加快保存图像 - iOS [英] Speed up saving image - iOS

问题描述

我正在研究更多小型项目，后来将其纳入新项目。它基本上是一个测试单元。

I am working on more of mini-project that will be later included into a new project. It is basically a test unit.

我正在做的是创建一个 AVCaptureSession ，然后为<创建一个方法code> OutputSampleBufferDelegate 。在该方法中，我将 sampleBuffer 转换为 UIImage 并保存 UIImage 。当我在iPhone 4上运行应用程序时，它每秒只能保存2-3张图像。必须有一种更有效的方法来保存图像。

What I am doing is creating an AVCaptureSession and then creating a method for OutputSampleBufferDelegate. In the method, I convert the sampleBuffer into a UIImage and save the UIImage. When I run the application on my iPhone 4 it can only save 2-3 images per second. There must be a more efficient way to save the image.

有人可以帮助我加快速度吗？

Can someone help me speed it up?

谢谢！

许多代码来自这里

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{   
    UIImage *resultUIImage = [self imageFromSampleBuffer:sampleBuffer];

    NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(resultUIImage)];

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [paths objectAtIndex:0];

    CMTime frameTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);

    NSString *filename =  [NSString stringWithFormat:@"%f.png", CMTimeGetSeconds(frameTime)];

    NSString *finalPath = [path stringByAppendingString:filename];

    [imageData writeToFile:finalPath atomically:YES];
}

// Create a UIImage from sample buffer data
- (UIImage *)imageFromSampleBuffer:(CMSampleBufferRef)sampleBuffer 
{
    // Get a CMSampleBuffer's Core Video image buffer for the media data
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
    // Lock the base address of the pixel buffer
    CVPixelBufferLockBaseAddress(imageBuffer, 0); 

    // Get the number of bytes per row for the pixel buffer
    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer); 

    // Get the number of bytes per row for the pixel buffer
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
    // Get the pixel buffer width and height
    size_t width = CVPixelBufferGetWidth(imageBuffer); 
    size_t height = CVPixelBufferGetHeight(imageBuffer); 

    // Create a device-dependent RGB color space
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

    // Create a bitmap graphics context with the sample buffer data
    CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); 
    // Create a Quartz image from the pixel data in the bitmap graphics context
    CGImageRef quartzImage = CGBitmapContextCreateImage(context); 
    // Unlock the pixel buffer
    CVPixelBufferUnlockBaseAddress(imageBuffer,0);

    // Free up the context and color space
    CGContextRelease(context); 
    CGColorSpaceRelease(colorSpace);

    // Create an image object from the Quartz image
    UIImage *image = [UIImage imageWithCGImage:quartzImage];

    // Release the Quartz image
    CGImageRelease(quartzImage);

    return image;
}

推荐答案

使用此代码我可以获得它将图像保存到0.1秒的时间。

Using this code I can get the time it saves the image down to 0.1 sec.

- (void)captureOutput:(AVCaptureOutput *)captureOutput
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
       fromConnection:(AVCaptureConnection *)connection 
{  

    double frameTime = CFAbsoluteTimeGetCurrent();
    UIImage *resultUIImage = [self imageFromSampleBuffer:sampleBuffer];

    // takes freaking forever to do.
    double pre = CFAbsoluteTimeGetCurrent();
    NSData *imageData = UIImageJPEGRepresentation(resultUIImage, 0.9);
    NSLog(@"It took to write the file:%f",CFAbsoluteTimeGetCurrent()-pre);

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory
                                                         ,NSUserDomainMask
                                                         , YES);
    NSString *path = [paths objectAtIndex:0];
    NSString *filename =  [NSString stringWithFormat:@"%f.png", frameTime];
    NSString *finalPath = [path stringByAppendingString:filename];
    [imageData writeToFile:finalPath atomically:YES];
}

这篇关于加快保存图像 - iOS的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！