Struct AVMutableTimedMetadataGroup

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pub struct AVMutableTimedMetadataGroup { /* private fields */ }

Available on crate feature AVTimedMetadataGroup only.

Expand description

AVMutableTimedMetadataGroup is used to represent a mutable collection of metadata items that are valid for use during a specific range of time.

Implementations§

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impl AVMutableTimedMetadataGroup

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pub unsafe fn timeRange(&self) -> CMTimeRange

Available on crate feature objc2-core-media only.

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pub unsafe fn setTimeRange(&self, time_range: CMTimeRange)

Available on crate feature objc2-core-media only.

Setter for timeRange.

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

Available on crate feature AVMetadataItem only.

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pub unsafe fn setItems(&self, items: &NSArray<AVMetadataItem>)

Available on crate feature AVMetadataItem only.

Setter for items.

This is copied when set.

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impl AVMutableTimedMetadataGroup

Methods declared on superclass AVTimedMetadataGroup.

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pub unsafe fn initWithItems_timeRange( this: Allocated<Self>, items: &NSArray<AVMetadataItem>, time_range: CMTimeRange, ) -> Retained<Self>

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

Initializes an instance of AVTimedMetadataGroup with a collection of metadata items.

Parameter items: An NSArray of AVMetadataItems.

Parameter timeRange: The timeRange of the collection of AVMetadataItems.

Returns: An instance of AVTimedMetadataGroup.

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pub unsafe fn initWithSampleBuffer( this: Allocated<Self>, sample_buffer: &CMSampleBuffer, ) -> Option<Retained<Self>>

Available on crate feature objc2-core-media only.

Initializes an instance of AVTimedMetadataGroup with a sample buffer.

Parameter sampleBuffer: A CMSampleBuffer with media type kCMMediaType_Metadata.

Returns: An instance of AVTimedMetadataGroup.

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impl AVMutableTimedMetadataGroup

Methods declared on superclass NSObject.

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

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

Methods from Deref<Target = AVTimedMetadataGroup>§

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pub unsafe fn timeRange(&self) -> CMTimeRange

Available on crate feature objc2-core-media only.

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

Available on crate feature AVMetadataItem only.

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pub unsafe fn copyFormatDescription( &self, ) -> Option<Retained<CMMetadataFormatDescription>>

Available on crate feature objc2-core-media only.

Creates a format description based on the receiver’s items.

Returns: An instance of CMMetadataFormatDescription sufficient to describe the contents of all the items referenced by the receiver.

The returned format description is suitable for use as the format hint parameter when creating an instance of AVAssetWriterInput.

Each item referenced by the receiver must carry a non-nil value for its dataType property. An exception will be thrown if any item does not have a data type.

Methods from Deref<Target = AVMetadataGroup>§

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

Available on crate feature AVMetadataItem only.

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

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

Methods from Deref<Target = NSObject>§

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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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());

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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.

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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`
    }
}