1.rgba转UIimage

+(UIImage *_Nullable)covertBitmapRGBA8ToUIImage:(unsigned char*)buffer
                                          width:(int)width
                                         height:(int)heigth
{
    size_t bufferlength = width * heigth * 4;
    CGDataProviderRef provide = CGDataProviderCreateWithData(NULL, buffer, bufferlength, NULL);
    size_t bitsPerComponent = 8;
    size_t bitsPerPixl = 32;
    size_t bytesPerRow = 4 * width;
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
    if (colorSpaceRef == NULL) {
        DLog(@"error allocating color space...");
        CGDataProviderRelease(provide);
        return nil;
    }
    
    CGBitmapInfo bitmapinfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast;
    CGColorRenderingIntent renderingintent = kCGRenderingIntentDefault;
    CGImageRef iref = CGImageCreate(width, heigth, bitsPerComponent, bitsPerPixl, bytesPerRow, colorSpaceRef, bitmapinfo, provide, NULL, YES, renderingintent);
    uint32_t *pixels = (uint32_t*)malloc(bufferlength);
    if (pixels == NULL) {
        NSLog(@"error: memory not allocated for bitmap");
        CGDataProviderRelease(provide);
        CGColorSpaceRelease(colorSpaceRef);
        CGImageRelease(iref);
        return nil;
    }
    
    CGContextRef context = CGBitmapContextCreate(pixels, width, heigth, bitsPerComponent, bytesPerRow, colorSpaceRef, bitmapinfo);
    if (context == NULL) {
        DLog(@"error context not created...");
        free(pixels);
    }
    UIImage *image = nil;
    if (context) {
        CGContextDrawImage(context, CGRectMake(0.0, 0.0, width, heigth), iref);
        CGImageRef imageRef = CGBitmapContextCreateImage(context);
        if ([UIImage respondsToSelector:@selector(imageWithCGImage:scale:orientation:)]) {
            float scale = [[UIScreen mainScreen] scale];
            image = [UIImage imageWithCGImage:imageRef scale:scale orientation:UIImageOrientationUp];
        } else {
            image = [UIImage imageWithCGImage:imageRef];
        }
        
        CGImageRelease(imageRef);
        CGContextRelease(context);
    }
    
    CGColorSpaceRelease(colorSpaceRef);
    CGImageRelease(iref);
    CGDataProviderRelease(provide);
    if(pixels) {
        free(pixels);
    }
    return image;
}

1.yuv 转UIimage

a.YUV(NV12)-->CIImage--->UIImage

+(UIImage *)yuvToUIImage:(int)w h:(int)h buffer:(unsigned char *_Nullable)buffer 
{
    NSDictionary *pixelAttributes = @{(id)kCVPixelBufferIOSurfacePropertiesKey:@{}};
    CVPixelBufferRef pixelBuffer = NULL;
    CVReturn result = CVPixelBufferCreate(kCFAllocatorDefault,
                                          w,
                                          h,
                                          kCVPixelFormatType_420YpCbCr8BiPlanarFullRange,
                                          (__bridge CFDictionaryRef)(pixelAttributes),
                                          &pixelBuffer);
    
    CVPixelBufferLockBaseAddress(pixelBuffer,0);
    unsigned char *yDestPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
    
    // Here y_ch0 is Y-Plane of YUV(NV12) data.
    unsigned char *y_ch0 = buffer;
    
    unsigned char *y_ch1 = buffer + w * h;
    memcpy(yDestPlane, y_ch0, w * h);
    unsigned char *uvDestPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);
    
    // Here y_ch1 is UV-Plane of YUV(NV12) data.
    memcpy(uvDestPlane, y_ch1, w * h/2);
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
    
    if (result != kCVReturnSuccess) {
        NSLog(@"Unable to create cvpixelbuffer %d", result);
        return nil;
    }
    
    // CIImage Conversion
    CIImage *coreImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];
    CIContext *MytemporaryContext = [CIContext contextWithOptions:nil];
   // size_t size = CVPixelBufferGetDataSize(pixelBuffer);
   // CVPixelBufferGetHeight(pixelBuffer)
   // CVPixelBufferGetWidth(pixelBuffer)
    CGImageRef MyvideoImage = [MytemporaryContext createCGImage:coreImage fromRect:CGRectMake(0, 0, w, h)];
    // UIImage Conversion
    UIImage *Mynnnimage = [[UIImage alloc] initWithCGImage:MyvideoImage scale:1.0 orientation:UIImageOrientationRight];
    
    CVPixelBufferRelease(pixelBuffer);
    CGImageRelease(MyvideoImage);
    return Mynnnimage;
}