// 创建 TXVideoJoiner。TXPreviewParam为nil 表示这里不需要预览
TXVideoJoiner* _videoJoin = [[TXVideoJoiner alloc] initWithPreview:nil];

// 设置待拼接的视频文件组 _composeArray
[_videoJoin setVideoPathList:_composeArray];

// 设置回调，监听合并进度和合并完成事件
_videoJoin.joinerDelegate = self;

// 开始合并
[_videoJoin joinVideo:VIDEO_COMPRESSED_540P videoOutputPath:_outFilePath]

//准备预览 View
TXPreviewParam *param = [[TXPreviewParam alloc] init];
param.videoView = _videoPreview.renderView;
param.renderMode = PREVIEW_RENDER_MODE_FILL_EDGE;

// 创建 TXVideoJoiner 对象并设置预览 view
TXVideoJoiner* _videoJoin = [[TXVideoJoiner alloc] initWithPreview:param];
_videoJoin.previewDelegate = _videoPreview;

// 设置待拼接的视频文件组 _composeArray
[_videoJoin setVideoPathList:_composeArray];

// 开始预览
[_videoJoin startPlay]

TXVideoJoiner* _videoJoin = [[TXVideoJoiner alloc] initWithPreview:nil];

[_videoJoin setVideoPathList:_composeArray];

_videoJoin.joinerDelegate = self;

// 设置合演画面参数
TXSplitScreenParams* splitScreenParams = [[TXSplitScreenParams alloc] init];
splitScreenParams.canvasWidth = 720 * 2; // 合演时的画面宽度
splitScreenParams.canvasHeight = 1280;   // 合演时画面的高度
// 每个视频在画面中的位置和大小
splitScreenParams.rects = @[[NSValue valueWithCGRect:CGRectMake(0, 0, splitScreenParams.canvasWidth / 2, 
                                                                 splitScreenParams.canvasHeight)],
                            [NSValue valueWithCGRect:CGRectMake(splitScreenParams.canvasWidth / 2, 0, 
                                      splitScreenParams.canvasWidth / 2, splitScreenParams.canvasHeight)]];

splitScreenParams.durationMode = ALIGNS_TO_LONGEST; // // 指定合演视频的长度跟最长的视频一致
[_videoJoiner setSplitScreenList:splitScreenParams];

// 设置合演时，每个视频音频混合时的比重
[_videoJoiner setVideoVolumes:@[@0, @1]];

[_videoJoin joinVideo:VIDEO_COMPRESSED_540P videoOutputPath:_outFilePath]