kAudioFormat为.AIF音频文件转换？ [英] kAudioFormat for .aif audio file conversion?

问题描述

我想转换/ AAC从格式保存音频文件AIFF音频格式。默认我和LineraPCM尝试。 。但音频格式保存在AAC格式。 。我想保存在AIFF format.Here是我的code中的音频文件。

 的NSDictionary * outputSettings = [NSDictionary的dictionaryWithObjectsAndKeys：
                                  [NSNumber的numberWithInt：kAudioFormatLinearPCM]，AVFormatIDKey，
                                  [NSNumber的numberWithFloat：44100.0]，AVSampleRateKey，
                                  [的NSNumber numberWithInt：2]，AVNumberOfChannelsKey，
                                  [NSData的dataWithBytes：放大器; channelLayout长度：的sizeof（AudioChannelLayout），AVChannelLayoutKey，
                                  [的NSNumber numberWithInt：16]，AVLinearPCMBitDepthKey，
                                  [NSNumber的numberWithBool：NO]，AVLinearPCMIsNonInterleaved，
                                  [NSNumber的numberWithBool：NO]，AVLinearPCMIsFloatKey，
                                  [NSNumber的numberWithBool：NO]，AVLinearPCMIsBigEndianKey，
                                  零];
 

任何人都可以请咨询对kAudioFormat或音频设置使用AVAssetWriterInput将其保存在AIFF音频格式写入文件？

解决方案

我的避风港'与AVAssetWriter工作至今

，但我认为它基本上是一个格式描述为核心音频与ASBDs。

有关AIFF定义的AudioBasicStreamDescription的例子看，例如在这里：

  aiffFormat.mSampleRate =采样率;
aiffFormat.mFormatID = kAudioFormatLinearPCM;
aiffFormat.mBytesPerPacket = 2;
aiffFormat.mFramesPerPacket = 1;
aiffFormat.mBytesPerFrame = 2;
aiffFormat.mChannelsPerFrame = 2; //为STEREO
aiffFormat.mBitsPerChannel = 16;
aiffFormat.mFormatFlags =（kLinearPCMFormatFlagIsBigEndian | kAudioFormatFlagIsPacked | kLinearPCMFormatFlagIsSignedInteger）;
aiffFormat.mBitsPerChannel = sizeof的（浮点）* 8;
aiffFormat.mBytesPerFrame = aiffFormat.mChannelsPerFrame * sizeof运算（浮点32）;
aiffFormat.mBytesPerPacket = aiffFormat.mFramesPerPacket * aiffFormat.mBytesPerFrame;
 

在您的上述code大字节顺序已被设置为YES。正如前面提到的我从来没有与AVAssetWriter工作，所以我不知道这进一步参数进行设置或没有，但上面的例子流描述，应该不是太难获得运行。

I would like to convert/save audio file to AIFF audio format from AAC format. Default i'm trying with LineraPCM . . But the audio format saving in AAC format. . I would like to save the audio file in AIFF format.Here's my code

NSDictionary *outputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                  [NSNumber numberWithInt:kAudioFormatLinearPCM], AVFormatIDKey, 
                                  [NSNumber numberWithFloat:44100.0], AVSampleRateKey,
                                  [NSNumber numberWithInt:2], AVNumberOfChannelsKey,
                                  [NSData dataWithBytes:&channelLayout length:sizeof(AudioChannelLayout)], AVChannelLayoutKey,
                                  [NSNumber numberWithInt:16], AVLinearPCMBitDepthKey,
                                  [NSNumber numberWithBool:NO], AVLinearPCMIsNonInterleaved,
                                  [NSNumber numberWithBool:NO],AVLinearPCMIsFloatKey,
                                  [NSNumber numberWithBool:NO], AVLinearPCMIsBigEndianKey,
                                  nil];

Can anyone please advice on the kAudioFormat or audio settings to write the file using AVAssetWriterInput to save it in AIFF audio format ?

解决方案

I haven' worked with AVAssetWriter so far, but I assume its basically a format description as in Core Audio with ASBDs.

An example of a AudioBasicStreamDescription defined for AIFF see for example here:

aiffFormat.mSampleRate = sampleRate;
aiffFormat.mFormatID = kAudioFormatLinearPCM;
aiffFormat.mBytesPerPacket = 2;
aiffFormat.mFramesPerPacket = 1;
aiffFormat.mBytesPerFrame = 2;
aiffFormat.mChannelsPerFrame = 2; // for STEREO
aiffFormat.mBitsPerChannel = 16;
aiffFormat.mFormatFlags = (kLinearPCMFormatFlagIsBigEndian | kAudioFormatFlagIsPacked | kLinearPCMFormatFlagIsSignedInteger) ;
aiffFormat.mBitsPerChannel = sizeof(float) * 8;
aiffFormat.mBytesPerFrame = aiffFormat.mChannelsPerFrame * sizeof(Float32);
aiffFormat.mBytesPerPacket = aiffFormat.mFramesPerPacket * aiffFormat.mBytesPerFrame;

In your above code big endianess has to be set to YES. As mentioned I have never worked with AVAssetWriter, so I am not sure which further parameters have to be set or which not, but with the example stream description above, it should be not too hard to get running.

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