Fix GPUImage3 MovieInput 内存爆增问题

在使用 GPUImage3 examples -> iOS ->SimpleMovieFilter 读取视频时 发现内存爆增 查找发现 是 MovieInput 的锅

修改后的代码

func process(movieFrame:CVPixelBuffer, withSampleTime:CMTime) {
        autoreleasepool {
                ........ 
         }
    }

添加 autoreleasepool 能让在autoreleasepool 创建的对象及时被释放

示例代码：我这里被没有需要 yuv 转 RBG 所以直接获取纹理 注释掉了多余的代码

 func process(movieFrame:CVPixelBuffer, withSampleTime:CMTime) {
        
        autoreleasepool {
                    
        let bufferHeight = CVPixelBufferGetHeight(movieFrame)
        let bufferWidth = CVPixelBufferGetWidth(movieFrame)
        CVPixelBufferLockBaseAddress(movieFrame, CVPixelBufferLockFlags(rawValue:CVOptionFlags(0)))

        let conversionMatrix = colorConversionMatrix601FullRangeDefault
        // TODO: Get this color query working
//        if let colorAttachments = CVBufferGetAttachment(movieFrame, kCVImageBufferYCbCrMatrixKey, nil) {
//            if(CFStringCompare(colorAttachments, kCVImageBufferYCbCrMatrix_ITU_R_601_4, 0) == .EqualTo) {
//                _preferredConversion = kColorConversion601FullRange
//            } else {
//                _preferredConversion = kColorConversion709
//            }
//        } else {
//            _preferredConversion = kColorConversion601FullRange
//        }
        
        let startTime = CFAbsoluteTimeGetCurrent()

        let texture:Texture?
        var luminanceTextureRef:CVMetalTexture? = nil
        // var chrominanceTextureRef:CVMetalTexture? = nil
        // Luminance plane
        let _ = CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, self.videoTextureCache!, movieFrame, nil, .bgra8Unorm, bufferWidth, bufferHeight, 0, &luminanceTextureRef)
        // Chrominance plane
        //let _ = CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, self.videoTextureCache!, movieFrame, nil, .rg8Unorm, bufferWidth / 2, bufferHeight / 2, 1, &chrominanceTextureRef)
        
        if let concreteLuminanceTextureRef = luminanceTextureRef,
            let luminanceTexture = CVMetalTextureGetTexture(concreteLuminanceTextureRef) {
            let outputTexture = Texture.init(orientation:.portrait, texture: luminanceTexture)
           texture = outputTexture
        } else {
            texture = nil
        }
        

        CVPixelBufferUnlockBaseAddress(movieFrame, CVPixelBufferLockFlags(rawValue:CVOptionFlags(0)))

        if texture != nil {
            self.updateTargetsWithTexture(texture!)
        }
        
        if self.runBenchmark {
            let currentFrameTime = (CFAbsoluteTimeGetCurrent() - startTime)
            self.numberOfFramesCaptured += 1
            self.totalFrameTimeDuringCapture += currentFrameTime
            print("Average frame time : \(1000.0 * self.totalFrameTimeDuringCapture / Double(self.numberOfFramesCaptured)) ms")
            print("Current frame time : \(1000.0 * currentFrameTime) ms")
        }
        
         }
    }