[Objective-C] AVCaptureとvImageを使ってリアルタイムフィルタを作ってみる ref: http://qiita.com/edo_m18/items/727bee5affe6e36d77c2

file0.m

#import <Accelerate/Accelerate.h>
#import <AVFoundation/AVFoundation.h>

file1.m

self.captureSession = [[AVCaptureSession alloc] init];

file10.m

gaussianblur(&inputvImage, &outputvImage);

file11.m

// ビットマップコンテキストの生成
CGBitmapInfo bitmapInfo    = kCGBitmapByteOrder32Little | kCGImageAlphaPremultipledFirst;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef cgContext     = CGBitmapContextCreate(outputvImage.data, width, height, 8, bytesPerRow, colorSpace, bitmapInfo);

// 画像の作成
CGImageRef dstImage = CGBitmapContextCreateImage(cgContext);

__typeof(self) __weak wself = self;
dispatch_sync(dispatch_get_main_queue(), ^{
    wself.previewLayer.contents = (__bredge id)dstImage;
});

// 解放処理
free(outBuffer);
CGImageRelease(dstImage);
CGContextReleaes(cgContext);
CGColorSpaceRelease(colorSpace);

// バッファのアンロック
CVPicelBufferUnlockBaseAddress(imageBufer, 0);

file12.m

void gaussianblur(const vImage_Buffer *src, const vImage_Buffer *dst) {
    const int16_t kernel[] = {
       1,  4,  6,  4, 1,
       4, 16, 24, 16, 4,
       6, 24, 36, 24, 6,
        4, 16, 24, 16, 4,
        1,  4,  6,  4, 1
    };

    int length = sizeof(kernel) / sizeof(int16_t);
    int32_t divisor = 0;

    for (int i = 0; i < length; i++) {
        divisor += kernel[i];
    }

    unsigned int size = sqrt(length);
    uint32_t kernel_height = size;
    uint32_t kernel_width  = size;
    vImageConvolve_ARGB8888(src, dst, NULL, 0, 0, kernel, kernel_height, kernel_width, divisor, NULL, kvImageCopyInPlace);
}

file13.m

typedef short int16_t;

typedef int int32_t;

/* 8 bit planar pixel value */
typedef uint8_t Pixel_8;

typedef unsigned char uint8_t;

/* ARGB interleaved (8 bit/channel) pixel value. uint8_t[4] = { alpha, red, green, blue } */
typedef uint8_t Pixel_8888[4];

/* Pedantic: A number of pixels. For LP64 (ppc64/x86_64) this is a 64-bit quantity.  */
typedef unsigned long vImagePixelCount;

typedef struct vImage_Buffer
{
    void                *data;    /* Pointer to the top left pixel of the buffer.    */
    vImagePixelCount    height;   /* The height (in pixels) of the buffer        */
    vImagePixelCount    width;    /* The width (in pixels) of the buffer         */
    size_t              rowBytes; /* The number of bytes in a pixel row, including any unused space between one row and the next. */
} vImage_Buffer;

/* Pedantic: A number of pixels. For LP64 (ppc64/x86_64) this is a 64-bit quantity. */
typedef unsigned long vImagePixelCount;

file14.m

vImageConvolve_ARGB8888(
    &src,              // const vImage_Buffer *src
    &dst,              // const vImage_Buffer *dest
    NULL,              // void *tempBuffer
    0,                 // vImagePixelCount srcOffsetToROI_X
    0,                 // vImagePixelCount srcOffsetToROI_Y
    kernelArray,       // const int16_t *kernel
    3,                 // uint32_t kernel_height
    3,                 // uint32_t kernel_width
    divisor,           // int32_t divisor
    NULL,              // Pixel_8888 backgroundColor
    kvImageCopyInPlace // vImage_Flags flags
);

file14.txt

<Error>: CGBitmapContextCreate: invalid data bytes/row: should be at least 1920 for 8 integer bits/component, 3 components, kCGImageAlphaPremultipliedFirst.

file15.m

// 実際に使ってるやつ
const size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);

// 以下のように自前で計算してもOK
const size_t bufferSize = sizeof(uint8_t) * width * height * 4;

file15.txt

<Error>: CGBitmapContextCreate: invalid data bytes/row: should be at least 1920 for 8 integer bits/component, 3 components, kCGImageAlphaPremultipliedFirst.

file16.m

// 実際に使ってるやつ
const size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);

// 以下のように自前で計算してもOK
const size_t bufferSize = sizeof(uint8_t) * width * height * 4;

file2.m

NSArray *devices = [AVCaptureDevice devices];
AVCaptureDeviceInput *frontInput;
AVCaptureDeviceInput *backInput;

for (AVCaptureDevice *device in devices) {
    if ([device hasMediaType:AVMediaTypeVideo]) {
        NSError *error = nil;

        if (device.position == AVCaptureDevicePositionFront) {
            frontInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
        }
        else {
            backInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
        }
    }
}

file3.m

[self.captureSession addInput:backInput];

NSDictionary *settings;
settings = @{(NSString *)kCVPixelBufferPixelFormatTypeKey:@(kCVPixelFormatType_32BGRA)};

self.videoOutput = [[AVCaptureVideoDataOutput alloc] init];
[self.videoOutput setVideoSettings:settings];
[self.videoOutput setAlwaysDiscardsLateVideoFrame:YES];

[self.captureSession addOutput:self.videoOutput];

file4.m

// カメラの向きを設定
AVCaptureConnection *videoConnection = nil;

[self.captureSession beginConfiguration];

for (AVCaptureConnection *connection in [self.videoOutput connections]) {
    for (AVCaptureInputPort *port in [connection inputPorts]) {
        if ([[port mediaType] isEqual:AVMediaTypeVideo]) {
            videoConnection = connection;
        }
    }
}

if ([videoConnection isVideoOrientationSupported]) {
    [videoConnection setVideoOrientation:AVCaptureVideoOrientationPortrait];
}

[self.captureSession commitConfiguration];

file5.m

dispatch_queue_t queue = dispatch_queue_create("VideoQueue", DISPATCH_QUEUE_SERIAL);
[self.videoOutput setSampleBufferDelegate:self queue:queue];

file6.m

self.previewLayer = [AVCaptureVideoPreviewLayer layer];
self.previewLayer.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
self.previewLayer.position = CGPointMake(self.view.frame.size.width / 2, self.view.frame.size.height / 2);

[self.view.layer addSublayer:self.previewLayer];

file7.m

CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer, 0);

file8.m

size_t width  = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
const size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);

file9.m

// 入力用
uint_8 *buffer = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer);
const vImage_Buffer inputvImage = {buffer, height, width, bytesPerRow};

// 出力用
void *outBuffer = malloc(bufferSize); // 出力用に空のメモリを確保
const vImage_Buffer outputvImage = {outBuffer, height, width, bytesPerRow};