Use TORY/DATE tags for release year

Our best understanding is that the MP3 ID3 tag TORY[1] should be used to
store the *year* (i.e. as a 4-digit number) the music was
released. The convention for FLAC tags seems to have even less
consensus/real-world usage, so for simplicity in the code, we've
decided to use the four digit year in the DATE tag.

[1] https://community.mp3tag.de/t/how-do-i-add-the-tag-for-when-my-music-was-released/55319

Co-authored-by: James Mead <[email protected]>

app/models/track.rb

@@ -34,7 +34,7 @@ def metadata
       artist_name: artist.name
     }
 
-    data[:release_date] = album.released_on if album.released_on
+    data[:release_year] = album.released_on.year if album.released_on
     data
   end
 

app/models/transcode_command.rb

@@ -6,15 +6,15 @@ class TranscodeCommand
     track_number: 'TRCK',
     album_title: 'TALB',
     artist_name: 'TPE1',
-    release_date: 'DATE'
+    release_year: 'TORY'
   }.freeze
 
   METADATA_KEYS_VS_FLAC_TAGS = {
     track_title: 'TITLE',
     track_number: 'TRACKNUMBER',
     album_title: 'ALBUM',
     artist_name: 'ARTIST',
-    release_date: 'DATE'
+    release_year: 'DATE'
   }.freeze
 
   def initialize(input, output, format, metadata = {}, image = nil)

test/jobs/transcode_job_test.rb

@@ -53,7 +53,7 @@ class TranscodeJobTest < ActiveJob::TestCase
   end
 
   test 'it adds metadata to the generated MP3 file' do
-    album = create(:album, released_on: Time.zone.today)
+    album = create(:album, released_on: Date.parse('2024-10-03'))
     track = create(:track, album:)
     TranscodeJob.perform_now(track)
 
@@ -66,12 +66,12 @@ class TranscodeJobTest < ActiveJob::TestCase
       assert_equal '01', metadata['format']['tags']['track']
       assert_equal album.title, metadata['format']['tags']['album']
       assert_equal album.artist.name, metadata['format']['tags']['artist']
-      assert_equal album.released_on.to_s, metadata['format']['tags']['date']
+      assert_equal '2024', metadata['format']['tags']['TORY']
     end
   end
 
   test 'it adds metadata to the generated flac file' do
-    album = create(:album, released_on: Time.zone.today)
+    album = create(:album, released_on: Date.parse('2024-10-03'))
     track = create(:track, album:)
     TranscodeJob.perform_now(track, format: :flac)
 
@@ -84,7 +84,7 @@ class TranscodeJobTest < ActiveJob::TestCase
       assert_equal '01', metadata['format']['tags']['track']
       assert_equal album.title, metadata['format']['tags']['ALBUM']
       assert_equal album.artist.name, metadata['format']['tags']['ARTIST']
-      assert_equal album.released_on.to_s, metadata['format']['tags']['DATE']
+      assert_equal '2024', metadata['format']['tags']['DATE']
     end
   end
 end

test/models/track_test.rb

@@ -112,7 +112,7 @@ class TrackTest < ActiveSupport::TestCase
 
     metadata = track.metadata
 
-    assert_equal track.album.released_on, metadata[:release_date]
+    assert_equal track.album.released_on.year, metadata[:release_year]
   end
 
   test '#number' do

test/models/transcode_command_test.rb

@@ -48,7 +48,7 @@ class TranscodeCommandTest < ActiveSupport::TestCase
       track_number: 'track-number',
       album_title: 'album-title',
       artist_name: 'artist-name',
-      release_date: 'release-date'
+      release_year: 'release-year'
     }
     command_string = TranscodeCommand.new(@input, @output, :mp3v0, metadata).generate
     assert_contains_pair(command_string, ['-write_id3v2', '1'])
@@ -57,7 +57,7 @@ class TranscodeCommandTest < ActiveSupport::TestCase
     assert_contains_pair(command_string, ['-metadata', 'TRCK="track-number"'])
     assert_contains_pair(command_string, ['-metadata', 'TALB="album-title"'])
     assert_contains_pair(command_string, ['-metadata', 'TPE1="artist-name"'])
-    assert_contains_pair(command_string, ['-metadata', 'DATE="release-date"'])
+    assert_contains_pair(command_string, ['-metadata', 'TORY="release-year"'])
   end
 
   test 'adds metadata tags for FLAC format' do
@@ -66,14 +66,14 @@ class TranscodeCommandTest < ActiveSupport::TestCase
       track_number: 'track-number',
       album_title: 'album-title',
       artist_name: 'artist-name',
-      release_date: 'release-date'
+      release_year: 'release-year'
     }
     command_string = TranscodeCommand.new(@input, @output, :flac, metadata).generate
     assert_contains_pair(command_string, ['-metadata', 'TITLE="track-title"'])
     assert_contains_pair(command_string, ['-metadata', 'TRACKNUMBER="track-number"'])
     assert_contains_pair(command_string, ['-metadata', 'ALBUM="album-title"'])
     assert_contains_pair(command_string, ['-metadata', 'ARTIST="artist-name"'])
-    assert_contains_pair(command_string, ['-metadata', 'DATE="release-date"'])
+    assert_contains_pair(command_string, ['-metadata', 'DATE="release-year"'])
   end
 
   test 'transcodes audio to mp3 using libmp3lame codec highest audio quality' do