Struct AVAssetTrack

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

Available on crate feature AVAssetTrack only.

An AVAsset is an abstract class that defines AVFoundation’s model for timed audiovisual media.

Each asset contains a collection of tracks that are intended to be presented or processed together, each of a uniform media type, including but not limited to audio, video, text, closed captions, and subtitles.

AVAssets are often instantiated via its concrete subclass AVURLAsset with NSURLs that refer to audiovisual media resources, such as streams (including HTTP live streams), QuickTime movie files, MP3 files, and files of other types.

They can also be instantiated using other concrete subclasses that extend the basic model for audiovisual media in useful ways, as AVComposition does for temporal editing.

Properties of assets as a whole are defined by AVAsset. Additionally, references to instances of AVAssetTracks representing tracks of the collection can be obtained, so that each of these can be examined independently.

Because of the nature of timed audiovisual media, upon successful initialization of an AVAsset some or all of the values for its keys may not be immediately available. The value of any key can be requested at any time, and AVAsset will always return its value synchronously, although it may have to block the calling thread in order to do so.

In order to avoid blocking, clients can register their interest in particular keys and to become notified when their values become available. For further details, see AVAsynchronousKeyValueLoading.h. For clients who want to examine a subset of the tracks, metadata, and other parts of the asset, asynchronous methods like -loadTracksWithMediaType:completionHandler: can be used to load this information without blocking. When using these asynchronous methods, it is not necessary to load the associated property beforehand. Swift clients can also use the load(:) method to load properties in a type safe manner.

On platforms other than macOS, it is particularly important to avoid blocking. To preserve responsiveness, a synchronous request that blocks for too long (eg, a property request on an asset on a slow HTTP server) may lead to media services being reset.

To play an instance of AVAsset, initialize an instance of AVPlayerItem with it, use the AVPlayerItem to set up its presentation state (such as whether only a limited timeRange of the asset should be played, etc.), and provide the AVPlayerItem to an AVPlayer according to whether the items is to be played by itself or together with a collection of other items. Full details available in AVPlayerItem.h and AVPlayer.h.

AVAssets can also be inserted into AVMutableCompositions in order to assemble audiovisual constructs from one or more source assets.

See also Apple’s documentation

Implementations

impl AVAssetTrack

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

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

pub unsafe fn asset(&self) -> Option<Retained<AVAsset>>

Available on crate feature AVAsset only.

pub unsafe fn trackID(&self) -> CMPersistentTrackID

Available on crate feature objc2-core-media only.

impl AVAssetTrack

AVAssetTrackBasicPropertiesAndCharacteristics.

pub unsafe fn mediaType(&self) -> Retained<AVMediaType>

Available on crate feature AVMediaFormat only.

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

pub unsafe fn isPlayable(&self) -> bool

pub unsafe fn isDecodable(&self) -> bool

pub unsafe fn isEnabled(&self) -> bool

pub unsafe fn isSelfContained(&self) -> bool

pub unsafe fn totalSampleDataLength(&self) -> c_longlong

pub unsafe fn hasMediaCharacteristic( &self, media_characteristic: &AVMediaCharacteristic, ) -> bool

Available on crate feature AVMediaFormat only.

Reports whether the track references media with the specified media characteristic.

Parameter mediaCharacteristic: The media characteristic of interest, e.g. AVMediaCharacteristicVisual, AVMediaCharacteristicAudible, AVMediaCharacteristicLegible, etc., as defined above.

Returns: YES if the track references media with the specified characteristic, otherwise NO.

impl AVAssetTrack

AVAssetTrackTemporalProperties.

pub unsafe fn timeRange(&self) -> CMTimeRange

Available on crate feature objc2-core-media only.

pub unsafe fn naturalTimeScale(&self) -> CMTimeScale

Available on crate feature objc2-core-media only.

pub unsafe fn estimatedDataRate(&self) -> c_float

impl AVAssetTrack

AVAssetTrackLanguageProperties.

pub unsafe fn languageCode(&self) -> Option<Retained<NSString>>

pub unsafe fn extendedLanguageTag(&self) -> Option<Retained<NSString>>

impl AVAssetTrack

AVAssetTrackPropertiesForVisualCharacteristic.

pub unsafe fn naturalSize(&self) -> CGSize

Available on crate feature objc2-core-foundation only.

pub unsafe fn preferredTransform(&self) -> CGAffineTransform

Available on crate feature objc2-core-foundation only.

impl AVAssetTrack

AVAssetTrackPropertiesForAudibleCharacteristic.

pub unsafe fn preferredVolume(&self) -> c_float

pub unsafe fn hasAudioSampleDependencies(&self) -> bool

impl AVAssetTrack

AVAssetTrackPropertiesForFrameBasedCharacteristic.

pub unsafe fn nominalFrameRate(&self) -> c_float

For tracks that carry a full frame per media sample, indicates the frame rate of the track in units of frames per second.

For field-based video tracks that carry one field per media sample, the value of this property is the field rate, not the frame rate.

pub unsafe fn minFrameDuration(&self) -> CMTime

Available on crate feature objc2-core-media only.

pub unsafe fn requiresFrameReordering(&self) -> bool

Indicates whether samples in the track may have different values for their presentation and decode timestamps.

impl AVAssetTrack

AVAssetTrackSegments.

pub unsafe fn segments(&self) -> Retained<NSArray<AVAssetTrackSegment>>

Available on crate feature AVAssetTrackSegment only.

pub unsafe fn segmentForTrackTime( &self, track_time: CMTime, ) -> Option<Retained<AVAssetTrackSegment>>

👎Deprecated: Use loadSegmentForTrackTime:completionHandler: instead

Available on crate features AVAssetTrackSegment and objc2-core-media only.

Supplies the AVAssetTrackSegment from the segments array with a target timeRange that either contains the specified track time or is the closest to it among the target timeRanges of the track’s segments.

Parameter trackTime: The trackTime for which an AVAssetTrackSegment is requested.

Returns: An AVAssetTrackSegment.

If the trackTime does not map to a sample presentation time (e.g. it’s outside the track’s timeRange), the segment closest in time to the specified trackTime is returned.

pub unsafe fn loadSegmentForTrackTime_completionHandler( &self, track_time: CMTime, completion_handler: &Block<dyn Fn(*mut AVAssetTrackSegment, *mut NSError)>, )

Available on crate features AVAssetTrackSegment and block2 and objc2-core-media only.

Loads the AVAssetTrackSegment from the segments array with a target timeRange that either contains the specified track time or is the closest to it among the target timeRanges of the track’s segments.

Parameter trackTime: The trackTime for which an AVAssetTrackSegment is requested.

Parameter completionHandler: A block that is invoked when loading is complete, vending an AVAssetTrackSegment or an error.

If the trackTime does not map to a sample presentation time (e.g. it’s outside the track’s timeRange), the segment closest in time to the specified trackTime is returned.

pub unsafe fn samplePresentationTimeForTrackTime( &self, track_time: CMTime, ) -> CMTime

👎Deprecated: Use loadSamplePresentationTimeForTrackTime:completionHandler: instead

Available on crate feature objc2-core-media only.

Maps the specified trackTime through the appropriate time mapping and returns the resulting sample presentation time.

Parameter trackTime: The trackTime for which a sample presentation time is requested.

Returns: A CMTime; will be invalid if the trackTime is out of range

pub unsafe fn loadSamplePresentationTimeForTrackTime_completionHandler( &self, track_time: CMTime, completion_handler: &Block<dyn Fn(CMTime, *mut NSError)>, )

Available on crate features block2 and objc2-core-media only.

Maps the specified trackTime through the appropriate time mapping and loads the resulting sample presentation time.

Parameter trackTime: The trackTime for which a sample presentation time is requested.

Parameter completionHandler: A block that is invoked when loading is complete, vending a CMTime (which will be invalid if the trackTime is out of range) or an error.

impl AVAssetTrack

AVAssetTrackMetadataReading.

pub unsafe fn commonMetadata(&self) -> Retained<NSArray<AVMetadataItem>>

Available on crate feature AVMetadataItem only.

pub unsafe fn metadata(&self) -> Retained<NSArray<AVMetadataItem>>

Available on crate feature AVMetadataItem only.

pub unsafe fn availableMetadataFormats( &self, ) -> Retained<NSArray<AVMetadataFormat>>

Available on crate feature AVMetadataFormat only.

pub unsafe fn metadataForFormat( &self, format: &AVMetadataFormat, ) -> Retained<NSArray<AVMetadataItem>>

👎Deprecated: Use loadMetadataForFormat:completionHandler: instead

Available on crate features AVMetadataFormat and AVMetadataItem only.

Provides an NSArray of AVMetadataItems, one for each metadata item in the container of the specified format.

Parameter format: The metadata format for which items are requested.

Returns: An NSArray containing AVMetadataItems.

Becomes callable without blocking when the key “ availableMetadataFormats“ has been loaded

pub unsafe fn loadMetadataForFormat_completionHandler( &self, format: &AVMetadataFormat, completion_handler: &Block<dyn Fn(*mut NSArray<AVMetadataItem>, *mut NSError)>, )

Available on crate features AVMetadataFormat and AVMetadataItem and block2 only.

Loads an NSArray of AVMetadataItems, one for each metadata item in the container of the specified format.

Parameter format: The metadata format for which items are requested.

Parameter completionHandler: A block that is invoked when loading is complete, vending the array of metadata items (which may be empty if there is no metadata of the specified format) or an error.

impl AVAssetTrack

AVAssetTrackTrackAssociations.

pub unsafe fn availableTrackAssociationTypes( &self, ) -> Retained<NSArray<AVTrackAssociationType>>

pub unsafe fn associatedTracksOfType( &self, track_association_type: &AVTrackAssociationType, ) -> Retained<NSArray<AVAssetTrack>>

👎Deprecated: Use loadAssociatedTracksOfType:completionHandler: instead

Provides an NSArray of AVAssetTracks, one for each track associated with the receiver with the specified type of track association.

Parameter trackAssociationType: The type of track association for which associated tracks are requested.

Returns: An NSArray containing AVAssetTracks; may be empty if there is no associated tracks of the specified type.

Becomes callable without blocking when the key “ availableTrackAssociationTypes“ has been loaded.

pub unsafe fn loadAssociatedTracksOfType_completionHandler( &self, track_association_type: &AVTrackAssociationType, completion_handler: &Block<dyn Fn(*mut NSArray<AVAssetTrack>, *mut NSError)>, )

Available on crate feature block2 only.

Provides an NSArray of AVAssetTracks, one for each track associated with the receiver with the specified type of track association.

Parameter trackAssociationType: The type of track association for which associated tracks are requested.

Parameter completionHandler: A block that is invoked when loading is comlete, vending an array of tracks (which may be empty if there is no associated tracks of the specified type) or an error. `

impl AVAssetTrack

AVAssetTrackSampleCursorProvision.

pub unsafe fn canProvideSampleCursors(&self) -> bool

pub unsafe fn makeSampleCursorWithPresentationTimeStamp( &self, presentation_time_stamp: CMTime, ) -> Option<Retained<AVSampleCursor>>

Available on crate features AVSampleCursor and objc2-core-media only.

Creates an instance of AVSampleCursor and positions it at or near the specified presentation timestamp.

Parameter presentationTimeStamp: The desired initial presentation timestamp of the returned AVSampleCursor.

Returns: An instance of AVSampleCursor.

If the receiver’s asset has a value of YES for providesPreciseDurationAndTiming, the sample cursor will be accurately positioned at the receiver’s last media sample with presentation timestamp less than or equal to the desired timestamp, or, if there are no such samples, the first sample in presentation order. If the receiver’s asset has a value of NO for providesPreciseDurationAndTiming, and it is prohibitively expensive to locate the precise sample at the desired timestamp, the sample cursor may be approximately positioned. This method will return nil if there are no samples in the track.

pub unsafe fn makeSampleCursorAtFirstSampleInDecodeOrder( &self, ) -> Option<Retained<AVSampleCursor>>

Available on crate feature AVSampleCursor only.

Creates an instance of AVSampleCursor and positions it at the receiver’s first media sample in decode order.

Returns: An instance of AVSampleCursor.

This method will return nil if there are no samples in the track.

pub unsafe fn makeSampleCursorAtLastSampleInDecodeOrder( &self, ) -> Option<Retained<AVSampleCursor>>

Available on crate feature AVSampleCursor only.

Creates an instance of AVSampleCursor and positions it at the receiver’s last media sample in decode order.

Returns: An instance of AVSampleCursor.

This method will return nil if there are no samples in the track.

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 AVAsynchronousKeyValueLoading for AVAssetTrack

Available on crate feature AVAsynchronousKeyValueLoading only.

unsafe fn loadValuesAsynchronouslyForKeys_completionHandler( &self, keys: &NSArray<NSString>, handler: Option<&Block<dyn Fn()>>, )

where Self: Sized + Message,

Available on crate feature block2 only.

Directs the target to load the values of any of the specified keys that are not already loaded.

impl AsRef<AVAssetTrack> for AVAssetTrack

fn as_ref(&self) -> &Self

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

impl AsRef<AVAssetTrack> for AVCompositionTrack

Available on crate feature AVCompositionTrack only.

fn as_ref(&self) -> &AVAssetTrack

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

impl AsRef<AVAssetTrack> for AVFragmentedAssetTrack

fn as_ref(&self) -> &AVAssetTrack

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

impl AsRef<AVAssetTrack> for AVFragmentedMovieTrack

Available on crate feature AVMovieTrack only.

fn as_ref(&self) -> &AVAssetTrack

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

impl AsRef<AVAssetTrack> for AVMovieTrack

Available on crate feature AVMovieTrack only.

fn as_ref(&self) -> &AVAssetTrack

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

impl AsRef<AVAssetTrack> for AVMutableCompositionTrack

Available on crate feature AVCompositionTrack only.

fn as_ref(&self) -> &AVAssetTrack

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

impl AsRef<AVAssetTrack> for AVMutableMovieTrack

Available on crate feature AVMovieTrack only.

fn as_ref(&self) -> &AVAssetTrack

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

impl AsRef<AnyObject> for AVAssetTrack

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVAssetTrack

fn as_ref(&self) -> &NSObject

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

impl Borrow<AVAssetTrack> for AVCompositionTrack

Available on crate feature AVCompositionTrack only.

fn borrow(&self) -> &AVAssetTrack

Immutably borrows from an owned value.

impl Borrow<AVAssetTrack> for AVFragmentedAssetTrack

fn borrow(&self) -> &AVAssetTrack

Immutably borrows from an owned value.

impl Borrow<AVAssetTrack> for AVFragmentedMovieTrack

Available on crate feature AVMovieTrack only.

fn borrow(&self) -> &AVAssetTrack

Immutably borrows from an owned value.

impl Borrow<AVAssetTrack> for AVMovieTrack

Available on crate feature AVMovieTrack only.

fn borrow(&self) -> &AVAssetTrack

Immutably borrows from an owned value.

impl Borrow<AVAssetTrack> for AVMutableCompositionTrack

Available on crate feature AVCompositionTrack only.

fn borrow(&self) -> &AVAssetTrack

Immutably borrows from an owned value.

impl Borrow<AVAssetTrack> for AVMutableMovieTrack

Available on crate feature AVMovieTrack only.

fn borrow(&self) -> &AVAssetTrack

Immutably borrows from an owned value.

impl Borrow<AnyObject> for AVAssetTrack

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVAssetTrack

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVAssetTrack

const NAME: &'static str = "AVAssetTrack"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVAssetTrack 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 CopyingHelper for AVAssetTrack

type Result = AVAssetTrack

The immutable counterpart of the type, or Self if the type has no immutable counterpart.

impl Debug for AVAssetTrack

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

Formats the value using the given formatter.

impl Deref for AVAssetTrack

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVAssetTrack

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 AVAssetTrack

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSCopying for AVAssetTrack

fn copy(&self) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

unsafe fn copyWithZone(&self, zone: *mut NSZone) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

impl NSObjectProtocol for AVAssetTrack

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 AVAssetTrack

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 AVAssetTrack

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

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

impl DowncastTarget for AVAssetTrack

impl Eq for AVAssetTrack