AVAssetImageGenerator returns sometimes same image from 2 successive frames

Question

I\'m currently extracting every frame from a video with AVAssetImageGenerator, but sometimes it returns me successively 2 times almost the same image (they do not h

Answer 1

Please see the following properties of AVAssetImageGenerator. You should set kCMTimeZero for both properties to get the exact frames.

/* The actual time of the generated images will be within the range [requestedTime-toleranceBefore, requestedTime+toleranceAfter] and may differ from the requested time for efficiency.
   Pass kCMTimeZero for both toleranceBefore and toleranceAfter to request frame-accurate image generation; this may incur additional decoding delay.
   Default is kCMTimePositiveInfinity. */
@property (nonatomic) CMTime requestedTimeToleranceBefore NS_AVAILABLE(10_7, 5_0);
@property (nonatomic) CMTime requestedTimeToleranceAfter NS_AVAILABLE(10_7, 5_0);

Before I set kCMTimeZero for both properties, I got some same images for different request time as you experienced. Just try the following code.

self.imageGenerator = [AVAssetImageGenerator assetImageGeneratorWithAsset:myAsset];
self.imageGenerator.requestedTimeToleranceBefore = kCMTimeZero;
self.imageGenerator.requestedTimeToleranceAfter = kCMTimeZero;