PTS and DTS calculation for video and audio frames

I am getting video files recorded in H264 format and G.711 PCM audio encoded data from two different streams to mux / write to container mov

.

Write function signatures are written as:

bool WriteAudio(const unsigned char *pEncodedData, size_t iLength);
bool WriteVideo(const unsigned char *pEncodedData, size_t iLength, bool const bIFrame);

      

        
        
        
      

    

And the function for adding audio and video streams looks like this:

AVStream* AudioVideoRecorder::AddMediaStream(enum AVCodecID codecID) {
    Log("Adding stream: %s.", avcodec_get_name(codecID));
    AVCodecContext* pCodecCtx;
    AVStream* pStream;

    /* find the encoder */
    AVCodec* codec = avcodec_find_encoder(codecID);
    if (!codec) {
        LogErr("Could not find encoder for %s", avcodec_get_name(codecID));
        return NULL;
    }

    pStream = avformat_new_stream(m_pFormatCtx, codec);
    if (!pStream) {
        LogErr("Could not allocate stream.");
        return NULL;
    }
    pStream->id = m_pFormatCtx->nb_streams - 1;
    pStream->time_base = (AVRational){1, VIDEO_FRAME_RATE};
    pCodecCtx = pStream->codec;


    switch(codec->type) {
    case AVMEDIA_TYPE_VIDEO:
        pCodecCtx->codec_id = codecID;
        pCodecCtx->bit_rate = VIDEO_BIT_RATE;
        pCodecCtx->width = PICTURE_WIDTH;
        pCodecCtx->height = PICTURE_HEIGHT;
        pCodecCtx->gop_size = VIDEO_FRAME_RATE;
        pCodecCtx->pix_fmt = PIX_FMT_YUV420P;
        m_pVideoStream = pStream;
        break;

    case AVMEDIA_TYPE_AUDIO:
        pCodecCtx->codec_id = codecID;
        pCodecCtx->sample_fmt = AV_SAMPLE_FMT_S16;
        pCodecCtx->bit_rate = 64000;
        pCodecCtx->sample_rate = 8000;
        pCodecCtx->channels = 1;
        m_pAudioStream = pStream;
        break;

    default:
        break;
    }

    /* Some formats want stream headers to be separate. */
    if (m_pOutputFmt->flags & AVFMT_GLOBALHEADER)
        m_pFormatCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;

    return pStream;
}

      

        
        
        
      

    

Inside functions WriteAudio(..)

and WriteVideo(..)

I create AVPakcet

with av_init_packet(...)

and install pEncodedData

and iLength

like packet.data

and packet.size

. I printed packet.pts

and packet.dts

and its equivalent AV_NOPTS_VALUE

.

Now, how can I correctly calculate the PTS, DTS and packet ( packet.dts

, packet.pts

and packet.duration

) durations for audio and video data so that I can sync the audio and video and play them correctly? I've seen many examples on the internet, but none of them make sense to me. I am new to ffmpeg

and my concept may be wrong in some context. I want to do it accordingly.

Thanks in advance!

EDIT: There is no B-frame in my video streams. So, I think PTS and DTS can stay the same here.