Skip to content

Latest commit

 

History

History
39 lines (32 loc) · 2.49 KB

249.md

File metadata and controls

39 lines (32 loc) · 2.49 KB
Raw
contributors originalUrl
Blackjacx

  • Supported on iPhone XS, XS Max, XR, iPad Pro 3rd Gen

  • AVCaptureMultiCamSession

    • Multiple AVCaptureDeiceInputs, AVCaptureDeiceOutputs of the same type, AVCaptureVideoPreviewLayers
    • Don't use implicit connection forming but use addInputWithNoConnections, addOutputWithNoConnections or AVCaptureVideoPreviewLayer.setSessionWithNoConnection

  • AVCaptureSession is still the way to got for single cam session

    • Simultaneous photo shooting, movie recording, barcode scanning, etc.

  • Limitiations

    • only one input per camera in a session
    • connecting one camera to multiple video data outouts is not possible
    • no presets supported on session since different cams might run with different qualities
    • multi-cam session has hardwareCost reporting. Session runnable when 0 <= cost <= 1
    • lower cost by lower resolution, choose binned format, deviceInput.videoMinFrameDurationOverride = CMTimeMake(1, 30) to set max framerate override /* 30 FPS */
    • lower system pressure like temperature, power demands, infrared projector temperature by
      • lowering frame rates, throttle GPU/CPU processing code, disable one camera
    • run indefinitely with multiSession.systemPressureCost < 1.0; device shutdown with cost > 3.0
    • iOS can run only one session at a time (with mutli cams though)

  • Virtual Camera is the new name wor software cameras like True-Tone- or Dual-Camera

  • device.isVirtualDevice - get its physical devices by device.constituentDevices for e.g. synchronized camera streaming

  • AVCaptureDataOutputSynchronizer ensures you get two outputs in one callback

  • virtual devices have secret ports so you can get 2 streams - you need to explicitly query them

  • Dual Camera Hography Aids

    • CameraIntrinsics (Optical center / focal length) and CameraExtrinsics (rotation matrix / translation vector for both wide- and tele cameras)

  • Multi-Microphone capture

    • By default front cam uses front mic and back cam uses back mic
    • actually front mic and back mic are a lie since different devices have multiple mics but not explicitly fron/back ones. This is achieved by Microphone Beam Forming - done automatically by CoreAudio micInput.ports(for: .audio, sourceDeviceType: micDevice.deviceType, sourceDevicePosition: .front).first
    • Beam forming only works with built-in mics
    • audio can be arbitrarily configured by creating custom AVAudioSession