AV Foundation Programming Guide.pdf

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1、AVFoundationProgrammingGuideContentsAboutAVFoundation5AtaGlance6RepresentingandUsingMediawithAVFoundation6ConcurrentProgrammingwithAVFoundation8Prerequisites9UsingAssets10CreatinganAssetObject10OptionsforInitializinganAsset10AccessingtheUser’sAssets11

2、PreparinganAssetforUse12GettingStillImagesFromaVideo13GeneratingaSingleImage14GeneratingaSequenceofImages15TrimmingandTranscodingaMovie16Playback19PlayingAssets19HandlingDifferentTypesofAsset21PlayinganItem23ChangingthePlaybackRate23Seeking—Reposition

3、ingthePlayhead23PlayingMultipleItems24MonitoringPlayback25RespondingtoaChangeinStatus26TrackingReadinessforVisualDisplay27TrackingTime27ReachingtheEndofanItem28PuttingitallTogether:PlayingaVideoFileUsingAVPlayerLayer28ThePlayerView29ASimpleViewControl

4、ler29CreatingtheAsset30RespondingtothePlayerItem’sStatusChange32PlayingtheItem332013-08-08

5、Copyright©2013AppleInc.AllRightsReserved.2ContentsEditing34CreatingaComposition37OptionsforInitializingaCompositionTrack38AddingAudiovisualDatatoaComposition38R

6、etrievingCompatibleCompositionTracks39GeneratingaVolumeRamp39PerformingCustomVideoProcessing40ChangingtheComposition’sBackgroundColor40ApplyingOpacityRamps40IncorporatingCoreAnimationEffects41PuttingitallTogether:CombiningMultipleAssetsandSavingtheRes

7、ulttotheCameraRoll42CreatingtheComposition43AddingtheAssets43CheckingtheVideoOrientations44ApplyingtheVideoCompositionLayerInstructions45SettingtheRenderSizeandFrameDuration46ExportingtheCompositionandSavingittotheCameraRoll47MediaCapture49UseaCapture

8、SessiontoCoordinateDataFlow50ConfiguringaSession51MonitoringCaptureSessionState52AnAVCaptureDeviceObjectRepresentsanInputDevice52DeviceCharacteristics53DeviceCaptureSettings54ConfiguringaDevice57SwitchingBetweenDevices58UseCaptureInputstoAddaCaptureDe

9、vicetoaSession58UseCaptureOutputstoGetOutputfromaSession59SavingtoaMovieFile60ProcessingFramesofVideo63CapturingStillImages64ShowingtheUserWhat’sBeingRecorded66VideoPreview66ShowingAudioLevels67PuttingitallTogether:CapturingVideoFramesasUIImag