如何在iOS中连接2或3个音频文件？

Question

我是Objective-C的新手,在iPhone开发方面只有5个月的经验.

我需要的是:
我需要将两个或多个音频文件连接成一个,并将结果导出为aiff,mp3,caf或m4a格式.

例如:
第一个音频文件包含"您需要",第二个"下载"和第三个"文档".
每个音频部分都取决于用户的操作.

我花了2天没运气.那个地方是我的最后一个边疆.

我将非常感谢您提供一段代码.

Answer 1

下面的代码可用于合并音频文件.

输入文件:要在数组audioIds中提供的文件的ID.例如.audio1.mp3,audio2.mp3 ... audioN.mp3在文件夹中可用输出文件:combined.m4a

     - (BOOL) combineVoices {

       NSError *error = nil;
       BOOL ok = NO;


         NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,    NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0]; 


       CMTime nextClipStartTime = kCMTimeZero;
        //Create AVMutableComposition Object.This object will hold our multiple AVMutableCompositionTrack.
        AVMutableComposition *composition = [[AVMutableComposition alloc] init];

     AVMutableCompositionTrack *compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

     for (int i = 0; i< [self.audioIds count]; i++) {
        int key = [[self.audioIds objectAtIndex:i] intValue];
        NSString *audioFileName = [NSString stringWithFormat:@"audio%d", key];

        //Build the filename with path
        NSString *soundOne = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.mp3", audioFileName]];
        //NSLog(@"voice file - %@",soundOne);

        NSURL *url = [NSURL fileURLWithPath:soundOne];    
        AVAsset *avAsset = [AVURLAsset URLAssetWithURL:url options:nil];
        NSArray *tracks = [avAsset tracksWithMediaType:AVMediaTypeAudio];
        if ([tracks count] == 0) 
            return NO;
        CMTimeRange timeRangeInAsset = CMTimeRangeMake(kCMTimeZero, [avAsset duration]);
        AVAssetTrack *clipAudioTrack = [[avAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
        ok = [compositionAudioTrack insertTimeRange:timeRangeInAsset  ofTrack:clipAudioTrack atTime:nextClipStartTime error:&error];
        if (!ok) {
            NSLog(@"Current Video Track Error: %@",error);
        }
        nextClipStartTime = CMTimeAdd(nextClipStartTime, timeRangeInAsset.duration);
    }

    // create the export session
    // no need for a retain here, the session will be retained by the
    // completion handler since it is referenced there
    AVAssetExportSession *exportSession = [AVAssetExportSession
                                           exportSessionWithAsset:composition
                                           presetName:AVAssetExportPresetAppleM4A];
    if (nil == exportSession) return NO;

    NSString *soundOneNew = [documentsDirectory stringByAppendingPathComponent:@"combined.m4a"];
    //NSLog(@"Output file path - %@",soundOneNew);

    // configure export session  output with all our parameters
    exportSession.outputURL = [NSURL fileURLWithPath:soundOneNew]; // output path
    exportSession.outputFileType = AVFileTypeAppleM4A; // output file type

    // perform the export
    [exportSession exportAsynchronouslyWithCompletionHandler:^{

        if (AVAssetExportSessionStatusCompleted == exportSession.status) {
            NSLog(@"AVAssetExportSessionStatusCompleted");
        } else if (AVAssetExportSessionStatusFailed == exportSession.status) {
            // a failure may happen because of an event out of your control
            // for example, an interruption like a phone call comming in
            // make sure and handle this case appropriately
            NSLog(@"AVAssetExportSessionStatusFailed");
        } else {
            NSLog(@"Export Session Status: %d", exportSession.status);
        }
    }];

    return YES;
}

Answer 2

我有一个想法，不确定是否可行。尝试从这3个文件中获取NSData，将数据附加到另一个NSData中，然后写入。就像是：

NSMutableData *concatenatedData = [NSMutableData alloc] init];
NSData *data1 = [[NSData alloc] initWithContentsOfFile:(NSString *)path];
NSData *data2 = [[NSData alloc] initWithContentsOfFile:(NSString *)path];
NSData *data3 = [[NSData alloc] initWithContentsOfFile:(NSString *)path];
[concatenatedData appendData: data1];
[concatenatedData appendData: data2];
[concatenatedData appendData: data3];
[concatenatedData writeToFile:@"/path/to/concatenatedData.mp3" atomically:YES];

这是一个理论，我不确定它会起作用:)，如果我用十六进制编辑器打开一个 mp3，它实际上会起作用 - 复制所有内容并将其粘贴到最后 - 然后我有两次相同的声音。请尝试一下并告诉我们是否有效。