MiXiD API Reference: Compositing and Mixing

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Reference size:
52 headers
260 properties
354 methods and callbacks

Detailed MiXiD XCFramework reference for Compositing and Mixing. Read through each header, class, protocol, and function section to inspect Objective-C declarations, parameters, return values, and usage guidance.

Compositing and Mixing

MXDCompositeAudioRenderer.h

Audio playback renderer for mixed or decoded media.

MXDCompositeAudioRenderer

start

- (void)start;

Kind	Instance method
Return	`void`
Details	Starts the component and begins the related capture, server, playback, publish, recording, or discovery workflow.
Parameters	No parameters.
Swift usage	`instance.start()`

pause

- (void)pause;

Kind	Instance method
Return	`void`
Details	Pauses playback while keeping the object available for a later resume.
Parameters	No parameters.
Swift usage	`instance.pause()`

flush

- (void)flush;

Kind	Instance method
Return	`void`
Details	Clears queued decoder/player state so future media starts from a clean point.
Parameters	No parameters.
Swift usage	`instance.flush()`

stop

- (void)stop;

Kind	Instance method
Return	`void`
Details	Stops the component and releases or finalizes active workflow resources.
Parameters	No parameters.
Swift usage	`instance.stop()`

enqueueAudioBuffer:when:

- (void)enqueueAudioBuffer:(AVAudioPCMBuffer *)buffer when:(AVAudioTime * _Nullable)when;

Kind	Instance method
Return	`void`
Details	Queues encoded audio data for playback. Call in timestamp order for stable audio scheduling.
Parameters	`enqueueAudioBuffer` (`AVAudioPCMBuffer `, buffer); `when` (`AVAudioTime _Nullable`, when)
Swift usage	`instance.enqueueAudioBuffer(enqueueAudioBuffer: audioBuffer, when: when)`

enqueueAACAccessUnit:sampleRate:channels:objectType:config:

- (void)enqueueAACAccessUnit:(NSData *)accessUnit sampleRate:(Float64)sampleRate channels:(UInt32)channels objectType:(UInt32)objectType config:(NSData * _Nullable)config;

Kind	Instance method
Return	`void`
Details	Queues encoded audio data for playback. Call in timestamp order for stable audio scheduling.
Parameters	`enqueueAACAccessUnit` (`NSData `, accessUnit); `sampleRate` (`Float64`, sampleRate); `channels` (`UInt32`, channels); `objectType` (`UInt32`, objectType); `config` (`NSData _Nullable`, config)
Swift usage	`instance.enqueueAACAccessUnit(enqueueAACAccessUnit: data, sampleRate: 0.0, channels: channels, objectType: objectType, config: data)`

MXDCompositeMediaMixer.h

Four-slot audio/video mixer.

MXDCompositeMediaMixerDelegate Protocol

compositeMediaMixerDidOutputAudioBuffer:

- (void)compositeMediaMixerDidOutputAudioBuffer:(AVAudioPCMBuffer *)audioBuffer;

Kind	Delegate / protocol callback
Return	`void`
Details	Callback invoked by MiXiD for compositeMediaMixerDidOutputAudioBuffer. Implement this method to observe lifecycle, media output, status, or error events.
Parameters	`compositeMediaMixerDidOutputAudioBuffer` (`AVAudioPCMBuffer *`, audioBuffer)
Swift usage	`instance.compositeMediaMixerDidOutputAudioBuffer(compositeMediaMixerDidOutputAudioBuffer: audioBuffer)`

compositeMediaMixerDidUpdateAudioLevels:masterLevel:

- (void)compositeMediaMixerDidUpdateAudioLevels:(NSArray<NSNumber *> *)slotLevels masterLevel:(Float32)masterLevel;

Kind	Delegate / protocol callback
Return	`void`
Details	Callback invoked by MiXiD for compositeMediaMixerDidUpdateAudioLevels masterLevel. Implement this method to observe lifecycle, media output, status, or error events.
Parameters	`compositeMediaMixerDidUpdateAudioLevels` (`NSArray<NSNumber > `, slotLevels); `masterLevel` (`Float32`, masterLevel)
Swift usage	`instance.compositeMediaMixerDidUpdateAudioLevels(compositeMediaMixerDidUpdateAudioLevels: 0, masterLevel: 0.0)`

compositeMediaMixerNeedsVideoRenderForBuffers:count:outputWidth:outputHeight:presentationTime:

- (void)compositeMediaMixerNeedsVideoRenderForBuffers:(CVPixelBufferRef _Nullable const * _Nonnull)videoBuffers count:(NSInteger)count outputWidth:(NSInteger)outputWidth outputHeight:(NSInteger)outputHeight presentationTime:(CMTime)presentationTime;

Kind	Delegate / protocol callback
Return	`void`
Details	Callback invoked by MiXiD for compositeMediaMixerNeedsVideoRenderForBuffers count outputWidth outputHeight presentationTime. Implement this method to observe lifecycle, media output, status, or error events.
Parameters	`compositeMediaMixerNeedsVideoRenderForBuffers` (`CVPixelBufferRef _Nullable const * _Nonnull`, videoBuffers); `count` (`NSInteger`, count); `outputWidth` (`NSInteger`, outputWidth); `outputHeight` (`NSInteger`, outputHeight); `presentationTime` (`CMTime`, presentationTime)
Swift usage	`instance.compositeMediaMixerNeedsVideoRenderForBuffers(compositeMediaMixerNeedsVideoRenderForBuffers: imageBuffer, count: 0, outputWidth: 0, outputHeight: 0, presentationTime: 0.0)`

compositeMediaMixerDidFailWithError:

- (void)compositeMediaMixerDidFailWithError:(NSError *)error;

Kind	Delegate / protocol callback
Return	`void`
Details	Callback invoked by MiXiD for compositeMediaMixerDidFailWithError. Implement this method to observe lifecycle, media output, status, or error events.
Parameters	`compositeMediaMixerDidFailWithError` (`NSError *`, error)
Swift usage	`instance.compositeMediaMixerDidFailWithError(compositeMediaMixerDidFailWithError: nil)`

MXDCompositeMediaMixer

Name	Declaration	Details
`delegate`	`@property (nonatomic, weak, nullable) id<MXDCompositeMediaMixerDelegate> delegate;`	Receives lifecycle, media output, status, or error callbacks.
`running`	`@property (nonatomic, assign, readonly, getter=isRunning) BOOL running;`	Read-only runtime state flag.

start

- (void)start;

Kind	Instance method
Return	`void`
Details	Starts the component and begins the related capture, server, playback, publish, recording, or discovery workflow.
Parameters	No parameters.
Swift usage	`instance.start()`

stop

- (void)stop;

Kind	Instance method
Return	`void`
Details	Stops the component and releases or finalizes active workflow resources.
Parameters	No parameters.
Swift usage	`instance.stop()`

appendVideoFrame:forSlot:presentationTime:

- (void)appendVideoFrame:(CVImageBufferRef)imageBuffer forSlot:(NSInteger)slotIndex presentationTime:(CMTime)presentationTime;

Kind	Instance method
Return	`void`
Details	Appends media into the component. Use presentation timestamps and matching stream configuration so downstream encoders, mixers, or recorders stay synchronized.
Parameters	`appendVideoFrame` (`CVImageBufferRef`, imageBuffer); `forSlot` (`NSInteger`, slotIndex); `presentationTime` (`CMTime`, presentationTime)
Swift usage	`instance.appendVideoFrame(appendVideoFrame: imageBuffer, forSlot: 0, presentationTime: 0.0)`

appendAudioBuffer:forSlot:

- (void)appendAudioBuffer:(AVAudioPCMBuffer *)audioBuffer forSlot:(NSInteger)slotIndex;

Kind	Instance method
Return	`void`
Details	Appends media into the component. Use presentation timestamps and matching stream configuration so downstream encoders, mixers, or recorders stay synchronized.
Parameters	`appendAudioBuffer` (`AVAudioPCMBuffer *`, audioBuffer); `forSlot` (`NSInteger`, slotIndex)
Swift usage	`instance.appendAudioBuffer(appendAudioBuffer: audioBuffer, forSlot: 0)`

appendAACAccessUnit:forSlot:sampleRate:channels:objectType:config:

- (void)appendAACAccessUnit:(NSData *)accessUnit forSlot:(NSInteger)slotIndex sampleRate:(Float64)sampleRate channels:(UInt32)channels objectType:(UInt32)objectType config:(NSData * _Nullable)config;

Kind	Instance method
Return	`void`
Details	Appends media into the component. Use presentation timestamps and matching stream configuration so downstream encoders, mixers, or recorders stay synchronized.
Parameters	`appendAACAccessUnit` (`NSData `, accessUnit); `forSlot` (`NSInteger`, slotIndex); `sampleRate` (`Float64`, sampleRate); `channels` (`UInt32`, channels); `objectType` (`UInt32`, objectType); `config` (`NSData _Nullable`, config)
Swift usage	`instance.appendAACAccessUnit(appendAACAccessUnit: data, forSlot: 0, sampleRate: 0.0, channels: channels, objectType: objectType, config: data)`

setAudioGain:forSlot:

- (void)setAudioGain:(Float32)gain forSlot:(NSInteger)slotIndex;

Kind	Instance method
Return	`void`
Details	Updates configuration on an existing object. Some changes apply immediately; transport or stream changes may reconnect or reload internal resources.
Parameters	`setAudioGain` (`Float32`, gain); `forSlot` (`NSInteger`, slotIndex)
Swift usage	`instance.setAudioGain(setAudioGain: 0.0, forSlot: 0)`

audioGainForSlot:

- (Float32)audioGainForSlot:(NSInteger)slotIndex;

Kind	Instance method
Return	`Float32`
Details	Performs the audioGainForSlot operation on this MiXiD component.
Parameters	`audioGainForSlot` (`NSInteger`, slotIndex)
Swift usage	`let result = instance.audioGainForSlot(audioGainForSlot: 0)`

setMaximumQueuedAudioSeconds:forSlot:

- (void)setMaximumQueuedAudioSeconds:(Float64)seconds forSlot:(NSInteger)slotIndex;

Kind	Instance method
Return	`void`
Details	Updates configuration on an existing object. Some changes apply immediately; transport or stream changes may reconnect or reload internal resources.
Parameters	`setMaximumQueuedAudioSeconds` (`Float64`, seconds); `forSlot` (`NSInteger`, slotIndex)
Swift usage	`instance.setMaximumQueuedAudioSeconds(setMaximumQueuedAudioSeconds: 0.0, forSlot: 0)`

setOutputAudioGain:

- (void)setOutputAudioGain:(Float32)gain;

Kind	Instance method
Return	`void`
Details	Updates configuration on an existing object. Some changes apply immediately; transport or stream changes may reconnect or reload internal resources.
Parameters	`setOutputAudioGain` (`Float32`, gain)
Swift usage	`instance.setOutputAudioGain(setOutputAudioGain: 0.0)`

MXDCompositeRenderer.h

Video compositor for mixer output.

MXDCompositeRendererDelegate Protocol

compositeRenderer:didRenderVideoFrame:presentationTime:

- (void)compositeRenderer:(MXDCompositeRenderer *)renderer didRenderVideoFrame:(CVImageBufferRef)imageBuffer presentationTime:(CMTime)presentationTime;

Kind	Delegate / protocol callback
Return	`void`
Details	Callback invoked by MiXiD for compositeRenderer didRenderVideoFrame presentationTime. Implement this method to observe lifecycle, media output, status, or error events.
Parameters	`compositeRenderer` (`MXDCompositeRenderer *`, renderer); `didRenderVideoFrame` (`CVImageBufferRef`, imageBuffer); `presentationTime` (`CMTime`, presentationTime)
Swift usage	`instance.compositeRenderer(compositeRenderer: renderer, didRenderVideoFrame: imageBuffer, presentationTime: 0.0)`

compositeRenderer:willRenderCompositeImage:outputRect:presentationTime:

- (CIImage *)compositeRenderer:(MXDCompositeRenderer *)renderer willRenderCompositeImage:(CIImage *)compositeImage outputRect:(CGRect)outputRect presentationTime:(CMTime)presentationTime;

Kind	Delegate / protocol callback
Return	`CIImage *`
Details	Callback invoked by MiXiD for compositeRenderer willRenderCompositeImage outputRect presentationTime. Implement this method to observe lifecycle, media output, status, or error events.
Parameters	`compositeRenderer` (`MXDCompositeRenderer `, renderer); `willRenderCompositeImage` (`CIImage `, compositeImage); `outputRect` (`CGRect`, outputRect); `presentationTime` (`CMTime`, presentationTime)
Swift usage	`let result = instance.compositeRenderer(compositeRenderer: renderer, willRenderCompositeImage: compositeImage, outputRect: outputRect, presentationTime: 0.0)`

MXDCompositeRenderer

Name	Declaration	Details
`delegate`	`@property (nonatomic, weak, nullable) id<MXDCompositeRendererDelegate> delegate;`	Receives lifecycle, media output, status, or error callbacks.

renderVideoBuffers:count:outputWidth:outputHeight:presentationTime:

- (void)renderVideoBuffers:(CVPixelBufferRef _Nullable const * _Nonnull)videoBuffers count:(NSInteger)count outputWidth:(NSInteger)outputWidth outputHeight:(NSInteger)outputHeight presentationTime:(CMTime)presentationTime;

Kind	Instance method
Return	`void`
Details	Performs the renderVideoBuffers count outputWidth outputHeight presentationTime operation on this MiXiD component.
Parameters	`renderVideoBuffers` (`CVPixelBufferRef _Nullable const * _Nonnull`, videoBuffers); `count` (`NSInteger`, count); `outputWidth` (`NSInteger`, outputWidth); `outputHeight` (`NSInteger`, outputHeight); `presentationTime` (`CMTime`, presentationTime)
Swift usage	`instance.renderVideoBuffers(renderVideoBuffers: imageBuffer, count: 0, outputWidth: 0, outputHeight: 0, presentationTime: 0.0)`

MXDCompositeVideoRenderer.h

CALayer-backed video preview renderer.

MXDCompositeVideoRenderer

Name	Declaration	Details
`startupPrerollSeconds`	`@property (nonatomic, assign) NSTimeInterval startupPrerollSeconds;`	Public configuration or state exposed by this API.

initWithLayer:

- (instancetype)initWithLayer:(CALayer *)layer;

Kind	Instance method
Return	`instancetype`
Details	Initializes the receiver for initWithLayer. Use this to provide required URLs, ports, names, peer connections, or configuration objects.
Parameters	`initWithLayer` (`CALayer *`, layer)
Swift usage	`let value = MXDCompositeVideoRenderer(initWithLayer: layer)`

enqueueImageBuffer:presentationTime:

- (void)enqueueImageBuffer:(CVImageBufferRef)imageBuffer presentationTime:(CMTime)presentationTime;

Kind	Instance method
Return	`void`
Details	Queues encoded audio data for playback. Call in timestamp order for stable audio scheduling.
Parameters	`enqueueImageBuffer` (`CVImageBufferRef`, imageBuffer); `presentationTime` (`CMTime`, presentationTime)
Swift usage	`instance.enqueueImageBuffer(enqueueImageBuffer: imageBuffer, presentationTime: 0.0)`

flush

- (void)flush;

Kind	Instance method
Return	`void`
Details	Clears queued decoder/player state so future media starts from a clean point.
Parameters	No parameters.
Swift usage	`instance.flush()`

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