Multi-client recording

    audio_io_handle_t input = AudioSystem::getInput(mInputSource, mSampleRate, mFormat,

            mChannelMask, mSessionId);

    if (input == 0) {

        ALOGE("Could not get audio input for record source %d", mInputSource);

        ALOGE("Could not get audio input for record source %d, sample rate %u, format %#x, "

              "channel mask %#x, session %d",

              mInputSource, mSampleRate, mFormat, mChannelMask, mSessionId);

        return BAD_VALUE;

    }

    {

    // releaseBuffer() not overridden

    bool                mOverflow;  // overflow on most recent attempt to fill client buffer

           // updated by RecordThread::readInputParameters()

            AudioResampler                      *mResampler;

            // interleaved stereo pairs of fixed-point signed Q19.12

            int32_t                             *mRsmpOutBuffer;

            // current allocated frame count for the above, which may be larger than needed

            size_t                              mRsmpOutFrameCount;

            size_t                              mRsmpInUnrel;   // unreleased frames remaining from

                                                                // most recent getNextBuffer

                                                                // for debug only

            // rolling counter that is never cleared

            int32_t                             mRsmpInFront;   // next available frame

            AudioBufferProvider::Buffer mSink;  // references client's buffer sink in shared memory

            // sync event triggering actual audio capture. Frames read before this event will

            // be dropped and therefore not read by the application.

            sp<SyncEvent>                       mSyncStartEvent;

            // number of captured frames to drop after the start sync event has been received.

            // when < 0, maximum frames to drop before starting capture even if sync event is

            // not received

            ssize_t                             mFramesToDrop;

            // used by resampler to find source frames

            ResamplerBufferProvider *mResamplerBufferProvider;

};