ios - 操作 CVPixelBufferRef 高度和宽度
<p><p>我正在使用 GPUImage 库函数来操作 CVPixelbuffer 的高度和宽度。我正在纵向录制视频，当用户旋转设备时，我的屏幕会自行调整为横向模式。我希望横向框架适合屏幕。 </p>
<p>例如:- 我以 320x568 的纵向模式开始视频，当我将设备转为横向时，我的帧是 568x320，我想适应 320x568。为了调整这个东西，我想操纵 CVPixelBuffer。但这会占用大量内存，最后我的应用程序崩溃了。</p>
<pre><code> - (CVPixelBufferRef) GPUImageCreateResizedSampleBufferWithBuffer:(CVPixelBufferRef)cameraFrame withBuffer:(CGSize)finalSize withSampleBuffer:(CMSampleBufferRef)sampleBuffer
{
CVPixelBufferRef pixel_buffer = NULL;
// CVPixelBufferCreateWithPlanarBytes for YUV input
@autoreleasepool {
CGSize originalSize = CGSizeMake(CVPixelBufferGetWidth(cameraFrame), CVPixelBufferGetHeight(cameraFrame));
CVPixelBufferLockBaseAddress(cameraFrame, 0);
GLubyte *sourceImageBytes = (GLubyte *)CVPixelBufferGetBaseAddress(cameraFrame);
CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, sourceImageBytes, CVPixelBufferGetBytesPerRow(cameraFrame) * originalSize.height, NULL);
CGColorSpaceRef genericRGBColorspace = CGColorSpaceCreateDeviceRGB();
CGImageRef cgImageFromBytes = CGImageCreate((int)originalSize.width, (int)originalSize.height, 8, 32, CVPixelBufferGetBytesPerRow(cameraFrame), genericRGBColorspace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst, dataProvider, NULL, NO, kCGRenderingIntentDefault);
GLubyte *imageData = (GLubyte *) calloc(1, ((int)finalSize.width * (int)finalSize.height * 4));
CGContextRef imageContext = CGBitmapContextCreate(imageData, (int)finalSize.width, (int)finalSize.height, 8, (int)finalSize.width * 4, genericRGBColorspace,kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
CGRect scaledRect = AVMakeRectWithAspectRatioInsideRect(originalSize, CGRectMake(0, 0, finalSize.width, finalSize.height));
CGContextDrawImage(imageContext, scaledRect, cgImageFromBytes);
CGImageRelease(cgImageFromBytes);
CGContextRelease(imageContext);
CGColorSpaceRelease(genericRGBColorspace);
CGDataProviderRelease(dataProvider);
CVPixelBufferCreateWithBytes(kCFAllocatorDefault, finalSize.width, finalSize.height, kCVPixelFormatType_32BGRA, imageData, finalSize.width * 4, stillImageDataReleaseCallback, NULL, NULL, &pixel_buffer);
CMVideoFormatDescriptionRef videoInfo = NULL;
CMVideoFormatDescriptionCreateForImageBuffer(NULL, pixel_buffer, &videoInfo);
CMTime frameTime = CMTimeMake(1, 30);
CMSampleTimingInfo timing = {frameTime, frameTime, kCMTimeInvalid};
CMSampleBufferCreateForImageBuffer(kCFAllocatorDefault, pixel_buffer, YES, NULL, NULL, videoInfo, &timing, &sampleBuffer);
CVPixelBufferUnlockBaseAddress(cameraFrame, 0);
CFRelease(videoInfo);
// CVPixelBufferRelease(pixel_buffer);
}
return pixel_buffer;
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p><strong>CG* - CoreGraphics 使用 CPU，对于实时视频来说太慢了，使用 CV* 和 GPU</strong> </p>
<pre><code> // - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
CVPixelBufferLockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);
CIImage *baseImg = ;
CIImage *resultImg = ;
resultImg = ;
// created once
// glCtx = [ initWithAPI:kEAGLRenderingAPIOpenGLES2];
// ciContext = }];
// ciContextColorSpace = CGColorSpaceCreateDeviceRGB();
// CVReturn res = CVPixelBufferPoolCreatePixelBuffer(kCFAllocatorDefault, VTCompressionSessionGetPixelBufferPool(compressionSession), &finishPixelBuffer);
;
CVPixelBufferUnlockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);
</code></pre></p>
<p style="font-size: 20px;">关于ios - 操作 CVPixelBufferRef 高度和宽度，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/41424549/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/41424549/
</a>
</p>
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