How to convert NSData object with JPEG data into CVPixelBufferRef in OS X?

问题

As the title mentioned.

I search with Google and Stackoverflow, all resources are for UIImage converting, or convert NSImage FROM CVPixelBufferRef. Now what I want to do is convert JPEG raw data TO CVPixelBufferRef so that I could generate a movie file with live jpeg streams.

回答1:

You can use the following method to convert from NSImage to 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;
}

The resulting buffer can be appended to an AVAssetWriter via AVAssetWriterInputPixelBufferAdaptor's appendPixelBuffer::

来源：https://stackoverflow.com/questions/17481254/how-to-convert-nsdata-object-with-jpeg-data-into-cvpixelbufferref-in-os-x

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