Playtag is a simple tool that allows you to play audio and video files that have playback options – such as volume adjust, or starting playing the file in the middle – set in their tags (in the Playtag tag). You may want to do this if you want to apply a change to a media file, so that it takes effect every time the file is read, without reencoding the file.
A Playtag tag is a line of text that looks like this:
v1; t = 0:26; vol = +3dB
This repo provides:
- An mpv script that adds Playtag support to mpv.
- A player that
- acts as a wrapper to VLC adding Playtag support;
- allows you to edit the Playtag tag on any supported file.
Files with a Playtag tag can still be read with any player that does not support Playtag; the tag will then simply be ignored.
The tag format is intended to be application-independent.
A Playtag tag is a semicolon-separated list of fields. The first field is
always v1. Other fields are of the form <parameter> = <value>. Whitespace
around ; and = is ignored.
Valid parameters are:
aspect-ratio = <string>
av-delay = <float> (audio-video delay, in seconds)
mirror = true (left<>right flip)
t = <time>-<time> (start and stop times)
t = <time>[-] (start time)
t = -<time> (stop time)
where <time> matches ((\d+:)?\d+:)?\d+(\.\d+)? (e.g. 1:26:03.14)
vol = <value> <unit> (volume adjust)
where <value> is a float
and <unit> is "dB"/"decibel" or "vg"/"volt gain" or "sg"/"sone gain"
e.g. -3.2dB (whitespace between value and unit is optional)
Usage: playtag COMMAND [options] [file]
Commands:
e[dit] FILE Edit playtag for FILE interactively
v[lc] [VLC_ARGS] FILE Play FILE with VLC using playtag parameters
c[lear] FILE Clear playtag tag from FILE
r[ead] FILE Read playtag from FILE
w[rite] TAG FILE Write TAG to FILE
Options:
-d, --debug Enable debug output
-h, --help Show this help message
The playtag program can read media files with (or without) a Playtag tag by acting as a
wrapper to VLC. Do
Open with > VLC+playtag
from your file manager (you can set it as the default application), or from the command line:
$ playtag vlc <file>+
You may want to alias it in your .bashrc or .zshrc:
alias vlc='playtag vlc'
playtag works by reading the tag of the file(s) to open, then calling VLC
with the appropriate command-line arguments. As a consequence, doing
Open... from inside VLC is not supported: the file will open but the
tag will be ignored. When called on several files at a time, playtag will start
one instance of VLC for each file, one after the other.
$ playtag e[dit] toto.ogg
v1; t=10; _
You can also use any tag editor that lets you edit arbitrary tags and follow the above specification.
Requirements:
- GNU/Linux (might work on other systems, but not tested)
- Ruby
- TagLib 2.x and taglib-ruby
- MKVToolNix
- Task and Bundler to install
- mpv or VLC to play the fi 6B24 les
To install dependencies on Ubuntu/Debian:
sudo apt-get install ruby-dev ruby-rubygems build-essential \
libtag1-dev mkvtoolnix mpv
sudo snap install task
sudo gem install bundler
sudo bundle installThen to install:
git clone https://github.com/nahoj/playtag.git
cd playtag
task installSome alternatives to Playtag (some of which I didn't know about when I started writing it):
- ReplayGain tags, same as Playtag for volume adjust only
- File-specific configuration for MPlayer and mpv, similar to Playtag but stored in separate files
- The aspect ratio of a video is metadata so it can be changed without
reencoding it, e.g.
ffmpeg -i input.mkv -c copy -aspect 2.35 output.mkv.
As of 2025, Playtag cannot be implemented as a VLC Lua script. Indeed,
- VLC extensions in the strict sense don't run until they are manually activated via the View menu each time VLC is started.
- meta, intf, and service-discovery scripts cannot control playback (e.g. seek).