Struct SNClassifySoundRequest 

pub struct SNClassifySoundRequest { /* private fields */ }

Available on crate feature SNClassifySoundRequest only.

Configure an analyzer to perform sound classification using the provided MLModel.

When a new classification result is produced, the results observer will be called with an SNClassificationResult. Audio buffers provided to SNAudioStreamAnalyzer may vary in size, and the analyzer will reblock the audio data to the block size expected by the MLModel. By default, analysis will occur on the first audio channel in the audio stream, and the analyzer will apply sample rate conversion if the provided audio does not match the sample rate required by the MLModel.

See also Apple’s documentation

Implementations

impl SNClassifySoundRequest

pub unsafe fn overlapFactor(&self) -> c_double

The overlap factor of the windows of audio data provided to the classifier, if the model operates on fixed audio block sizes.

When performing audio analysis on fixed audio block sizes, it is common for the analysis windows to overlap by some factor. Without overlapping the analysis windows (when the overlap factor is 0.0), a sound might be split across two analysis windows, which could negatively affect classification performance. Overlapping the analysis windows by 50% ensures each sound will fall near the center of at least one analysis window. The supported range is [0.0, 1.0), and the default value is 0.5. Increasing the overlap factor increases computational complexity, so values greater than 0.5 should be used with care.

pub unsafe fn setOverlapFactor(&self, overlap_factor: c_double)

Setter for overlapFactor.

pub unsafe fn windowDuration(&self) -> CMTime

Available on crate feature objc2-core-media only.

The duration of a single analysis window.

When performing classification over an audio stream, a classifier computes each classification result based on a single ‘analysis window’ of audio. Analysis windows are uniformly-sized time intervals, where the size of any given window is considered that window’s ‘duration’. Some classifiers can operate over analysis windows which conform to one of several different duration options. Larger window durations allow classification to execute less frequently over larger contexts of audio, potentially improving classification performance. Smaller window durations allow classification to execute more frequently over smaller contexts of audio, producing results with sharper time resolution. Depending on the use-case, a larger or smaller window may be preferable. When configuring the window duration, it is important to respect the capabilities of the classifier. A classifier’s supported window durations can be discovered using the windowDurationConstraint property. If an unsupported window duration is selected, the window duration will be automatically rounded down to the nearest supported value if possible, else rounded up.

pub unsafe fn setWindowDuration(&self, window_duration: CMTime)

Available on crate feature objc2-core-media only.

Setter for windowDuration.

pub unsafe fn windowDurationConstraint( &self, ) -> Retained<SNTimeDurationConstraint>

Available on crate feature SNTimeDurationConstraint only.

The constraints governing permitted analysis window durations.

The analysis window duration is controlled using the windowDuration property. If an analysis window duration is selected which does not meet the necessary constraints, it will automatically be adjusted to meet these constraints (see windowDuration for more information regarding how this adjustment will be applied).

pub unsafe fn knownClassifications(&self) -> Retained<NSArray<NSString>>

Lists all labels that can be produced by this request.

• Returns: An array of strings containing all sound identifiers which can be produced by this request.

pub unsafe fn initWithMLModel_error( this: Allocated<Self>, ml_model: &MLModel, ) -> Result<Retained<Self>, Retained<NSError>>

Available on crate feature objc2-core-ml only.

Initializes a sound classification request with the provided MLModel

• Parameter mlModel: The CoreML audio classification model to be used with this request

The provided model must accept audio data as input, and output a classification dictionary containing the probability of each category.

pub unsafe fn initWithClassifierIdentifier_error( this: Allocated<Self>, classifier_identifier: &SNClassifierIdentifier, ) -> Result<Retained<Self>, Retained<NSError>>

Available on crate feature SNTypes only.

Initializes a sound classification request with a known classifier.

• Parameters:

• classifierIdentifier: An identifier identifying the particular classifier to use for labeling sounds.

• error: An output parameter which, in the case of an error, will be populated with details about that error. Upon success, the contents of this output parameter are undefined. Please use the return value of this method to determine whether or not an error occurred before using the value assigned to this output parameter.

• Returns Upon failure, nil; upon success, an SNClassifySoundRequest instance which can be added to an analyzer to classify sounds using a recognized classifier.

This initializer may be used to classify sounds using Apple-provided sound classifiers. Note that Apple may add new classifiers in the future, but it commits to ensuring the consistent performance of existing classifiers.

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

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

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<AnyObject> for SNClassifySoundRequest

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for SNClassifySoundRequest

fn as_ref(&self) -> &NSObject

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

impl AsRef<SNClassifySoundRequest> for SNClassifySoundRequest

fn as_ref(&self) -> &Self

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

impl Borrow<AnyObject> for SNClassifySoundRequest

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for SNClassifySoundRequest

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for SNClassifySoundRequest

const NAME: &'static str = "SNClassifySoundRequest"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<SNClassifySoundRequest 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 SNClassifySoundRequest

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

Formats the value using the given formatter.

impl Deref for SNClassifySoundRequest

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for SNClassifySoundRequest

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 SNClassifySoundRequest

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for SNClassifySoundRequest

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 SNClassifySoundRequest

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 SNClassifySoundRequest

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

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

impl DowncastTarget for SNClassifySoundRequest

impl Eq for SNClassifySoundRequest

impl SNRequest for SNClassifySoundRequest