iOS GPUImage使用 短视频录制 暂停录制 滤镜 自定义美颜滤镜 gif动态及文本水印添加 视频拼接

主要功能（有示例代码）：

1.基于GPUImage自定义美颜滤镜
2.基于GPUImage添加文本水印及动态水印
3.录制过程中各种滤镜随意切换，及文本水印动态水印随意切换可以加载gif图作为水印
4.录制过程中可以暂停并继续录制
5.使用AVFoundation框架进行视频拼接
6.获取短视频第一帧图片，示例代码中有方法
录制页面：

暂停功能：

由于音视频同步过程中需要用到时间戳，视频录制过程中有时间戳，暂停过程如果只是停止编码是不行的，暂停后开始编码时间戳就有问题，不连续了。于是就采用暂停录制就录制成为一段完成视频，结束录制时再把录制的所有视频拼接起来。

美颜滤镜：

不想下载示例代码可以到这里看：
iOS GPUImage 自定义美颜滤镜

动态水印功能：

这个动态水印就像抖音的抖动水印一样，可以加载gif图，没有使用第三方框架加载gif图，是把gif图当中的所有图片提取出来，然后动态替换水印图片，直接使用UIImageView的animation加载图片没有效果，就在GPUImage的回调当中进行动态改变水印图片：

 ///gif
    NSString *path = [[NSBundle mainBundle] pathForResource:@"video.gif" ofType:nil] ;
    NSData *imageData = [NSData dataWithContentsOfFile:path];
    NSArray * arrImage =  [YHHelp changeGifToImage:imageData];
    UIImageView * imageV = [[UIImageView alloc]initWithFrame:CGRectMake(80, 0, 100, 80)];
    imageV.image = arrImage[0];
    
    //创建滤镜 GPUImageDissolveBlendFilter
    gifFilter = [[GPUImageAlphaBlendFilter alloc] init];
    // GPUImageGaussianBlurFilter *filter = [[GPUImageGaussianBlurFilter alloc] init];
    gifFilter.mix = 0.8;
    //创建水印图形
    
    UIView* watermarkView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 180, 380)];
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 80, 80)];
    label.text = @"Record";
    label.textColor = [UIColor whiteColor];
    label.textAlignment = NSTextAlignmentCenter;
    label.font = [UIFont systemFontOfSize:20 weight:UIFontWeightBold];
    [watermarkView addSubview:imageV];
    [watermarkView addSubview:label];
    
    GPUImageUIElement *uiElement = [[GPUImageUIElement alloc] initWithView:watermarkView];
    videoFilter = [[GPUImageFilter alloc] init];
    [videoFilter addTarget:gifFilter];
    [uiElement addTarget:gifFilter];
    __block NSInteger imageIndex = 0;
    __block GPUImageUIElement *weakElement = uiElement;
    __block NSInteger timeCount = 0;
    [videoFilter setFrameProcessingCompletionBlock:^(GPUImageOutput *output, CMTime time) {
        NSInteger tempCount = time.value/(time.timescale/1000);
        //控制水印图片刷新速率
        if (tempCount - timeCount > 100) {
            imageIndex ++;
            dispatch_async(dispatch_get_main_queue(), ^{
                imageV.image = arrImage[imageIndex];
            });
            if (imageIndex == arrImage.count -1) {
                imageIndex = 0;
            }
            timeCount = tempCount;
        }
        [weakElement update];
    }];      

视频拼接，使用AVMutableComposition进行拼接：

- (void)mergeAndExportVideos:(NSArray*)videosPathArray withOutPath:(NSString*)outpath{
    
    if (videosPathArray.count == 0) {
        [YHToastHUD showToast:@"没有可处理视频文件！"];
        return;
    }
    //音频视频合成体
    AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];

    //创建音频通道容器
    AVMutableCompositionTrack *audioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
    //创建视频通道容器
    AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
    
    
    CMTime totalDuration = kCMTimeZero;
    for (int i = 0; i < videosPathArray.count; i++) {
        //        AVURLAsset *asset = [AVURLAsset assetWithURL:[NSURL URLWithString:videosPathArray[i]]];
        NSDictionary* options = @{AVURLAssetPreferPreciseDurationAndTimingKey:@YES};
        AVAsset* asset = [AVURLAsset URLAssetWithURL:videosPathArray[i] options:options];
        
        NSError *erroraudio = nil;
        //获取AVAsset中的音频 或者视频
        AVAssetTrack *assetAudioTrack = [[asset tracksWithMediaType:AVMediaTypeAudio] firstObject];
        //向通道内加入音频或者视频
        BOOL ba = [audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, asset.duration)
                                      ofTrack:assetAudioTrack
                                       atTime:totalDuration
                                        error:&erroraudio];
        
        NSLog(@"erroraudio:%@%d",erroraudio,ba);
        NSError *errorVideo = nil;
        AVAssetTrack *assetVideoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo]firstObject];
        BOOL bl = [videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, asset.duration)
                                      ofTrack:assetVideoTrack
                                       atTime:totalDuration
                                        error:&errorVideo];
        
        NSLog(@"errorVideo:%@%d",errorVideo,bl);
        totalDuration = CMTimeAdd(totalDuration, asset.duration);
    }
    NSLog(@"%@",NSHomeDirectory());
    
    CGSize videoSize = [videoTrack naturalSize];
    
    AVMutableVideoComposition* videoComp = [AVMutableVideoComposition videoComposition];
    videoComp.renderSize = videoSize;
    videoComp.frameDuration = CMTimeMake(1, 30);
    
    AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
    instruction.timeRange = CMTimeRangeMake(kCMTimeZero, [mixComposition duration]);
    AVAssetTrack *mixVideoTrack = [[mixComposition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    AVMutableVideoCompositionLayerInstruction *layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:mixVideoTrack];
    instruction.layerInstructions = [NSArray arrayWithObject:layerInstruction];
    videoComp.instructions = [NSArray arrayWithObject: instruction];
    
    NSURL *mergeFileURL = [NSURL fileURLWithPath:outpath];
    
    //视频导出工具
#pragma mark 录制分辨率设置
    AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetMediumQuality];
    exporter.videoComposition = videoComp;
    
    exporter.outputURL = mergeFileURL;
    exporter.outputFileType = AVFileTypeMPEG4;
    exporter.shouldOptimizeForNetworkUse = YES;
    __weak typeof(self) weak_self = self;
    [exporter exportAsynchronouslyWithCompletionHandler:^{
        dispatch_async(dispatch_get_main_queue(), ^{
            [YHToastHUD showToast:@"处理完毕...." completion:^{
                [weak_self dismissViewControllerAnimated:YES completion:nil];
            }];
        });
    }];
}

示例代码调试文件查看：

视频录制文件保存到了document目录下面了，这个目录会被iTunes同步，所以可以使用iTunes把视频保存目录Video给直接导出（拖出即可），或者直接Window->Devices and Simulators 找到相应设备及app导出沙盒里面的内容查看。


test.mp4为最终合成文件。

示例代码：https://github.com/huizai0705/VideoRecorder_iOS