GStreamer Bridge Components

Authors: NVIDIA Corporation (NVIDIA Corporation)
Supported platforms: x86_64, aarch64
Language: C++, Python
Last modified: April 27, 2026
Latest version: 1.0.0
Minimum Holoscan SDK version: 3.8.0
Tested Holoscan SDK versions: 3.8.0
Contribution metric: Level 2 - Trusted

This directory contains components that provide a bridge between Holoscan and GStreamer, enabling integration with the vast ecosystem of GStreamer plugins for video encoding, streaming, and multimedia processing.

Overview

The GStreamer bridge provides:

• Operators for integrating GStreamer functionality into Holoscan pipelines
• Resources for managing GStreamer elements and memory allocation within the Holoscan resource framework
• Low-level bridge objects that can be used in both Holoscan and non-Holoscan applications
• C++ RAII wrappers for safe and convenient GStreamer API usage

These components allow you to:

• Integrate GStreamer's extensive plugin ecosystem into Holoscan applications
• Record and stream video using GStreamer encoders and protocols
• Support both host (CPU) and device (GPU) memory for efficient processing
• Build complex media processing pipelines combining Holoscan and GStreamer
• Use GStreamer functionality in custom applications outside the Holoscan framework

Components

Operators

GstVideoRecorderOp

Records incoming Holoscan tensors to video files using GStreamer encoding pipelines.

This operator is available in both C++ and Python. The Python binding mirrors the C++ interface and supports the same constructor keywords.

Key Features:

• Multiple codec support: H.264 (nvh264, x264), H.265 (nvh265, x265)
• Configurable encoder properties (bitrate, preset, quality, etc.)
• Support for both host and device (CUDA) memory
• MP4 and MKV container output

Input:

• Port "input": Video frames as Holoscan tensors (RGB888/RGBA8888 format)

Parameters:

• filename (string): Output video file path (default: "output.mp4")
• encoder (string): Encoder to use - "nvh264", "nvh265", "x264", "x265" (default: "nvh264")
• format (string): Pixel format - "RGBA", "RGB", "BGRA", "BGR", "GRAY8" (default: "RGBA")
• framerate (string): Target framerate as fraction "num/den" or decimal (default: "30/1")
• properties (map): Encoder-specific properties (e.g., bitrate, preset, gop-size)
• max-buffers (size_t): Maximum number of buffers to queue, 0 = unlimited (default: 10)
• block (bool): Block when queue is full vs. drop/timeout (default: true)

Resources

Resources provide Holoscan-managed wrappers for GStreamer elements and allocators, integrating them into the Holoscan resource lifecycle and memory management system.

Note: Resource implementations will be added in future updates.

Low-Level Bridge Objects

Low-level bridge objects implement core GStreamer integration functionality in a framework-agnostic way. These can be used:

• Within Holoscan applications (via operators and resources)
• In standalone C++ applications without Holoscan dependencies
• In custom integration scenarios

These objects handle the detailed work of data transfer, format conversion, and GStreamer API interaction.

GstSrcBridge

GstSrcBridge is a framework-agnostic class that bridges tensor/video data into GStreamer pipelines via the appsrc element. It can be used independently of Holoscan in any C++ application that needs to feed data into GStreamer.

Key capabilities:

• Push video frames from host or device (CUDA) memory into GStreamer pipelines
• Configurable caps (capabilities) for proper format specification
• Buffer queuing with configurable size limits and blocking behavior
• Support for various pixel formats (RGBA, RGB, NV12, I420, etc.)
• Automatic timestamp generation based on framerate
• End-of-stream (EOS) signaling
• Zero-copy operation when wrapping tensor memory

C++ Wrapper Classes

The bridge includes a set of C++ RAII wrapper classes for GStreamer objects (located in the gst/ subdirectory).

Key wrapper classes include (subset):

• gst::Element: Wrapper for GstElement (pipeline elements)
• gst::Pipeline: Wrapper for GstPipeline (top-level pipelines)
• gst::Bus: Wrapper for GstBus (message handling)
• gst::Caps: Wrapper for GstCaps (media format capabilities)
• gst::Buffer: Wrapper for GstBuffer (data buffers)
• gst::Message: Wrapper for GstMessage (bus messages)
• gst::Allocator: Wrapper for GstAllocator (memory allocation)

These wrappers provide:

• Automatic reference counting and cleanup
• Type-safe property setting with compile-time string conversion
• Convenient API for common GStreamer operations
• Exception-based error handling

Note: These wrapper classes can be used independently in non-Holoscan applications for safer GStreamer programming.

Usage Example

For a complete working example demonstrating how to use GstVideoRecorderOp in a Holoscan application, see the gst_video_recorder application. It shows:

• Integration with V4L2VideoCaptureOp for camera input
• Integration with pattern generators for synthetic video
• Proper use of FormatConverterOp for format handling
• Configuration of encoder properties
• YAML-based configuration

Requirements

System Packages:

A Dockerfile with all dependencies pre-installed is provided at operators/gstreamer/Dockerfile for containerized builds.

For local development, install all required dependencies using the provided script:

./operators/gstreamer/install_deps.sh

Optional (for CUDA support):

• gstreamer1.0-cuda (requires GStreamer 1.24+)

Holoscan SDK:

• Minimum version: 3.8.0

Advanced Configuration

Encoder Properties

Encoder properties are passed directly to the underlying GStreamer encoder element. Common properties include:

NVIDIA H.264/H.265 (nvh264enc/nvh265enc):

• bitrate: Target bitrate in kbps (e.g., "5000")
• preset: Encoding preset 0-3 (0=slowest/best quality, 3=fastest/lower quality)
• gop-size: GOP (Group of Pictures) size in frames

x264/x265 (software encoders):

• bitrate: Target bitrate in kbps
• speed-preset: Encoding speed preset (e.g., "ultrafast", "medium", "slow")
• tune: Tuning preset (e.g., "zerolatency", "film")

For a complete list of available properties, consult the GStreamer plugin documentation or use gst-inspect-1.0 <encoder> (e.g., gst-inspect-1.0 nvh264enc).

CUDA Memory Support

When HOLOSCAN_GSTREAMER_CUDA_SUPPORT is enabled (requires GStreamer 1.24+), the operator automatically detects and uses CUDA memory for zero-copy data transfer from GPU to encoder.

References

• GStreamer Documentation
• Holoscan SDK Documentation
• Application Example: gst_video_recorder

API Reference

C++Python

holoscan::gst::Allocator

Inherits from: holoscan::gst::AllocatorBase< Allocator, ::GstAllocator >

Wrapper class for ::GstAllocator.

Methods

Method	Description
Allocator(::GstAllocator *allocator=nullptr)
Allocator(const AllocatorBase &other)
Allocator(AllocatorBase &&other)
GType get_type_func()

holoscan::gst::AllocatorBase

Inherits from: holoscan::gst::ObjectBase< Derived, NativeType >

Templated base class for GStreamer allocator types (GstAllocator and its derivatives)

Methods

Method	Description
AllocatorBase(NativeType *allocator=nullptr)
AllocatorBase(const ObjectBase< Derived, NativeType > &other)
AllocatorBase(ObjectBase< Derived, NativeType > &&other)

holoscan::gst::AppSink

Inherits from: holoscan::gst::AppSinkBase< AppSink, ::GstAppSink >

Wrapper class for ::GstAppSink.

Methods

Method	Description
AppSink(::GstAppSink *appsink=nullptr)
AppSink(const AppSinkBase &other)
AppSink(AppSinkBase &&other)
::GType get_type_func()

holoscan::gst::AppSinkBase

Inherits from: holoscan::gst::ElementBase< Derived, NativeType >

Base template class for GstAppSink-derived wrappers.

Methods

Method	Description
AppSinkBase(NativeType *appsink=nullptr)
AppSinkBase(const ObjectBase< Derived, NativeType > &other)
AppSinkBase(ObjectBase< Derived, NativeType > &&other)
void set_callbacks(::GstAppSinkCallbacks *callbacks, ::gpointer user_data, ::GDestroyNotify notify)	Set callbacks for the AppSink element.
Sample try_pull_sample(::GstClockTime timeout)	Try to pull a sample from the appsink with timeout.

holoscan::gst::AppSrc

Inherits from: holoscan::gst::AppSrcBase< AppSrc, ::GstAppSrc >

Wrapper class for ::GstAppSrc.

Methods

Method	Description
AppSrc(::GstAppSrc *appsrc=nullptr)
AppSrc(const AppSrcBase &other)
AppSrc(AppSrcBase &&other)
::GType get_type_func()

holoscan::gst::AppSrcBase

Inherits from: holoscan::gst::ElementBase< Derived, NativeType >

Base template class for GstAppSrc-derived wrappers.

Methods

Method	Description
AppSrcBase(NativeType *appsrc=nullptr)
AppSrcBase(const ObjectBase< Derived, NativeType > &other)
AppSrcBase(ObjectBase< Derived, NativeType > &&other)
::GstFlowReturn push_buffer(Buffer buffer)	Push a buffer into the AppSrc element.
::GstFlowReturn end_of_stream()	Signal end of stream to the AppSrc element.

holoscan::gst::BinBase

Inherits from: holoscan::gst::ElementBase< Derived, NativeType >

Templated base class for GStreamer bin types (GstBin, GstPipeline, etc.)

Methods

Method	Description
BinBase(NativeType *bin=nullptr)
BinBase(const ElementBase< Derived, NativeType > &other)
BinBase(ElementBase< Derived, NativeType > &&other)
bool add(const Element &element)	Add a single element to the bin.
void add_many(const Elements &... elements)	Add multiple elements to the bin.
Element get_by_name(const std::string &name) const	Get an element from the bin by name.

holoscan::gst::Pipeline

Inherits from: holoscan::gst::BinBase< Pipeline, ::GstPipeline >

Wrapper class for ::GstPipeline.

Methods

Method	Description
Pipeline(::GstPipeline *pipeline=nullptr)
Pipeline(const BinBase &other)
Pipeline(BinBase &&other)
Pipeline create(const std::string &name)	Create a new pipeline with the given name.
GType get_type_func()

holoscan::gst::Buffer

Inherits from: holoscan::gst::MiniObjectBase< Buffer, ::GstBuffer >

RAII wrapper for GstBuffer with automatic reference counting and member functions.

Methods

Method	Description
Buffer(::GstBuffer *buffer=nullptr)	Constructor from native GstBuffer.
gsize get_size() const	Get buffer size in bytes.
GstBufferFlags flags() const	Get buffer flags.
void append_memory(const gst::Memory &memory)	Append a memory block to the buffer.
guint n_memory() const	Get the number of memory blocks in the buffer.
gst::Memory get_memory(guint idx) const	Get a memory block from the buffer.
bool map(::GstMapInfo *info, ::GstMapFlags flags) const	Map buffer for access.
void unmap(::GstMapInfo *info) const	Unmap previously mapped buffer.
Buffer create()	Create a new empty GStreamer buffer.

holoscan::gst::Bus

Inherits from: holoscan::gst::BusBase< Bus, ::GstBus >

Wrapper class for ::GstBus.

Methods

Method	Description
Bus(::GstBus *bus=nullptr)
Bus(const BusBase &other)
Bus(BusBase &&other)
GType get_type_func()

holoscan::gst::BusBase

Inherits from: holoscan::gst::ObjectBase< Derived, NativeType >

Templated base class for GStreamer bus types (GstBus and its derivatives)

Methods

Method	Description
BusBase(NativeType *bus=nullptr)
BusBase(const ObjectBase< Derived, NativeType > &other)
BusBase(ObjectBase< Derived, NativeType > &&other)
Message pop_filtered(::GstMessageType types) const	Pop a message from the bus with filtering (non-blocking)
Message timed_pop_filtered(::GstClockTime timeout, ::GstMessageType types) const	Pop a message from the bus with timeout and filtering.

holoscan::gst::Caps

Inherits from: holoscan::gst::MiniObjectBase< Caps, ::GstCaps >

RAII wrapper for GstCaps with automatic reference counting and member functions.

Methods

Method	Description
Caps(::GstCaps *caps=nullptr)	Constructor from GstCaps pointer (takes ownership)
Caps(const std::string &caps_string)	Constructor from caps string.
const char * get_structure_name(guint index=0) const	Get the name of the first structure in the caps.
const GValue * get_structure_value(const char *fieldname, guint index=0) const	Get the value of a specific field in a specific structure.
::GstStructure * get_structure(guint index=0) const	Get a structure from the caps at the specified index.
std::optional<VideoInfo> get_video_info() const	Extract video format information from caps.
bool is_empty() const	Check if caps are empty (follows GStreamer semantics) Note: Empty caps means gst_caps_new_empty(), NOT nullptr.
guint get_size() const	Get the number of structures in caps.
bool has_feature(const char *feature_name) const	Check if caps contain a specific feature.
std::string to_string() const	Convert caps to human-readable string.

holoscan::gst::Element

Inherits from: holoscan::gst::ElementBase< Element, ::GstElement >

Wrapper class for ::GstElement.

Methods

Method	Description
Element(::GstElement *element=nullptr)
Element(const ElementBase &other)
Element(ElementBase &&other)
GType get_type_func()

holoscan::gst::ElementBase

Inherits from: holoscan::gst::ObjectBase< Derived, NativeType >

Templated base class for GStreamer element types (GstElement and its derivatives)

Methods

Method	Description
ElementBase(NativeType *element=nullptr)
ElementBase(const ObjectBase< Derived, NativeType > &other)
ElementBase(ObjectBase< Derived, NativeType > &&other)
Bus get_bus() const	Get the bus from this element.
::GstStateChangeReturn set_state(::GstState state)	Set the state of this element.
::GstStateChangeReturn get_state(::GstState *state, ::GstState *pending, ::GstClockTime timeout=GST_CLOCK_TIME_NONE) const	Get the state of this element.
bool link(const T &dest) const	Link this element to another element.
bool link_many(Elements &&... elements) const	Link this element to multiple elements in sequence.
std::string get_name() const	Get the name of this element.
Pad get_static_pad(const std::string &name) const	Get a static pad from this element.

holoscan::gst::Error

RAII wrapper for GError with automatic cleanup.

Methods

Method	Description
Error(::GError *error=nullptr)	Constructor from raw pointer (takes ownership)
::GError * get() const	Get the raw pointer.
const ::GError * operator->() const	Access GError members directly.
operator bool() const	Bool conversion.

holoscan::GstSinkBridge

Bridge between GStreamer and external data consumers.

Methods

Method	Description
GstSinkBridge(const std::string &name, const std::string &caps_string, size_t max_buffers, bool qos)	Constructor - creates and initializes the GStreamer appsink element.
GstSinkBridge(const GstSinkBridge &)=delete
GstSinkBridge & operator=(const GstSinkBridge &)=delete
GstSinkBridge(GstSinkBridge &&)=delete
GstSinkBridge & operator=(GstSinkBridge &&)=delete
gst::Element get_gst_element() const	Get the underlying GStreamer element.
std::shared_future<void> get_eos_future() const	Get a future that will be ready when EOS is received by the appsink.
std::future<gst::Buffer> pull_buffer()	Asynchronously pull the next buffer from the GStreamer pipeline.
TensorMap create_tensor_map_from_buffer(gst::Buffer buffer) const	Create a TensorMap from GStreamer buffer with zero-copy.
gst::Caps get_current_caps() const	Get the current negotiated caps from the sink pad.

holoscan::GstSinkOp

Inherits from: Operator

Operator for bridging GStreamer data into Holoscan.

Methods

Method	Description
void setup(OperatorSpec &spec) override	Setup the operator specification.
void compute(InputContext &input, OutputContext &output, ExecutionContext &context) override	Compute function that processes GStreamer buffers.

holoscan::GstSinkResource

Inherits from: Resource

Holoscan Resource that wraps GstSinkBridge for GStreamer pipeline integration.

Methods

Method	Description
void setup(ComponentSpec &spec) override	Setup the resource parameters.
void initialize() override	Initialize the GStreamer sink resource.
std::shared_future<gst::Element> get_gst_element() const	Get the underlying GStreamer element.
std::future<gst::Buffer> pull_buffer()	Asynchronously pull the next buffer from the GStreamer pipeline.
TensorMap create_tensor_map_from_buffer(gst::Buffer buffer) const	Create a TensorMap from GStreamer buffer with zero-copy.

holoscan::GstSrcBridge

Bridge between GStreamer and external data sources.

Methods

Method	Description
GstSrcBridge(const std::string &name, const std::string &caps_string, size_t max_buffers, bool block=true)	Constructor - creates and initializes the GStreamer appsrc element.
GstSrcBridge(const GstSrcBridge &)=delete
GstSrcBridge & operator=(const GstSrcBridge &)=delete
GstSrcBridge(GstSrcBridge &&)=delete
GstSrcBridge & operator=(GstSrcBridge &&)=delete
gst::Element get_gst_element() const	Get the underlying GStreamer element.
bool send_eos()	Send End-Of-Stream signal to appsrc.
bool push_buffer(gst::Buffer buffer)	Push a buffer into the GStreamer pipeline.
gst::Buffer create_buffer_from_tensor_map(const TensorMap &tensor_map)	Create a GStreamer buffer from a TensorMap.
gst::Caps get_current_caps() const	Get the current negotiated caps from the source pad.

holoscan::GstSrcOp

Inherits from: Operator

Operator for bridging Holoscan data into GStreamer.

Methods

Method	Description
void setup(OperatorSpec &spec) override	Setup the operator specification.
void compute(InputContext &input, OutputContext &output, ExecutionContext &context) override	Compute function that processes Holoscan entities.
void stop() override	Stop function called when operator execution ends.

holoscan::GstSrcResource

Inherits from: Resource

Holoscan Resource that wraps GstSrcBridge for GStreamer pipeline integration.

Methods

Method	Description
void setup(ComponentSpec &spec) override	Setup the resource parameters.
void initialize() override	Initialize the GStreamer source resource.
std::shared_future<gst::Element> get_gst_element() const	Get the underlying GStreamer element.
bool send_eos()	Send End-Of-Stream signal to appsrc.
bool push_buffer(gst::Buffer buffer)	Push a buffer into the GStreamer pipeline.
gst::Buffer create_buffer_from_tensor_map(const TensorMap &tensor_map) const	Create a GStreamer buffer from a TensorMap.

holoscan::GstVideoRecorderOp

Inherits from: Operator

Operator for recording video streams to file using GStreamer.

Methods

Method	Description
void setup(OperatorSpec &spec) override	Setup the operator specification.
void start() override	Start function called after initialization but before first compute.
void compute(InputContext &input, OutputContext &output, ExecutionContext &context) override	Compute function that processes video frames.
void stop() override	Stop function called when recording ends.

holoscan::GstWaitGroup

GstWaitGroup for tracking active operations and waiting for completion.

Methods

Method	Description
GstWaitGroup()	Construct a GstWaitGroup with initial count of 0.
GstWaitGroup(const GstWaitGroup &)=delete
GstWaitGroup & operator=(const GstWaitGroup &)=delete
GstWaitGroup(GstWaitGroup &&)=delete
GstWaitGroup & operator=(GstWaitGroup &&)=delete
void add()	Increment the counter.
void done()	Decrement the counter and notify waiters if it reaches zero.
void wait()	Wait until the counter reaches zero.
size_t count() const	Get the current counter value.

holoscan::GstWaitGroupGuard

RAII guard for GstWaitGroup add/done.

Methods

Method	Description
GstWaitGroupGuard(GstWaitGroup &wg)
GstWaitGroupGuard(const GstWaitGroupGuard &)=delete
GstWaitGroupGuard & operator=(const GstWaitGroupGuard &)=delete
GstWaitGroupGuard(GstWaitGroupGuard &&)=delete
GstWaitGroupGuard & operator=(GstWaitGroupGuard &&)=delete

holoscan::gst::Memory

Inherits from: holoscan::gst::MiniObjectBase< Memory, ::GstMemory >

RAII wrapper for GstMemory with automatic cleanup.

Methods

Method	Description
Memory(::GstMemory *memory=nullptr)	Constructor from raw pointer (takes ownership)
gsize get_sizes(gsize *offset=nullptr, gsize *max_size=nullptr) const	Get the size of the memory.
bool map(::GstMapInfo *info, ::GstMapFlags flags) const	Map memory for access.
void unmap(::GstMapInfo *info) const	Unmap previously mapped memory.
Memory create_wrapped(::GstMemoryFlags flags, void *data, gsize maxsize, gsize offset, gsize size, void *user_data, ::GDestroyNotify notify)	Create a memory object that wraps existing data.

holoscan::gst::Message

Inherits from: holoscan::gst::MiniObjectBase< Message, ::GstMessage >

RAII wrapper for GstMessage with automatic cleanup.

Methods

Method	Description
Message(::GstMessage *message=nullptr)	Constructor from raw pointer (takes ownership)
::GstMessageType get_type() const	Get the type of this message.
Error parse_error() const	Parse error message and extract error information.
Error parse_error(std::string &debug_info) const	Parse error message and extract error and debug information.
void parse_state_changed(::GstState *oldstate, ::GstState *newstate, ::GstState *pending) const	Parse state changed message and extract state information.

holoscan::gst::MiniObjectBase

Inherits from: holoscan::gst::GstWrapperBase

Internal RAII base class for GStreamer GstMiniObject types with automatic cleanup.

Methods

Method	Description
MiniObjectBase(NativeType *object=nullptr)
NativeType * get() const
NativeType * operator->() const
operator bool() const
Derived & ref()
const Derived & ref() const
void reset()

holoscan::gst::ObjectBase

Inherits from: holoscan::gst::GstWrapperBase

Internal RAII base class for GStreamer GstObject types with automatic cleanup.

Methods

Method	Description
ObjectBase(NativeType *object=nullptr)
NativeType * get() const
NativeType * operator->() const
operator bool() const
Derived & ref()	Increment GStreamer reference count (advanced: for external ownership transfer)
const Derived & ref() const	Const overload of ref() for const objects.
Derived & ref_sink()	Sink floating reference.
const Derived & ref_sink() const
void set_properties(Args &&... args)
bool find_and_set_property(const std::string &name, const std::string &value)
void reset()

holoscan::gst::Pad

Inherits from: holoscan::gst::PadBase< Pad, ::GstPad >

Wrapper class for ::GstPad.

Methods

Method	Description
Pad(::GstPad *pad=nullptr)
Pad(const PadBase &other)
Pad(PadBase &&other)
GType get_type_func()

holoscan::gst::PadBase

Inherits from: holoscan::gst::ObjectBase< Derived, NativeType >

Templated base class for GStreamer pad types (GstPad and its derivatives)

Methods

Method	Description
PadBase(NativeType *pad=nullptr)
PadBase(const ObjectBase< Derived, NativeType > &other)
PadBase(ObjectBase< Derived, NativeType > &&other)
Caps get_current_caps() const	Get the current caps of this pad.

holoscan::gst::PipelineBusMonitor

Base class for monitoring GStreamer pipeline bus messages.

Methods

Method	Description
PipelineBusMonitor(Pipeline pipeline)	Construct a pipeline bus monitor.
PipelineBusMonitor(const PipelineBusMonitor &)=delete
PipelineBusMonitor & operator=(const PipelineBusMonitor &)=delete
void start()	Start monitoring the pipeline bus in a background thread.
void stop()	Stop monitoring the pipeline bus.
bool is_running() const	Check if the monitor is currently running.
std::shared_future<void> get_completion_future()	Get the future for monitoring completion.

holoscan::gst::Sample

Inherits from: holoscan::gst::MiniObjectBase< Sample, ::GstSample >

RAII wrapper for GstSample with automatic cleanup.

Methods

Method	Description
Sample(::GstSample *sample=nullptr)	Constructor from raw pointer (takes ownership)
Buffer get_buffer() const	Get the buffer associated with this sample.

holoscan::gst::VideoInfo

Video information extracted from GstCaps.

Methods

Method	Description
VideoInfo()	Default constructor - initializes empty video info.
VideoInfo(const Caps &caps)	Constructor from Caps object.
gsize get_size() const	Get total buffer size for all planes.
gsize get_stride(int plane_index) const	Get stride (bytes per line) for a specific plane.
gsize get_comp_height(int plane_index) const	Get component height for a specific plane.
gsize get_comp_width(int plane_index) const	Get component width for a specific plane.
gsize get_size(int plane_index) const	Get plane size for a specific plane.
gsize get_n_components() const	Get number of components.
gsize get_n_planes() const	Get number of planes.
gsize get_comp_pstride(int component) const	Get pixel stride for a specific component.
GstVideoFormat get_format() const	Get video format.
gint get_width() const	Get width.
gint get_height() const	Get height.
bool set_format(GstVideoFormat format, gint width, gint height)	Set video format information.
const ::GstVideoInfo * get() const	Get underlying GstVideoInfo pointer.

GstVideoRecorderOp

Operator for recording video streams to file using GStreamer.

==Named Inputs==

input : TensorMap Video frames to encode and write to file. Width, height, and storage type are automatically detected from the first frame.

Parameters

fragment : holoscan.core.Fragment Fragment that owns the operator. encoder : str Encoder base name (e.g. "nvh264", "nvh265", "x264", or "x265"). The "enc" suffix is automatically appended to form the element name. Default value is "nvh264". format : str Pixel format for video data (e.g. "RGBA", "RGB", "BGRA", "BGR", and "GRAY8"). Default value is "RGBA". framerate : str Video framerate as a fraction or decimal, for example "30/1", "30000/1001", "29.97", or "60". Special value "0/1" enables live mode with no framerate control. Default value is "30/1" max_buffers : int Maximum number of buffers to queue (0 = unlimited). Default value is 10. block : bool Whether push_buffer() blocks when the internal queue is full (True = block, False = non-blocking, may drop/timeout). Default value is True. filename : str Output video filename. If no extension is provided, ".mp4" is automatically appended. Default value is "output.mp4". properties : dict of str to str Map of encoder-specific properties. Examples include {"bitrate": "8000", "preset": "1", "gop-size": "30"}. Default value is an empty dictionary. name : str Operator name. Default value is "gst_video_recorder".

Methods

• initialize: Initialize the operator.
• setup: Define the operator specification.