Question

我想接受两个mp3文件。这两个mp3文件应该存储在同一个m4a文件中（覆盖？），当播放特定的m4a文件时，两个mp3应该同时播放。

我想播放m4a歌曲并确定UIButton动作中m4a歌曲的路径。 UIButton行动的代码已在下面给出。

我已经使用两个不同的AVAudioPlayer来接受两个mp3并使用一个变量（* audioFileOutput）来存储目标m4a文件。

我在.m文件中导入了两个库：

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h> 

-(IBAction)playTheSong
{    
    // Path of your source audio file
    NSString *strInputFilePath1 = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"saewill.mp3"];
    NSString *strInputFilePath2 = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"kick.mp3"];
    NSURL *audioFileInput1 = [NSURL fileURLWithPath:strInputFilePath1];
    NSURL *audioFileInput2 = [NSURL fileURLWithPath:strInputFilePath2];

    // Path of your destination save audio file
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
    NSString *libraryCachesDirectory = [paths objectAtIndex:0];

    NSString *strOutputFilePath = [libraryCachesDirectory stringByAppendingPathComponent:@"output.mov"];
    NSString *requiredOutputPath = [libraryCachesDirectory stringByAppendingPathComponent:@"output.m4a"];
    NSURL *audioFileOutput = [NSURL fileURLWithPath:requiredOutputPath];

    [[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
    AVAsset *asset1 = [AVAsset assetWithURL:audioFileInput1];
    AVAsset *asset2 = [AVAsset assetWithURL:audioFileInput2];

    AVAssetExportSession *exportSession1 = [AVAssetExportSession exportSessionWithAsset:asset1
                                                                            presetName:AVAssetExportPresetAppleM4A];
    AVAssetExportSession *exportSession2 = [AVAssetExportSession exportSessionWithAsset:asset2
                                                                            presetName:AVAssetExportPresetAppleM4A];

    //two store two diifrent mp3 in same variable        

    exportSession1.outputURL = audioFileOutput;
    exportSession1.outputFileType = AVFileTypeAppleM4A;
    exportSession2.outputURL = audioFileOutput;
    exportSession2.outputFileType = AVFileTypeAppleM4A;

    //initialised AVAudioplayer for 1st mp3.       
    [exportSession1 exportAsynchronouslyWithCompletionHandler:^
     {
         if (exportSession1.status == AVAssetExportSessionStatusCompleted)
         {
             NSLog(@"Success!");
             NSLog(@" OUtput path is \n %@", requiredOutputPath);
             NSFileManager * fm = [[NSFileManager alloc] init];
             [fm moveItemAtPath:strOutputFilePath toPath:requiredOutputPath error:nil];


             NSURL *url=[NSURL fileURLWithPath:requiredOutputPath];
             NSError *error;
             audioPlayer1=[[AVAudioPlayer alloc]initWithContentsOfURL:url error:&error];
             audioPlayer1.numberOfLoops=0;
             [audioPlayer1 setVolume:0.75];
             [audioPlayer1 play];


         }
         else if (AVAssetExportSessionStatusFailed == exportSession1.status)
         {
             NSLog(@"failed %@", exportSession1.error.localizedDescription);
         }
     }];

    //initialised AVAudioplayer for 2nd mp3.         

    [exportSession2 exportAsynchronouslyWithCompletionHandler:^
     {
         if (exportSession2.status == AVAssetExportSessionStatusCompleted)
         {
             NSLog(@"Success!");
             NSLog(@" OUtput path is \n %@", requiredOutputPath);
             NSFileManager * fm = [[NSFileManager alloc] init];
             [fm moveItemAtPath:strOutputFilePath toPath:requiredOutputPath error:nil];


             NSURL *url=[NSURL fileURLWithPath:requiredOutputPath];
             NSError *error;
             audioPlayer2=[[AVAudioPlayer alloc]initWithContentsOfURL:url error:&error];
             audioPlayer2.numberOfLoops=0;
             [audioPlayer2 setVolume:0.75];
             [audioPlayer2 play];


         }
         else if (AVAssetExportSessionStatusFailed == exportSession2.status)
         {
             NSLog(@"failed %@", exportSession2.error.localizedDescription);
         }
     }];        
}

Answer 1

不要自己做，让一些iOS音频库帮助您实现它，这里有两个不错的选择：

EZAudio TheAmazingAudioEngine

编辑：

在Apple的医生：

同时播放多个声音

要同时播放多个声音，请为每个声音创建一个播放音频队列对象。对于每个音频队列，使用AudioQueueEnqueueBufferWithParameters函数安排第一个音频缓冲区同时启动。

您应该使用audio queue

执行此操作

另外我认为还有第二种选择：每次调用AVPlayer之前，将两个音频文件混合到一个临时的单个音频文件中。

Answer 2

我已经解决了我的问题。

as i am new to the ios development so it took much time to obtain the desired result. thanks for your suggestions. 
and here is what i did.



-(void)mixAudio{



CFAbsoluteTime currentTime=CFAbsoluteTimeGetCurrent();
AVMutableComposition *composition = [[AVMutableComposition alloc] init];

AVMutableCompositionTrack *compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[compositionAudioTrack setPreferredVolume:0.8];
NSString *soundOne  =[[NSBundle mainBundle]pathForResource:@"Kick 1" ofType:@"mp3"];
NSURL *url = [NSURL fileURLWithPath:soundOne];
AVAsset *avAsset = [AVURLAsset URLAssetWithURL:url options:nil];
NSArray *tracks = [avAsset tracksWithMediaType:AVMediaTypeAudio];
AVAssetTrack *clipAudioTrack = [tracks objectAtIndex:0];
[compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, avAsset.duration) ofTrack:clipAudioTrack atTime:kCMTimeZero error:nil];

AVMutableCompositionTrack *compositionAudioTrack1 = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[compositionAudioTrack setPreferredVolume:0.8];
NSString *soundOne1  =[[NSBundle mainBundle]pathForResource:@"Kick 2" ofType:@"mp3"];
NSURL *url1 = [NSURL fileURLWithPath:soundOne1];
AVAsset *avAsset1 = [AVURLAsset URLAssetWithURL:url1 options:nil];
NSArray *tracks1 = [avAsset1 tracksWithMediaType:AVMediaTypeAudio];
AVAssetTrack *clipAudioTrack1 = [tracks1 objectAtIndex:0];
[compositionAudioTrack1 insertTimeRange:CMTimeRangeMake(kCMTimeZero, avAsset1.duration) ofTrack:clipAudioTrack1 atTime: kCMTimeZero error:nil];




NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *libraryCachesDirectory = [paths objectAtIndex:0];
NSString *strOutputFilePath = [libraryCachesDirectory stringByAppendingPathComponent:@"output.mov"];
NSString *requiredOutputPath = [libraryCachesDirectory stringByAppendingPathComponent:@"output.m4a"];
NSURL *audioFileOutput = [NSURL fileURLWithPath:requiredOutputPath];
[[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];



AVAssetExportSession *exporter=[[AVAssetExportSession alloc] initWithAsset:composition presetName:AVAssetExportPresetAppleM4A];
exporter.outputURL=audioFileOutput;
exporter.outputFileType=AVFileTypeAppleM4A;





[exporter exportAsynchronouslyWithCompletionHandler:^{


    NSLog(@" OUtput path is \n %@", requiredOutputPath);
    NSFileManager * fm = [[NSFileManager alloc] init];
    [fm moveItemAtPath:strOutputFilePath toPath:requiredOutputPath error:nil];

     NSLog(@" OUtput path is \n %@", requiredOutputPath);
    NSLog(@"export complete: %lf",CFAbsoluteTimeGetCurrent()-currentTime);
    NSError *error;
    audioPlayer=[[AVAudioPlayer alloc]initWithContentsOfURL:audioFileOutput error:&error];
    audioPlayer.numberOfLoops=0;
    [audioPlayer play];

}];

}

如何在iOS中的同一个m4a文件中存储两个不同的音频？

2 个答案: