圖片轉化為視訊

• 圖片轉為視訊流

``` Swift
// 圖片轉為視訊頻
- (void) testchangeImageToVideo{
    NSArray *imageArr = [NSArray arrayWithObjects:[[UIImage imageNamed:@"114.png"] CGImage],[[UIImage imageNamed:@"114.png"] CGImage],[[UIImage imageNamed:@"placeholderImage.png"] CGImage],[[UIImage imageNamed:@"dfd.png"] CGImage],[[UIImage imageNamed:@"viewbg.png"] CGImage], nil];
    CGSize size = CGSizeMake(480, 320);
    NSString *betaCompressionDirectory = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Movie.m4v"];
    NSError *error = nil;
    unlink([betaCompressionDirectory UTF8String]);
    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:betaCompressionDirectory]
                                
                                                        fileType:AVFileTypeQuickTimeMovie
                                
                                                            error:&error];
    
    NSParameterAssert(videoWriter);
    if(error)
        NSLog(@"error = %@", [error localizedDescription]);
    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264, AVVideoCodecKey,
                                [NSNumber numberWithInt:size.width], AVVideoWidthKey,
                                [NSNumber numberWithInt:size.height], AVVideoHeightKey, nil];
    AVAssetWriterInput *writerInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
    
    NSDictionary *sourcePixelBufferAttributesDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
                                                        
                                                        [NSNumber numberWithInt:kCVPixelFormatType_32ARGB], kCVPixelBufferPixelFormatTypeKey, nil];
    AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput sourcePixelBufferAttributes:sourcePixelBufferAttributesDictionary];
    NSParameterAssert(writerInput);
    NSParameterAssert([videoWriter canAddInput:writerInput]);
    if ([videoWriter canAddInput:writerInput])
        NSLog(@"I can add this input");
    else
        NSLog(@"i can't add this input");
    [videoWriter addInput:writerInput];
    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];
    // insert demo debugging code to write the same image repeated as a movie
    CGImageRef theImage = [[UIImage imageNamed:@"114.png"] CGImage];
    dispatch_queue_t    dispatchQueue = dispatch_queue_create("mediaInputQueue", NULL);
    int __block         frame = 0;
    [writerInput requestMediaDataWhenReadyOnQueue:dispatchQueue usingBlock:^{
        while ([writerInput isReadyForMoreMediaData]){
            if(++frame >= imageArr.count * 40){
                [writerInput markAsFinished];
                [videoWriter finishWriting];
                break;
            }
            int idx = frame/40;
            CVPixelBufferRef buffer = (CVPixelBufferRef)[self pixelBufferFromCGImage:(__bridge CGImageRef)([imageArr objectAtIndex:idx]) size:size];
            if (buffer){
                if(![adaptor appendPixelBuffer:buffer withPresentationTime:CMTimeMake(frame, 20)])
                    NSLog(@"FAIL");
                else
                    NSLog(@"Success:%d", frame);
            CFRelease(buffer);
            }
        }
    }];
NSLog(@"outside for loop");
}
- (CVPixelBufferRef )pixelBufferFromCGImage:(CGImageRef)image size:(CGSize)size{
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                            [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                            [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey, nil];
    CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, size.width, size.height, kCVPixelFormatType_32ARGB, (__bridge CFDictionaryRef) options, &pxbuffer);
    
    // CVReturn status = CVPixelBufferPoolCreatePixelBuffer(NULL, adaptor.pixelBufferPool, &pxbuffer);
    NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);
    CVPixelBufferLockBaseAddress(pxbuffer, 0);
    void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
    NSParameterAssert(pxdata != NULL);
    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(pxdata, size.width, size.height, 8, 4*size.width, rgbColorSpace, kCGImageAlphaPremultipliedFirst);
    NSParameterAssert(context);
    CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image), CGImageGetHeight(image)), image);
    
    CGColorSpaceRelease(rgbColorSpace);
    CGContextRelease(context);
    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
    return pxbuffer;
    
}
```
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