//

// MediaUtils.m

// APIExample

//

// Created by Arlin on 2022/4/12.

// Copyright © 2022 Agora Corp. All rights reserved.

//

#import "MediaUtils.h"

#import <CoreImage/CoreImage.h>

@implementation MediaUtils

+ (UIImage *)i420ToImage:(void *)srcY srcU:(void *)srcU srcV:(void *)srcV width:(int)width height:(int)height {

int size = width * height * 3 / 2;

int yLength = width * height;

int uLength = yLength / 4;

unsigned char *buf = (unsigned char *)malloc(size);

memcpy(buf, srcY, yLength);

memcpy(buf + yLength, srcU, uLength);

memcpy(buf + yLength + uLength, srcV, uLength);

unsigned char * NV12buf = (unsigned char *)malloc(size);

[self yuv420p_to_nv12:buf nv12:NV12buf width:width height:height];

int w = width;

int h = height;

NSDictionary *pixelAttributes = @{(NSString*)kCVPixelBufferIOSurfacePropertiesKey:@{}};

CVPixelBufferRef pixelBuffer = NULL;

CVReturn result = CVPixelBufferCreate(kCFAllocatorDefault,

w,

h,

kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,

(__bridge CFDictionaryRef)(pixelAttributes),

&pixelBuffer);

if (result != kCVReturnSuccess) {

NSLog(@"Unable to create cvpixelbuffer %d", result);

return nil;

}

CVPixelBufferLockBaseAddress(pixelBuffer,0);

void *yDestPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);

// Here y_ch0 is Y-Plane of YUV(NV12) data.

unsigned char *y_ch0 = NV12buf;

unsigned char *y_ch1 = NV12buf + w * h;

memcpy(yDestPlane, y_ch0, w * h);

void *uvDestPlane = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);

// Here y_ch1 is UV-Plane of YUV(NV12) data.

memcpy(uvDestPlane, y_ch1, w * h * 0.5);

CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);

// CIImage Conversion

CIImage *coreImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];

CIContext *temporaryContext = [CIContext contextWithOptions:nil];

CGImageRef videoImage = [temporaryContext createCGImage:coreImage

fromRect:CGRectMake(0, 0, w, h)];

UIImage *finalImage = [[UIImage alloc] initWithCGImage:videoImage

scale:1.0

orientation:UIImageOrientationRight];

CVPixelBufferRelease(pixelBuffer);

CGImageRelease(videoImage);

return finalImage;

}

+ (void)yuv420p_to_nv12:(unsigned char*)yuv420p nv12:(unsigned char*)nv12 width:(int)width height:(int)height {

int i, j;

int y_size = width * height;

unsigned char* y = yuv420p;

unsigned char* u = yuv420p + y_size;

unsigned char* v = yuv420p + y_size * 5 / 4;

unsigned char* y_tmp = nv12;

unsigned char* uv_tmp = nv12 + y_size;

memcpy(y_tmp, y, y_size);

for (j = 0, i = 0; j < y_size * 0.5; j += 2, i++) {

uv_tmp[j] = u[i];

uv_tmp[j+1] = v[i];

}

}

@end