downsample

Overview

downsample.sh is a simple POSIX-compliant shell script that resamples 24-bit FLAC files to 16-bit using the appropriate sampling rate scaling for each file.

Appropriate sampling rate scaling?

Downsampling lossless files to a common multiple may minimize the chance of introducing various artifacts during the conversion. For example, a sampling rate of 88.2 kHz shall be converted to 44.1 kHz, not 48 kHz.

Usage

$ ./downsample.sh <DIR> [<DIR2>..]

Examples

Suppose we have the following directory structure:

directory structure before downsampling

music/
└── experimental/
    ├── musique concrete/
    │   └── Brume/
    │       └── 2012 - Fractisum/
    │           ├── 01 - Fractisum (Part 1).flac
    │           ├── 02 - Fractisum (Part 2).flac
    │           ├── cover.jpg
    │           └── lineage.txt
    └── noise/
        └── Masonna/
            └── 1991 - Split w. Violent Onsen Geisha/
                ├── 01 - Violent Onsen Geisha - Ultra Psychotic Piss Drunk Bunny Girl!.flac
                ├── 02 - Violent Onsen Geisha - Cock Guillotine 1965.flac
                ├── <...>
                ├── 12 - Masonna - Key.asasggkjkieeee.flac
                ├── 13 - Masonna - Sax.asqqqrtefdhkgjriukhvjbmosfjiejp.flac
                ├── cover.jpg
                └── lineage.txt

If we were to downsample all these files, we would use either

$ ./downsample.sh music

or

$ ./downsample.sh music/experimental

or even

$ ./downsample.sh music/experimental/{noise,musique\ concrete}

and any of the three commands would produce the desired output. Now, let’s take a look at the directory structure after running the script:

directory structure after downsampling

music/
└── experimental/
    ├── musique concrete/
    │   └── Brume/
    │       └── 2012 - Fractisum/
    │           ├── resampled-16-44/
    │           │   ├── 01 - Fractisum (Part 1).flac
    │           │   └── 02 - Fractisum (Part 2).flac
    │           ├── 01 - Fractisum (Part 1).flac
    │           ├── 02 - Fractisum (Part 2).flac
    │           ├── cover.jpg
    │           └── lineage.txt
    └── noise/
        └── Masonna/
            └── 1991 - Split w. Violent Onsen Geisha/
                ├── resampled-16-48/
                │   ├── 01 - Violent Onsen Geisha - Ultra Psychotic Piss Drunk Bunny Girl!.flac
                │   ├── 02 - Violent Onsen Geisha - Cock Guillotine 1965.flac
                │   ├── <...>
                │   ├── 12 - Masonna - Key.asasggkjkieeee.flac
                │   └── 13 - Masonna - Sax.asqqqrtefdhkgjriukhvjbmosfjiejp.flac
                ├── 01 - Violent Onsen Geisha - Ultra Psychotic Piss Drunk Bunny Girl!.flac
                ├── 02 - Violent Onsen Geisha - Cock Guillotine 1965.flac
                ├── <...>
                ├── 12 - Masonna - Key.asasggkjkieeee.flac
                ├── 13 - Masonna - Sax.asqqqrtefdhkgjriukhvjbmosfjiejp.flac
                ├── cover.jpg
                └── lineage.txt

Dependencies

sox is the only dependency here. On Debian-based distros, the package can be installed by running the following command:

$ sudo apt-get install sox