【滤镜】CVPixelBufferRef处理成黑屏帧

注意点 ：

1、processFrame:方法中 resultPixelBuffer避免内存暴涨的写法

@interface VideoProcessingManager ()

@property (nonatomic, strong) MFPixelBufferHelper *pixelBufferHelper;

@property (nonatomic, assign) CVPixelBufferRef resultPixelBuffer;

@end

@implementation VideoProcessingManager

- (instancetype)init {
    self = [super init];
    if (self) {
    }
    return self;
}

#pragma mark - CapturerManagerDelegate
- (CVPixelBufferRef)processFrame:(CVPixelBufferRef)pixelBuffer {
    CVPixelBufferRef outputPixelBuffer = pixelBuffer;
    // 关键代码 这里一定要这么写 否则内存暴涨
    if (!self.resultPixelBuffer) {
        CVPixelBufferRef pixelBuffer = [self renderByGPUImage:outputPixelBuffer];
        self.resultPixelBuffer = pixelBuffer;
        CVPixelBufferRelease(pixelBuffer);
    }
    outputPixelBuffer = self.resultPixelBuffer;

    return outputPixelBuffer;
}

- (void)setResultPixelBuffer:(CVPixelBufferRef)resultPixelBuffer {
    if (_resultPixelBuffer &&
        resultPixelBuffer &&
        CFEqual(resultPixelBuffer, _resultPixelBuffer)) {
        return;
    }
    if (resultPixelBuffer) {
        CVPixelBufferRetain(resultPixelBuffer);
    }
    if (_resultPixelBuffer) {
        CVPixelBufferRelease(_resultPixelBuffer);
    }
    _resultPixelBuffer = resultPixelBuffer;
}


- (MFPixelBufferHelper *)pixelBufferHelper {
    if (!_pixelBufferHelper) {
        EAGLContext *context = [[GPUImageContext sharedImageProcessingContext] context];
        _pixelBufferHelper = [[MFPixelBufferHelper alloc] initWithContext:context];
    }
    return _pixelBufferHelper;
}

- (CVPixelBufferRef)renderByGPUImage:(CVPixelBufferRef)pixelBuffer {
    
    CVPixelBufferRetain(pixelBuffer);
    __block CVPixelBufferRef output = nil;
    __weak typeof(self) weakSelf = self;
    runSynchronouslyOnVideoProcessingQueue(^{
        [GPUImageContext useImageProcessingContext];
        
        // (1)
        GLuint textureID = [weakSelf.pixelBufferHelper convertYUVPixelBufferToTexture:pixelBuffer];
        CGSize size = CGSizeMake(CVPixelBufferGetWidth(pixelBuffer),
                                 CVPixelBufferGetHeight(pixelBuffer));

        [GPUImageContext setActiveShaderProgram:nil];
        // (2)
        GPUImageTextureInput *textureInput = [[GPUImageTextureInput alloc] initWithTexture:textureID size:size];
//        GPUImageSmoothToonFilter *filter = [[GPUImageSmoothToonFilter alloc] init];
//        [textureInput addTarget:filter];

        GPUImageBrightnessFilter *brightNessFilter = [[GPUImageBrightnessFilter alloc] init];
        brightNessFilter.brightness = -1;
        [textureInput addTarget:brightNessFilter];
        GPUImageTextureOutput *textureOutput = [[GPUImageTextureOutput alloc] init];
//        [filter addTarget:textureOutput];
//
        [brightNessFilter addTarget:textureOutput];
        [textureInput processTextureWithFrameTime:kCMTimeZero];

        // (3)
        output = [weakSelf.pixelBufferHelper convertTextureToPixelBuffer:textureOutput.texture
                                                         textureSize:size];

        [textureOutput doneWithTexture];

        glDeleteTextures(1, &textureID);
    });
    CVPixelBufferRelease(pixelBuffer);
    return output;
}

@end

MFPixelBufferHelper 见：【CVPixelBufferRef】添加滤镜的方法_allanGold的博客-优快云博客