问题描述
请耐心听，因为我对音频编解码器的了解有限.我有一个来自IPCAM的音频源(通过htto//... CGI接口).我正在尝试编写一些客户端程序来在Windows，MAC和Android手机上播放此音频源.音频以G711(PCM ulaw)编码.
Please bear with me as my understanding of audio codec is limited.I have this audio source from a IPCAM (through a htto//... CGI interface).I am trying to write several client programs to play this audio source on Windows, MAC, as well as Android phone. The audio is encoded in G711 (PCM ulaw).
在将PCM音频数据传递到音频引擎进行播放之前，是否需要将PCM音频数据解码为原始音频数据?如果是这样，是否有一些有关如何解码的示例代码?我感到困惑，因为我以某种方式认为PCM已经是RAW.例如，我可以直接将其直接馈送到Android上的音频引擎吗?
Do I need to decode the PCM audio data to a raw audio data before I could pass it to the audio engine to play? If so, is there some sample code on how to decode it?I am confused as somehow I believe PCM is already RAW. Could I just feed it directly to the audio engine on Android for example?
非常感谢
推荐答案
这取决于您用来播放声音的API，但是大多数需要线性PCM并且您具有µ-law PCM，因此除非您的API支持µ-law回放时，您需要将µ-law采样值转换为线性值.
It depends on what API you are using to play sound, but most require linear PCM and you have µ-law PCM, so unless your API supports µ-law playback you will need to convert the µ-law sample values to linear.
对于G.711，压缩后的µ-law样本为8位，它们将转换为14位线性值，您将以每个样本2个字节的形式将其存储在缓冲区中. G.711 Wikipedia页面.
With G.711 the compressed µ-law samples are 8 bits and these will be converted to 14 bit linear values which you will store in a buffer as 2 bytes per sample. There is a brief description of the µ-law encoding on the G.711 Wikipedia page.
这篇关于解码G711(PCM u-law)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！