Convert an AVFrame to CVPixelbuffer

gistfile1.m

-(void)getPixelBuffer:(CVPixelBufferRef *)pbuf {
    @synchronized (self) {
        
        if(!_pFrame || !_pFrame->data[0])
            return;
        
        NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                                 //                             [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                                 //                             [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                                 @(_pFrame->linesize[0]), kCVPixelBufferBytesPerRowAlignmentKey,
                                 [NSNumber numberWithBool:YES], kCVPixelBufferOpenGLESCompatibilityKey,
                                 [NSDictionary dictionary], kCVPixelBufferIOSurfacePropertiesKey,
                                 nil];
        
        
        if (_pFrame->linesize[1] != _pFrame->linesize[2]) {
            return;
        }
        
        size_t srcPlaneSize = _pFrame->linesize[1]*_pFrame->height/2;
        size_t dstPlaneSize = srcPlaneSize *2;
        uint8_t *dstPlane = malloc(dstPlaneSize);
        
        // interleave Cb and Cr plane
        for(size_t i = 0; i<srcPlaneSize; i++){
            dstPlane[2*i  ]=_pFrame->data[1][i];
            dstPlane[2*i+1]=_pFrame->data[2][i];
        }
        
        
        int ret = CVPixelBufferCreate(kCFAllocatorDefault,
                                      _pFrame->width,
                                      _pFrame->height,
                                      kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
                                      (__bridge CFDictionaryRef)(options),
                                      pbuf);
        
        CVPixelBufferLockBaseAddress(*pbuf, 0);
        
        size_t bytePerRowY = CVPixelBufferGetBytesPerRowOfPlane(*pbuf, 0);
        size_t bytesPerRowUV = CVPixelBufferGetBytesPerRowOfPlane(*pbuf, 1);
        
        void* base =  CVPixelBufferGetBaseAddressOfPlane(*pbuf, 0);
        memcpy(base, _pFrame->data[0], bytePerRowY*_pFrame->height);
        
        base = CVPixelBufferGetBaseAddressOfPlane(*pbuf, 1);
        memcpy(base, dstPlane, bytesPerRowUV*_pFrame->height/2);
        
        
        CVPixelBufferUnlockBaseAddress(*pbuf, 0);
        
        free(dstPlane);
        
        
        if(ret != kCVReturnSuccess)
        {
            NSLog(@"CVPixelBufferCreate Failed");
        }
        
    }
}

what is _pFrame?