::MemoryMap;
pub use crate::memory::MemoryRef;
pub use crate::sample::Sample;
pub use crate::sample::SampleRef;
pub use crate::bufferlist::BufferList;
pub use crate::bufferlist::BufferListRef;
pub use crate::query::Query;
pub use crate::query::QueryRef;
pub use crate::query::QueryView;
pub use crate::event::Event;
pub use crate::event::EventRef;
pub use crate::event::EventView;
pub use crate::event::GroupId;
pub use crate::event::Seqnum;
pub use crate::context::Context;
pub use crate::context::ContextRef;
pub use promise::Promise;
pub use promise::PromiseError;
pub use crate::format::FormattedValue;
pub use crate::format::FormattedValueIntrinsic;
pub use crate::format::GenericFormattedValue;
pub use crate::format::SpecificFormattedValue;
pub use crate::format::SpecificFormattedValueIntrinsic;
pub use crate::toc::Toc;
pub use crate::toc::TocEntry;
pub use crate::toc::TocEntryRef;
pub use crate::toc::TocRef;
pub use crate::functions::*;





Parameters to control the allocation of memory

Memory is usually created by allocators with a AllocatorExt::alloc() method call. When None is used as the allocator, the default allocator will be used.

Bin is an element that can contain other Element, allowing them to be managed as a group. Pads from the child elements can be ghosted to the bin, see GhostPad. This makes the bin look like any other elements and enables creation of higher-level abstraction elements.

GstBinFlags are a set of flags specific to bins. Most are set/used internally. They can be checked using the GST_OBJECT_FLAG_IS_SET() macro, and (un)set using GST_OBJECT_FLAG_SET() and GST_OBJECT_FLAG_UNSET().

A set of flags that can be provided to the [Buffer::copy_into()][crate::Buffer::copy_into()] function to specify which items should be copied.

A set of buffer flags used to describe properties of a Buffer.

A BufferPool is an object that can be used to pre-allocate and recycle buffers of the same size and with the same properties.

Additional flags to control the allocation of a buffer

The Bus is an object responsible for delivering Message packets in a first-in first-out way from the streaming threads (see GstTask) to the application.

CapsFeatures can optionally be set on a Caps to add requirements for additional features for a specific Structure. Caps structures with the same name but with a non-equal set of caps features are not compatible. If a pad supports multiple sets of features it has to add multiple equal structures with different feature sets to the caps.

This interface abstracts handling of property sets for elements with children. Imagine elements such as mixers or polyphonic generators. They all have multiple Pad or some kind of voice objects. Another use case are container elements like Bin. The element implementing the interface acts as a parent for those child objects.

GStreamer uses a global clock to synchronize the plugins in a pipeline. Different clock implementations are possible by implementing this abstract base class or, more conveniently, by subclassing SystemClock.

The capabilities of this clock

A base class for value mapping objects that attaches control sources to glib::Object properties. Such an object is taking one or more ControlSource instances, combines them and maps the resulting value to the type and value range of the bound property.

The ControlSource is a base class for control value sources that could be used to get timestamp-value pairs. A control source essentially is a function over time.

Struct to store date, time and timezone information altogether. DateTime is refcounted and immutable.

These are some terminal style flags you can use when creating your debugging categories to make them stand out in debugging output.

Available details for pipeline graphs produced by GST_DEBUG_BIN_TO_DOT_FILE() and GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS().

Device are objects representing a device, they contain relevant metadata about the device, such as its class and the Caps representing the media types it can produce or handle.

Applications should create a DeviceMonitor when they want to probe, list and monitor devices of a specific type. The DeviceMonitor will create the appropriate DeviceProvider objects and manage them. It will then post messages on its Bus for devices that have been added and removed.

A DeviceProvider subclass is provided by a plugin that handles devices if there is a way to programmatically list connected devices. It can also optionally provide updates to the list of connected devices.

DeviceProviderFactory is used to create instances of device providers. A GstDeviceProviderfactory can be added to a Plugin as it is also a PluginFeature.

GstElement is the abstract base class needed to construct an element that can be used in a GStreamer pipeline. Please refer to the plugin writers guide for more information on creating Element subclasses.

ElementFactory is used to create instances of elements. A GstElementFactory can be added to a Plugin as it is also a PluginFeature.

The standard flags that an element may have.

EventTypeFlags indicate the aspects of the different EventType values. You can get the type flags of a EventType with the EventType::flags() function.

The different flags that can be set on EventType::Gap events. See [Event::set_gap_flags()][crate::Event::set_gap_flags()] for details.

GhostPads are useful when organizing pipelines with Bin like elements. The idea here is to create hierarchical element graphs. The bin element contains a sub-graph. Now one would like to treat the bin-element like any other Element. This is where GhostPads come into play. A GhostPad acts as a proxy for another pad. Thus the bin can have sink and source ghost-pads that are associated with sink and source pads of the child elements.

Flags for wrapped memory.

Object provides a root for the object hierarchy tree filed in by the GStreamer library. It is currently a thin wrapper on top of GInitiallyUnowned. It is an abstract class that is not very usable on its own.

The standard flags that an gstobject may have.

A Element is linked to other elements via “pads”, which are extremely light-weight generic link points.

Pad state flags

The amount of checking to be done when linking pads. CAPS and TEMPLATE_CAPS are mutually exclusive. If both are specified, expensive but safe CAPS are performed.

The different probing types that can occur. When either one of IDLE or BLOCK is used, the probe will be a blocking probe.

Padtemplates describe the possible media types a pad or an elementfactory can handle. This allows for both inspection of handled types before loading the element plugin as well as identifying pads on elements that are not yet created (request or sometimes pads).

Opaque structure.

Parsing options.

A Pipeline is a special Bin used as the toplevel container for the filter graph. The Pipeline will manage the selection and distribution of a global Clock as well as provide a Bus to the application.

Pipeline flags

GStreamer is extensible, so Element instances can be loaded at runtime. A plugin system can provide one or more of the basic GStreamer PluginFeature subclasses.

Flags used in connection with Plugin::add_dependency().

This is a base class for anything that can be added to a Plugin.

The plugin loading state

This interface offers methods to query and manipulate parameter preset sets. A preset is a bunch of property settings, together with meta data and a name. The name of a preset serves as key for subsequent method calls to manipulate single presets. All instances of one type will share the list of presets. The list is created on demand, if presets are not used, the list is not created.


One registry holds the metadata of a set of plugins.

The different scheduling flags.

Flags to be used with ElementExtManual::seek() or gst_event_new_seek(). All flags can be used together.

Flags for the GstSegment structure. Currently mapped to the corresponding values of the seek flags.

Data structure to initialize Caps from a string description usually used in conjunction with GST_STATIC_CAPS() and get() to instantiate a Caps.

Structure describing the StaticPadTemplate.

A high-level object representing a single stream. It might be backed, or not, by an actual flow of data in a pipeline (Pad).

A collection of Stream that are available.

StreamType describes a high level classification set for flows of data in Stream objects.

The GStreamer core provides a GstSystemClock based on the system time. Asynchronous callbacks are scheduled from an internal thread.

Element interface that allows setting of media metadata.

Element interface that allows setting of the TOC.

Tracing modules will subclass Tracer and register through gst_tracer_register(). Modules can attach to various hook-types - see [tracing_register_hook()][crate::tracing_register_hook()]. When invoked they receive hook specific contextual data, which they must not modify.

Use list() to get a list of tracer factories known to GStreamer.

The following functions allow you to detect the media type of an unknown stream.

These functions allow querying information about registered typefind functions. How to create and register these functions is described in the section “Writing typefind functions”</link>.

The URIHandler is an interface that is implemented by Source and Sink Element to unify handling of URI.


The different types of buffering methods.

The result values for a GstBusSyncHandler.

Modes of caps intersection

The type of the clock entry

The return value of a clock operation.

The different kind of clocks.

Core errors are errors inside the core GStreamer library.

The level defines the importance of a debugging message. The more important a message is, the greater the probability that the debugging system outputs it.

EventType lists the standard event types that can be sent in a pipeline.

The result of passing data to a pad.

Standard predefined formats

Library errors are for errors from the library being used by elements (initializing, finalizing, settings, …)

The direction of a pad.

Result values from gst_pad_link and friends.

The status of a GstPad. After activating a pad, which usually happens when the parent element goes from READY to PAUSED, the GstPadMode defines if the pad operates in push or pull mode.

Indicates when this pad will become available.

Different return values for the GstPadProbeCallback.

The different parsing errors that can occur.

The plugin loading errors

The type of a GST_MESSAGE_PROGRESS. The progress messages inform the application of the status of asynchronous tasks.

The result of a Promise

The different types of QoS events that can be given to the gst_event_new_qos() method.

Element priority ranks. Defines the order in which the autoplugger (or similar rank-picking mechanisms, such as e.g. Element::make_from_uri()) will choose this element over an alternative one with the same function.

Resource errors are for any resource used by an element: memory, files, network connections, process space, … They’re typically used by source and sink elements.

The different types of seek events. When constructing a seek event with gst_event_new_seek() or when doing gst_segment_do_seek ().

The possible states an element can be in. States can be changed using ElementExt::set_state() and checked using ElementExt::state().

These are the different state changes an element goes through. State::NullState::Playing is called an upwards state change and State::PlayingState::Null a downwards state change.

The possible return values from a state change function such as ElementExt::set_state(). Only Failure is a real failure.

Stream errors are for anything related to the stream being processed: format errors, media type errors, … They’re typically used by decoders, demuxers, converters, …

The type of a GST_MESSAGE_STREAM_STATUS. The stream status messages inform the application of new streaming threads and their status.


Extra tag flags used when registering tags.

The different tag merging modes are basically replace, overwrite and append, but they can be seen from two directions. Given two taglists: (A) the tags already in the element and (B) the ones that are supplied to the element ( e.g. via TagSetterExt::merge_tags() / gst_tag_setter_add_tags() or a EventType::Tag), how are these tags merged? In the table below this is shown for the cases that a tag exists in the list (A) or does not exists (!A) and combinations thereof.

GstTagScope specifies if a taglist applies to the complete medium or only to one single stream.

The different states a task can be in

The different types of TOC entries (see TocEntry).

How a TocEntry should be repeated. By default, entries are played a single time.

The scope of a TOC.

The probability of the typefind function. Higher values have more certainty in doing a reliable typefind.

Different URI-related errors that can occur.

The different types of URI direction.



Name and contact details of the author(s). Use \n to separate multiple author details. E.g: “Joe Bloggs <joe.blogs at>”

Sentence describing the purpose of the element. E.g: “Write stream to a file”

Set uri pointing to user documentation. Applications can use this to show help for e.g. effects to users.

Elements that bridge to certain other products can include an icon of that used product. Application can show the icon in menus/selectors to help identifying specific elements.

String describing the type of element, as an unordered list separated with slashes (‘/’). See draft-klass.txt of the design docs for more details and common types. E.g: “Sink/File”

The long English name of the element. E.g. “File Sink”



Adds a memory ringbuffer based debug logger that stores up to max_size_per_thread bytes of logs per thread and times out threads after thread_timeout seconds of inactivity.

To aid debugging applications one can use this method to obtain the whole network of gstreamer elements that form the pipeline into a dot file. This data can be processed with graphviz to get an image.

To aid debugging applications one can use this method to write out the whole network of gstreamer elements that form the pipeline into a dot file. This file can be processed with graphviz to get an image.

This works like debug_bin_to_dot_file(), but adds the current timestamp to the filename, so that it can be used to take multiple snapshots.

Returns the default threshold that is used for new categories.


Checks if debugging output is activated.

Checks if the debugging output should be colored.

If libunwind, glibc backtrace or DbgHelp are present a stack trace is printed.

Removes any previously added ring buffer logger with debug_add_ring_buffer_logger().

Fetches the current logs per thread from the ring buffer logger. See debug_add_ring_buffer_logger() for details.

If activated, debugging messages are sent to the debugging handlers. It makes sense to deactivate it for speed issues.

Sets or unsets the use of coloured debugging output. Same as gst_debug_set_color_mode () with the argument being being GST_DEBUG_COLOR_MODE_ON or GST_DEBUG_COLOR_MODE_OFF.

Sets the default threshold to the given level and updates all categories to use this threshold.

Sets all categories which match the given glob style pattern to the given level.

Sets the debug logging wanted in the same form as with the GST_DEBUG environment variable. You can use wildcards such as ‘*’, but note that the order matters when you use wild cards, e.g. “foosrc:6,src:3,:2” sets everything to log level 2.

Resets all categories with the given name back to the default level.

Deinitialize GStreamer

Initializes the GStreamer library, setting up internal path lists, registering built-in elements, and loading standard plugins.

This helper is mostly helpful for plugins that need to inspect the folder of the main executable to determine their set of features.

This is a convenience wrapper around parse_launch() to create a Bin from a gst-launch-style pipeline description. See parse_launch() and the gst-launch man page for details about the syntax. Ghost pads on the bin for unlinked source or sink pads within the bin can automatically be created (but only a maximum of one ghost pad for each direction will be created; if you expect multiple unlinked source pads or multiple unlinked sink pads and want them all ghosted, you will have to create the ghost pads yourself).

Create a new pipeline based on command line syntax. Please note that you might get a return value that is not None even though the error is set. In this case there was a recoverable parsing error and you can try to play the pipeline.

Create a new element based on command line syntax. error will contain an error message if an erroneous pipeline is specified. An error does not mean that the pipeline could not be constructed.

Get a list of all active tracer objects owned by the tracing framework for the entirety of the run-time of the process or till gst_deinit() is called.

Marks type_ as plugin API. This should be called in class_init of elements that expose new types (i.e. enums, flags or internal GObjects) via properties, signals or pad templates.

Forces GStreamer to re-scan its plugin paths and update the default plugin registry.

Get a timestamp as GstClockTime to be used for interval measurements. The timestamp should not be interpreted in any other way.

Gets the version number of the GStreamer library.

This function returns a string that is useful for describing this version of GStreamer to the outside world: user agent strings, logging, …

Type Definitions