Files
songtrace/README.md
T
branderson be67e01943 webui: bring a selected song's inputs back into the form
Selecting a queue entry filled the review panel but left the form empty, so
the only way to adjust a song was the EDIT & REBUILD button, and the only way
to see what a song was built from was to click it. Selection now loads the
job's inputs, which is what the form is for: pick a song, change a line of
lyrics, hit REBUILD SONG.

That makes the EDIT & REBUILD action redundant, so it goes. CANCEL becomes
NEW SONG INSTEAD, which is what it does now that the form is rarely empty.

The landing page deliberately keeps its blank form: the job auto-selected on
load fills the review panel only, so opening the page is still the way to
start a new song.

Three things the old button-driven flow never had to handle:

- Advanced is opened when the job has a genre, year, language, bpm or a kept
  cover. Those carry into a rebuild either way, so leaving them behind a
  closed summary meant rebuilding with values that were never on screen.
- Submit is disabled, with the reason shown, while the selected job is queued
  or running, since /rebuild answers 409 until it settles.
- Selecting a different entry asks before discarding edits, and deleting the
  job the form is holding drops it rather than leaving the form pointed at an
  id that would 404.
2026-09-25 22:48:43 -07:00

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songtrace

Turn a song and its lyrics into a playable UltraStar chart.

A CLI and minimal web UI that turns a song — title, artist, lyrics you supply, and a YouTube URL or local video file — into a playable UltraStar-format song folder. Also compatible with Melody Mania.

Web UI

The pipeline:

  1. acquire — download audio/video via yt-dlp (or use a local video file)
  2. separate — split vocals/instrumental with Demucs
  3. transcribe — send the vocal stem to your own intranet Whisper server (OpenAI-compatible, or onerahmet/openai-whisper-asr-webservice), as a sanity check that the supplied lyrics match the audio and to locate vocal sections
  4. align — forced-align the supplied reference lyrics against the vocal stem with wav2vec2 (torchaudio's MMS_FA) to get word timings
  5. pitch — track pitch on the vocal stem with torchcrepe
  6. notes — turn word timings + pitch into UltraStar notes
  7. grid — quantise notes to a beat grid
  8. package — write the final song folder (.txt + .mp3 + video + cover)

The shipped .mp3 is the full original mix (vocals included) — the separated stems are used for analysis only and are not included in the output.

The output is a best-effort draft, not a finished song. Every run ends by printing the low-confidence regions it found (e.g. 3 low-confidence notes near 0:42–0:47) — open the result in an UltraStar editor such as Yass or USDX and touch those spots up before playing.

Configuration

Config is TOML. Resolution order:

  1. --config <path> passed explicitly on the command line
  2. the SONGTRACE_CONFIG environment variable
  3. ~/.config/songtrace/config.toml

Copy the example and fill in your Whisper server:

cp config.example.toml config.toml
$EDITOR config.toml   # set whisper_url at minimum

See config.example.toml for every available field (whisper_url, whisper_api_key, whisper_model, whisper_api, output_dir, work_dir, creator, demucs_model, crepe_model, device, bind_host, port, ytdlp_clients, ytdlp_cookies, ytdlp_impersonate, ytdlp_pot_provider_url).

whisper_api selects the wire format: "openai" (default) speaks the OpenAI-compatible POST {whisper_url}/audio/transcriptions API; "asr-webservice" speaks onerahmet/openai-whisper-asr-webservice's POST {whisper_url}/asr API instead (point whisper_url at that server's base URL with no /v1 suffix — whisper_model/whisper_api_key are unused for this backend, since the model is fixed by how that server was started).

Docker

cp config.example.toml config.toml
$EDITOR config.toml
docker compose up -d

The web UI is then at http://localhost:8000. Downloaded model weights (Demucs, wav2vec2, ...) are cached under ./data on the host so they survive container recreation.

Run the CLI inside the container instead of the web UI:

docker compose run --rm songtrace songtrace make \
  --title "Song Title" --artist "Artist Name" \
  --lyrics /data/lyrics.txt --youtube https://youtu.be/...

GPU passthrough requires the NVIDIA Container Toolkit installed on the host; docker-compose.yml requests one GPU via the nvidia device driver.

Bare-metal

pip install -e .
songtrace make --help
songtrace make --title TITLE --artist ARTIST --lyrics LYRICS_FILE \
  (--youtube URL | --video PATH) \
  [--genre GENRE] [--year YEAR] [--language LANGUAGE] [--cover COVER_IMAGE] \
  [--bpm BPM] [--force-from STAGE] [--config CONFIG]

Run the web UI instead with songtrace serve [--config CONFIG].

Re-running a stage

Each stage caches its output under work_dir. If a later stage needs another pass (e.g. you want to retry alignment with different lyrics, or pitch tracking looks off), re-run with --force-from <stage> to redo that stage and everything after it, reusing the cached output of everything before it:

songtrace make --title "..." --artist "..." --lyrics lyrics.txt \
  --youtube https://youtu.be/... --force-from align

Valid stages, in pipeline order: acquire, separate, transcribe, align, pitch, notes, grid, package.

In the web UI this is what selecting a queue entry does: its title, artist, lyrics and the rest come back up in the form, so you can adjust them and hit REBUILD SONG. Only the stages your edit actually invalidates are rerun — fixing a line of lyrics realigns without re-downloading or re-separating. NEW SONG INSTEAD clears the form to start a fresh song.

YouTube download failures

HTTP Error 403: Forbidden from the acquire stage means YouTube served the page but refused the media URL. In rough order of likelihood:

  1. yt-dlp is stale. YouTube changes its defences every few weeks and the version baked into the image does not. Hotfix a running container, then rebuild so it sticks:

    docker compose exec songtrace pip install -U 'yt-dlp[default,curl-cffi,deno]'
    docker compose restart songtrace
    docker compose build --pull songtrace   # permanent
    
  2. Missing JS runtime. yt-dlp needs yt-dlp-ejs plus a JavaScript engine to solve YouTube's player challenges; without them it silently falls back to formats that 403. The [default,curl-cffi,deno] extras in pyproject.toml cover this. Check with docker compose exec songtrace yt-dlp -v --simulate <url> — the debug header must show a JS runtimes: line that is not none.

  3. The IP is rate-limited or flagged. Datacenter and VPN ranges get throttled hardest. Try from another network before changing config.

  4. A PO token is required. If the log says so explicitly, run bgutil-ytdlp-pot-provider as a sidecar, install its plugin into the image, and point ytdlp_pot_provider_url at it.

ytdlp_clients retries the download against each listed player client in turn, so a client that YouTube has broken is skipped automatically. ytdlp_cookies (a Netscape cookie jar, for age-gated videos) and ytdlp_impersonate (a browser TLS fingerprint, e.g. "chrome") are the other two levers. Do not use a cookie jar from an account you care about — YouTube bans for automated access.

Failed downloads leave the work dir intact, so re-running the job resumes rather than starting over.

Regenerating the web UI screenshot

scripts/screenshot_webui.py seeds the real app with a fixed set of jobs covering every status and screenshots it to docs/images/webui.png:

pip install -e '.[dev]'
playwright install chromium
python scripts/screenshot_webui.py

License

AGPLv3