获取Video IOS 6的所有帧 [英] Get all frames of Video IOS 6

问题描述

我想将iOS6中视频的所有帧转换为 NSArray 。
我使用此代码：

I would like to get all frames of a Video in iOS6 into NSArray. I use this code:

-(void) getAllImagesFromVideo
{
   imagesArray = [[NSMutableArray alloc] init];
   times = [[NSMutableArray alloc] init];

   for (Float64 i = 0; i < 15; i += 0.033) // For 25 fps in 15 sec of Video
   {
       CMTime time = CMTimeMakeWithSeconds(i, 60);
      [times addObject:[NSValue valueWithCMTime:time]];
   } 

   [imageGenerator generateCGImagesAsynchronouslyForTimes:times completionHandler:^(CMTime requestedTime, CGImageRef image, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error) {

      if (result == AVAssetImageGeneratorSucceeded)
      {
         UIImage *generatedImage = [[UIImage alloc] initWithCGImage:image];

         [imagesArray addObject:generatedImage];
     }
   }];
}

在iPad模拟器上，延迟时间为90~100秒，在iPad设备上，已收到内存警告并最终崩溃。

On iPad simulator the delay is 90~100 seconds, on iPad device, recieved Memory Warnings and finally crash.

任何想法，解决方案？使用另一个更低级的框架/库？ C ++？
对我来说非常重要！帮我！ ：）

Any idea, solution? Using another more low-level Framework/Library? C++? Is very important for me! Help me! :)

谢谢!!!

推荐答案

您需要：

1. 使用CGImageRelease作为@zimmryan提到


2. 在循环中使用@autoreleasepool块


3. 不将图像存储在内存中，将它们存储在文档目录中

这是怎么回事我这样做:(注意我使用同步版本来提取图像，如果选择异步版本则无关紧要）

This is how I do it: (notice I use the sync version for extracting images, it shouldn't matter if you choose the async version)

AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:url options:nil];
AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
generator.requestedTimeToleranceAfter =  kCMTimeZero;
generator.requestedTimeToleranceBefore =  kCMTimeZero;
for (Float64 i = 0; i < CMTimeGetSeconds(asset.duration) *  FPS ; i++){
  @autoreleasepool {
    CMTime time = CMTimeMake(i, FPS);
    NSError *err;
    CMTime actualTime;
    CGImageRef image = [generator copyCGImageAtTime:time actualTime:&actualTime error:&err];
    UIImage *generatedImage = [[UIImage alloc] initWithCGImage:image];
    [self saveImage: generatedImage atTime:actualTime]; // Saves the image on document directory and not memory
    CGImageRelease(image);
  }
}

编辑：

在创建大量临时对象时，应始终考虑使用@autoreleasepool（参见 https://developer.apple.com/library/mac/documentation/cocoa/conceptual/memorymgmt/articles/mmAutoreleasePools.html ）

you should always consider using @autoreleasepool when creating alot of temporary objects (see https://developer.apple.com/library/mac/documentation/cocoa/conceptual/memorymgmt/articles/mmAutoreleasePools.html)

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