Script to quickly generate nightcore versions of your favorite songs! (using ffmpeg)

nightcorify.sh

#!/bin/bash

# ./nightcorify.sh $input_file $output_file [$speed]

set -ex;

input_file=$1;
output_file=$2;
speed=${3-1.25}

[[ $input_file = ""  ]] && echo "You must specify an input file"  && exit 1;
[[ $output_file = "" ]] && echo "You must specify an output file" && exit 1;

sample_rate=$( \
	(ffprobe "$input_file" -select_streams a:0 -show_entries stream=sample_rate 2> /dev/null) \
	| grep sample_rate \
	| cut -d'=' -f2 \
);

echo "Sample rate: $sample_rate Hz";

ffmpeg -i "$input_file" -af "asetrate=$sample_rate*$speed" "$output_file";