YouTube breaks old yt-dlp releases faster than songtrace is released.
songtrace now checks PyPI daily, and again after a download fails outright,
installs a newer stable release into its cache dir and tries it before the
bundled copy, which is never modified. yt-dlp runs in a subprocess through
its CLI, all from one module, so a cached release never mixes with the
imported one. ytdlp_version pins a release or turns updating off.
songtrace serve is long-lived but only wants the GPU in bursts, and until now
it kept everything it ever loaded. align cached wav2vec2 in a module dict that
was never cleared, torchcrepe caches its model on its own infer() function,
and even once the last reference to a model goes, PyTorch keeps the freed
blocks in its allocator rather than returning them to the driver. On a shared
box that is the whole GPU held against one idle process.
Stages now hand it back as soon as they are done with it. A stage that caches
a model registers how to drop it with @on_release, so models.py needs to know
nothing about the pipeline, and run_pipeline calls release() in a finally
after each stage — not once per job, because transcribe sits between separate
and align waiting on the Whisper server, which can be minutes of a GPU nothing
is using.
release() answers the bytes it handed back and the stage logs a line when that
is not zero, which is the only part of this visible from outside. It will not
initialise CUDA just to clean up after a run that never touched it.
The cost is reloading each model once per job rather than once per process,
seconds against stages that run for minutes. The CUDA context itself stays
until the process exits; releasing that would mean a subprocess per stage.
Two problems found in review.
CREATE SONG emptied the form but left the previous song's review, player,
output path and queue selection in place, which reads as though the blank
form and that song belong together. It now clears the page down to a blank
sheet, and a `composing` flag stops the next poll selecting the newest song
back into it.
The reason it cleared so little is that clearDetail reached for an element id
that no longer exists, so it threw partway through and left everything after
the first two lines untouched. It now targets the review box and takes the
reason to show, since "no songs queued yet" is wrong when you have simply
deselected.
Separately, rebuild plans from the fields that changed, which cannot see a
change in songtrace itself: rebuilding a song packaged before the video's
audio was stripped found every stage cached and kept the echo. The rebuild
form gains "restart from", the CLI's --force-from, which combines with the
planner rather than replacing it — an explicit stage may widen what is rerun
but never narrow it below what the edit requires.
Also: a browser submits a textarea with CRLF, so every rebuild from the page
looked like a lyrics edit and redid the alignment. Lyrics are normalised to LF
on the way in. And [hidden] is only display:none, which .field's display:flex
was winning, so the new control showed in new-song mode despite the property
being set.
Checking whether the notes line up meant packaging the song, finding it in
the game and starting it there. The review panel now plays the song folder
itself: a transport above the lyrics, the line being sung highlighted, words
lighting up as they are reached, and a playhead sweeping each line against
its notes. Clicking a line or a word plays from there.
Playback is modelled on the game rather than on whatever is convenient: #MP3
is the audio and the clock, #VIDEO is muted background slaved to it, and the
times are the same seconds the notes were generated from. A word that lights
up late here is late in the game.
package now strips the audio track from the video it writes. It is the same
recording as the #MP3, so a player that does not mute the video plays both a
few frames apart, which is heard as an echo. The compatible-video branch
remuxes with -c copy -an rather than copying the file, so it still does not
re-encode. The browser player mutes the video as well, which covers song
folders built before this.
A new /api/jobs/{id}/media/{audio,video,cover} serves what the song's own
#MP3/#VIDEO/#COVER headers name, refusing anything resolving outside the song
folder. Range requests come from FileResponse, so seeking works.
Also, per review: CREATE SONG moves out of the form and into the top of the
queue, where it is always available, and a successful submission keeps the
fields it sent instead of emptying them.
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.
yt-dlp declares `dependencies = []` and puts everything in extras, so the
bare `yt-dlp` requirement installed it with no yt-dlp-ejs and no JavaScript
runtime. Without those it cannot solve YouTube's player challenges and falls
back to media URLs that YouTube rejects with HTTP 403, which is the failure
seen when adding a song. Require `yt-dlp[default,curl-cffi,deno]` instead;
the deno extra ships the JS runtime as a wheel, so the image needs no extra
apt packages.
Around that, make the stage survive the next time YouTube changes something:
the download is retried against each player client in `ytdlp_clients`
(default `["default", "tv"]`, the latter not needing a PO token) before
giving up, yt-dlp's retry counts are raised, and its own log lines are routed
into the job log so a PO-token demand can be told apart from a rate limit.
The final error names the running yt-dlp version, since a stale one is the
usual cause.
Cookies, TLS impersonation and a bgutil PO token provider URL are now config
fields, so an operator can work around a block without a code change.
`_classify_downloads` skips .part/.ytdl scratch files, which retries make far
more likely to be lying around.
python:3.11-slim base relies on pip torch wheels bundling CUDA runtime libs,
with the host NVIDIA driver passed through via the nvidia container runtime
(compose GPU reservation); TORCH_HOME and XDG_CACHE_HOME point into the
mounted /data volume so Demucs/wav2vec2 weights survive container
recreation.
Docker was not installed in the implementation sandbox, so the image was
not built or run and remains untested. PyYAML was also unavailable, so
docker-compose.yml was not parse-checked programmatically — only hand
reviewed.
branderson