Android Audio 之OMX &&Codec2

Google在Android Q 引入Codec 2.0 ，与MediaCodec 合作，用于decoding/encoding，之前的版本是MediaCodec 与ACodec/OMX 合作来进行decoding/encoding,两种Flow并存，通过debug.stagefright.ccodec 这个property 以及rank 来决定使用哪个flow。

1.debug.stagefright.ccodec

AndroidS 下，这个property 有5个值，分别定义如下。

Codec2InfoBuilder.cpp
    // debug.stagefright.ccodec supports 5 values.
    //   0 - No Codec 2.0 components are available.
    //   1 - Audio decoders and encoders with prefix "c2.android." are available
    //       and ranked first.
    //       All other components with prefix "c2.android." are available with
    //       their normal ranks.
    //       Components with prefix "c2.vda." are available with their normal
    //       ranks.
    //       All other components with suffix ".avc.decoder" or ".avc.encoder"
    //       are available but ranked last.
    //   2 - Components with prefix "c2.android.&#