Struct AVSampleBufferAudioRenderer

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

Available on crate feature AVSampleBufferAudioRenderer only.

Expand description

Apple’s documentation

Implementations§

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impl AVSampleBufferAudioRenderer

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pub unsafe fn status(&self) -> AVQueuedSampleBufferRenderingStatus

Available on crate feature AVQueuedSampleBufferRendering only.

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pub unsafe fn error(&self) -> Option<Retained<NSError>>

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

Specifies the unique ID of the Core Audio output device used to play audio.

By default, the value of this property is nil, indicating that the default audio output device is used. Otherwise the value of this property is an NSString containing the unique ID of the Core Audio output device to be used for audio output.

Core Audio’s kAudioDevicePropertyDeviceUID is a suitable source of audio output device unique IDs.

Modifying this property while the timebase’s rate is not 0.0 may cause the rate to briefly change to 0.0.

On macOS, the audio device clock may be used as the AVSampleBufferRenderSynchronizer’s and all attached AVQueuedSampleBufferRendering’s timebase’s clocks. If the audioOutputDeviceUniqueID is modified, the clocks of all these timebases may also change.

If multiple AVSampleBufferAudioRenderers with different values for audioOutputDeviceUniqueID are attached to the same AVSampleBufferRenderSynchronizer, audio may not stay in sync during playback. To avoid this, ensure that all synchronized AVSampleBufferAudioRenderers are using the same audio output device.

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pub unsafe fn setAudioOutputDeviceUniqueID( &self, audio_output_device_unique_id: Option<&NSString>, )

Setter for audioOutputDeviceUniqueID.

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pub unsafe fn audioTimePitchAlgorithm( &self, ) -> Retained<AVAudioTimePitchAlgorithm>

Available on crate feature AVAudioProcessingSettings only.

Indicates the processing algorithm used to manage audio pitch at varying rates.

Constants for various time pitch algorithms, e.g. AVAudioTimePitchSpectral, are defined in AVAudioProcessingSettings.h.

The default value for applications linked on or after iOS 15.0 or macOS 12.0 is AVAudioTimePitchAlgorithmTimeDomain. For iOS versions prior to 15.0 the default value is AVAudioTimePitchAlgorithmLowQualityZeroLatency. For macOS versions prior to 12.0 the default value is AVAudioTimePitchAlgorithmSpectral.

If the timebase’s rate is not supported by the audioTimePitchAlgorithm, audio will be muted.

Modifying this property while the timebase’s rate is not 0.0 may cause the rate to briefly change to 0.0.

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pub unsafe fn setAudioTimePitchAlgorithm( &self, audio_time_pitch_algorithm: &AVAudioTimePitchAlgorithm, )

Available on crate feature AVAudioProcessingSettings only.

Setter for audioTimePitchAlgorithm.

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pub unsafe fn allowedAudioSpatializationFormats( &self, ) -> AVAudioSpatializationFormats

Available on crate feature AVAudioProcessingSettings only.

Indicates the source audio channel layouts allowed by the receiver for spatialization.

Spatialization uses psychoacoustic methods to create a more immersive audio rendering when the content is played on specialized headphones and speaker arrangements. When an AVSampleBufferAudioRenderer’s allowedAudioSpatializationFormats property is set to AVAudioSpatializationFormatMonoAndStereo the AVSampleBufferAudioRenderer will attempt to spatialize content tagged with a stereo channel layout, two-channel content with no layout specified as well as mono. It is considered incorrect to render a binaural recording with spatialization. A binaural recording is captured using two carefully placed microphones at each ear where the intent, when played on headphones, is to reproduce a naturally occurring spatial effect. Content tagged with a binaural channel layout will ignore this property value. When an AVSampleBufferAudioRenderer’s allowedAudioSpatializationFormats property is set to AVAudioSpatializationFormatMultichannel the AVSampleBufferAudioRenderer will attempt to spatialize any decodable multichannel layout. Setting this property to AVAudioSpatializationFormatMonoStereoAndMultichannel indicates that the sender allows the AVSampleBufferAudioRenderer to spatialize any decodable mono, stereo or multichannel layout. This property is not observable. The default value for this property is AVAudioSpatializationFormatMultichannel.

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pub unsafe fn setAllowedAudioSpatializationFormats( &self, allowed_audio_spatialization_formats: AVAudioSpatializationFormats, )

Available on crate feature AVAudioProcessingSettings only.

Setter for allowedAudioSpatializationFormats.

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impl AVSampleBufferAudioRenderer

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>

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impl AVSampleBufferAudioRenderer

AVSampleBufferAudioRendererVolumeControl.

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pub unsafe fn volume(&self) -> c_float

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pub unsafe fn setVolume(&self, volume: c_float)

Setter for volume.

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pub unsafe fn isMuted(&self) -> bool

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pub unsafe fn setMuted(&self, muted: bool)

Setter for isMuted.

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impl AVSampleBufferAudioRenderer

AVSampleBufferAudioRendererQueueManagement.

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pub unsafe fn flushFromSourceTime_completionHandler( &self, time: CMTime, completion_handler: &Block<dyn Fn(Bool)>, )

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

Flushes enqueued sample buffers with presentation time stamps later than or equal to the specified time.

Parameter completionHandler: A block that is invoked, possibly asynchronously, after the flush operation completes or fails.

This method can be used to replace media data scheduled to be rendered in the future, without interrupting playback. One example of this is when the data that has already been enqueued is from a sequence of two songs and the second song is swapped for a new song. In this case, this method would be called with the time stamp of the first sample buffer from the second song. After the completion handler is executed with a YES parameter, media data may again be enqueued with timestamps at the specified time.

If NO is provided to the completion handler, the flush did not succeed and the set of enqueued sample buffers remains unchanged. A flush can fail becuse the source time was too close to (or earlier than) the current time or because the current configuration of the receiver does not support flushing at a particular time. In these cases, the caller can choose to flush all enqueued media data by invoking the -flush method.

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.

§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`
    }
}