iOS 音视频分离（导出视频中的音频）

分离出视频中的音频（目前仅支持本地视频文件）

/**
*  获取视频中的音频
*
*  @param videoUrl 视频的本地路径
*  @param newFile 导出音频的路径
*  @completionHandle 音频路径的回调
*/
- (void)videoManagerGetBackgroundMiusicWithVideoUrl:(NSURL *)videoUrl newFile:(NSString*)newFile completion:(void(^)(NSString*data))completionHandle{
    
    AVURLAsset *videoAsset = [[AVURLAsset alloc] initWithURL:videoUrl options:nil];;
    NSArray *keys = @[@"duration",@"tracks"];
    [videoAsset loadValuesAsynchronouslyForKeys:keys completionHandler:^{
        NSError *error = nil;
        AVKeyValueStatus status = [videoAsset statusOfValueForKey:@"tracks" error:&error];
        if(status == AVKeyValueStatusLoaded) {//数据加载完成
            AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];
            // 2 - Video track
            //Audio Recorder
            //创建一个轨道,类型是AVMediaTypeAudio
            AVMutableCompositionTrack *firstTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
            //获取videoAsset中的音频,插入轨道
            [firstTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];
            NSURL *url = [NSURL fileURLWithPath:newFile];
            AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetAppleM4A];//输出为M4A音频
            exporter.outputURL = url;
            exporter.outputFileType = @"com.apple.m4a-audio";//类型和输出类型一致
            exporter.shouldOptimizeForNetworkUse = YES;
            [exporter exportAsynchronouslyWithCompletionHandler:^{
                dispatch_async(dispatch_get_main_queue(), ^{
                    if (exporter.status == AVAssetExportSessionStatusCompleted) {
                        completionHandle(newFile);
                    }else{
                        NSLog(@"提取失败原因：%@",exporter.error);
                        completionHandle(nil);
                    }
                });
            }];
        }
    }];

}

提取音频，获取播放时长，获取视频第一帧图片请到
Demo分享 https://github.com/LXHugh/AVSeparation