nv12 yuv420p的相互转换

//初始化输入，输出的类型
-(void)initCapureSession{
    //创建AVCaptureDevice的视频设备对象
    AVCaptureDevice* videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
    NSError* error;
    //创建视频输入端对象
    AVCaptureDeviceInput* input = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];
    if (error) {
        NSLog(@"创建输入端失败,%@",error);
        return;
    }
    
    //创建功能会话对象
    self.captureSession = [[AVCaptureSession alloc] init];
    //设置会话输出的视频分辨率
    [self.captureSession setSessionPreset:AVCaptureSessionPreset1280x720];
    
    //添加输入端
    if (![self.captureSession canAddInput:input]) {
        NSLog(@"输入端添加失败");
        return;
    }
    [self.captureSession addInput:input];
    
    //显示摄像头捕捉到的数据
    AVCaptureVideoPreviewLayer* layer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
    layer.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height - 100);
    [self.view.layer addSublayer:layer];
    
    //创建输出端
    
    AVCaptureVideoDataOutput *videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
    NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey;
    NSNumber* value = [NSNumber
                       numberWithUnsignedInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange];
    NSDictionary* videoSettings = [NSDictionary
                                   dictionaryWithObject:value forKey:key];
    [videoDataOutput setVideoSettings:videoSettings];
    //会话对象添加输出端
    if ([self.captureSession canAddOutput:videoDataOutput]) {
        [self.captureSession addOutput:videoDataOutput];
        self.videoDataOutput = videoDataOutput;
        //创建输出调用的队列
        dispatch_queue_t videoDataOutputQueue = dispatch_queue_create("videoDataOutputQueue", DISPATCH_QUEUE_SERIAL);
        self.videoDataOutputQueue = videoDataOutputQueue;
        //设置代理和调用的队列
        [self.videoDataOutput setSampleBufferDelegate:self queue:videoDataOutputQueue];
        //设置延时丢帧
        self.videoDataOutput.alwaysDiscardsLateVideoFrames = NO;
    }
}


#pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate
- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    NSLog(@"did get %@",output);
    NSData *data22 = [self convertVideoSmapleBufferToYuvData:sampleBuffer];
    [self.h264Tool addFrame:sampleBuffer];
}
// CMSampleBufferRef代表一帧图像，调用苹果提供的api可以获取具体的yuv的数据
-(NSData *) convertVideoSmapleBufferToYuvData:(CMSampleBufferRef) videoSample{
    // 获取yuv数据
    // 通过CMSampleBufferGetImageBuffer方法，获得CVImageBufferRef。
    // 这里面就包含了yuv420(NV12)数据的指针
    CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(videoSample);
    
    //表示开始操作数据
    CVPixelBufferLockBaseAddress(pixelBuffer, 0);
    
    //图像宽度（像素）
    size_t pixelWidth = CVPixelBufferGetWidth(pixelBuffer);
    //图像高度（像素）
    size_t pixelHeight = CVPixelBufferGetHeight(pixelBuffer);
    //yuv中的y所占字节数
    size_t y_size = pixelWidth * pixelHeight;
    //yuv中的uv所占的字节数
    size_t uv_size = y_size / 2;
    
    uint8_t *yuv_frame = malloc(uv_size + y_size);
    
    //获取CVImageBufferRef中的y数据
    uint8_t *y_frame = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
    memcpy(yuv_frame, y_frame, y_size);
    
    //获取CMVImageBufferRef中的uv数据
    uint8_t *uv_frame = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);
    memcpy(yuv_frame + y_size, uv_frame, uv_size);
    
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
    uint8_t *I420 = malloc(uv_size + y_size);
    NSString *path = [self getHomePath];
    const char *resultCString = NULL;
    if ([path canBeConvertedToEncoding:NSUTF8StringEncoding]) {
        resultCString = [path cStringUsingEncoding:NSUTF8StringEncoding];
    }
    NSString *path2 = [self getHome2Path];
    const char *resultCString2 = NULL;
    if ([path2 canBeConvertedToEncoding:NSUTF8StringEncoding]) {
        resultCString2 = [path2 cStringUsingEncoding:NSUTF8StringEncoding];
    }
    dispatch_sync(dispatch_get_main_queue(), ^{
        func(yuv_frame, I420,pixelWidth,pixelHeight,resultCString,resultCString2);
        func5(yuv_frame, I420,pixelWidth,pixelHeight,resultCString,resultCString2);
    });
    
    //返回数据
    return [NSData dataWithBytesNoCopy:yuv_frame length:y_size + uv_size];
}
// nv12 写入本地
void func0(uint8_t *NV12, uint8_t *I420,size_t pixelWidth,size_t pixelHeight,const char *resultCString,const char *resultCString2){
    NSLog(@"start");
    int len = (int)pixelHeight * pixelWidth + pixelHeight * pixelWidth / 2;
    FILE* fpyuv = fopen(resultCString, "wb");
    for (int i = 0; i < len; i ++) {
        fwrite(NV12, 1, 1, fpyuv);
        NV12 ++;
    }
    fclose(fpyuv);
    free(NV12);
    NSLog(@"end");
}
// nv12 转 yuv 并写入本地
void func(uint8_t *NV12, uint8_t *I420,size_t pixelWidth,size_t pixelHeight,const char *resultCString,const char *resultCString2){
    unsigned char *ybuf = (unsigned char *)malloc(pixelHeight * pixelWidth);
    unsigned char *ubuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *vbuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *y = ybuf;
    unsigned char *u = ubuf;
    unsigned char *v = vbuf;
    int len = (int)pixelHeight * pixelWidth + pixelHeight * pixelWidth / 2;
    FILE* fpyuv = fopen(resultCString, "wb");
    for (int i = 0; i < len; i ++) {
        if (i < (pixelWidth * pixelHeight)) {  //yyyyy
            *y = *NV12;
            y++;
        }
        else{//uvuvuv
            if (i % 2 == 0) {//uuuuu
                *u = *NV12;
                u ++;
            }else{//vvvvv
                *v = *NV12;
                v ++;
            }
        }
        NV12 ++;
    }
    fwrite(ybuf, 1, pixelWidth*pixelHeight, fpyuv);
    fwrite(ubuf, 1, pixelWidth*pixelHeight/4, fpyuv);
    fwrite(vbuf, 1, pixelWidth*pixelHeight/4, fpyuv);
    fclose(fpyuv);
    free(ybuf);
    free(ubuf);
    free(vbuf);
}
// 从本地文件获取yuv的数据 并实现180度的翻转 并写入本地
void func2(uint8_t *NV12, uint8_t *I420,size_t pixelWidth,size_t pixelHeight,const char *resultCString,const char *resultCString2){
    unsigned char *ybuf = (unsigned char *)malloc(pixelHeight * pixelWidth);
    unsigned char *ubuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *vbuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *y = ybuf;
    unsigned char *u = ubuf;
    unsigned char *v = vbuf;
    FILE* fpyuv = fopen(resultCString, "rb");
    FILE* fpyuv2 = fopen(resultCString2, "wb");
    uint8_t* yuvbuf = malloc(pixelHeight * pixelWidth * 3 / 2);
    fread(yuvbuf, pixelWidth*pixelHeight * 3 / 2, 1, fpyuv);
    fclose(fpyuv);
    // y
    for (int i = pixelHeight -1; i >= 0; i --) {
        for (int j = pixelWidth - 1; j >= 0; j--) {
            *(y++) = *(yuvbuf +(i*pixelWidth + j));
        }
    }
    //U
    uint8_t* uheader = yuvbuf + pixelWidth*pixelHeight;
    for (int i = pixelHeight/2 - 1; i >= 0; i--){
        for (int j = pixelWidth/2-1 ; j >= 0; j--){
            *(u++) = *(uheader +(i*pixelWidth/2 + j));
        }
    }
    //v
    uint8_t* vheader = uheader + pixelWidth*pixelHeight/4;
    for (int i = pixelHeight/2 - 1; i >= 0; i--){
        for (int j = pixelWidth/2-1 ; j >= 0; j--){
            *(v++) = *(vheader +(i*pixelWidth/2 + j));
        }
    }
    fwrite(ybuf, 1, pixelWidth*pixelHeight, fpyuv2);
    fwrite(ubuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fwrite(vbuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fclose(fpyuv2);
    free(ybuf);
    free(ubuf);
    free(vbuf);
}
// 从本地文件获取yuv的数据 并实现逆时针90度的翻转 并写入本地
void func3(uint8_t *NV12, uint8_t *I420,size_t pixelWidth,size_t pixelHeight,const char *resultCString,const char *resultCString2){
    unsigned char *ybuf = (unsigned char *)malloc(pixelHeight * pixelWidth);
    unsigned char *ubuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *vbuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *y = ybuf;
    unsigned char *u = ubuf;
    unsigned char *v = vbuf;
    FILE* fpyuv = fopen(resultCString, "rb");
    FILE* fpyuv2 = fopen(resultCString2, "wb");
    uint8_t* yuvbuf = malloc(pixelHeight * pixelWidth * 3 / 2);
    fread(yuvbuf, pixelWidth*pixelHeight * 3 / 2, 1, fpyuv);
    fclose(fpyuv);
    for (int i = 0; i < pixelWidth; i ++) {
        for (int j = pixelHeight - 1; j >= 0; j --) {
            *(y++) = *(yuvbuf +(j*pixelWidth +i));
        }
    }
    uint8_t* uheader = yuvbuf + pixelWidth*pixelHeight;
    for (int i = 0; i < pixelWidth/2; i ++) {
        for (int j = pixelHeight/2 - 1; j >= 0; j --) {
            *(u++) = *(uheader +(j*pixelWidth/2 + i));
        }
    }
    uint8_t* vheader = uheader + pixelWidth*pixelHeight/4;
    for (int i = 0; i < pixelWidth/2; i ++) {
        for (int j = pixelHeight/2 - 1; j >= 0; j --) {
            *(v++) = *(vheader +(j*pixelWidth/2 + i));
        }
    }
    fwrite(ybuf, 1, pixelWidth*pixelHeight, fpyuv2);
    fwrite(ubuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fwrite(vbuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fclose(fpyuv2);
    free(ybuf);
    free(ubuf);
    free(vbuf);
}
// 从本地文件获取yuv的数据 并实现顺时针90度的翻转 并写入本地
void func4(uint8_t *NV12, uint8_t *I420,size_t pixelWidth,size_t pixelHeight,const char *resultCString,const char *resultCString2){
    unsigned char *ybuf = (unsigned char *)malloc(pixelHeight * pixelWidth);
    unsigned char *ubuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *vbuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *y = ybuf;
    unsigned char *u = ubuf;
    unsigned char *v = vbuf;
    FILE* fpyuv = fopen(resultCString, "rb");
    FILE* fpyuv2 = fopen(resultCString2, "wb");
    uint8_t* yuvbuf = malloc(pixelHeight * pixelWidth * 3 / 2);
    fread(yuvbuf, pixelWidth*pixelHeight * 3 / 2, 1, fpyuv);
    fclose(fpyuv);
    for (int i = pixelWidth - 1; i >= 0; i --) {
        for (int j = 0; j < pixelHeight; j ++) {
            *(y++) = *(yuvbuf +(j*pixelWidth +i));
        }
    }
    uint8_t* uheader = yuvbuf + pixelWidth*pixelHeight;
    for (int i = pixelWidth/2 - 1; i >= 0; i --) {
        for (int j = 0; j < pixelHeight/2; j ++) {
            *(u++) = *(uheader +(j*pixelWidth/2 +i));
        }
    }
    uint8_t* vheader = uheader + pixelWidth*pixelHeight/4;
    for (int i = pixelWidth/2 - 1; i >= 0; i --) {
        for (int j = 0; j < pixelHeight/2; j ++) {
            *(v++) = *(vheader +(j*pixelWidth/2 +i));
        }
    }
    fwrite(ybuf, 1, pixelWidth*pixelHeight, fpyuv2);
    fwrite(ubuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fwrite(vbuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fclose(fpyuv2);
    free(ybuf);
    free(ubuf);
    free(vbuf);
}
// 从本地文件获取yuv的数据 制作水平方向的镜像 并写入本地
void func5(uint8_t *NV12, uint8_t *I420,size_t pixelWidth,size_t pixelHeight,const char *resultCString,const char *resultCString2){
    unsigned char *ybuf = (unsigned char *)malloc(pixelHeight * pixelWidth);
    unsigned char *ubuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *vbuf = (unsigned char *)malloc((pixelHeight/2) * (pixelWidth/2));
    unsigned char *y = ybuf;
    unsigned char *u = ubuf;
    unsigned char *v = vbuf;
    FILE* fpyuv = fopen(resultCString, "rb");
    FILE* fpyuv2 = fopen(resultCString2, "wb");
    uint8_t* yuvbuf = malloc(pixelHeight * pixelWidth * 3 / 2);
    fread(yuvbuf, pixelWidth*pixelHeight * 3 / 2, 1, fpyuv);
    fclose(fpyuv);
    for (int i = 0; i < pixelHeight - 1; i ++) {
        for (int j = pixelWidth - 1; j >= 0; j --) {
            *(y++) = *(yuvbuf +(i*pixelWidth +j));
        }
    }
    uint8_t* uheader = yuvbuf + pixelWidth*pixelHeight;
    for (int i = 0; i < pixelHeight/2 - 1; i ++) {
        for (int j = pixelWidth/2 - 1; j >= 0; j --) {
            *(u++) = *(uheader +(i*pixelWidth/2 +j));
        }
    }
    uint8_t* vheader = uheader + pixelWidth*pixelHeight/4;
    for (int i = 0; i < pixelHeight/2 - 1; i ++) {
        for (int j = pixelWidth/2 - 1; j >= 0; j --) {
            *(v++) = *(vheader +(i*pixelWidth/2 +j));
        }
    }
    fwrite(ybuf, 1, pixelWidth*pixelHeight, fpyuv2);
    fwrite(ubuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fwrite(vbuf, 1, pixelWidth*pixelHeight/4, fpyuv2);
    fclose(fpyuv2);
    free(ybuf);
    free(ubuf);
    free(vbuf);
}
- (NSString *)getHomePath{
    NSString *path = NSHomeDirectory();
    
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *docDir = [paths objectAtIndex:0];
    return [NSString stringWithFormat:@"%@/outforyuv420p_new_new.yuv",docDir];
}
- (NSString *)getHome2Path{
    NSString *path = NSHomeDirectory();
    
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *docDir = [paths objectAtIndex:0];
    return [NSString stringWithFormat:@"%@/outforyuv420p_new_new_rala.yuv",docDir];
}