How to use av_rescale_q_rnd/av_rescale_q in beamcoder ?

Hello,

I am trying to generate a stream with video/audio packets in sync.
To set pts/dts in need to calculate, using native ffmpeg av_rescale_q_rnd and av_rescale_q function are used for this purpose.

Can you please elborate API in beamcoder for this purpose ? Any example would be really helpful.

Thanks