Struct AVOutputSettingsAssistant

#[repr(C)]
pub struct AVOutputSettingsAssistant { /* private fields */ }

Available on crate feature AVOutputSettingsAssistant only.

A class, each instance of which specifies a set of parameters for configuring objects that use output settings dictionaries, for example AVAssetWriter & AVAssetWriterInput, so that the resulting media file conforms to some specific criteria

Instances of AVOutputSettingsAssistant are typically created using a string constant representing a specific preset configuration, such as AVOutputSettingsPreset1280x720. Once you have an instance, its properties can be used as a guide for creating and configuring an AVAssetWriter object and one or more AVAssetWriterInput objects. If all the suggested properties are respected, the resulting media file will conform to the criteria implied by the preset. Alternatively, the properties of an instance can be used as a “base” configuration which can be customized to suit your individual needs.

The recommendations made by an instance get better as you tell it more about the format of your source data. For example, if you set the sourceVideoFormat property, the recommendation made by the videoSettings property will ensure that your video frames are not scaled up from a smaller size.

See also Apple’s documentation

Implementations

impl AVOutputSettingsAssistant

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

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

pub unsafe fn availableOutputSettingsPresets() -> Retained<NSArray<AVOutputSettingsPreset>>

Returns the list of presets that can be used to create an instance of AVOutputSettingsAssistant

Returns: An NSArray of NSString objects, each of which is a preset identifier

Each preset in the returned list can be passed in to +outputSettingsAssistantWithPreset: to create a new instance of AVOutputSettingsAssistant.

On iOS, the returned array may be different between different device models.

pub unsafe fn outputSettingsAssistantWithPreset( preset_identifier: &AVOutputSettingsPreset, ) -> Option<Retained<Self>>

Returns an instance of AVOutputSettingsAssistant corresponding to the given preset

Parameter presetIdentifier: The string identifier, for example AVOutputSettingsPreset1280x720, for the desired preset

Returns: An instance of AVOutputSettingsAssistant with properties corresponding to the given preset, or nil if there is no such available preset.

The properties of the returned object can be used as a guide for creating and configuring an AVAssetWriter object and one or more AVAssetWriterInput objects. If all the suggested properties are respected in creating the AVAssetWriter, the resulting media file will conform to the criteria implied by the preset.

Use +availableOutputSettingsPresets to get a list of presets identifiers that can be used with this method.

pub unsafe fn audioSettings( &self, ) -> Option<Retained<NSDictionary<NSString, AnyObject>>>

A dictionary of key/value pairs, as specified in AVAudioSettings.h, to be used when e.g. creating an instance of AVAssetWriterInput

The value of this property may change as a result of setting a new value for the sourceAudioFormat property.

pub unsafe fn videoSettings( &self, ) -> Option<Retained<NSDictionary<NSString, AnyObject>>>

A dictionary of key/value pairs, as specified in AVVideoSettings.h, to be used when e.g. creating an instance of AVAssetWriterInput

The value of this property may change as a result of setting a new value for the sourceVideoFormat property.

pub unsafe fn outputFileType(&self) -> Retained<AVFileType>

Available on crate feature AVMediaFormat only.

A UTI indicating the type of file to be written, to be used when e.g. creating an instance of AVAssetWriter

Use [[UTType typeWithIdentifier:outputFileType] preferredFilenameExtension] to get a suitable file extension for a given file type.

impl AVOutputSettingsAssistant

AVOutputSettingsAssistant_SourceInformation.

pub unsafe fn sourceAudioFormat( &self, ) -> Option<Retained<CMAudioFormatDescription>>

Available on crate feature objc2-core-media only.

A CMAudioFormatDescription object describing the format of you audio data

Setting this property will allow the receiver to make a more informed recommendation for the audio settings that should be used. After setting this property, you should re-query the audioSettings property to get the new recommendation. The default value is NULL, which means that the receiver does not know anything about the format of your audio data.

If you set a non-NULL value for this property, and are using the receiver to initialize an AVAssetWriterInput, the same format description should be used to initialize the AVAssetWriterInput, along with the dictionary from the audioSettings property.

pub unsafe fn setSourceAudioFormat( &self, source_audio_format: Option<&CMAudioFormatDescription>, )

Available on crate feature objc2-core-media only.

Setter for sourceAudioFormat.

pub unsafe fn sourceVideoFormat( &self, ) -> Option<Retained<CMVideoFormatDescription>>

Available on crate feature objc2-core-media only.

A CMVideoFormatDescription object describing the format of your video data

Setting this property will allow the receiver to make a more informed recommendation for the video settings that should be used. After setting this property, you should re-query the videoSettings property to get the new recommendation. The default value is NULL, which means that the receiver does not know anything about the format of your video data.

If you set a non-NULL value for this property, and are using the receiver to initialize an AVAssetWriterInput, the same format description should be used to initialize the AVAssetWriterInput, along with the dictionary from the videoSettings property.

pub unsafe fn setSourceVideoFormat( &self, source_video_format: Option<&CMVideoFormatDescription>, )

Available on crate feature objc2-core-media only.

Setter for sourceVideoFormat.

pub unsafe fn sourceVideoAverageFrameDuration(&self) -> CMTime

Available on crate feature objc2-core-media only.

A CMTime describing the average frame duration (reciprocal of average frame rate) of your video data

Setting this property will allow the receiver to make a more informed recommendation for the video settings that should be used. After setting this property, you should re-query the videoSettings property to get the new recommendation.

The default value is 1/30, which means that the receiver is assuming that your source video has an average frame rate of 30fps.

It is an error to set this property to a value that is not positive or not numeric. See CMTIME_IS_NUMERIC.

pub unsafe fn setSourceVideoAverageFrameDuration( &self, source_video_average_frame_duration: CMTime, )

Available on crate feature objc2-core-media only.

Setter for sourceVideoAverageFrameDuration.

pub unsafe fn sourceVideoMinFrameDuration(&self) -> CMTime

Available on crate feature objc2-core-media only.

A CMTime describing the minimum frame duration (reciprocal of the maximum frame rate) of your video data

Setting this property will allow the receiver to make a more informed recommendation for the video settings that should be used. After setting this property, you should re-query the videoSettings property to get the new recommendation.

If your source of video data is an instance of AVAssetReaderOutput, you can discover the minimum frame duration of your source asset using the AVAssetTrack.minFrameDuration property.

The default value is 1/30, which means that the receiver is assuming that your source video has a maximum frame rate of 30fps.

It is an error to set this property to a value that is not positive or not numeric. See CMTIME_IS_NUMERIC.

pub unsafe fn setSourceVideoMinFrameDuration( &self, source_video_min_frame_duration: CMTime, )

Available on crate feature objc2-core-media only.

Setter for sourceVideoMinFrameDuration.

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.

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<AVOutputSettingsAssistant> for AVOutputSettingsAssistant

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVOutputSettingsAssistant

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVOutputSettingsAssistant

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVOutputSettingsAssistant

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVOutputSettingsAssistant

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVOutputSettingsAssistant

const NAME: &'static str = "AVOutputSettingsAssistant"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVOutputSettingsAssistant 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 AVOutputSettingsAssistant

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

Formats the value using the given formatter.

impl Deref for AVOutputSettingsAssistant

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVOutputSettingsAssistant

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 AVOutputSettingsAssistant

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVOutputSettingsAssistant

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 AVOutputSettingsAssistant

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 AVOutputSettingsAssistant

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

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

impl DowncastTarget for AVOutputSettingsAssistant

impl Eq for AVOutputSettingsAssistant