Use metaflac to rename .flac files from flac tags recursively

Question

I am trying to rename a bunch of songs using metaflac (sudo apt-get install flac) from their respective tags recursively, because I'm dealing with an unknown number of subfolders.

Output should be: $TRACKNUMBER. $TITLE.flac

This is my attempt, however it does not work recursively:

for a in *.flac; do
TITLE=`metaflac "$a" --show-tag=TITLE | sed s/.*=//g`
TRACKNUMBER=`metaflac "$a" --show-tag=TRACKNUMBER | sed s/.*=//g`
mv "$a" "`printf %02g $TRACKNUMBER`. $TITLE.flac";
done

I do not know why, but sometimes I get "The FLAC file could not be opened. Most likely the file does not exist or is not readable. *.flac: ERROR: reading metadata, status = "FLAC__METADATA_CHAIN_STATUS_ERROR_OPENING_FILE"".

Is there a better way to do it in a recursive manner? I also prefer oneliners. Thanks in advance!

Solution 1

I have found a python script written by Louis-Philippe Véronneau.

The up to date code can be found on his git repository: https://gitlab.com/baldurmen/rename-flac

You need to install python-docopt (sudo apt-get install python-docopt) and run this script after you chmod +x rename-flac.py it:

#!/usr/bin/python

"""
rename-flac takes the information from FLAC metadata to batch rename
the files according to a filenaming scheme.

Usage:
    rename-flac.py [--verbose] <scheme> <directory>
    rename-flac.py (-h | --help)
    rename-flac.py --version

Arguments:
    <scheme>         The filenaming scheme. Has to be between quotation marks
    <directory>      The path to the directory containing the album

Options:
    -h  --help       Shows the help screen
    --version        Outputs version information
    --verbose        Runs the program as verbose mode

    These are the options you can use to define the filenaming scheme:
      %a = Artist  |   %b = Album         |   %d = Date
      %g = Genre   |   %n = Tracknumber   |   %t = Title
"""
import sys

try:
    from docopt import docopt  # Creating command-line interface
except ImportError:
    sys.stderr.write("""
        %s is not installed: this program won't run correctly.
        To install %s, run: aptitude install %s
        """ % ("python-docopt", "python-docopt", "python-docopt"))

import subprocess
import re
import os


TAGS = dict(a='artist', b='album', d='date',
            g='genre', n='tracknumber', t='title')


# Defining the function that fetches metadata and formats it
def metadata(filepath): 
    args = ["--show-tag=%s" % tag for tag in TAGS.values()]
    tags = ["%s=" % tag for tag in TAGS.values()]
    formatter = dict()
    pipe = subprocess.Popen(["metaflac"] + args + [filepath],
                            stdout=subprocess.PIPE)
    output, error = pipe.communicate()
    if pipe.returncode:
        raise IOError("metaflac failed: %s" % error)
    output = output.splitlines()
    for tag in tags:
        for item in output:
            x = re.compile(re.escape(tag), re.IGNORECASE)
            if bool(re.match(x, item)) ==  True:
                tag = tag.replace("=", "")
                if tag == "tracknumber":
                    formatter[tag] = x.sub("", item).zfill(2)
                else:
                    formatter[tag] = x.sub("", item)
    return formatter


# Defining function that renames the files
def rename(scheme, dirname, filename, args):
    filepath = os.path.join(dirname, filename)
    new_filename = scheme % metadata(filepath) + ".flac"
    if new_filename == filename:
        if args["--verbose"] == True:
            print("%s is already named correctly") % (filename)
    else:
        new_filepath = os.path.join(dirname, new_filename)
        os.rename(filepath, new_filepath)
        if args["--verbose"] == True:
            print("%s >> %s") % (filename, new_filename)


# Defining main function
def main():
    args = docopt(__doc__, version="rename-flac 1.0")
    scheme = args["<scheme>"]
    if not re.search("%[tn]", scheme):  # To have a unique filename
        sys.stderr.write("%t or %n has to be present in <scheme>\n")
        return
    scheme = re.sub('%%([%s])' % ''.join(TAGS.keys()),
                lambda m: '%%(%s)s' % TAGS[m.group(1)],
                scheme)
    for dirname, _, filenames in os.walk(
                                   args["<directory>"],
                                   topdown=False):
        for filename in filenames:
            if os.path.splitext(filename)[1] == ".flac":
                try:
                    rename(scheme, dirname, filename, args)
                except KeyboardInterrupt:
                    raise
                except OSError:
                    print("Song title contains /. Please rename it")


# Calling main function
if __name__ == "__main__":
    main()

I tested it and everything works like a charm! Thank you!

Solution 2

If you put your code into its own file, make it executable, and place in your binary path (e.g. ~/bin).

e.g. rename_flac_tracks_from_meta.sh

You could then use find and xargs to recursively go through your directories and apply your script to each one.

$ cd path/to/flac/folders
$ find . -type d -print0 | xargs -0 -t -I{} sh -c 'cd "{}"  && rename_flac_tracks_from_meta.sh'

Bear in mind that will crawl into directories that might not have flacs in, but it should just hiccup rather than die.

Comments

[Amir Uval]

I got this error only in file names that contained spaces