Struct AVAudioOutputNode 

pub struct AVAudioOutputNode { /* private fields */ }

Available on crate features AVAudioIONode and AVAudioNode only.

A node that performs audio output in the engine.

When the engine is rendering to/from an audio device, this node connects to the system’s audio output. When the engine is operating in manual rendering mode, this node performs output in response to client’s requests.

This node has one element. The format of the output scope reflects:

• the audio hardware sample rate and channel count, when connected to the hardware
• the engine’s manual rendering mode output format (see AVAudioEngine(manualRenderingFormat)), in the manual rendering mode

The format of the input scope is initially the same as that of the output, but you may set it to a different format, in which case the node will convert.

See also Apple’s documentation

Implementations

impl AVAudioOutputNode

pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

impl AVAudioOutputNode

Methods declared on superclass NSObject.

pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = AVAudioIONode>

pub unsafe fn presentationLatency(&self) -> NSTimeInterval

The presentation or hardware latency, applicable when the engine is rendering to/from an audio device.

This corresponds to kAudioDevicePropertyLatency and kAudioStreamPropertyLatency. See <CoreAudio /AudioHardwareBase.h>.

pub unsafe fn audioUnit(&self) -> AudioUnit

Available on crate feature objc2-audio-toolbox and non-watchOS only.

The node’s underlying AudioUnit, if any.

This is only necessary for certain advanced usages.

pub unsafe fn isVoiceProcessingEnabled(&self) -> bool

Indicates whether voice processing is enabled.

pub unsafe fn setVoiceProcessingEnabled_error( &self, enabled: bool, ) -> Result<(), Retained<NSError>>

Enable or disable voice processing on the IO node.

Parameter enabled: Whether voice processing is to be enabled.

Parameter outError: On exit, if the IO node cannot enable or diable voice processing, a description of the error

Returns: YES for success

If enabled, the input node does signal processing on the incoming audio (taking out any of the audio that is played from the device at a given time from the incoming audio). Disabling this mode on either of the IO nodes automatically disabled it on the other IO node.

Voice processing requires both input and output nodes to be in the voice processing mode. Enabling this mode on either of the IO nodes automatically enables it on the other IO node. Voice processing is only supported when the engine is rendering to the audio device and not in the manual rendering mode. Voice processing can only be be enabled or disabled when the engine is in a stopped state.

The output format of the input node and the input format of the output node have to be the same and they can only be changed when the engine is in a stopped state.

Methods from Deref<Target = AVAudioNode>

pub unsafe fn reset(&self)

Clear a unit’s previous processing state.

pub unsafe fn inputFormatForBus( &self, bus: AVAudioNodeBus, ) -> Retained<AVAudioFormat>

Available on crate features AVAudioFormat and AVAudioTypes only.

Obtain an input bus’s format.

pub unsafe fn outputFormatForBus( &self, bus: AVAudioNodeBus, ) -> Retained<AVAudioFormat>

Available on crate features AVAudioFormat and AVAudioTypes only.

Obtain an output bus’s format.

pub unsafe fn nameForInputBus( &self, bus: AVAudioNodeBus, ) -> Option<Retained<NSString>>

Available on crate feature AVAudioTypes only.

Return the name of an input bus.

pub unsafe fn nameForOutputBus( &self, bus: AVAudioNodeBus, ) -> Option<Retained<NSString>>

Available on crate feature AVAudioTypes only.

Return the name of an output bus.

pub unsafe fn installTapOnBus_bufferSize_format_block( &self, bus: AVAudioNodeBus, buffer_size: AVAudioFrameCount, format: Option<&AVAudioFormat>, tap_block: AVAudioNodeTapBlock, )

Available on crate features AVAudioBuffer and AVAudioFormat and AVAudioTime and AVAudioTypes and block2 only.

Create a “tap” to record/monitor/observe the output of the node.

Parameter bus: the node output bus to which to attach the tap

Parameter bufferSize: the requested size of the incoming buffers in sample frames. Supported range is [100, 400] ms.

Parameter format: If non-nil, attempts to apply this as the format of the specified output bus. This should only be done when attaching to an output bus which is not connected to another node; an error will result otherwise. The tap and connection formats (if non-nil) on the specified bus should be identical. Otherwise, the latter operation will override any previously set format.

Parameter tapBlock: a block to be called with audio buffers

Only one tap may be installed on any bus. Taps may be safely installed and removed while the engine is running.

Note that if you have a tap installed on AVAudioOutputNode, there could be a mismatch between the tap buffer format and AVAudioOutputNode’s output format, depending on the underlying physical device. Hence, instead of tapping the AVAudioOutputNode, it is advised to tap the node connected to it.

E.g. to capture audio from input node:

AVAudioEngine *engine = [[AVAudioEngine alloc] init];
AVAudioInputNode *input = [engine inputNode];
AVAudioFormat *format = [input outputFormatForBus: 0];
[input installTapOnBus: 0 bufferSize: 8192 format: format block: ^(AVAudioPCMBuffer *buf, AVAudioTime *when) {
// ‘buf' contains audio captured from input node at time 'when'
}];
....
// start engine

Safety

tap_block must be a valid pointer.

pub unsafe fn removeTapOnBus(&self, bus: AVAudioNodeBus)

Available on crate feature AVAudioTypes only.

Destroy a tap.

Parameter bus: the node output bus whose tap is to be destroyed

pub unsafe fn engine(&self) -> Option<Retained<AVAudioEngine>>

Available on crate feature AVAudioEngine only.

The engine to which the node is attached (or nil).

pub unsafe fn numberOfInputs(&self) -> NSUInteger

The node’s number of input busses.

pub unsafe fn numberOfOutputs(&self) -> NSUInteger

The node’s number of output busses.

pub unsafe fn lastRenderTime(&self) -> Option<Retained<AVAudioTime>>

Available on crate feature AVAudioTime only.

Obtain the time for which the node most recently rendered.

Will return nil if the engine is not running or if the node is not connected to an input or output node.

pub unsafe fn AUAudioUnit(&self) -> Retained<AUAudioUnit>

Available on crate feature objc2-audio-toolbox and non-watchOS only.

An AUAudioUnit wrapping or underlying the implementation’s AudioUnit.

This provides an AUAudioUnit which either wraps or underlies the implementation’s AudioUnit, depending on how that audio unit is packaged. Applications can interact with this AUAudioUnit to control custom properties, select presets, change parameters, etc.

No operations that may conflict with state maintained by the engine should be performed directly on the audio unit. These include changing initialization state, stream formats, channel layouts or connections to other audio units.

pub unsafe fn latency(&self) -> NSTimeInterval

The processing latency of the node, in seconds.

This property reflects the delay between when an impulse in the audio stream arrives at the input vs. output of the node. This should reflect the delay due to signal processing (e.g. filters, FFT’s, etc.), not delay or reverberation which is being applied as an effect. A value of zero indicates either no latency or an unknown latency.

pub unsafe fn outputPresentationLatency(&self) -> NSTimeInterval

The maximum render pipeline latency downstream of the node, in seconds.

This describes the maximum time it will take for the audio at the output of a node to be presented. For instance, the output presentation latency of the output node in the engine is:

• zero in manual rendering mode
• the presentation latency of the device itself when rendering to an audio device (see AVAudioIONode(presentationLatency)) The output presentation latency of a node connected directly to the output node is the output node’s presentation latency plus the output node’s processing latency (see latency).

For a node which is exclusively in the input node chain (i.e. not connected to engine’s output node), this property reflects the latency for the output of this node to be presented at the output of the terminating node in the input chain.

A value of zero indicates either an unknown or no latency.

Note that this latency value can change as the engine is reconfigured (started/stopped, connections made/altered downstream of this node etc.). So it is recommended not to cache this value and fetch it whenever it’s needed.

Methods from Deref<Target = NSObject>

pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

pub unsafe fn get_ivar<T>(&self, name: &str) -> &T

where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

pub fn downcast_ref<T>(&self) -> Option<&T>

where T: DowncastTarget,

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}

Trait Implementations

impl AsRef<AVAudioIONode> for AVAudioOutputNode

fn as_ref(&self) -> &AVAudioIONode

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<AVAudioNode> for AVAudioOutputNode

fn as_ref(&self) -> &AVAudioNode

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<AVAudioOutputNode> for AVAudioOutputNode

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<AnyObject> for AVAudioOutputNode

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for AVAudioOutputNode

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AVAudioIONode> for AVAudioOutputNode

fn borrow(&self) -> &AVAudioIONode

Immutably borrows from an owned value.

impl Borrow<AVAudioNode> for AVAudioOutputNode

fn borrow(&self) -> &AVAudioNode

Immutably borrows from an owned value.

impl Borrow<AnyObject> for AVAudioOutputNode

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVAudioOutputNode

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVAudioOutputNode

const NAME: &'static str = "AVAudioOutputNode"

The name of the Objective-C class that this type represents.

type Super = AVAudioIONode

The superclass of this class.

type ThreadKind = <<AVAudioOutputNode as ClassType>::Super as ClassType>::ThreadKind

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl Debug for AVAudioOutputNode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for AVAudioOutputNode

type Target = AVAudioIONode

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for AVAudioOutputNode

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for AVAudioOutputNode

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVAudioOutputNode

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl PartialEq for AVAudioOutputNode

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for AVAudioOutputNode

const ENCODING_REF: Encoding = <AVAudioIONode as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl DowncastTarget for AVAudioOutputNode

impl Eq for AVAudioOutputNode