Use VLC without a UI to cast videos to chromecast

cast.sh

#!/bin/bash

MEDIA_FILE="$1"

if [ -z "$1" ]; then
    echo "Please specify a media file as the first argument."
    exit 1
fi

CHROMECAST_IP4_ADDRESS="$2"

if [ -z "$CHROMECAST_IP4_ADDRESS" ]; then
    if [ -e "$HOME/.castrc" ]; then
        . $HOME/.castrc
    else
        echo "Please give a chromecast IP4 address as the second argument."
        exit 1
    fi
fi

/usr/bin/env vlc "$MEDIA_FILE" \
    -I dummy \
    --sout "#chromecast" \
    --sout-chromecast-ip="$CHROMECAST_IP4_ADDRESS" \
    --demux-filter=demux_chromecast

I want to stream a video and an audio file to the chromecast. The way I do it is:

cvlc "http://video" --input-slave="http://audo" --sout "#chromecast" --sout-chromecast-ip=192.168.178.51 --demux-filter=demux_chromecast

In this command the --input-slave is not played by the chromecast. If I remove the --demux-filter, the video and audio are played, but they are played like lightspeed.

Is there any solution? Thank you