Making a short film to amateur competition - 16 bit audio sounds terrible

H!

Totally newbie amateur just want to have a hobby and making a shortfilm to competition.

The film is quite ready and the sound in project is fine (enough for me). Now using Media Encoder to export this.

Competition rules are simple:

H264, 1920 x 1080, 25 fps for video and for audio stereo, 16 bit/s, 48 kHz

Setting the encoder done and the result - fine video with sound so bad that it realy hurts ones soul. Something goes badly wrong with the voice!

The input contains a .MOV file:

And for audio a .WAV file

Please, you with skills and knowledge: It would be nice to learn about this and maybe to be able to make a decent movie.

And so you don't need to ask - no money reward in this competition (like I could win) - just fun!