RV1126 播放和录音同时工作的时候异常，播放的声音会进到录音里面

使用了ES8311 CODEC，现在单独录音，单独放音都是OK的。但是当我们整合代码的时候发现，录音和放音同时工作的时候，录音会采集到播放的声音(我们把mic和喇叭拔了）。
下面是一些调试信息：

[root@RV1126_RV1109:/mnt/rv1126/debug]# arecord -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=rockchipi2s0sou
    rockchip,i2s0-sound, ff800000.i2s-ES8311 HiFi ES8311 HiFi-0
    Default Audio Device
sysdefault:CARD=rockchipi2s0sou
    rockchip,i2s0-sound, ff800000.i2s-ES8311 HiFi ES8311 HiFi-0
    Default Audio Device
default:CARD=Loopback
    Loopback, Loopback PCM
    Default Audio Device
sysdefault:CARD=Loopback
    Loopback, Loopback PCM
    Default Audio Device
front:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    Front speakers
surround21:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers

//采集编码代码片段
int  ai_aenc_start()
{
  MPP_CHN_S mpp_chn_ai, mpp_chn_aenc;
  mpp_chn_ai.enModId = RK_ID_AI;
  mpp_chn_ai.s32ChnId = 0;
  mpp_chn_aenc.enModId = RK_ID_AENC;
  mpp_chn_aenc.s32ChnId = 0;
  RK_U32 samplerate = 44100;//16000;   // 采样率
  int channels = 2;    // 通道数，单声道还是双声道
  RK_S32 ret = 0;
  AI_CHN_ATTR_S ai_attr;
  ai_attr.pcAudioNode = "default";
  ai_attr.enSampleFormat = RK_SAMPLE_FMT_FLTP;// RK_SAMPLE_FMT_S16;
  ai_attr.u32NbSamples = AAC_NB_SAMPLES;
  ai_attr.u32SampleRate = samplerate;
  ai_attr.u32Channels = channels;
  ai_attr.enAiLayout = AI_LAYOUT_NORMAL;   // AI_LAYOUT_MIC_REF; // chanel layout: [ref:mic]; remove
                                          // ref, output mic mono
  AENC_CHN_ATTR_S aenc_attr;
  aenc_attr.enCodecType = RK_CODEC_TYPE_AAC;
  aenc_attr.u32Bitrate = 64000;
  aenc_attr.u32Quality = 1;
  aenc_attr.stAencAAC.u32Channels = channels;
  aenc_attr.stAencAAC.u32SampleRate = samplerate;
//================================================================
// 播放代码片段
int audio_play_pcm(int channel, const char* filename, int isAutoRemove)
{
    int ret;
    pthread_t  threadid=0;
    RK_S32 s32CurrentVolmue = 100;
    AO_CHN_ATTR_S ao_attr;
    ao_attr.pcAudioNode = "default";
    ao_attr.enSampleFormat = RK_SAMPLE_FMT_S16;
    ao_attr.u32NbSamples = 1024;//u32FrameCnt;
    ao_attr.u32SampleRate = 16000;
    ao_attr.u32Channels = 2;
    ret = RK_MPI_AO_SetChnAttr(0, &ao_attr);
    ret |= RK_MPI_AO_EnableChn(0);
    if (ret) {
        log_e("ERROR: create ao[0] failed! ret=%d", ret);
        return -1;
    }