使用libyuv 进行 i420 转 BGRA PixelBuf

参考 demo

typedef struct {
    uint8_t *y_frame;
    uint8_t *u_frame;
    uint8_t *v_frame;
    
    int width;
    int height;
    
    int stride_y;
    int stride_u;
    int stride_v;
} I420Buffer;

+ (CVPixelBufferRef)convertToBGRAPixelBufferWithI420Buffer:(I420Buffer)i420Buffer
{
    if (!i420Buffer.y_frame) {
        return NULL;
    }
    
    //create rgb buffer
    NSDictionary *att = @{(NSString *)kCVPixelBufferIOSurfacePropertiesKey : @{}};

    CVPixelBufferRef bgraBuffer;
    CVPixelBufferCreate(kCFAllocatorDefault,
                        (size_t)i420Buffer.width,
                        (size_t)i420Buffer.height,
                        kCVPixelFormatType_32BGRA,
                        (__bridge CFDictionaryRef _Nullable)att,
                        &bgraBuffer);
    if (!bgraBuffer) {
        //create error
        NSLog(@"%s, create error,  line = %d", __func__, __LINE__);
        return NULL;
    }

    CVPixelBufferLockBaseAddress(bgraBuffer, 0);

    uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(bgraBuffer);
    int bytesPerRow = (int)CVPixelBufferGetBytesPerRow(bgraBuffer);

    int ret =  libyuv::I420ToARGB(i420Buffer.y_frame, i420Buffer.stride_y,
                       i420Buffer.u_frame, i420Buffer.stride_u,
                       i420Buffer.v_frame, i420Buffer.stride_v,
                       baseAddress, bytesPerRow,
                       i420Buffer.width, i420Buffer.height);

    assert(ret == 0);
    CVPixelBufferUnlockBaseAddress(bgraBuffer, 0);
    return (CVPixelBufferRef)CFAutorelease(bgraBuffer);
}