如何生成使用AVAssetImageGeneratorCompletionHandler块从已经录制的视频图像？ [英] How to generate images from already recorded video using AVAssetImageGeneratorCompletionHandler block?
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问题描述
因为我是一个新手到iPhone，这可能是为一个愚蠢的问题，但遗憾。
我要生成视频的每一帧图像，并显示在里面的UIScrollView的UIImageView。
当我试图这样做，我收到内存警告和我的应用程序崩溃。
下面是我的code。
- （IBAction为）onCameraButton pressed：（ID）发送者
{
//初始化的UIImagePickerController选择短片从相机胶卷。
*的UIImagePickerController = videoPicker [的UIImagePickerController页头]初始化];
videoPicker.delegate =自我;
videoPicker.modal presentationStyle = UIModal presentationCurrentContext;
videoPicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
videoPicker.mediaTypes = @（* NSString的）kUTTypeMovie]
[自presentViewController：videoPicker动画：是完成：无];
}的#pragma标记图像选取器控制器代表 - （无效）imagePickerController：（*的UIImagePickerController）选择器didFinishPickingMediaWithInfo：（NSDictionary的*）信息
{
[个体经营dismissViewControllerAnimated：YES完成：无];
currentVideoURL =信息[UIImagePickerControllerReferenceURL]
//视频URL =资产库：//asset/asset.MOV ID = D0A4A3EE-C5F3-49C8-9E45-ADF775B9FA8C和放大器; EXT = MOV
//的NSLog（@视频URL =％@，currentVideoURL）;
// imageIndex指定= 0;
对于（*的UIImageView在thumbnailScrollView.subviews子视图）
{
[子视图removeFromSuperview]
}
[个体经营generateThumbnailsFromVideoURL：currentVideoURL];
// [自generateAVAssetThumbnails：currentVideoURL];
// [自appleImageGenerator：currentVideoURL];
} - （无效）generateThumbnailsFromVideoURL：（NSURL *）videoURL
{
AVURLAsset *资产= [[AVURLAsset页头] initWithURL：videoURL选项：无];
//的NSLog（@视频长度％LLD秒，asset.duration.value / asset.duration.timescale）;
INT videoDuration =（asset.duration.value / asset.duration.timescale）; 如果（cmTimeArray.count大于0）{
[cmTimeArray removeAllObjects]
}
的for（int i = 0; I＆LT; videoDuration;我++）
{
tempInt的int64_t = I;
CMTime tempCMTime = CMTimeMake（tempInt，1）;
int32_t间隔= 15;
对于（INT J = 1; J＆LT; 16; J ++）
{
CMTime newCMtime = CMTimeMake（J，间隔）;
CMTime此外= CMTimeAdd（tempCMTime，newCMtime）;
[cmTimeArray ADDOBJECT：[NSValue valueWithCMTime：除了]];
}
}
//的NSLog（@％时间@计数=％d个数组，cmTimeArray，cmTimeArray.count）;
/ *为（INT T = 0; T＆LT; asset.duration.value;吨++）{
CMTime thumbTime = CMTimeMake（T，asset.duration.timescale）;
NSValue * V = [NSValue valueWithCMTime：thumbTime];
[cmTimeArray ADDOBJECT：V];
}
的NSLog（@％时间@计数=％d个数组，cmTimeArray，cmTimeArray.count）; * /
__block INT I = 0;
// __块的UIImage * currentImage =零;
AVAssetImageGeneratorCompletionHandler处理器= ^（CMTime requestedTime，CGImageRef IM，CMTime actualTime，AVAssetImageGeneratorResult结果，NSError *错误）{
如果（结果== AVAssetImageGeneratorSucceeded）{
// currentImage = [UIImage的imageWithCGImage：IM]。
// [framesArray ADDOBJECT：[UIImage的imageWithCGImage：即时]];
[个体经营performSelectorOnMainThread：@selector（insertImageToScrollView :) withObject：[UIImage的imageWithCGImage：IM] waitUntilDone：NO];
}
其他
的NSLog（@哎哟：％@，error.description）;
我++;
= imageIndex指定我;
如果（我== cmTimeArray.count）{
// [自performSelectorOnMainThread：@selector（insertImageToScrollView :) withObject：framesArray waitUntilDone：YES];
}
}; //启动过程中...
self.generator = [[AVAssetImageGenerator页头] initWithAsset：资产];
self.generator.applies preferredTrackTransform = TRUE;
self.generator.requestedTimeToleranceBefore = kCMTimeZero;
self.generator.requestedTimeToleranceAfter = kCMTimeZero;
self.generator.maximumSize = CGSizeMake（40，40）;
[self.generator generateCGImagesAsynchronouslyForTimes：cmTimeArray completionHandler：处理程序];
} - （无效）insertImageToScrollView：（*的UIImage）图像
{
INT xPosition位置=（5 * imageIndex指定）+（宽* imageIndex指定）+ OFFSET;
*的UIImageView = currentImageView [[UIImageView的页头] initWithFrame：方法CGRectMake（xPosition位置，5，宽，Width）];
currentImageView.tag = + imageIndex指定10;
currentImageView.image =图像;
[thumbnailScrollView addSubview：currentImageView];
[thumbnailScrollView setContentSize：CGSizeMake（xPosition位置+宽+ 5，thumbnailScrollView.frame.size.height）];
}
解决方案
我发现我错了。我在我的40 * 40的图像视图分配原/完整图像。这是产生记忆警告。为了解决提供所需的图像尺寸，同时采用以下code生成图像。
self.generator.maximumSize = CGSizeMake（40，40）;
This might be a silly question but sorry for that as i am a newbie to iPhone.
I want to generate images for every frames of video and display that in UIScrollview inside UIImageView.
When i am trying to do that i am getting memory warning and my app crashes.
Below is my code.
- (IBAction)onCameraButtonPressed:(id)sender
{
// Initialize UIImagePickerController to select a movie from the camera roll.
UIImagePickerController *videoPicker = [[UIImagePickerController alloc] init];
videoPicker.delegate = self;
videoPicker.modalPresentationStyle = UIModalPresentationCurrentContext;
videoPicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
videoPicker.mediaTypes = @[(NSString*)kUTTypeMovie];
[self presentViewController:videoPicker animated:YES completion:nil];
}
#pragma mark Image Picker Controller Delegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
[self dismissViewControllerAnimated:YES completion:nil];
currentVideoURL = info[UIImagePickerControllerReferenceURL];
//Video URL = assets-library://asset/asset.MOV?id=D0A4A3EE-C5F3-49C8-9E45-ADF775B9FA8C&ext=MOV
//NSLog(@"Video URL = %@",currentVideoURL);
//imageIndex = 0;
for (UIImageView *subView in thumbnailScrollView.subviews)
{
[subView removeFromSuperview];
}
[self generateThumbnailsFromVideoURL:currentVideoURL];
//[self generateAVAssetThumbnails:currentVideoURL];
//[self appleImageGenerator:currentVideoURL];
}
- (void)generateThumbnailsFromVideoURL:(NSURL *)videoURL
{
AVURLAsset *asset=[[AVURLAsset alloc] initWithURL:videoURL options:nil];
//NSLog(@"Video duration %lld seconds",asset.duration.value/asset.duration.timescale);
int videoDuration = (asset.duration.value/asset.duration.timescale);
if (cmTimeArray.count>0) {
[cmTimeArray removeAllObjects];
}
for (int i = 0; i<videoDuration; i++)
{
int64_t tempInt = i;
CMTime tempCMTime = CMTimeMake(tempInt,1);
int32_t interval = 15;
for (int j = 1; j<16; 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);
/*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);*/
__block int i = 0;
//__block UIImage *currentImage = nil;
AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime, CGImageRef im, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error){
if (result == AVAssetImageGeneratorSucceeded) {
// currentImage = [UIImage imageWithCGImage:im];
//[framesArray addObject:[UIImage imageWithCGImage:im]];
[self performSelectorOnMainThread:@selector(insertImageToScrollView:) withObject:[UIImage imageWithCGImage:im] waitUntilDone:NO];
}
else
NSLog(@"Ouch: %@", error.description);
i++;
imageIndex = i;
if(i == cmTimeArray.count) {
//[self performSelectorOnMainThread:@selector(insertImageToScrollView:) withObject:framesArray waitUntilDone:YES];
}
};
// Launching the process...
self.generator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
self.generator.appliesPreferredTrackTransform=TRUE;
self.generator.requestedTimeToleranceBefore = kCMTimeZero;
self.generator.requestedTimeToleranceAfter = kCMTimeZero;
self.generator.maximumSize = CGSizeMake(40, 40);
[self.generator generateCGImagesAsynchronouslyForTimes:cmTimeArray completionHandler:handler];
}
-(void)insertImageToScrollView:(UIImage *)image
{
int xPosition = (5*imageIndex)+(WIDTH*imageIndex)+OFFSET;
UIImageView *currentImageView = [[UIImageView alloc]initWithFrame:CGRectMake(xPosition, 5, WIDTH, WIDTH)];
currentImageView.tag = imageIndex+10;
currentImageView.image = image;
[thumbnailScrollView addSubview:currentImageView];
[thumbnailScrollView setContentSize:CGSizeMake(xPosition+WIDTH+5,thumbnailScrollView.frame.size.height)];
}
解决方案
I found my mistake. I was assigning original/full image to my 40*40 image view. That was generating memory warning. To solve provide required image size while generating image using below code.
self.generator.maximumSize = CGSizeMake(40, 40);
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