第51月第27天 AAPLEAGLLayer.m

1.

https://github.com/stevenyao/iOSHardwareDecoder

https://github.com/LevyGG/iOS-H.264-hareware-encode-and-decode

2.

opengles

https://www.jianshu.com/c/30e2e76bc140

https://github.com/QinminiOS/OpenGLES

gpuimage

https://github.com/QinminiOS/GPUImage

https://www.jianshu.com/c/4510dd854806

3.

toyuv

CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sample);

CVPixelBufferLockBaseAddress(pixelBuffer, 0);
    
    // 获取CVImageBufferRef中的y数据
    UInt8 *pY = (UInt8 *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
    // 获取CMVImageBufferRef中的uv数据
    UInt8 *pUV = (UInt8 *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);
    
    size_t width = CVPixelBufferGetWidth(pixelBuffer);
    size_t height = CVPixelBufferGetHeight(pixelBuffer);
    size_t pYBytes = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
    size_t pUVBytes = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 1);
    
    UInt8 *pYUV420P = (UInt8 *)malloc(width * height * 3 / 2);
    UInt8 *pU = pYUV420P + (width * height);
    UInt8 *pV = pU + (width * height / 4);
    
    for(int i = 0; i < height; i++) {
        memcpy(pYUV420P + i * width, pY + i * pYBytes, width);
    }
    
    for(int j = 0; j < height / 2; j++) {
        for(int i = 0; i < width / 2; i++) {
            *(pU++) = pUV[i<<1];
            *(pV++) = pUV[(i<<1) + 1];
        }
        
        pUV += pUVBytes;
    }

    free(pYUV420P);
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);

topixelBuffer

- (CVPixelBufferRef) copyDataFromBuffer:(const unsigned char*)buffer toYUVPixelBufferWithWidth:(size_t)width Height:(size_t)height
{
    
    uint8_t* nv12 = buffer;
    
    NSDictionary *pixelAttributes = @{(NSString*)kCVPixelBufferIOSurfacePropertiesKey:@{}};
    CVPixelBufferRef pixelBuffer = NULL;
    CVReturn result = CVPixelBufferCreate(kCFAllocatorDefault,
                                          width,
                                          height,
                                          kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
                                          (__bridge CFDictionaryRef)(pixelAttributes),
                                          &pixelBuffer);
    
    size_t pYBytes = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
    size_t pUVBytes = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 1);
    
    CVPixelBufferLockBaseAddress(pixelBuffer,0);
    unsigned char *yDestPlane = (unsigned char *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
    unsigned char *y_ch0 = nv12;
    unsigned char *y_ch1 = nv12 + width * height;
//    memcpy(yDestPlane, y_ch0, width * height);
    for(int i = 0; i < height; i++) {
        memcpy(yDestPlane + i * pYBytes, y_ch0 + i * width, width);
    }
    unsigned char *uvDestPlane = (unsigned char *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);
//    memcpy(uvDestPlane, y_ch1, width * height/2);
    
    UInt8 *pU = nv12 + (width * height);
    UInt8 *pV = pU + (width * height / 4);
    
    for(int j = 0; j < height / 2; j++) {
        for(int i = 0; i < width / 2; i++) {
            uvDestPlane[i<<1] = *(pU++) ;
            uvDestPlane[(i<<1) + 1] = *(pV++);
        }
        
        uvDestPlane += pUVBytes;
    }
    
    //    if (nv12) {
    //        free(nv12);
    //    }
    
    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
    
    if (result != kCVReturnSuccess) {
        NSLog(@"Unable to create cvpixelbuffer %d", result);
    }

    return pixelBuffer;
    
}

 https://www.jianshu.com/p/7da76246ce82

//nv12,uv分量交替存储；YUV420，uv分量分层存储

https://blog.csdn.net/u013472201/article/details/105300770/