日常问题总结

遇到SDWebImage (~> 4.0.0)required byPodfile`

工程Target-General-Deployment Target 需要设置运行对应的系统最低版本，如最低要求iOS8.0>

Xcode9 FFmpeg AVMediaType与系统的AVFoundation框架冲突

报错信息：Typedef ‘AVMediaType’ cannot be referenced with a enum specifier xxx….
解决方法：将FFmpeg的源码中的AVMediaType改个名字之后重新编译FFmpeg再导入工程即可编译通过。
打开终端 cd到FFMpeg源码路径，执行命令
sed -i ” “s/AVMediaType/FFMAVMediaType/g” grep -rl AVMediaType ./ffmpeg-* 然后重新编译即可>

UIImage与CVPixelBufferRef转换

- (CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image{    NSDictionary *options = @{                              (NSString*)kCVPixelBufferCGImageCompatibilityKey : @YES,                              (NSString*)kCVPixelBufferCGBitmapContextCompatibilityKey : @YES,                              };    CVPixelBufferRef pxbuffer = NULL;    CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, CGImageGetWidth(image),                                          CGImageGetHeight(image), kCVPixelFormatType_32ARGB, (__bridge CFDictionaryRef) options,                                          &pxbuffer);    if (status!=kCVReturnSuccess) {        NSLog(@"Operation failed");    }    NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);    CVPixelBufferLockBaseAddress(pxbuffer, 0);    void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();    CGContextRef context = CGBitmapContextCreate(pxdata, CGImageGetWidth(image),                                                 CGImageGetHeight(image), 8, 4*CGImageGetWidth(image), rgbColorSpace,                                                 kCGImageAlphaNoneSkipFirst);    NSParameterAssert(context);    CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),                                           CGImageGetHeight(image)), image);    CGColorSpaceRelease(rgbColorSpace);    CGContextRelease(context);    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);    return pxbuffer;}-(UIImage*)pixelBufferToImage:(CVPixelBufferRef) pixelBuffer{    CIImage *ciImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];    CIContext *temporaryContext = [CIContext contextWithOptions:nil];    CGImageRef videoImage = [temporaryContext                             createCGImage:ciImage                             fromRect:CGRectMake(0, 0,                                                 CVPixelBufferGetWidth(pixelBuffer),                                                 CVPixelBufferGetHeight(pixelBuffer))];    UIImage *uiImage = [UIImage imageWithCGImage:videoImage];    CGImageRelease(videoImage);    return uiImage;}