我有一个应用程序，当选择音高按钮时会改变音频的音高，现在我使用installTapOnBus来保存文件，但这个方法在我按下音高按钮后被调用，因此只有部分保存音频，我想保存整个音频，无论何时选择音高按钮，有什么办法
此方法用于播放音频
-(void)playAudio
{
NSError *err = nil;
audioEngine = [[AVAudioEngine alloc] init];
AudioFileplayer = [[AVAudioPlayerNode alloc] init];
pitch = [[AVAudioUnitTimePitch alloc] init];
reverb = [[AVAudioUnitReverb alloc] init];
[audioEngine stop];
[AudioFileplayer stop];
[audioEngine reset];
file = [[AVAudioFile alloc] initForReading:[NSURL URLWithString:[self filePath]] error:&err];
[audioEngine attachNode:AudioFileplayer];
[audioEngine attachNode:pitch];
[audioEngine attachNode:reverb];
[audioEngine connect:AudioFileplayer to:reverb format:nil];
[audioEngine connect:reverb to:pitch format:nil];
[audioEngine connect:pitch to:audioEngine.outputNode format:nil];
[reverb loadFactoryPreset:AVAudioUnitReverbPresetLargeRoom2];
[AudioFileplayer scheduleFile:file atTime:nil completionHandler:^{
AudioFileplayer = nil;
}];
[audioEngine prepare];
[audioEngine startAndReturnError:&err];
if (err != nil) {
NSLog(@"An error occured");
}
[AudioFileplayer play];
}
此方法可以保存音调影响音频
-(void)saveEffectedAudioToFolder
{
NSError *error;
if (audioEngine) {
pitchEffect.pitch = 1000;
AVAudioFormat * commonFormat = [[AVAudioFormat alloc] initWithCommonFormat:AVAudioPCMFormatFloat32 sampleRate:44100 channels:2 interleaved:NO];
//
AVAudioFile *outputFile = [[AVAudioFile alloc] initForWriting:[NSURL URLWithString:[self filePath1]] settings:commonFormat.settings error:&error];
//
if (error) {
NSLog(@"Error is 1 %@",[error localizedDescription]);
}
[pitchEffect installTapOnBus:0 bufferSize:4096 format:commonFormat block:^(AVAudioPCMBuffer *buffer, AVAudioTime *when)
{
if (outputFile.length < file.length)
{//Let us know when to stop saving the file, otherwise saving infinitely
NSError *error;
NSAssert([outputFile writeFromBuffer:buffer error:&error], @"error writing buffer data to file, %@", [error localizedDescription]);
}else{
audioEngine = nil;
[pitchEffect removeTapOnBus:0];//if we dont remove it, will keep on tapping infinitely
}
}
];
}
}
任何解决方法都是有帮助的
答案 0 :(得分：3)
实际上我们在输出音频文件的设置中犯了错误。输出音频文件处理格式应与输入文件（放置效果或音高）相同。
输出文件格式应为wav或caf格式。此格式仅保存到输出音频文件。
- (IBAction)save_it_after_changes:(id)sender
{
engine = [[AVAudioEngine alloc] init];
audio_player_node= [[AVAudioPlayerNode alloc] init];
[engine attachNode:audio_player_node];
[self setupEQ];
AVAudioMixerNode *mixerNode = [engine mainMixerNode];
[engine connect:audio_player_node to:unitEq format:audioFile.processingFormat];
[engine connect:unitEq to:mixerNode format:audioFile.processingFormat];
NSError *error12;
[engine startAndReturnError:&error12];
if (!error12)
{
NSLog(@"Engine = %@",engine);
[audio_player_node scheduleFile:audioFile atTime:nil completionHandler:nil];
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];
[recordSetting setValue :[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];
[recordSetting setValue :[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];
NSError *error;
outputFile = [[AVAudioFile alloc] initForWriting:[self testFilePathURL] settings:recordSetting error:&error];
NSLog(@"outputfile = %@",outputFile);
if (error)
{
NSLog(@"outputFile error = %@",error);
}
else
{ //(AVAudioFrameCount)audioFile.length
[audio_player_node installTapOnBus:0 bufferSize:8192 format:audioFile.processingFormat block:^(AVAudioPCMBuffer *buffer, AVAudioTime *when) {
NSLog(@"Buffer Size = %@",buffer);
NSLog(@"when = %lld",when.sampleTime);
NSLog(@"outputfile length = %lli",outputFile.length);
NSLog(@"input file length = %lld",audioFile.length);
if (outputFile.length<audioFile.length)
{
NSError *error;
[outputFile writeFromBuffer:buffer error:&error];
if (error)
{
NSLog(@"writebuffererror =%@",error);
}
}
else
{
[audio_player_node removeTapOnBus:0];
NSError *error2;
// player2 = [[AVAudioPlayer alloc] initWithContentsOfURL:[self testFilePathURL] error:&error2];
//player2.delegate = self;
NSLog(@"Pathththt = %@",[self testFilePathURL]);
NSLog(@"error = %@",error2);
// [audio_player_node scheduleFile:outputFile atTime:nil completionHandler:nil];
//[audio_player_node play];
// [self toMp3];
}
}];
}
}
else
{
NSLog(@"error12 =%@",error12);
}
}
- (void)setupEQ
{
NSLog(@"setupEQ");
unitEq = [[AVAudioUnitEQ alloc] initWithNumberOfBands:12];
unitEq.globalGain = 3.0;
AVAudioUnitEQFilterParameters *filterParameters;
filterParameters = unitEq.bands[0];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 31;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[1];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 63;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[2];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 125;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[3];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 250;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[4];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 500;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[5];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 1000;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[6];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 2000;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[7];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 4000;
filterParameters.bandwidth = 1.0;
filterParameters.gain =-20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[8];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 8000;
filterParameters.bandwidth = 1.0;
filterParameters.gain = -20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[9];
filterParameters.filterType = AVAudioUnitEQFilterTypeParametric;
filterParameters.frequency = 16000;
filterParameters.bandwidth = 1.0;
filterParameters.gain =-20;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[10];
filterParameters.filterType = AVAudioUnitEQFilterTypeLowPass;
filterParameters.frequency = 16857;
filterParameters.bypass = FALSE;
filterParameters = unitEq.bands[11];
filterParameters.filterType = AVAudioUnitEQFilterTypeHighPass;
filterParameters.frequency = 205;
filterParameters.bypass = FALSE;
[engine attachNode:unitEq];
}
- (NSString *)applicationDocumentsDirectory
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *basePath = ([paths count] > 0) ? [paths objectAtIndex:0] : nil;
return basePath;
}
//------------------------------------------------------------------------------
- (NSURL *)testFilePathURL
{
return [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@/test.caf",
[self applicationDocumentsDirectory]]];
}
成功保存后请播放该文件。这个对我有用。看看吧。
请参阅以下链接，我从这里获得更多信息，Can I use AVAudioEngine to read from a file, process with an audio unit and write to a file, faster than real-time?
参考此示例项目。这是我们正在寻找的 https://github.com/VladimirKravchenko/AVAudioEngineOfflineRender