#! /usr/bin/env bash

dir=out
jobs=$(grep -c ^processor /proc/cpuinfo)

_encode() {
    ffmpeg -i "$1" -c:a libopus -b:a 96k "$dir/${1%.*}.ogg"
}

export -f _encode

for f; do printf "%s\0" "$f"; done | xargs -0 -n1 -P$jobs -I{} $SHELL -c '_encode "$1"' _ {}