dropcreations / Manzana-Apple-Music-Tagger

A python script to fetch credits info from apple music about albums, songs and music-videos and tag MP4 and M4A files using those credits info.

https://music.apple.com

MIT License

26 stars 5 forks source link

How can I embed synced lyrics into a MP3 or AAC file which also shows as synced Lyrics in Apple Music.app ? #8

Open porg opened 9 months ago

porg commented 9 months ago

You possibly have the knowhow, hence I dare to ask here

Concrete Question

What exact metadata format must synced lyrics comply to in MP3 and AAC (M4A) files so that Apple Music on macOS shows them indeed as synced lyrics?
- ID3 in MP3?
- XMP in M4A container with AAC audio codec?
- What text character encoding? (I'd prefer UTF-8)
- What timecode: Milliseconds or MPEG frames?

My failed experiments

With Kid3 I added this metadata to the ID3 metadata of a WAV file

Lyrics Nr.1, Language: "ger" (German), Title "Viennese German", as audible in the song, UTF8
Lyrics Nr.2, Language: "ger" (German), Title "High German" (the translation for those not familiar with the Viennese dialect), UTF8
Synchronized Lyrics, Language: "ger" (German), Title "Viennese German", milliseconds as time units, UTF8
- During playback in Kid3 the editor/preview windows jumps to the corresponding timestamped lines, so the timing is correct.
- I also managed to export those synced lyrics as a .LYR file, should that be needed.

Convert WAV to MP3 and AAC and preserve all metadata

The basic ffmpeg -i input.wav output.mp3 || output.m4a carries over most metadata (Artist, Title, Album) but not all:
- .mp3 (MP3 file with metadata in ID3 which ideally is preserved from the WAV file as-is)
- Lyrics "Viennese German" and "High German" are copied over, but the synced lyrics not.
- .m4a (MP4 container with AAC audio + metadata as XMP)
- No Lyrics copied at all.

Also manual postprocessing attempts with Kid3 failed

Copy tag from WAV and paste to MP3 or M4A file
Inspecting this mediainfo frontend "InvisorLite" on macOS shows me this:
- M4A
  - Lyrics: Shows the Viennese German version, the High German version is dropped.
  - Those M4A/XMP allow only one lyric record possibly?
  - In the source I had two lyric tags, both using language code "ger", only differing in the titles
  - So overall: In ID3 this seems to work, but in M4A/XMP only one seems to "make it"
  - SYLT - Synchronized lyric/text: Viennese German, whether only the title makes it, or also the content, I tried to determine by also inspecting with a Hex editor
  - Certain unique text phrases which are identical in German and Viennese German, occured only once. So this is a strong proof that this file has no 2 static lyrics + 1 synced lyrics., but rather only 1 static lyric. Unless ofc the "atomization" of the lyrics makes even ASCII text hard to find.
- MP3
  - Contains a Field Lyrics Which shows: "High German: all High German lines // Viennese German: all Viennese German lines".
  - Seems like a complete representation
  - Shows no Synced Lyrics at all

Thanks for any directions!

porg commented 9 months ago

Preliminary but seemingly quite final research answer

No, Apple Music on macOS as of 2024-01 does not support synchronized lyrics for local audio files from ripped CDs or self-produced files.
This feature is only available for songs from the Apple Music subscription service.
→ More details