Package org.freedesktop.gstreamer.gst

Class BufferPool

java.lang.Object

org.javagi.base.ProxyInstance

org.gnome.gobject.TypeInstance

org.gnome.gobject.GObject

org.gnome.gobject.InitiallyUnowned

org.freedesktop.gstreamer.gst.GstObject

org.freedesktop.gstreamer.gst.BufferPool

All Implemented Interfaces:

Proxy

Direct Known Subclasses:

VideoBufferPool

@Generated("io.github.jwharm.JavaGI")
public class BufferPool
extends GstObject

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

A GstBufferPool is created with gst_buffer_pool_new().

Once a pool is created, it needs to be configured. A call to gst_buffer_pool_get_config() returns the current configuration structure from the pool. With gst_buffer_pool_config_set_params() and gst_buffer_pool_config_set_allocator() the bufferpool parameters and allocator can be configured. Other properties can be configured in the pool depending on the pool implementation.

A bufferpool can have extra options that can be enabled with gst_buffer_pool_config_add_option(). The available options can be retrieved with gst_buffer_pool_get_options(). Some options allow for additional configuration properties to be set.

After the configuration structure has been configured, gst_buffer_pool_set_config() updates the configuration in the pool. This can fail when the configuration structure is not accepted.

After the pool has been configured, it can be activated with gst_buffer_pool_set_active(). This will preallocate the configured resources in the pool.

When the pool is active, gst_buffer_pool_acquire_buffer() can be used to retrieve a buffer from the pool.

Buffers allocated from a bufferpool will automatically be returned to the pool with gst_buffer_pool_release_buffer() when their refcount drops to 0.

The bufferpool can be deactivated again with gst_buffer_pool_set_active(). All further gst_buffer_pool_acquire_buffer() calls will return an error. When all buffers are returned to the pool they will be freed.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	BufferPool.BufferPoolClass	The GstBufferPool class.
static class	BufferPool.Builder<B extends BufferPool.Builder<B>>	Inner class implementing a builder pattern to construct a GObject with properties.

Nested classes/interfaces inherited from class org.freedesktop.gstreamer.gst.GstObject

GstObject.DeepNotifyCallback, GstObject.Object$Impl, GstObject.ObjectClass

Nested classes/interfaces inherited from class org.gnome.gobject.InitiallyUnowned

InitiallyUnowned.InitiallyUnownedClass

Nested classes/interfaces inherited from class org.gnome.gobject.GObject

GObject.NotifyCallback

Constructor Summary

Constructors

Constructor	Description
BufferPool()	Creates a new BufferPool.
BufferPool(MemorySegment address)	Create a BufferPool proxy instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
FlowReturn	acquireBuffer(@Nullable Out<Buffer> buffer, @Nullable BufferPoolAcquireParams params)	Acquires a buffer from pool. buffer should point to a memory location that can hold a pointer to the new buffer.
protected FlowReturn	allocBuffer(@Nullable Out<Buffer> buffer, @Nullable BufferPoolAcquireParams params)	Allocate a buffer.
protected BufferPool	asParent()	Returns this instance as if it were its parent type.
static BufferPool.Builder<? extends BufferPool.Builder>	builder()	A BufferPool.Builder object constructs a BufferPool with the specified properties.
static void	configAddOption(Structure config, String option)	Enables the option in config. This will instruct the bufferpool to enable the specified option on the buffers that it allocates.
static boolean	configGetAllocator(Structure config, @Nullable Out<Allocator> allocator, @Nullable AllocationParams params)	Gets the allocator and params from config.
static @Nullable String	configGetOption(Structure config, int index)	Parses an available config and gets the option at index of the options API array.
static boolean	configGetParams(Structure config, @Nullable Out<Caps> caps, @Nullable Out<Integer> size, @Nullable Out<Integer> minBuffers, @Nullable Out<Integer> maxBuffers)	Gets the configuration values from config.
static boolean	configHasOption(Structure config, String option)	Checks if config contains option.
static int	configNOptions(Structure config)	Retrieves the number of values currently stored in the options array of the config structure.
static void	configSetAllocator(Structure config, @Nullable Allocator allocator, @Nullable AllocationParams params)	Sets the allocator and params on config.
static void	configSetParams(Structure config, @Nullable Caps caps, int size, int minBuffers, int maxBuffers)	Configures config with the given parameters.
static boolean	configValidateParams(Structure config, @Nullable Caps caps, int size, int minBuffers, int maxBuffers)	Validates that changes made to config are still valid in the context of the expected parameters.
protected void	flushStart()	Enter the flushing state.
protected void	flushStop()	Leave the flushing state.
protected void	freeBuffer(Buffer buffer)	Free a buffer.
Structure	getConfig()	Gets a copy of the current configuration of the pool.
static MemoryLayout	getMemoryLayout()	The memory layout of the native struct.
String[]	getOptions()	Gets a null terminated array of string with supported bufferpool options for pool. An option would typically be enabled with gst_buffer_pool_config_add_option().
static @Nullable Type	getType()	Get the GType of the BufferPool class
boolean	hasOption(String option)	Checks if the bufferpool supports option.
boolean	isActive()	Checks if this BufferPool is active.
void	releaseBuffer(Buffer buffer)	Releases buffer to pool. buffer should have previously been allocated from this BufferPool with gst_buffer_pool_acquire_buffer().
protected void	resetBuffer(Buffer buffer)	Reset the buffer to its state when it was freshly allocated.
boolean	setActive(boolean active)	Controls the active state of pool. When the pool is inactive, new calls to gst_buffer_pool_acquire_buffer() will return with FlowReturn.FLUSHING.
boolean	setConfig(Structure config)	Sets the configuration of the pool.
void	setFlushing(boolean flushing)	Enables or disables the flushing state of a this BufferPool without freeing or allocating buffers.
protected boolean	start()	Start the bufferpool.
protected boolean	stop()	Stop the bufferpool.

Methods inherited from class org.freedesktop.gstreamer.gst.GstObject

addControlBinding, checkUniqueness, deepNotify, defaultDeepNotify, defaultError, emitDeepNotify, getControlBinding, getControlRate, getGValueArray, getName, getParent, getPathString, getValue, getValueArray, hasActiveControlBindings, hasAncestor, hasAsAncestor, hasAsParent, onDeepNotify, ref, refSink, removeControlBinding, replace, setControlBindingDisabled, setControlBindingsDisabled, setControlRate, setName, setParent, suggestNextSync, syncValues, unparent, unref

Methods inherited from class org.gnome.gobject.GObject

addToggleRef, addWeakPointer, bindProperty, bindProperty, bindProperty, bindPropertyFull, bindPropertyFull, bindPropertyWithClosures, bindPropertyWithClosures, compatControl, connect, connect, connect, constructed, disconnect, dispatchPropertiesChanged, dispose, dupData, dupQdata, emit, emitNotify, finalize_, forceFloating, freezeNotify, get, getData, getProperty, getProperty, getProperty, getQdata, getv, interfaceFindProperty, interfaceInstallProperty, interfaceListProperties, isFloating, newInstance, newInstance, newv, notify, notify, notifyByPspec, onNotify, refSink, removeToggleRef, removeWeakPointer, replaceData, replaceQdata, runDispose, set, setData, setDataFull, setProperty, setProperty, setProperty, setQdata, setQdataFull, setv, stealData, stealQdata, takeRef, thawNotify, watchClosure, weakRef, weakUnref, withProperties

Methods inherited from class org.gnome.gobject.TypeInstance

callParent, callParent, cast, getPrivate, readGClass, writeGClass

Methods inherited from class org.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

BufferPool

public BufferPool(MemorySegment address)

Create a BufferPool proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

BufferPool

public BufferPool()

Creates a new BufferPool.

Method Details

getType

public static @Nullable Type getType()

Get the GType of the BufferPool class

Returns:

the GType

getMemoryLayout

public static MemoryLayout getMemoryLayout()

The memory layout of the native struct.

Returns:

the memory layout

asParent

protected BufferPool asParent()

Returns this instance as if it were its parent type. This is mostly synonymous to the Java super keyword, but will set the native typeclass function pointers to the parent type. When overriding a native virtual method in Java, "chaining up" with super.methodName() doesn't work, because it invokes the overridden function pointer again. To chain up, call asParent().methodName(). This will call the native function pointer of this virtual method in the typeclass of the parent type.

Overrides:

asParent in class GstObject

configAddOption

public static void configAddOption(Structure config,
 String option)

Enables the option in config. This will instruct the bufferpool to enable the specified option on the buffers that it allocates.

The options supported by pool can be retrieved with gst_buffer_pool_get_options().

Parameters:

config - a GstBufferPool configuration

option - an option to add

configGetAllocator

public static boolean configGetAllocator(Structure config,
 @Nullable Out<Allocator> allocator,
 @Nullable AllocationParams params)

Gets the allocator and params from config.

Parameters:

config - a GstBufferPool configuration

allocator - a GstAllocator, or null

params - GstAllocationParams, or null

Returns:

true, if the values are set.

configGetOption

public static @Nullable String configGetOption(Structure config,
 int index)

Parses an available config and gets the option at index of the options API array.

Parameters:

config - a GstBufferPool configuration

index - position in the option array to read

Returns:

the option at index.

configGetParams

public static boolean configGetParams(Structure config,
 @Nullable Out<Caps> caps,
 @Nullable Out<Integer> size,
 @Nullable Out<Integer> minBuffers,
 @Nullable Out<Integer> maxBuffers)

Gets the configuration values from config.

Parameters:

config - a GstBufferPool configuration

caps - the caps of buffers

size - the size of each buffer, not including prefix and padding

minBuffers - the minimum amount of buffers to allocate.

maxBuffers - the maximum amount of buffers to allocate or 0 for unlimited.

Returns:

true if all parameters could be fetched.

configHasOption

public static boolean configHasOption(Structure config,
 String option)

Checks if config contains option.

Parameters:

config - a GstBufferPool configuration

option - an option

Returns:

true if the options array contains option.

configNOptions

public static int configNOptions(Structure config)

Retrieves the number of values currently stored in the options array of the config structure.

Parameters:

config - a GstBufferPool configuration

Returns:

the options array size as a guint.

configSetAllocator

public static void configSetAllocator(Structure config,
 @Nullable Allocator allocator,
 @Nullable AllocationParams params)

Sets the allocator and params on config.

One of allocator and params can be null, but not both. When allocator is null, the default allocator of the pool will use the values in param to perform its allocation. When param is null, the pool will use the provided allocator with its default GstAllocationParams.

A call to gst_buffer_pool_set_config() can update the allocator and params with the values that it is able to do. Some pools are, for example, not able to operate with different allocators or cannot allocate with the values specified in params. Use gst_buffer_pool_get_config() to get the currently used values.

Parameters:

config - a GstBufferPool configuration

allocator - a GstAllocator

params - GstAllocationParams

configSetParams

public static void configSetParams(Structure config,
 @Nullable Caps caps,
 int size,
 int minBuffers,
 int maxBuffers)

Configures config with the given parameters.

Parameters:

config - a GstBufferPool configuration

caps - caps for the buffers

size - the size of each buffer, not including prefix and padding

minBuffers - the minimum amount of buffers to allocate.

maxBuffers - the maximum amount of buffers to allocate or 0 for unlimited.

configValidateParams

public static boolean configValidateParams(Structure config,
 @Nullable Caps caps,
 int size,
 int minBuffers,
 int maxBuffers)

Validates that changes made to config are still valid in the context of the expected parameters. This function is a helper that can be used to validate changes made by a pool to a config when gst_buffer_pool_set_config() returns false. This expects that caps haven't changed and that minBuffers aren't lower then what we initially expected. This does not check if options or allocator parameters are still valid, won't check if size have changed, since changing the size is valid to adapt padding.

Parameters:

config - a GstBufferPool configuration

caps - the excepted caps of buffers

size - the expected size of each buffer, not including prefix and padding

minBuffers - the expected minimum amount of buffers to allocate.

maxBuffers - the expect maximum amount of buffers to allocate or 0 for unlimited.

Returns:

true, if the parameters are valid in this context.

Since:

1.4

acquireBuffer

public FlowReturn acquireBuffer(@Nullable Out<Buffer> buffer,
 @Nullable BufferPoolAcquireParams params)

Acquires a buffer from pool. buffer should point to a memory location that can hold a pointer to the new buffer. When the pool is empty, this function will by default block until a buffer is released into the pool again or when the pool is set to flushing or deactivated.

params can contain optional parameters to influence the allocation.

Parameters:

buffer - a location for a GstBuffer

params - parameters.

Returns:

a GstFlowReturn such as FlowReturn.FLUSHING when the pool is inactive.

getConfig

public Structure getConfig()

Gets a copy of the current configuration of the pool. This configuration can be modified and used for the gst_buffer_pool_set_config() call.

Returns:

a copy of the current configuration of pool.

getOptions

public String[] getOptions()

Gets a null terminated array of string with supported bufferpool options for pool. An option would typically be enabled with gst_buffer_pool_config_add_option().

Returns:

a null terminated array of strings.

hasOption

public boolean hasOption(String option)

Checks if the bufferpool supports option.

Parameters:

option - an option

Returns:

true if the buffer pool contains option.

isActive

public boolean isActive()

Checks if this BufferPool is active. A pool can be activated with the gst_buffer_pool_set_active() call.

Returns:

true when the pool is active.

releaseBuffer

public void releaseBuffer(Buffer buffer)

Releases buffer to pool. buffer should have previously been allocated from this BufferPool with gst_buffer_pool_acquire_buffer().

This function is usually called automatically when the last ref on buffer disappears.

Parameters:

buffer - a GstBuffer

setActive

public boolean setActive(boolean active)

Controls the active state of pool. When the pool is inactive, new calls to gst_buffer_pool_acquire_buffer() will return with FlowReturn.FLUSHING.

Activating the bufferpool will preallocate all resources in the pool based on the configuration of the pool.

Deactivating will free the resources again when there are no outstanding buffers. When there are outstanding buffers, they will be freed as soon as they are all returned to the pool.

Parameters:

active - the new active state

Returns:

false when the pool was not configured or when preallocation of the buffers failed.

setConfig

public boolean setConfig(Structure config)

Sets the configuration of the pool. If the pool is already configured, and the configuration hasn't changed, this function will return true. If the pool is active, this method will return false and active configuration will remain. Buffers allocated from this pool must be returned or else this function will do nothing and return false.

config is a GstStructure that contains the configuration parameters for the pool. A default and mandatory set of parameters can be configured with gst_buffer_pool_config_set_params(), gst_buffer_pool_config_set_allocator() and gst_buffer_pool_config_add_option().

If the parameters in config can not be set exactly, this function returns false and will try to update as much state as possible. The new state can then be retrieved and refined with gst_buffer_pool_get_config().

This function takes ownership of config.

Parameters:

config - a GstStructure

Returns:

true when the configuration could be set.

setFlushing

public void setFlushing(boolean flushing)

Enables or disables the flushing state of a this BufferPool without freeing or allocating buffers.

Parameters:

flushing - whether to start or stop flushing

Since:

1.4

allocBuffer

protected FlowReturn allocBuffer(@Nullable Out<Buffer> buffer,
 @Nullable BufferPoolAcquireParams params)

Allocate a buffer. the default implementation allocates buffers from the configured memory allocator and with the configured parameters. All metadata that is present on the allocated buffer will be marked as GST_META_FLAG_POOLED and GST_META_FLAG_LOCKED and will not be removed from the buffer in GstBufferPoolClass::reset_buffer. The buffer should have the GST_BUFFER_FLAG_TAG_MEMORY cleared.

Parameters:

buffer - a location for a GstBuffer

params - parameters.

Returns:

a GstFlowReturn to indicate whether the allocation was successful.

flushStart

protected void flushStart()

Enter the flushing state.

Since:

1.4

flushStop

protected void flushStop()

Leave the flushing state.

Since:

1.4

freeBuffer

protected void freeBuffer(Buffer buffer)

Free a buffer. The default implementation unrefs the buffer.

Parameters:

buffer - the GstBuffer to free

resetBuffer

protected void resetBuffer(Buffer buffer)

Reset the buffer to its state when it was freshly allocated. The default implementation will clear the flags, timestamps and will remove the metadata without the GST_META_FLAG_POOLED flag (even the metadata with GST_META_FLAG_LOCKED). If the GST_BUFFER_FLAG_TAG_MEMORY was set, this function can also try to restore the memory and clear the GST_BUFFER_FLAG_TAG_MEMORY again.

Parameters:

buffer - the GstBuffer to reset

start

protected boolean start()

Start the bufferpool. The default implementation will preallocate min-buffers buffers and put them in the queue.

Subclasses do not need to chain up to the parent's default implementation if they don't want min-buffers based preallocation.

Returns:

whether the pool could be started.

stop

protected boolean stop()

Stop the bufferpool. the default implementation will free the preallocated buffers. This function is called when all the buffers are returned to the pool.

Returns:

whether the pool could be stopped.

builder

public static BufferPool.Builder<? extends BufferPool.Builder> builder()

A BufferPool.Builder object constructs a BufferPool with the specified properties. Use the various set...() methods to set properties, and finish construction with BufferPool.Builder.build().

Returns:

the builder object