iOS AVFoundation - Converting video into images at 60 fps

Question

i\'m trying to convert a whole video into a sequence of images at a rate of 60fps, which means 60 images generated per second of video...

To do so, i\'m making use o

Answer 1

Hey @Sooriah Joel try using following code. It is working fine for me.

- (void)generateCMTimesArrayOfAllFramesUsingAsset:(AVURLAsset *)asset
{
    if (cmTimeArray.count>0) {
        [cmTimeArray removeAllObjects];
    }
    //Generate all frames present in video
    for(int t=0;t < asset.duration.value;t++) {
        CMTime thumbTime = CMTimeMake(t,asset.duration.timescale);
        NSValue *v=[NSValue valueWithCMTime:thumbTime];
        [cmTimeArray addObject:v];
    }
    NSLog(@"Array of time %@ count = %d",cmTimeArray, cmTimeArray.count);
    //NSLog(@"Array count = %d",cmTimeArray.count);
}


- (void)generateCMTimesArrayOfFrames:(int)framesInterval UsingAsset:(AVURLAsset *)asset
{
    int videoDuration = ceilf(((float)asset.duration.value/asset.duration.timescale));
    NSLog(@"Video duration %lld seconds timescale = %d",asset.duration.value,asset.duration.timescale);
    if (cmTimeArray.count>0) {
        [cmTimeArray removeAllObjects];
    }
    //Generate limited frames present in video
    for (int i = 0; i<videoDuration; i++)
   {
       int64_t tempInt = i;
       CMTime tempCMTime = CMTimeMake(tempInt,1);
       int32_t interval = framesInterval;
       for (int j = 1; j<framesInterval+1; j++)
       {
            CMTime newCMtime = CMTimeMake(j,interval);
            CMTime addition = CMTimeAdd(tempCMTime, newCMtime);
            [cmTimeArray addObject:[NSValue valueWithCMTime:addition]];
       }
   }
   NSLog(@"Array of time %@ count = %d",cmTimeArray, cmTimeArray.count);
   //NSLog(@"Array count = %d",cmTimeArray.count);
}


- (void)generateThumbnailsFromVideoURL:(AVURLAsset *)videoAsset
{
    //Generate CMTimes Array of required frames
    //1.Generate All Frames
    //[self generateCMTimesArrayOfAllFramesUsingAsset:asset];

    //2.Generate specific frames per second
    [self generateCMTimesArrayOfFrames:30 UsingAsset:videoAsset];

    __block int i = 0;
    AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime, CGImageRef im, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error){
    if (result == AVAssetImageGeneratorSucceeded) {
        [framesArray addObject:[UIImage imageWithCGImage:im]];
    }
    if (result == AVAssetImageGeneratorFailed) {
        NSLog(@"Failed with error: %@ code %d", [error localizedDescription],error.code);
    }
    if (result == AVAssetImageGeneratorCancelled) {
        NSLog(@"Canceled");
    }

    i++;
    imageIndex = i;

    if(i == cmTimeArray.count) {
        //Thumbnail generation completed
    }
};

    // Launching the process...
    self.generator = [[AVAssetImageGenerator alloc] initWithAsset:videoAsset];
    self.generator.apertureMode = AVAssetImageGeneratorApertureModeCleanAperture;
    self.generator.appliesPreferredTrackTransform=TRUE;
    self.generator.requestedTimeToleranceBefore = kCMTimeZero;
    self.generator.requestedTimeToleranceAfter = kCMTimeZero;
    self.generator.maximumSize = CGSizeMake(40, 40);
    [self.generator generateCGImagesAsynchronouslyForTimes:cmTimeArray completionHandler:handler];
}