The goal is to capture full screen video on a device with Swift. In the code below, video capture appears to happen at full screen (while recording the camera preview uses the full screen), but the rendering of the video happens at a different resolution. For a 5S specifically, it appears like capture happens at 320x568 but rendering occurs at 320x480.
How can you capture and render full screen video?
Code for video capture:
private func initPBJVision() {
// Store PBJVision in var for convenience
let vision = PBJVision.sharedInstance()
// Configure PBJVision
vision.delegate = self
vision.cameraMode = PBJCameraMode.Video
vision.cameraOrientation = PBJCameraOrientation.Portrait
vision.focusMode = PBJFocusMode.ContinuousAutoFocus
vision.outputFormat = PBJOutputFormat.Preset
vision.cameraDevice = PBJCameraDevice.Back
// Let taps start/pause recording
let tapHandler = UITapGestureRecognizer(target: self, action: "doTap:")
view.addGestureRecognizer(tapHandler)
// Log status
print("Configured PBJVision")
}
private func startCameraPreview() {
// Store PBJVision in var for convenience
let vision = PBJVision.sharedInstance()
// Connect PBJVision camera preview to <videoView>
// -- Get preview width
let deviceWidth = CGRectGetWidth(view.frame)
let deviceHeight = CGRectGetHeight(view.frame)
// -- Configure PBJVision's preview layer
let previewLayer = vision.previewLayer
previewLayer.frame = CGRectMake(0, 0, deviceWidth, deviceHeight)
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
...
}
Video rendering code:
func exportVideo(fileUrl: NSURL) {
// Create main composition object
let videoAsset = AVURLAsset(URL: fileUrl, options: nil)
let mainComposition = AVMutableComposition()
let compositionVideoTrack = mainComposition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
let compositionAudioTrack = mainComposition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
// -- Extract and apply video & audio tracks to composition
let sourceVideoTrack = videoAsset.tracksWithMediaType(AVMediaTypeVideo)[0]
let sourceAudioTrack = videoAsset.tracksWithMediaType(AVMediaTypeAudio)[0]
do {
try compositionVideoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), ofTrack: sourceVideoTrack, atTime: kCMTimeZero)
} catch {
print("Error with insertTimeRange. Video error: \(error).")
}
do {
try compositionAudioTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), ofTrack: sourceAudioTrack, atTime: kCMTimeZero)
} catch {
print("Error with insertTimeRange. Audio error: \(error).")
}
// Add text to video
// -- Create video composition object
let renderSize = compositionVideoTrack.naturalSize
let videoComposition = AVMutableVideoComposition()
videoComposition.renderSize = renderSize
videoComposition.frameDuration = CMTimeMake(Int64(1), Int32(videoFrameRate))
// -- Add instruction to video composition object
let instruction = AVMutableVideoCompositionInstruction()
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
let videoLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: compositionVideoTrack)
instruction.layerInstructions = [videoLayerInstruction]
videoComposition.instructions = [instruction]
// -- Define video frame
let videoFrame = CGRectMake(0, 0, renderSize.width, renderSize.height)
print("Video Frame: \(videoFrame)") // <-- Prints frame of 320x480 so render size already wrong here
...
