android在NDK / SDK中是否有本地amr编码库？

Question

I've come across some 3rd party libraries like opencore-amr and others which allows for raw PCM data to be directly encoded into amr as byte arrays. However these are all software encoders written in C/C++ and borrows from many sources.

Is there a official Amr library for android bundled in NDK or SDK where you can convert PCM to amr byte by byte?

Answer 1

There is such a component within the system, that you can access via the MediaCodec API. You can access it via Java since Android 4.1 (which you need to call via JNI if you want to use it in native code) or directly as native API since Android 5.0. This internally basically is the same code as opencore-amr, but wrapped up as a generic decoder/encoder component.

Answer 2

是的， MediaCodec支持 AMR-NB和AMR-WB