最近有個需求:把屏幕內(nèi)容錄制下來保持到本地
這里ReplayKit不做介紹，想了解請看下面的鏈接
iOS端使用replaykit錄制屏幕的技術(shù)細(xì)節(jié)
核心代碼（最后附demo）
請求同意使用攝像頭和麥克風(fēng)權(quán)限，如果用戶拒絕了，將無法進(jìn)行錄制。
不支持模擬器

{
    RPScreenRecorder *_recorder;
    NSURL *_movieUrl;
}

//    開始錄制
  [_recorder startRecordingWithHandler:^(NSError * _Nullable error) {
        NSLog(@"視頻錄制開啟產(chǎn)生問題=%@",error);
    }];

//    結(jié)束錄制
    [_recorder stopRecordingWithHandler:^(RPPreviewViewController * _Nullable previewViewController, NSError * _Nullable error) {
        self->_movieUrl = [previewViewController valueForKey:@"movieURL"];
        [self export:[_movieUrl path] complete:^(ScreenRecError error, NSString *filePath) {
        [self writeVideoToAlbum:filePath];
    }];
    }];

//導(dǎo)出視頻 mp4
- (void)export:(NSString *)filePathUrl complete:(void(^)(ScreenRecError error,NSString* filePath))complete {
    if (!filePathUrl) {
        NSLog(@"filePathUrl為空");
        return;
    }
    NSDate *date = [NSDate date];
    NSString *exportPath = [NSString stringWithFormat:@"%@%d.mp4",[self getCacheDir],(int)[date timeIntervalSince1970]*1000 ];
    NSURL *fileUrl = [NSURL fileURLWithPath:filePathUrl];
    AVAsset *fileAsset = [AVURLAsset assetWithURL:fileUrl];
    AVMutableComposition *mixComposition = [AVMutableComposition composition];
    if (!([fileAsset tracksWithMediaType:AVMediaTypeVideo].count>0 && [fileAsset tracksWithMediaType:AVMediaTypeAudio].count>0)) {
        complete(exportError,filePathUrl);
        return;
    }
    for (AVAssetTrack *track in fileAsset.tracks) {
        if ([track.mediaType isEqual:AVMediaTypeVideo]) {
            AVMutableCompositionTrack *compositionTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
            NSError *error;
            [compositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, fileAsset.duration) ofTrack:track atTime:kCMTimeZero error:&error];
        }
        else if([track.mediaType isEqual:AVMediaTypeAudio]){
            AVMutableCompositionTrack *compositionTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
            NSError *error;
            [compositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, fileAsset.duration) ofTrack:track atTime:kCMTimeZero error:&error];
        }
    }
    AVAssetExportSession *assetExport = [AVAssetExportSession exportSessionWithAsset:mixComposition presetName:AVAssetExportPreset1280x720];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if ([fileManager fileExistsAtPath:exportPath]) {
        NSError *error = nil;
        [fileManager removeItemAtPath:exportPath error:&error];
        if (error) {
            NSLog(@"移除文件出錯=%@",error);
        }
    }
    
    assetExport.outputFileType = AVFileTypeMPEG4;
    assetExport.outputURL = [NSURL fileURLWithPath:exportPath];
    assetExport.shouldOptimizeForNetworkUse = false;
    
    [assetExport exportAsynchronouslyWithCompletionHandler:^{
        if (assetExport.status == AVAssetExportSessionStatusCompleted) {
            NSLog(@"Record SaveTmpVideo Success");
            complete(nil,exportPath);
        }
        else {
            complete(exportError,filePathUrl);
        }
    }];
    
}

//保存圖片到相冊
- (void)writeVideoToAlbum:(NSString *)exportFilePath{
    
    UISaveVideoAtPathToSavedPhotosAlbum(exportFilePath, self, @selector(video:didFinishSavingWithError:contextInfo:), nil);
}

//保存視頻完成之后的回調(diào)
- (void)video:(NSString *)videoPath didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
    if (error) {
        NSLog(@"保存視頻失敗%@", error.localizedDescription);
    }
    else {
        NSLog(@"保存視頻成功"); 
    }
}

demo地址