Planetary

Scan status ? Whether the station’s analyser could read this mp3. “OK” means every number in this box was measured from the actual audio, not copied from a tag that somebody typed.

OK

measured from the file itself

Scanned ? When the file was last analysed. If the mp3 is replaced afterwards, these numbers describe the old version until it is scanned again.

19 Sep 2026, 18:35 UTC

File size ? How much room the mp3 takes on a disk, and how much data you use when you play or download it. It is roughly the bit rate multiplied by the length.

4.6 MB

4 855 057 bytes

File last changed ? When the mp3 on our server was last written - usually the day it was uploaded, or encoded again.

22 Jun 2026, 07:06 UTC

Length ? How long the recording plays. It is measured from the audio itself, so it is right even when a tag in the file says something else.

3:22

minutes : seconds

Tempo ? How fast the tune goes, in beats per minute - the speed you would tap your foot at. This was measured automatically by the station's analyser (ffmpeg and bpm-tools' "bpm"), not typed in by a person, so it is not guaranteed to be 100% accurate: tunes without a steady beat can throw it, and where it is wrong it is usually exactly half or double the tempo you would count.

125 BPM

a dancing tempo

Bit rate ? How much data is spent on each second of sound. More data keeps more detail when the audio is squeezed into an mp3: 128 kbit/s is acceptable, 192 is good, and 320 is the most an mp3 can hold.

192 kbit/s

good quality

Sample rate ? Digital audio is a long row of measurements of the sound wave. This is how many are taken every second. 44.1 kHz is the CD standard and 48 kHz the video and broadcast standard - both capture everything a human ear can hear.

44.1 kHz

44 100 measurements a second

Channels ? How many separate signals the file holds. Mono is one. Stereo is two - left and right - which is what lets a sound be placed somewhere between your speakers.

Stereo

2 channels

Codec ? The method used to shrink the audio. MP3 leaves out the detail an ear is least likely to miss, which makes the file about a tenth of the size of the original recording.

MP3

Loudness ? The average loudness of the whole recording, the way a listener hears it (“integrated loudness”, in LUFS). The closer to 0, the louder. Music services aim for about -14 and podcasts for about -16, so that you do not have to reach for the volume between tracks.

−19.2 LUFS

on the quiet side

Loudness range ? The distance between the quiet passages and the loud ones, in LU (1 LU is 1 dB). A small number means an even, compressed sound - good in a car or on a phone. A large number means big swings between soft and loud.

4.8 LU

very even

True peak ? The highest level the signal ever reaches, including the peaks that appear between the measurements when the file is turned back into sound. 0 is the ceiling: above about -1 dBTP, a recording can crackle (“clip”) on some players.

−4.0 dBTP

safely below the ceiling

Dynamic range ? How far the loudest peaks stand above the loud parts of the recording, in dB - the “DR” number that music collectors compare albums by. A low number (under 8) means the sound has been squeezed until everything is equally loud: punchy, but tiring to listen to. 14 and up means the music has room to breathe, with real hits and real quiet. It says nothing about how loud the file is: turning the volume down does not change it. Chip music made of steady square waves naturally lands low.

DR 10

9.7 dB · moderately dynamic

Left channel level ? The average strength of the left channel over the whole recording (“RMS”), counted in dB below the loudest level a digital file can hold (dBFS). More negative means quieter. Compare it with the right channel.

−21.1 dBFS

average (RMS) over the whole file

Right channel level ? The average strength of the right channel over the whole recording (“RMS”), counted in dB below the loudest level a digital file can hold (dBFS). More negative means quieter. Compare it with the left channel.

−21.1 dBFS

average (RMS) over the whole file

Channel balance ? The left level minus the right level. Close to 0 dB means both sides are equally loud. More than about 1 dB and the whole mix leans towards one ear.

0.00 dB

balanced

Stereo width ? How strong the part that DIFFERS between left and right is, compared with the part they share. A very low number (-40 dB or less) means both sides carry the same sound - mono in practice. A higher number means a wider stereo picture; a very high one can sound thin on a single speaker.

−78.9 dB

practically mono

Cover art in the file ? Whether a picture is stored inside the mp3 itself. A player shows it as the album art when the file is played somewhere else - in a car, on a phone, offline.

No

ID3 tags ? Text stored inside the mp3 file itself - title, artist, album and so on. It is what a music player, a phone or a car stereo shows while it plays the file, and it travels with the file wherever it is copied.

encoder ? The program that made the mp3 file.

Lavf62.12.101

Measured from the mp3 file on our server by the station’s own analyser. Point at a label, or select its question mark, for what the number means.