如何填充 AudioStreamBasicDescription 以进行 AMR 播放

发布于 2024-09-02 20:51:03 字数 1032 浏览 5 评论 0原文

源数据是 AMR-NB 5.9kbit/s (AMR_5.90)

我已经尝试了以下设置（和十几个变体），但我得到的只是垃圾音频。有谁知道 AMR 的正确设置吗？

 AudioStreamBasicDescription asbd;
 asbd.mSampleRate = 8000.0;
 asbd.mFormatID = kAudioFormatAMR;
 asbd.mFormatFlags = 0;
 asbd.mBytesPerPacket = 15;  // (118>>3)
 asbd.mFramesPerPacket = 1;
 asbd.mBytesPerFrame = 15;
 asbd.mChannelsPerFrame = 1;
 asbd.mBitsPerChannel = 118;  //tried also 0 and 13
 asbd.mReserved = 0;

基于 AMR 维基百科的信息：

采样频率 8 kHz/13 位（20 ms 帧 160 个样本）

生成长度为 95、103、118、134、148、159、204 或 244 位的帧，比特率为 4.75，分别为 5.15、5.90、6.70、7.40、7.95、10.2 或 12.2 kbit/s

数据结构描述来自此处：

http://developer.apple.com/iphone/library/documentation/MusicAudio/Reference/CoreAudioDataTypesRef/Reference /reference.html#//apple_ref/doc/c_ref/AudioStreamBasicDescription

原文

source data is AMR-NB 5.9kbit/s (AMR_5.90)

I've tried the below settings (and a dozen variations) but I'm getting nothing more than garbage audio. Does anyone know the correct settings for AMR?

 AudioStreamBasicDescription asbd;
 asbd.mSampleRate = 8000.0;
 asbd.mFormatID = kAudioFormatAMR;
 asbd.mFormatFlags = 0;
 asbd.mBytesPerPacket = 15;  // (118>>3)
 asbd.mFramesPerPacket = 1;
 asbd.mBytesPerFrame = 15;
 asbd.mChannelsPerFrame = 1;
 asbd.mBitsPerChannel = 118;  //tried also 0 and 13
 asbd.mReserved = 0;

Based on info from wikipedia for AMR:

Sampling frequency 8 kHz/13-bit (160 samples for 20 ms frames)

Generates frame length of 95, 103, 118, 134, 148, 159, 204, or 244 bits for bit rates 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.2, or 12.2 kbit/s, respectively

And the data structure description from here:

http://developer.apple.com/iphone/library/documentation/MusicAudio/Reference/CoreAudioDataTypesRef/Reference/reference.html#//apple_ref/doc/c_ref/AudioStreamBasicDescription

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