macos - 如何在 OS X 中将带有 JPEG 数据的 NSData 对象转换为 CVPixelBufferRef？

Question

如标题所述。

我用谷歌和 Stackoverflow 搜索，所有资源都用于 UIImage 转换，或者从 CVPixelBufferRef 转换 NSImage。现在我想做的是将 JPEG 原始数据转换为 CVPixelBufferRef，这样我就可以生成带有实时 jpeg 流的电影文件。

Answer 1

您可以使用以下方法将 from 转换NSImage为CVPixelBufferRef：

- (CVPixelBufferRef)newPixelBufferFromNSImage:(NSImage*)image
{
    CGColorSpaceRef colorSpace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
    NSDictionary* pixelBufferProperties = @{(id)kCVPixelBufferCGImageCompatibilityKey:@YES, (id)kCVPixelBufferCGBitmapContextCompatibilityKey:@YES};
    CVPixelBufferRef pixelBuffer = NULL;
    CVPixelBufferCreate(kCFAllocatorDefault, [image size].width, [image size].height, k32ARGBPixelFormat, (__bridge CFDictionaryRef)pixelBufferProperties, &pixelBuffer);
    CVPixelBufferLockBaseAddress(pixelBuffer, 0);
    void* baseAddress = CVPixelBufferGetBaseAddress(pixelBuffer);
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer);
    CGContextRef context = CGBitmapContextCreate(baseAddress, [image size].width, [image size].height, 8, bytesPerRow, colorSpace, kCGImageAlphaNoneSkipFirst);
    NSGraphicsContext* imageContext = [NSGraphicsContext graphicsContextWithGraphicsPort:context flipped:NO];
    [NSGraphicsContext saveGraphicsState];
    [NSGraphicsContext setCurrentContext:imageContext];
    [image compositeToPoint:NSMakePoint(0.0, 0.0) operation:NSCompositeCopy];
    [NSGraphicsContext restoreGraphicsState];
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
    CFRelease(context);
    CGColorSpaceRelease(colorSpace);
    return pixelBuffer;
}

生成的缓冲区可以附加到AVAssetWriterviaAVAssetWriterInputPixelBufferAdaptor的appendPixelBuffer::