AVAudioRecorder/AVAudioPlayer - 将录音附加到文件

Question

有没有办法录制到音频文件的末尾？我们不能暂停录制而不是停止录制,因为用户需要以后能够返回应用并为录制添加更多音频.目前,音频作为NSData存储在CoreData中.NSData AppendData不起作用,因为生成的音频文件仍然报告它只与原始数据一样长.

另一种可能性是将原始音频文件与新音频文件连接起来,并将它们连接成一个音频文件,如果有任何方法可以做到这一点.

Answer 1

这可以很容易地使用AVMutableComposionTrack insertTimeRange:ofTrack:atTime:error.代码有点冗长,但它实际上就像4个步骤:

// Create a new audio track we can append to
AVMutableComposition* composition = [AVMutableComposition composition];
AVMutableCompositionTrack* appendedAudioTrack = 
    [composition addMutableTrackWithMediaType:AVMediaTypeAudio
                             preferredTrackID:kCMPersistentTrackID_Invalid];

// Grab the two audio tracks that need to be appended
AVURLAsset* originalAsset = [[AVURLAsset alloc]
    initWithURL:[NSURL fileURLWithPath:originalAudioPath] options:nil];
AVURLAsset* newAsset = [[AVURLAsset alloc] 
    initWithURL:[NSURL fileURLWithPath:newAudioPath] options:nil];

NSError* error = nil;

// Grab the first audio track and insert it into our appendedAudioTrack 
AVAssetTrack *originalTrack = [originalAsset tracksWithMediaType:AVMediaTypeAudio];
CMTimeRange timeRange = CMTimeRangeMake(kCMTimeZero, originalAsset.duration);
[appendedAudioTrack insertTimeRange:timeRange 
                            ofTrack:[originalTrack objectAtIndex:0]
                             atTime:kCMTimeZero
                              error:&error];
if (error)
{
    // do something
    return;
}

// Grab the second audio track and insert it at the end of the first one
AVAssetTrack *newTrack = [newAsset tracksWithMediaType:AVMediaTypeAudio]; 
timeRange = CMTimeRangeMake(kCMTimeZero, newAsset.duration);   
[appendedAudioTrack insertTimeRange:timeRange
                            ofTrack:[newTrack objectAtIndex:0]
                             atTime:originalAsset.duration
                              error:&error];

if (error)
{
    // do something
    return;
}

// Create a new audio file using the appendedAudioTrack      
AVAssetExportSession* exportSession = [AVAssetExportSession
                                       exportSessionWithAsset:composition
                                       presetName:AVAssetExportPresetAppleM4A];
if (!exportSession)
{
    // do something
    return;
}


NSString* appendedAudioPath= @""; // make sure to fill this value in    
exportSession.outputURL = [NSURL fileURLWithPath:appendedAudioPath];
exportSession.outputFileType = AVFileTypeAppleM4A; 
[exportSession exportAsynchronouslyWithCompletionHandler:^{

    // exported successfully?
    switch (exportSession.status)
    {
        case AVAssetExportSessionStatusFailed:
            break;
        case AVAssetExportSessionStatusCompleted:
            // you should now have the appended audio file
            break;
        case AVAssetExportSessionStatusWaiting:
            break;
        default:
            break;
    }
    NSError* error = nil;

}];

Answer 2

我没有完整的代码示例，但扩展音频文件服务可以帮助您连接两个音频文件。在 Xcode 中搜索扩展音频文件服务或访问下面的链接。

苹果文档