peter
5a42d76e8a
Bug hunt 2026-09, item 14 — "how does the multichannel downmix work, and is it
normalised?" It isn't: `plex/stream.py` has always encoded `-c:a aac -ac 2 -b:a
192k`, i.e. fixed stereo with ffmpeg's default downmix matrix and no loudness
handling at all, which is why a film mastered for a cinema arrives with whispered
dialogue and deafening action.
New admin knob `plex_audio_loudnorm` (Configuration → Plex), DEFAULT OFF: it makes
a film markedly louder and narrows its dynamic range, which is a taste call rather
than a fix. It sits at the end of the Plex group, after the software-transcode
knobs — it is an audio concern, not one of the libx264 ones.
-af aformat=channel_layouts=stereo,loudnorm=I=-16:TP=-1.5:LRA=11,aresample=48000
Three things about that chain are load-bearing and each has a test:
* the downmix is FORCED FIRST rather than left to `-ac 2` — measuring 5.1 and
folding it down afterwards would normalise something other than what is heard;
* the trailing resample is not decoration: `loudnorm` runs its own resampler at
192 kHz internally, which the AAC encoder will not take;
* one `-af`, no stream index, so EVERY audio rendition of a multi-audio file is
normalised — not just the first.
The knob is also part of the session directory name (`…_multi-ln_+0.00`), because
it changes the audio the segments contain, and a session left over from before the
admin flipped it must not be mistaken for one that honours it. The suffix is
appended with a DASH: `_SESSION_DIR_RE` treats the tag as one underscore-free
field, and that regex is the only thing keeping the orphan sweep off what may be a
shared scratch path. A test pins both halves — the name changes, and the sweep
still recognises it.
Measured end-to-end on the app's own HLS segments (a real 5.1 AC3 file, same item,
same 160 s offset, same ten segments): OFF -35.2 LUFS, ON -17.2 LUFS. On a 60 s
bench: I -27.6 → -16.6 LUFS with LRA 13.3 → 9.8 LU. A/V sync is untouched — under
this pipeline's own `-copyts` the audio start PTS is identical with and without the
filter, so the 3 s lookahead desyncs nothing.
Direct-played files are served untouched and stay so; a 5.1 mix is always `remux`,
so the reported case is fully covered.
Siftlode
Your YouTube subscriptions, the way a feed should work. Siftlode pulls every upload from the channels you follow into one clean, filterable feed — no algorithm deciding what you see, and no Shorts or livestream noise unless you want it. Self-hosted, multi-user, and private: your data stays on your own server.
Everything expensive (channels, videos, metadata) is fetched from YouTube once and stored locally, so filtering, searching and sorting are instant and don't burn API quota. Click a video to watch it in an in-app player that resumes where you left off — or open it on youtube.com so your own ad blocker and SponsorBlock keep working.
Features
- A readable subscription feed — sort and filter by channel, tag, language, topic, length, upload date or watch state; hide channels without unsubscribing; save filter setups as named views.
- Search all of YouTube from the feed — live results you can play, save or add to playlists like any other video; they stay temporary and out of your catalog unless you keep one.
- Channel pages & a channel manager — per-channel stats and uploads, priorities, and your own tags to slice the feed by.
- Playlists with two-way YouTube sync — build them locally, keep them in sync in both directions.
- In-app player with resume, plus keyboard/scroll controls.
- Download Center — save videos to the server with yt-dlp in a Plex-friendly layout (format presets, per-user storage quota), trim / crop / split & join them in a built-in editor, then save to your device, share with another user, or hand out a public watch link.
- Plex library (optional) — point Siftlode at your own Plex server to browse and play its movies and shows alongside your feed, with watch state kept in sync.
- Multi-user with per-user private state, a shared catalog, and a fair daily API-quota guard.
- Self-hosted & private, with a first-run web setup wizard and the interface in English and Hungarian.
Quick start (self-hosting)
You don't need to build anything — Siftlode runs from a prebuilt public image, and all configuration (your admin account, Google sign-in, email) happens in a first-run web wizard. You need Docker with the Compose plugin.
1. Get the files and run the installer:
git clone https://git.b1fr0st.eu/peter/siftlode.git
cd siftlode
./install.sh # Windows (PowerShell): ./install.ps1
The installer generates a private .env (secrets), pulls the image, starts the app + database, and
prints a one-time setup URL like http://localhost:8080/setup?token=….
2. Finish in your browser. Open that URL and follow the wizard:
- Admin account — the email + password you'll sign in with.
- Google sign-in (optional) — paste a Google OAuth client to enable "Sign in with Google" and pulling your YouTube subscriptions. Skip it to use email + password only.
- Email / SMTP (optional) — for verification/notification emails. Skip it and you (the admin) simply approve new accounts yourself.
Then sign in with your admin account. That's it. See docs/self-hosting.md for the full walkthrough.
Just trying it out? Press Enter at the installer's URL prompt to run on
http://localhost:8080.
Build from source (alternative)
Prefer to build the image yourself instead of pulling it:
git clone https://git.b1fr0st.eu/peter/siftlode.git
cd siftlode
cp .env.example .env
# generate the two secrets and paste them into .env:
python -c "import secrets;print('SECRET_KEY='+secrets.token_urlsafe(48))"
python -c "import base64,os;print('TOKEN_ENCRYPTION_KEY='+base64.urlsafe_b64encode(os.urandom(32)).decode())"
docker compose up --build -d # builds from the included Dockerfile
Open http://localhost:8080 and finish in the setup wizard as above. (Set a POSTGRES_PASSWORD in
.env too.)
HTTPS / public access
Port 8080 over plain HTTP is fine for a LAN or a quick trial. For public access put a reverse
proxy (Caddy, Nginx, Traefik…) in front to terminate TLS, and set the public URL (the installer
prompt, or OAUTH_REDIRECT_URL in .env) to your https://… address — this also marks the session
cookie secure. Add that same …/auth/callback URL to your Google OAuth client's authorized redirect
URIs. Behind a proxy, also set TRUSTED_PROXY_IPS so the rate limiters see the real client IP and
can't be bypassed via a forged X-Forwarded-For — see docs/self-hosting.md.
Updating & backups
docker compose -f docker-compose.selfhost.yml pull # or: docker compose pull
docker compose -f docker-compose.selfhost.yml up -d
That follows latest, which moves with every release. Set IMAGE_TAG=0.80.0 in .env to pin a
version and upgrade on your own schedule; released versions are listed in CHANGELOG.md
and in the app's Release Notes. The registry keeps only the newest few of those, so a pin decides
when you take the next hop rather than letting you stay put forever — see
docs/self-hosting.md.
Back up before upgrading. Migrations run automatically on startup and are not undone by pulling
the old image back. A backup is the database dump plus your .env — TOKEN_ENCRYPTION_KEY is
what decrypts the Google, SMTP and Plex secrets stored in that database, so a dump restored without it
is only half an instance. Use scripts/backup.sh (or backup.ps1 on Windows) and scripts/restore.sh;
the equivalent one-liners, the pinning recipe and the rollback steps are in
docs/self-hosting.md.
How it works
- Shared catalog, private state. Channels and videos are stored once and shared; each user's subscriptions, tags, playlists and watch/save/hide state are private.
- Cheap by design. Public reads are cached locally; a shared daily quota budget and a background scheduler keep unattended syncing within YouTube's free API limits. An optional API key lets backfill run without depending on a user's OAuth token.
Tech
FastAPI + PostgreSQL (SQLAlchemy, Alembic) backend; React + Vite + Tailwind + TanStack Query frontend; packaged as a single Docker image with Docker Compose.
License
GNU AGPL-3.0. You can run, study, modify and share Siftlode; if you modify it and let other people use it over a network, they are entitled to your modified source. Copyright © 2026 Siftlode contributors.
Note
This project is developed with AI assistance.