小编Imp*_*lub的帖子

我正在开发一个个人iOS项目,需要通过4G连接上传到后端的全屏视频(长度为15秒).虽然我可以很好地拍摄视频,但文件的输出大小达到30MB,这让我觉得在压缩时我做了一些严重的错误.下面是我用来设置AssetWriter的代码:

-(void)captureOutput:(AVCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections
{
    NSLog(@"Started Recording! *******************");
    self.movieWriter = [AVAssetWriter assetWriterWithURL:fileURL fileType:AVFileTypeMPEG4 error:nil];
    [self.movieWriter setShouldOptimizeForNetworkUse:YES];

    NSDictionary *videoCleanApertureSettings = @{
                                                 AVVideoCleanApertureWidthKey: [NSNumber numberWithFloat:self.view.frame.size.width],
                                                 AVVideoCleanApertureHeightKey: [NSNumber numberWithFloat:self.view.frame.size.height],
                                                 AVVideoCleanApertureHorizontalOffsetKey: [NSNumber numberWithInt:10],
                                                 AVVideoCleanApertureVerticalOffsetKey: [NSNumber numberWithInt:10],
                                                 };

    NSDictionary *videoCompressionSettings = @{
                                          AVVideoAverageBitRateKey: [NSNumber numberWithFloat:5000000.0],
                                          AVVideoMaxKeyFrameIntervalKey: [NSNumber numberWithInteger:1],
                                          AVVideoProfileLevelKey: AVVideoProfileLevelH264Baseline30,
                                          AVVideoCleanApertureKey: videoCleanApertureSettings,
                                          };

    NSDictionary *videoSettings = @{AVVideoCodecKey: AVVideoCodecH264,
                                    AVVideoWidthKey: [NSNumber numberWithFloat:self.view.frame.size.width],
                                    AVVideoHeightKey: [NSNumber numberWithFloat:self.view.frame.size.height],
                                    AVVideoCompressionPropertiesKey: videoCompressionSettings,
                                    };

    self.movieWriterVideoInput = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
    self.movieWriterVideoInput.expectsMediaDataInRealTime = YES;
    [self.movieWriter addInput:self.movieWriterVideoInput];

    NSDictionary *audioSettings …

我正在尝试编写一个程序,让用户可以生成1-75个Fibonacci数字,打印它们,然后将所有这些值一起添加到所有总和中.我没有问题生成数字和打印它们,但由于某种原因,我在sum函数方面遇到了很多麻烦.出于某种原因,它只返回0 ......并且在我盯着它看了几个小时后,我感到很茫然.任何和所有的帮助将不胜感激.我的代码如下:

#include <stdio.h>
#include <stdlib.h>

//function to calculate fibonacci number 1-75 (user specified)
int fibonacci(int * array, int size)
{
    int i;
    unsigned long long int Fibonacci[size]; //generating the array to save the Fibonacci values

    Fibonacci[0] = 0; //by definition
    Fibonacci[1] = 1; //by definition

    for (i = 2; i < size; i++) {
        Fibonacci[i] = Fibonacci[i-2] + Fibonacci[i-1]; //equation to calculate the numbers
    }

    for (i = 0; i < size; i++) {
        printf("%llu\t", Fibonacci[i]); //printing …