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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() | |
} | |
} | |
} |
https://stackoverflow.com/a/17331242/2742007
avPlayer.currentItem?.step(byCount: isForward ? 1 : -1)
https://developer.apple.com/documentation/avfoundation/avplayeritem/1387968-step
https://stackoverflow.com/a/17331242/2742007
avPlayer.currentItem?.step(byCount: isForward ? 1 : -1)
https://developer.apple.com/documentation/avfoundation/avplayeritem/1387968-step
This is not relevant I'm afraid. Or more importantly it's incomplete. If you read (or even try) that API out yourself, you'll note that it's not performant in most user-driven cases and cannot chase smoothly. This is because it doesn't cancel previous seeks.
The provided example solves this problem for high performance cases. The API you're suggesting is fine for non-interactive scenarios though 👍
@Talhasahi Did you solve your issue? I have the same problem when I'm using AVComposition.
Btw. looking briefly at your code:
CMTime(seconds:playerItem.duration.seconds, preferredTimescale: 1) this might fail if the duration is not exactly seconds as the preferredTimescale is 1 (ie. duration of 3.5 seconds will fail)