My experiments show that AVMutableComposition scaleTimeRange is limited to scaling up to 8x faster than the original composition. This limit is not documented anywhere. Is it a true limit? If so, is there any way around it? Relevant code below, with some boilerplate abstracted into functions not included here:    AVMutableComposition *comp = [[AVMutableComposition alloc] init];   AVMutableCompositionTrack *videoComp = [comp addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];   AVAsset* asset = AddVideoToTrack(videoComp, kCMTimeZero,                    CMTimeMake(startSeconds, 1),                    CMTimeMake(endSeconds, 1),                    videoFilepath);   float initialDuration = endSeconds - startSeconds;   CMTime startTime = kCMTimeZero;   CMTime endTime = CMTimeMake(initialDuration, 1);   CMTimeRange inputRange = CMTimeRangeFromTimeToTime(startTime, endTime);   [videoComp scaleTimeRange:inputRange toDuration:CMTimeMakeWithSeconds(initialDuration / playbackSpeed, 1)]; ExportWithSDAVAssetExportSession(videoComp);

I'm trying to get AVFoundation to provide the same low-light boost provided in the native camera app. I have tried: isLowLightBoostSupported (which always returns false, regardless of my configuration) setExposureTargetBias set to max AVCaptureSessionPreset set to various options without success Is automaticallyEnablesLowLightBoostWhenAvailable outdated? The documentation claims "capture device that supports this feature may only engage boost mode for certain source formats or resolutions", but with no explanation of which formats or resolutions. I can't tell if the option is no longer supported, or if there is some configuration permutation I haven't yet found.