首先附上libyuv的下载链接，需要自取，后面会用到：链接:https://pan.baidu.com/s/1DwtD5QdeTDHYqkqMxkpI2Q 密码:ijsj
#pragma mark - NV12转I420
/// NV12转I420
+ (CVPixelBufferRef)I420PixelBufferWithNV12:(CVImageBufferRef)cvpixelBufferRef {
CVPixelBufferLockBaseAddress(cvpixelBufferRef, 0);
//图像宽度（像素）
size_t pixelWidth = CVPixelBufferGetWidth(cvpixelBufferRef);
//图像高度（像素）
size_t pixelHeight = CVPixelBufferGetHeight(cvpixelBufferRef);
//获取CVPixelBufferRef中的y数据
const uint8* y_frame = (uint8*)CVPixelBufferGetBaseAddressOfPlane(cvpixelBufferRef,0);
//获取CMVImageBufferRef中的uv数据
const uint8* uv_frame = (uint8*)CVPixelBufferGetBaseAddressOfPlane(cvpixelBufferRef,1);
//y stride
size_t plane1_stride = CVPixelBufferGetBytesPerRowOfPlane (cvpixelBufferRef, 0);
//uv stride
size_t plane2_stride = CVPixelBufferGetBytesPerRowOfPlane (cvpixelBufferRef, 1);
//yuv_size(内存空间)
size_t frame_size = pixelWidth*pixelHeight*3/2;
//开辟frame_size大小的内存空间用于存放转换好的i420数据
uint8* buffer = (unsigned char *)malloc(frame_size);
//buffer为这段内存的首地址,plane1_size代表这一帧中y数据的长度
uint8* dst_u = buffer + pixelWidth*pixelHeight;
//dst_u为u数据的首地,plane1_size/4为u数据的长度
uint8* dst_v = dst_u + pixelWidth*pixelHeight/4;
//libyuv转换
int ret = NV12ToI420(y_frame,
(int)plane1_stride,
uv_frame,
(int)plane2_stride,
buffer,
(int)pixelWidth,
dst_u,
(int)pixelWidth/2,
dst_v,
(int)pixelWidth/2,
(int)pixelWidth,
(int)pixelHeight
);
if (ret) {
return NULL;
}
NSDictionary *pixelAttributes = @{(id)kCVPixelBufferIOSurfacePropertiesKey : @{}};
CVPixelBufferRef pixelBuffer = NULL;
CVReturn result = CVPixelBufferCreate(kCFAllocatorDefault,
pixelWidth,
pixelHeight,
kCVPixelFormatType_420YpCbCr8Planar,
(__bridge CFDictionaryRef)(pixelAttributes),
&pixelBuffer);
CVPixelBufferLockBaseAddress(pixelBuffer, 0);
size_t d = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
size_t ud = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 1);
size_t vd = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 2);
unsigned char* dsty = (unsigned char *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
unsigned char* dstu = (unsigned char *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);
unsigned char* dstv = (unsigned char *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 2);
unsigned char* srcy = buffer;
for (unsigned int rIdx = 0; rIdx < pixelHeight; ++rIdx, srcy += pixelWidth, dsty += d) {
memcpy(dsty, srcy, pixelWidth);
}
unsigned char* srcu = buffer + pixelHeight*pixelWidth;
for (unsigned int rIdx = 0; rIdx < pixelHeight/2; ++rIdx, srcu += pixelWidth/2, dstu += ud) {
memcpy(dstu, srcu, pixelWidth/2);
}
unsigned char* srcv = buffer + pixelHeight*pixelWidth*5/4;
for (unsigned int rIdx = 0; rIdx < pixelHeight/2; ++rIdx, srcv += pixelWidth/2, dstv += vd) {
memcpy(dstv, srcv, pixelWidth/2);
}
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
if (result != kCVReturnSuccess) {
NSLog(@"Unable to create cvpixelbuffer %d", result);
}
free(buffer);
// CVPixelBufferRelease(cvpixelBufferRef);
return pixelBuffer;
}
#pragma mark - NV12转BGRA
/// NV12转BGRA
+ (CVPixelBufferRef)RGBAPixelBufferWithNV12:(CVImageBufferRef)pixelBufferNV12{
CVPixelBufferLockBaseAddress(pixelBufferNV12, 0);
//图像宽度（像素）
size_t pixelWidth = CVPixelBufferGetWidth(pixelBufferNV12);
//图像高度（像素）
size_t pixelHeight = CVPixelBufferGetHeight(pixelBufferNV12);
//y_stride
size_t src_stride_y = CVPixelBufferGetBytesPerRowOfPlane(pixelBufferNV12, 0);
//uv_stride
size_t src_stride_uv = CVPixelBufferGetBytesPerRowOfPlane(pixelBufferNV12,1);
//获取CVImageBufferRef中的y数据
uint8_t *src_y = (unsigned char *)CVPixelBufferGetBaseAddressOfPlane(pixelBufferNV12, 0);
//获取CMVImageBufferRef中的uv数据
uint8_t *src_uv =(unsigned char *) CVPixelBufferGetBaseAddressOfPlane(pixelBufferNV12, 1);
// 创建一个空的32BGRA格式的CVPixelBufferRef
NSDictionary *pixelAttributes = @{(id)kCVPixelBufferIOSurfacePropertiesKey : @{}};
CVPixelBufferRef pixelBufferRGBA = NULL;
CVReturn result = CVPixelBufferCreate(kCFAllocatorDefault,
pixelWidth,pixelHeight,kCVPixelFormatType_32BGRA,
(__bridge CFDictionaryRef)pixelAttributes,&pixelBufferRGBA);//kCVPixelFormatType_32BGRA
if (result != kCVReturnSuccess) {
NSLog(@"Unable to create cvpixelbuffer %d", result);
return NULL;
}
result = CVPixelBufferLockBaseAddress(pixelBufferRGBA, 0);
if (result != kCVReturnSuccess) {
CFRelease(pixelBufferRGBA);
NSLog(@"Failed to lock base address: %d", result);
return NULL;
}
// 得到新创建的CVPixelBufferRef中 rgb数据的首地址
uint8_t *rgb_data = (uint8*)CVPixelBufferGetBaseAddress(pixelBufferRGBA);
// 使用libyuv为rgb_data写入数据，将NV12转换为BGRA
size_t bgraStride = CVPixelBufferGetBytesPerRowOfPlane(pixelBufferRGBA,0);
int ret = NV12ToARGB(src_y, (int)src_stride_y, src_uv, (int)src_stride_uv, rgb_data,(int)bgraStride, (int)pixelWidth, (int)pixelHeight);
if (ret) {
NSLog(@"Error converting NV12 VideoFrame to BGRA: %d", result);
CFRelease(pixelBufferRGBA);
return NULL;
}
CVPixelBufferUnlockBaseAddress(pixelBufferRGBA, 0);
CVPixelBufferUnlockBaseAddress(pixelBufferNV12, 0);
return pixelBufferRGBA;
}
