Struct AVSampleCursor 

pub struct AVSampleCursor { /* private fields */ }

Available on crate feature AVSampleCursor only.

Apple’s documentation

Implementations

impl AVSampleCursor

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

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

pub unsafe fn stepInDecodeOrderByCount(&self, step_count: i64) -> i64

Moves the cursor a given number of samples in decode order.

Parameter stepCount: The number of samples to move across. If positive, step forward this many samples. If negative, step backward (-stepCount) samples.

Returns: The number of samples the cursor traversed. If the beginning or the end of the sample sequence was reached before the requested number of samples was traversed, the absolute value of the result will be less than the absolute value of stepCount.

pub unsafe fn stepInPresentationOrderByCount(&self, step_count: i64) -> i64

Moves the cursor a given number of samples in presentation order.

Parameter stepCount: The number of samples to move across. If positive, step forward this many samples. If negative, step backward (-stepCount) samples.

Returns: The number of samples the cursor traversed. If the beginning or the end of the sample sequence was reached before the requested number of samples was traversed, the absolute value of the result will be less than the absolute value of stepCount.

pub unsafe fn stepByDecodeTime_wasPinned( &self, delta_decode_time: CMTime, out_was_pinned: *mut Bool, ) -> CMTime

Available on crate feature objc2-core-media only.

Moves the cursor by a given deltaTime on the decode timeline.

Parameter deltaDecodeTime: The amount of time to move in the decode timeline.

Parameter outWasPinned: If the beginning or the end of the sample sequence was reached before the requested deltaDecodeTime was traversed, the BOOL value at the address specified by outWasPinned will be set to YES. May be NULL if this information isn’t desired.

Returns: The amount of time the cursor was moved along the decode timeline. Because sample cursors snap to sample boundaries when stepped, this value may not be equal to deltaDecodeTime even if the cursor was not pinned.

Safety

out_was_pinned must be a valid pointer or null.

pub unsafe fn stepByPresentationTime_wasPinned( &self, delta_presentation_time: CMTime, out_was_pinned: *mut Bool, ) -> CMTime

Available on crate feature objc2-core-media only.

Moves the cursor by a given deltaTime on the presentation timeline.

Parameter deltaPresentationTime: The amount of time to move in the presentation timeline.

Parameter outWasPinned: If the beginning or the end of the sample sequence was reached before the requested deltaPresentationTime was traversed, the BOOL value at the address specified by outWasPinned will be set to YES. May be NULL if this information isn’t desired.

Returns: The amount of time the cursor was moved along the presentation timeline. Because sample cursors snap to sample boundaries when stepped, this value may not be equal to deltaPresentationTime even if the cursor was not pinned.

Safety

out_was_pinned must be a valid pointer or null.

impl AVSampleCursor

AVSampleCursorTemporalPosition.

pub unsafe fn presentationTimeStamp(&self) -> CMTime

Available on crate feature objc2-core-media only.

The presentation timestamp (PTS) of the sample at the current position of the cursor.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn decodeTimeStamp(&self) -> CMTime

Available on crate feature objc2-core-media only.

The decode timestamp (DTS) of the sample at the current position of the cursor.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn comparePositionInDecodeOrderWithPositionOfCursor( &self, cursor: &AVSampleCursor, ) -> NSComparisonResult

Compares the relative positions of two AVSampleCursors.

Parameter cursor: An instance of AVSampleCursor with which to compare positions.

Returns: kCFCompareLessThan, kCFCompareEqualTo or kCFCompareGreaterThan, depending on whether the receiver points at a sample before, the same as, or after the sample pointed to by the specified AVSampleCursor.

If the receiver and cursor reference different sequences of samples, as when they’re created by different instances of AVAssetTrack, results are undefined.

pub unsafe fn samplesWithEarlierDecodeTimeStampsMayHaveLaterPresentationTimeStampsThanCursor( &self, cursor: &AVSampleCursor, ) -> bool

This method tests a boundary in the reordering from decode order to presentation order, determining whether it’s possible for any sample earlier in decode order than the sample at the position of the receiver can have a presentation timestamp later than that of the specified sample cursor.

Parameter cursor: An instance of AVSampleCursor with which to test the sample reordering boundary.

Returns: YES if it’s possible for any sample earlier in decode order than the sample at the position of the receiver can have a presentation timestamp later than that of the specified sample cursor.

If the receiver and cursor reference different sequences of samples, as when they’re created by different instances of AVAssetTrack, results are undefined.

pub unsafe fn samplesWithLaterDecodeTimeStampsMayHaveEarlierPresentationTimeStampsThanCursor( &self, cursor: &AVSampleCursor, ) -> bool

This method tests a boundary in the reordering from decode order to presentation order, determining whether it’s possible for any sample later in decode order than the sample at the position of the receiver can have a presentation timestamp earlier than that of the specified sample cursor.

Parameter cursor: An instance of AVSampleCursor with which to test the sample reordering boundary.

Returns: YES if it’s possible for any sample later in decode order than the sample at the position of the receiver can have a presentation timestamp earlier than that of the specified sample cursor.

If the receiver and cursor reference different sequences of samples, as when they’re created by different instances of AVAssetTrack, results are undefined.

impl AVSampleCursor

AVSampleCursorCurrentSampleInfo.

pub unsafe fn currentSampleDuration(&self) -> CMTime

Available on crate feature objc2-core-media only.

Indicates the decode duration of the sample at the receiver’s current position.

If the receiver must be advanced past its current position in order to determine the decode duration of the current sample, the value of currentSampleDuration is equal to kCMTimeIndefinite. This can occur with streaming formats such as MPEG-2 transport streams.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn copyCurrentSampleFormatDescription( &self, ) -> Retained<CMFormatDescription>

Available on crate feature objc2-core-media only.

Provides the format description of the sample at the receiver’s current position.

pub unsafe fn currentSampleSyncInfo(&self) -> AVSampleCursorSyncInfo

Provides information about the current sample for consideration when resynchronizing a decoder, as when scrubbing.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn currentSampleDependencyInfo(&self) -> AVSampleCursorDependencyInfo

Provides information about dependencies between a media sample and other media samples in the same sample sequence, if known.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn currentSampleDependencyAttachments( &self, ) -> Option<Retained<NSDictionary>>

Provides a dictionary containing dependency related sample buffer attachments, if known. See kCMSampleAttachmentKey_… in CoreMedia/CMSampleBuffer.h.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn currentSampleAudioDependencyInfo( &self, ) -> AVSampleCursorAudioDependencyInfo

Provides information about the independent decodability of an audio sample.

In order to position a sample cursor at the first sample that the audio decoder requires for a full refresh, you will need to walk it back from the current sample until you find a sample that is independently decodable, and whose audioSamplePacketRefreshCount is greater than or equal to the number of steps back you have taken. This implies that if the current sample (before this walk) is independently decodable, with an audioSampleRefreshCount of zero, no walk is required.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn samplesRequiredForDecoderRefresh(&self) -> NSInteger

Count of samples prior to the current sample, in decode order, that the decoder requires in order to achieve fully coherent output at the current decode time, as after a seek. Zero will be returned if no samples are required for decoder refresh or if the track does not contain this information.

Some sample sequences that do not indicate sample dependencies may instead indicate that in order for a specific sample to be decoded with all available accuracy, samples prior to that sample in decode order must be decoded before the specific sample is decoded.

In order to position a sample cursor at the first sample that the decoder requires for a full refresh, you can use code like the following:

NSInteger samplesPriorToCurrentSampleToFeedToDecoder = [mySampleCursor samplesRequiredForDecoderRefresh]; AVSampleCursor *cursorForObtainingRefreshSamples = [mySampleCursor copy]; [cursorForObtainingRefreshSamples stepInDecodeOrderByCount: -samplesPriorToCurrentSampleToFeedToDecoder ];

// cursorForObtainingRefreshSamples is now positioned at the first sample that must be provided to the decoder // in order to decode the sample at the position of mySampleCursor in full

This property is not atomic.

Safety

This might not be thread-safe.

impl AVSampleCursor

AVSampleCursorSampleStorageInfo.

pub unsafe fn currentChunkStorageURL(&self) -> Option<Retained<NSURL>>

The URL of the storage container of the current sample, as well as other samples that are intended to be loaded in the same operation as a “chunk”.

May be nil; if nil, the storage location of the chunk is the URL of the sample cursor’s track’s asset, if it has one.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn currentChunkStorageRange(&self) -> AVSampleCursorStorageRange

The offset and length of samples in currentChunkStorageURL that are intended to be loaded together with the current sample as a “chunk”.

If the current chunk isn’t stored contiguously in its storage container, currentChunkStorageRange.offset will be -1. In such cases you can use AVSampleBufferGenerator to obtain the sample data.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn currentChunkInfo(&self) -> AVSampleCursorChunkInfo

Provides information about the “chunk” of samples to which the current sample belongs. If the media format that defines the sequence of samples does not signal “chunking” of samples in any way, each sample will be considered by the receiver as belonging to a chunk of one sample only.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn currentSampleIndexInChunk(&self) -> i64

The index of the current sample within the chunk to which it belongs.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn currentSampleStorageRange(&self) -> AVSampleCursorStorageRange

The offset and length of the current sample in currentChunkStorageURL.

If the current sample isn’t stored contiguously in its storage container, currentSampleStorageRange.offset will be -1. In such cases you can use AVSampleBufferGenerator to obtain the sample data.

This property is not atomic.

Safety

This might not be thread-safe.

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<AVSampleCursor> for AVSampleCursor

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVSampleCursor

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVSampleCursor

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVSampleCursor

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVSampleCursor

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVSampleCursor

const NAME: &'static str = "AVSampleCursor"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVSampleCursor 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 AVSampleCursor

type Result = AVSampleCursor

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

impl Debug for AVSampleCursor

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

Formats the value using the given formatter.

impl Deref for AVSampleCursor

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVSampleCursor

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 AVSampleCursor

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSCopying for AVSampleCursor

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 AVSampleCursor

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 AVSampleCursor

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 AVSampleCursor

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

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

impl DowncastTarget for AVSampleCursor

impl Eq for AVSampleCursor

impl Send for AVSampleCursor

impl Sync for AVSampleCursor