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October 22, 2024 07:48
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Enables smooth frame-by-frame scrubbing (in both directions) – similar to Apple's applications.
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public enum Direction { | |
case forward | |
case backward | |
} | |
internal var player: AVPlayer? | |
private var isSeekInProgress = false | |
private var chaseTime = kCMTimeZero | |
private var preferredFrameRate: Float = 23.98 | |
public func seek(to time: CMTime) { | |
seekSmoothlyToTime(newChaseTime: time) | |
} | |
public func stepByFrame(in direction: Direction) { | |
let frameRate = preferredFrameRate | |
?? player?.currentItem?.tracks | |
.first(where: { $0.assetTrack.mediaType == .video })? | |
.currentVideoFrameRate | |
?? -1 | |
let time = player?.currentItem?.currentTime() ?? kCMTimeZero | |
let seconds = Double(1) / Double(frameRate) | |
let timescale = Double(seconds) / Double(time.timescale) < 1 ? 600 : time.timescale | |
let oneFrame = CMTime(seconds: seconds, preferredTimescale: timescale) | |
let next = direction == .forward | |
? CMTimeAdd(time, oneFrame) | |
: CMTimeSubtract(time, oneFrame) | |
seekSmoothlyToTime(newChaseTime: next) | |
} | |
private func seekSmoothlyToTime(newChaseTime: CMTime) { | |
if CMTimeCompare(newChaseTime, chaseTime) != 0 { | |
chaseTime = newChaseTime | |
if !isSeekInProgress { | |
trySeekToChaseTime() | |
} | |
} | |
} | |
private func trySeekToChaseTime() { | |
guard player?.status == .readyToPlay else { return } | |
actuallySeekToTime() | |
} | |
private func actuallySeekToTime() { | |
isSeekInProgress = true | |
let seekTimeInProgress = chaseTime | |
player?.seek(to: seekTimeInProgress, toleranceBefore: kCMTimeZero, toleranceAfter: kCMTimeZero) { [weak self] _ in | |
guard let `self` = self else { return } | |
if CMTimeCompare(seekTimeInProgress, self.chaseTime) == 0 { | |
self.isSeekInProgress = false | |
} else { | |
self.trySeekToChaseTime() | |
} | |
} | |
} |
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Should be fixed now, sorry, there was no recent build enabled for external testing 😇