hisi 音频HI_MPI_ADEC_SendStream 立体声模式，左右声道输出为啥一样呢？

hisi3520dv400

使用sdk sample/audio的.c文件

立体声模式，左右声道输出确实一样的。
待播放的pcm文件是正确的，在电脑上打开听了，声音左右声道是没有问题的。
有人知道什么原因吗？感谢

程序代码：

static PAYLOAD_TYPE_E gs_enPayloadType = PT_LPCM;

stAioAttr.enSamplerate   = AUDIO_SAMPLE_RATE_44100;
stAioAttr.enBitwidth     = AUDIO_BIT_WIDTH_16;
stAioAttr.enWorkmode     = AIO_MODE_I2S_MASTER;
stAioAttr.enSoundmode    = AUDIO_SOUND_MODE_STEREO；
stAioAttr.u32EXFlag      = 1;
stAioAttr.u32FrmNum      = 30;
stAioAttr.u32PtNumPerFrm = SAMPLE_AUDIO_PTNUMPERFRM;
stAioAttr.u32ChnCnt      = 2;
stAioAttr.u32ClkChnCnt   = 2;
stAioAttr.u32ClkSel      = 0;

…

while (HI_TRUE == pstAdecCtl->bStart)
{
    /* read from file */
    stAudioStream.pStream = pu8AudioStream;
    u32ReadLen = fread(stAudioStream.pStream, 1, u32Len, pfd);
    if (u32ReadLen <= 0)
    {
        fseek(pfd, 0, SEEK_SET);/*read file again*/
        continue;
    }

    /* here only demo adec streaming sending mode, but pack sending mode is commended */
    stAudioStream.u32Len = u32ReadLen;
    s32Ret = HI_MPI_ADEC_SendStream(s32AdecChn, &stAudioStream, HI_TRUE);
    if(HI_SUCCESS != s32Ret)
    {
        printf("%s: HI_MPI_ADEC_SendStream(%d) failed with %#x!\n",\
               __FUNCTION__, s32AdecChn, s32Ret);
        break;
    }
}