Trimmer

MP3 song normalizer

Do you find it annoying when songs on YouTube are recorded quietly and there is a long silence before and after the song?

Trimmer corrects this by generating the normalized MP3 for you:

Downloads a song from a URL on Youtube (thanks to youtube-dl and yt-dlp)
Trims down the silence at the beginning and at the end of a song (thanks to pydub)
Normalizes volume (detects clipping), and applies fade-in and fade-out (thanks to pydub)
Adds MP3 ID3 tags - both ID3v1 & ID3v2 (thanks to eyed3)
Creates an mp3 file with a unified name Artist - Title.mp3

Downloading MP3

Create trimmed, normalized and tagged mp3 from Youtube URL:

$ trimmer https://www.youtube.com/watch?v=dQw4w9WgXcQ
<span class="code-gray">[2023-03-06 23:08:27]</span> <span class="code-blue">INFO</span>  source recognized as url <span class="code-green">source=</span><span class="code-bold-green">https://www.youtube.com/watch?v=dQw4w9WgXcQ</span>
<span class="code-gray">[2023-03-06 23:08:27]</span> <span class="code-blue">INFO</span>  fetching metadata from youtube page... <span class="code-green">url=</span><span class="code-bold-green">https://www.youtube.com/watch?v=dQw4w9WgXcQ</span>
<span class="code-gray">[2023-03-06 23:08:31]</span> <span class="code-blue">INFO</span>  youtube page metadata fetched <span class="code-green">yt_title="</span><span class="code-bold-green">Rick Astley - Never Gonna Give You Up (Official Music Video)</span><span class="code-green">" artist=</span><span class="code-bold-green">None</span>
<span class="code-gray">[2023-03-06 23:08:31]</span> <span class="code-blue">INFO</span>  artist & title extracted from youtube page <span class="code-green">artist="</span><span class="code-bold-green">Rick Astley</span><span class="code-green">" title="</span><span class="code-bold-green">Never Gonna Give You Up</span><span class="code-green">"</span>
Enter Artist ("Rick Astley" by default): <span>Rick Astley</span>
Enter Title ("Never Gonna Give You Up" by default): <span>Never Gonna Give You Up</span>
<span class="code-gray">[2023-03-06 23:08:36]</span> <span class="code-blue">INFO</span>  song name set <span class="code-green">name="</span><span class="code-bold-green">Rick Astley - Never Gonna Give You Up</span><span class="code-green">"</span>
<span class="code-gray">[2023-03-06 23:08:36]</span> <span class="code-blue">INFO</span>  downloading from youtube... <span class="code-green">url=</span><span class="code-bold-green">https://www.youtube.com/watch?v=dQw4w9WgXcQ</span>
<span class="code-gray">[2023-03-06 23:08:42]</span> <span class="code-blue">INFO</span>  song downloaded <span class="code-green">tmpfile=</span><span class="code-bold-green">trimmer_dl_b737b09b-beb7-412e-901a-425e14418b5c.mp3</span>
<span class="code-gray">[2023-03-06 23:08:42]</span> <span class="code-blue">INFO</span>  song renamed <span class="code-green">new_name="</span><span class="code-bold-green">Rick Astley - Never Gonna Give You Up.mp3</span><span class="code-green">"</span>
<span class="code-gray">[2023-03-06 23:08:42]</span> <span class="code-blue">INFO</span>  loading song...
<span class="code-gray">[2023-03-06 23:08:42]</span> <span class="code-blue">INFO</span>  normalizing volume level... <span class="code-green">volume=</span><span class="code-bold-green">-0.98dB</span> <span class="code-green">dBFS=</span><span class="code-bold-green">-16.97dB</span>
<span class="code-gray">[2023-03-06 23:08:42]</span> <span class="code-blue">INFO</span>  volume normalized <span class="code-green">gain=</span><span class="code-bold-green">0.98dB</span>
<span class="code-gray">[2023-03-06 23:08:42]</span> <span class="code-blue">INFO</span>  trimming silence...
<span class="code-gray">[2023-03-06 23:08:43]</span> <span class="code-blue">INFO</span>  silence trimmed <span class="code-green">trim_start=</span><span class="code-bold-green">0.000s</span> <span class="code-green">trim_end=</span><span class="code-bold-green">2.000s</span> <span class="code-green">duration_before=</span><span class="code-bold-green">3:32.045</span> <span class="code-green">duration_after=</span><span class="code-bold-green">3:30.045</span>
<span class="code-gray">[2023-03-06 23:08:43]</span> <span class="code-blue">INFO</span>  applying fade-in & fade-out... <span class="code-green">fade_in=</span><span class="code-bold-green">0.100s</span> <span class="code-green">fade_out=</span><span class="code-bold-green">1.000s</span>
<span class="code-gray">[2023-03-06 23:08:43]</span> <span class="code-blue">INFO</span>  saving song... <span class="code-green">mp3_file="</span><span class="code-bold-green">Rick Astley - Never Gonna Give You Up.mp3</span><span class="code-green">" duration=</span><span class="code-bold-green">3:30.045</span>
<span class="code-gray">[2023-03-06 23:08:46]</span> <span class="code-blue">INFO</span>  tagging mp3... <span class="code-green">artist="</span><span class="code-bold-green">Rick Astley</span><span class="code-green">" title="</span><span class="code-bold-green">Never Gonna Give You Up</span><span class="code-green">"</span>
<span class="code-gray">[2023-03-06 23:08:46]</span> <span class="code-blue">INFO</span>  song saved <span class="code-green">mp3_file="</span><span class="code-bold-green">Rick Astley - Never Gonna Give You Up.mp3</span><span class="code-green">"</span>

Editing MP3

trimmer "unknown001.mp3"

From this:
unknown001.mp3
Usage example
trimmer does that:
Mike Oldfield - Tubular Bells Part I.mp3

You can also trim song manually using --trim-start and --trim-end (e.g. for cutting long applause at the end of song).

Installation

pip3 install trimmer

It requires Python 3.6 (or newer) with pip.

For Linux make sure that required libs are installed: apt install ffmpeg libavcodec-extra

For Windows you might need to put ffmpeg binaries to PATH.

Upgrading

Keep up-to-date frequently changing dependencies (due to Youtube API changes):

pip3 install --upgrade --upgrade-strategy eager trimmer

or do the same with:

trimmer --upgrade

Help

$ trimmer --help
trimmer v1.0.0 (nuclear v1.3.4) - MP3 song normalizer

Usage:
trimmer [OPTIONS] SOURCE

Arguments:
   SOURCE - song source (youtube URL or MP3 file)

Options:
  --version                   - Print version information and exit
  -h, --help [SUBCOMMANDS...] - Display this help and exit
  --artist ARTIST             - song artist
  --title TITLE               - song title
  --trim-start TRIM_START     - trim given seconds at the beginning
  --trim-end TRIM_END         - trim given seconds at the end
  --gain GAIN                 - increase volume by given dB
  --output OUTPUT             - output MP3 file (Artist - Title.mp3 by default)
  --no-normalize              - skip normalizing volume level
  --no-trim                   - skip trimming silence at the edges of song
  --no-fade                   - skip applying fade-in & fade-out
  --no-rename                 - skip renaming song to normalized filename (Artist - Title.mp3)

Install locally in develop mode

make setup
. venv/bin/activate