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![Composing Assets
Tracks and Segments
AVMutableComposition *composition = [AVMutableComposition composition];
AVComposition](https://image.slidesharecdn.com/mastervideo-static-140131012052-phpapp02/85/Master-Video-with-AV-Foundation-18-320.jpg)
![Composing Assets
Tracks and Segments
AVMutableCompositionTrack *videoTrack =
[composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:0];
AVMutableCompositionTrack *audioTrack =
[composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:1];
AVComposition
AVCompositionTrack (Video)
AVCompositionTrack (Audio)](https://image.slidesharecdn.com/mastervideo-static-140131012052-phpapp02/85/Master-Video-with-AV-Foundation-19-320.jpg)
![Composing Assets
Tracks and Segments
AVAssetTrack *srcVideoTrack1 = // source video track 1
[videoTrack insertTimeRange:timeRange ofTrack:srcVideoTrack1 atTime:startTime error:&error];
AVAssetTrack *srcVideoTrack2 = // source video track 2
[videoTrack insertTimeRange:timeRange ofTrack:srcVideoTrack2 atTime:startTime error:&error];
AVAssetTrack *srcAudioTrack = // source audio track
[audioTrack insertTimeRange:timeRange ofTrack:srcAudioTrack atTime:startTime error:&error];
AVComposition
AVCompositionTrack (Video)
AVCompositionTrackSegment
AVCompositionTrackSegment
Seconds 10-30 of “goldengate.m4v”
Seconds 20-60 of “wharf.m4v”
AVCompositionTrack (Audio)
AVCompositionTrackSegment
Seconds 0-60 of “soundtrack.m4a”](https://image.slidesharecdn.com/mastervideo-static-140131012052-phpapp02/85/Master-Video-with-AV-Foundation-20-320.jpg)
Uploaded byBob McCune
Master Video with AV Foundation
The document discusses the AV Foundation framework for advanced media processing on iOS, highlighting components such as AVAsset, AVPlayer, and AVComposition for handling and editing audio and video. It covers concepts like video playback, audio mixing, and video transitions, emphasizing the tools available for managing media. Although steep in learning, mastering these tools is presented as beneficial for effective media app development.
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Master Video with AV Foundation
- 1. Renaissance 2014: Master Video BobMcCune @bobmccune
- 2. Vatican Square Anything lookdifferent?
- 3. Vatican Square Anything lookdifferent?
- 4. Vatican Square Anything lookdifferent?
- 5. Vatican Square Anything lookdifferent?
- 7. AV Foundation Overview ‣ Objective-C frameworkfor advanced media processing ‣ ‣ ‣ High performance, asynchronous processing Hardware accelerated handling of AV media Available in its current form since iOS 4 ‣ ‣ Significant additions and enhancements iOS 6 and 7 Apple’s focus for media apps on both iOS and Mac
- 8. iOS Media Environment AnEmbarrassment of Riches AssetsLibrary UIKit MediaPlayer AV Founda6on CoreAudio CoreMedia CoreVideo CoreAnima6on
- 9. Media Assets Understanding Assets AVAssetprovides abstract representation of media resource ‣ Abstracts away the format and location AVAssetTrack models the individual media streams within an asset ‣ Tracks are of a uniform type (video, audio, etc.) AVAssetTrack (Video) AVAssetTrack (Audio)
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- 11. AVPlayer Playback Controller ‣ AVPlayer isa controller for managing playback - pause - ‣ play seekToTime: Use KVO to observe playback readiness and state - ‣ status Timed Observations - addPeriodicTimeObserverForInterval:queue:usingBlock - addBoundaryTimeObserverForInterval:queue:usingBlock
- 12. Playing Media Static vsDynamic Models ‣ AV Foundation distinguishes between static and dynamic aspects of media AVAsset AVAsset AVAssetTrack AVAsset S ta t i c AVPlayerItemTrack AVPlayerItemTrack AVPlayerItem AVPlayerItemTrack Dy n a m ic
- 13. Video Playback Playback InAction AVAsset AVAsset AVAsset AVAssetTrack AVPlayerItem AVPlayerItemTrack AVPlayerItemTrack AVPlayerItemTrack AVPlayer
- 14. Video Playback Playback InAction AVPlayerItem AVPlayerItemTrack AVPlayerItemTrack AVPlayerItemTrack AVPlayer AVPlayerLayer
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- 16.
- 17. Composing Assets AVComposition ‣ Concreteextension of AVAsset ‣ Composes asset segments on a timeline
- 18. Composing Assets Tracks andSegments AVMutableComposition *composition = [AVMutableComposition composition]; AVComposition
- 19. Composing Assets Tracks andSegments AVMutableCompositionTrack *videoTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:0]; AVMutableCompositionTrack *audioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:1]; AVComposition AVCompositionTrack (Video) AVCompositionTrack (Audio)
- 20. Composing Assets Tracks andSegments AVAssetTrack *srcVideoTrack1 = // source video track 1 [videoTrack insertTimeRange:timeRange ofTrack:srcVideoTrack1 atTime:startTime error:&error]; AVAssetTrack *srcVideoTrack2 = // source video track 2 [videoTrack insertTimeRange:timeRange ofTrack:srcVideoTrack2 atTime:startTime error:&error]; AVAssetTrack *srcAudioTrack = // source audio track [audioTrack insertTimeRange:timeRange ofTrack:srcAudioTrack atTime:startTime error:&error]; AVComposition AVCompositionTrack (Video) AVCompositionTrackSegment AVCompositionTrackSegment Seconds 10-30 of “goldengate.m4v” Seconds 20-60 of “wharf.m4v” AVCompositionTrack (Audio) AVCompositionTrackSegment Seconds 0-60 of “soundtrack.m4a”
- 21.
- 22.
- 23. Audio Mixing AVAudioMix ‣ ‣ Composition tracksplay at their natural volume AVAudioMix applies track-level volume adjustments ‣ Composed of AVAudioMixInputParameters ‣ Parameters control individual track volume over time Time Time Range
- 24.
- 25.
- 26. Video Transitions AVVideoComposition AVVideoComposition AVVideoCompositionInstruction AVVideoCompositionInstruction AVVideoCompositionInstruction Defines howtwo or more video tracks are composited together Configured through collection of composition instructions describing compositing behavior
- 27. Video Transitions AVVideoCompositionInstruction AVVideoComposition AVVideoCompositionInstruction AVVideoCompositionInstruction AVVideoCompositionInstruction AVAsset AVAsset AVVideoCompositionLayerInstruction Defines thetime range of compositing behavior Composed of layer instructions describing compositing behavior
- 28. Video Transitions AVVideoCompositionLayerInstruction AVVideoComposition AVVideoCompositionInstruction AVVideoCompositionInstruction AVVideoCompositionInstruction AVAsset AVAsset AVVideoCompositionLayerInstruction Defines thetransform and opacity ramps of input layers Transform and opacity changes modified over given time range
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- 31. Layering Content Core Animation CoreAnimation a natural choice ‣ ‣ High performance, inherently time-based CALayer subclasses used for all video rendering CALayer: used to layer images and text CAAnimation: used to animate layered content CABasicAnimation CAKeyframeAnimation
- 32. Animation Timing AVSynchronizedLayer ‣ Core Animationoperates on host time ‣ ‣ Starts at boot, marches towards infinity AVSynchronizedLayer Timeline animations need to use movie time ‣ Starts at time zero and runs to duration ‣ ‣ AVPlayerItem Can be started, stopped, rewound, etc. Timing CATextLayer Use AVSynchronizedLayer to use movie time ‣ Confers player item timing on to its sublayer tree CABasicAnimation
- 33. Core Animation Timeline vsRealtime Animations ‣ Exactly the same, almost... ‣ Animations with zero beginTime won’t be seen ‣ ‣ Set beginTime = AVCoreAnimationBeginTimeZero Animations removed by default ‣ Set removedOnCompletion = NO ‣ Unable to use CAAnimationGroup?
- 34.
- 35. Summary Master iOS Videowith AV Foundation! ‣ Powerful tools for audio and video playback ‣ ‣ AVPlayer, AVPlayerItem, AVPlayerLayer Powerful tools for composing/editing media: ‣ ‣ AVAudioMix ‣ AVVideoComposition ‣ ‣ AVComposition AVSynchronizedLayer Relatively steep learning curve, but worth the investment!
- 36. Resources Presentation Materials http://www.speakerdeck.com/bobmccune/ https://github.com/tapharmonic/AVFoundationEditor Learning AVFoundation http://my.safaribooksonline.com/9780133563856 Contact Info http://bobmccune.com @bobmccune