linux 嵌入式ffmpeg音视频不同步，时间戳设置不合理，要怎么设置时间基呢？

嵌入式板子，从摄像头中拿h264 和aac，直接拿去封装成mp4文件，但音视频不同步，大概率是写入的时间戳有问题

附上使用ffmpeg写入音视频数据的实现

int WriteVideoAudio(uint8_t* data, int nLen,unsigned long int timestamp,const int keyframe)
{
    int ret;
    int64_t calc_duration;
    // Init packet
    AVPacket pkt;
    av_init_packet( &pkt );

    if(keyframe >= 0)//轮到视频写入
    {
        // 我的添加，为了计算pts
        AVCodecContext *c = m_pVideoSt->codec;

        int isI = keyframe;
        pkt.flags |=  isI ? AV_PKT_FLAG_KEY : 0;

        pkt.stream_index = m_pVideoSt->index;
        pkt.data = data;
        pkt.size = nLen;
        if ( waitkey ){
            if ( 0 == ( pkt.flags & AV_PKT_FLAG_KEY ) ){
                ret = -1;
                goto EXIT;
            }
            else
                waitkey = 0;
        }

        if(isI && !m_bHadFillGlobalHeader)
        {
            memcpy(m_pVideoSt->codec->extradata + m_pVideoSt->codec->extradata_size, pkt.data, 32);
            m_pVideoSt->codec->extradata_size += 32;
            m_bHadFillGlobalHeader = 1;
            pkt.data += 32;
        }
        pkt.pts = av_rescale_q((frameindex++), m_pVideoSt->codec->time_base,m_pVideoSt->time_base);//不同时间基的转换
        pkt.dts = pkt.pts;
        pkt.duration = av_rescale_q(pkt.duration,m_pVideoSt->time_base, m_pVideoSt->time_base);
        pkt.pos = -1;
        cur_pts_v=pkt.pts;

        pkt.pts = av_rescale_q(pkt.pts,m_pVideoSt->codec->time_base,m_pAudioSt->codec->time_base);//转成视频时间基
        pkt.dts=pkt.pts;
        pkt.duration=av_rescale_q(pkt.duration,m_pVideoSt->codec->time_base,m_pAudioSt->codec->time_base);

    }
    else{//轮到音频写入
        pkt.stream_index = m_pAudioSt->index;
        pkt.data = data;
        pkt.size = nLen;
        
        pkt.pts = av_rescale_q(Audioframeindex++, m_pAudioSt->codec->time_base,m_pAudioSt->time_base);//不同时间基的转换
        pkt.dts = pkt.pts;
        pkt.duration = av_rescale_q(pkt.duration,m_pAudioSt->time_base, m_pAudioSt->time_base);
        pkt.pos = -1;
        
        cur_pts_a=pkt.pts;
        cur_pts_a=pkt.pts;
    }
    ret = av_interleaved_write_frame( m_pOc, &pkt );
    if (ret < 0)
    {
        printf("cannot write frame");
        ret = -1;
    }
    av_free_packet(&pkt);
EXIT:
    return ret;
}

附上音视频时间戳比较的实现

int ffmpegMp4_compare_ts(){
    return av_compare_ts(cur_pts_v,m_pVideoSt->codec->time_base,cur_pts_a,m_pAudioSt->codec->time_base);
}

时间基的设置有点烦恼，该怎么设置？