/**
音视频合成

@param assetURL 原始视频路径
@param BGMPath 背景音乐路径
@param needOriginalVoice 是否添加原视频的声音
@param videoVolume 视频音量
@param BGMVolume 背景音乐音量
@param completionHandle 合成后的回调
*/

(void)editVideoSynthesizeVieoPath:(NSURL *)assetURL BGMPath:(NSURL *)BGMPath needOriginalVoice:(BOOL)needOriginalVoice videoVolume:(CGFloat)videoVolume BGMVolume:(CGFloat)BGMVolume complition:(void (^)(NSURL *outputPath,BOOL isSucceed)) completionHandle{
// 素材
AVAsset *asset = [AVAsset assetWithURL:assetURL];
AVAsset *audioAsset = [AVAsset assetWithURL:BGMPath];

// 分离素材
AVAssetTrack *videoAssetTrack = [[asset tracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0];//视频素材
AVAssetTrack *audioAssetTrack = [[audioAsset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];//音频素材

// 编辑视频环境
AVMutableComposition *composition = [[AVMutableComposition alloc]init];

// 视频素材加入视频轨道
AVMutableCompositionTrack *videoCompositionTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
[videoCompositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAssetTrack.timeRange.duration) ofTrack:videoAssetTrack atTime:kCMTimeZero error:nil];

// 音频素材加入音频轨道
AVMutableCompositionTrack *audioCompositionTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[audioCompositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAssetTrack.timeRange.duration) ofTrack:audioAssetTrack atTime:kCMTimeZero error:nil];

// 是否加入视频原声
AVMutableCompositionTrack *originalAudioCompositionTrack = nil;
if (needOriginalVoice) {
AVAssetTrack *originalAudioAssetTrack = [[asset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];
originalAudioCompositionTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[originalAudioCompositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAssetTrack.timeRange.duration) ofTrack:originalAudioAssetTrack atTime:kCMTimeZero error:nil];
}

// 导出素材
AVAssetExportSession *exporter = [[AVAssetExportSession alloc]initWithAsset:composition presetName:AVAssetExportPresetMediumQuality];

// 音量控制
exporter.audioMix = [self buildAudioMixWithVideoTrack:originalAudioCompositionTrack VideoVolume:videoVolume BGMTrack:audioCompositionTrack BGMVolume:BGMVolume controlVolumeRange:kCMTimeZero];

// 设置输出路径
NSURL *outputPath = [self exporterPath];
exporter.outputURL = [self exporterPath];
exporter.outputFileType = AVFileTypeMPEG4;//指定输出格式

[exporter exportAsynchronouslyWithCompletionHandler:^{
    switch ([exporter status]) {
        case AVAssetExportSessionStatusFailed: {
            NSLog(@"合成失败：%@",[[exporter error] description]);
            completionHandle(outputPath,NO);
        } break;
        case AVAssetExportSessionStatusCancelled: {
            completionHandle(outputPath,NO);
        } break;
        case AVAssetExportSessionStatusCompleted: {
            completionHandle(outputPath,YES);
        } break;
        default: {
            completionHandle(outputPath,NO);
        } break;
    }
}];
}