v0.5.0

Compatibility changes

• Plain CLI sessions no longer automatically select devices named DJS- as the test target. Pass --target PLAYER|IP for /api/unit, unit_* events and unit scenarios. Existing Python defaults and the explicit emulator adapter keep their previous target behavior.
• Clearing Events no longer resets event timestamps. Times remain relative to session start, matching Network capture. Event numbering still restarts on clear. Use session and generation to distinguish histories.

MASTER, SYNC and player controls

• Serialize automatic MASTER handoffs with explicit requests and skip device snapshots when no handoff is needed.
• Reconcile early MASTER commands with the sender's late status through a coordinated handoff.
• Decode acceptance in standard-length master takeover replies.
• Add opt-in SYNC and MASTER commands on discovered player cards.
• Hand a stopped virtual master's role to an eligible playing, synced follower.
• Add opt-in fader-start transport controls for discovered players without enabling the simulated mixer.
• Explain that hardware fader-start commands require a stopped player at cue to start and a playing player to return to cue.
• Keep delayed simulated-mixer packets from restoring on-air state after the mixer is switched off.
• Make the demo's observed synced player follow master tempo and bar phase, with matching packet-log values.

Observation and diagnostics

• Add an announced observer mode without simulated playback decks or database servers.
• Clear an observer's number-conflict warning when the conflict ends, without discarding other network errors.
• Add continuous UDP capture, a full retained-capture export and explicit view limits.
• Keep Events and Network on one session clock and reset replayed history on reconnect.
• Report external-player state changes and allow an explicit test target without auto-selecting a DJS.
• Record incoming database queries for hardware troubleshooting.
• Decode mixer tempo status and CDJ-3000 precise positions without inventing beat grids.
• Query loaded-track metadata on demand and serve meaningful synthetic tempo and duration fields.
• Export full packet payloads and replay captures offline with seeded loss, delay and jitter.

Platform support and reliability

• Add native macOS interface and MAC discovery, a dedicated CI job and Ethernet/VM bridge setup guidance.
• Print a usable browser URL with the actual port and token, including in phone mode.
• Bound listener waits during shutdown and use a configured localhost address for the Mac mixer endpoint.
• Add explicit network worker shutdown, socket cleanup and cancellable handoff timers.
• Isolate CLI sleep mocking so checks cannot interrupt other network workers.
• Make the startup-error test own its conflicting port without a timing-sensitive helper process.

v0.4.0

Phone access and setup

• Add phone pairing links and optional QR codes with --phone.
• Select the wired DJ adapter with --dj-interface and inspect available interfaces with --network-info.
• Add a Windows firewall helper with scoped installation, inspection and removal.
• Clarify browser connectivity, DJ network addressing and optional second-adapter setups.

Real-device interoperability

• Support MASTER and SYNC handoffs between simulated decks and physical players.
• Use actual adapter MAC addresses and send player status directly to discovered peers.
• Fix compatibility fields associated with older-firmware warnings and advertise no shared USB or SD media.
• Show broadcast tempo and beat position without enabling a simulated deck.
• Treat physical DJS-1000 units as normal players unless an emulator test adapter is configured.

Beat display and browser audio

• Align physical-player beat grids and retain loop shading across loop wraps.
• Show a compact master beat reference above each deck's beat indicators.
• Support browser audition of broadcast-only beats and explain unavailable or suspended audio.

Network tools

• Keep the visible log stable with Follow off while packets continue collecting.
• Preserve text selection and export held rows when the view is frozen.
• Clearly distinguish simulated mixer controls from discovered physical mixers.

v0.3.0

191 tests pass on Windows with Python 3.10. The GitHub Action passes on Ubuntu and Windows with Python 3.8 and 3.12.

Packaging and reliability

• Installed packages include adapters, with an isolated CLI and asset check.
• The sampler phase check establishes status-before-beat ordering across UDP ports instead of depending on thread scheduling.
• CI keeps full verbose logs and uses fixed OS images without automatic retries.
• The README is shorter, with CLI and API detail in docs/reference.md.

The page

• Play is play and pause: a deck that pauses stays where it is and plays on from there (it used to start again from its first beat). A deck is at its first beat when its track is loaded.
• CUE, as a CDJ has it: while playing it goes back to the cue point and pauses, held on the cue point it plays until let go, paused elsewhere it sets the cue point. POST /api/deck/<n>/cue[/<1|0>]. The status says cued and cue playing besides paused and playing.
• The deck's number is its on / off switch, and the ON button is gone.
• A deck that is off shows only its number and its name, so the page is not mostly dimmed controls. Its card is as tall as that, not as tall as the decks that are on.
• The header says what each sound is for: the chip unit input is the port the decks' sound is served on for a unit, and the button Listen plays it in the browser (it was Sound).
• A chip recording a session shows while a journal is kept (see docs/link.md).
• A message that something went through (a file sent, a scenario kept or copied) has a green outline, like a deck that is on. The red outline is for errors, and there is a yellow one for a warning (toast(text, "warn")).

Cue, loops and moves on the grid

• CUE and a loop go to the nearest beat, before or after where the deck is (a loop started 0.3 beats late used to start on the beat before, and a cue was wherever it was pressed). A deck that sets its cue is on it, so CUE held there plays from it.
• The deck can be moved in its track: POST /api/deck/N/seek/BEAT and jump/BEATS (negative goes back), and a Move row on the page: to the first beat, and a bar or four bars back or forward. A cue set late in a track could not be left before. A loop that is set stays through a move: waited for when it is ahead, gone round when the deck is in it, left behind (still marked) when the deck is moved past it.
• A pause stops where the playhead was when the page was clicked. The page sends the moment of the click (?at=, in the bench's clock), so a request that is slow to arrive (a bench across WSL) no longer makes the deck run on, or the strip jump, before it stops.
• A loop that is set is drawn ahead of the playhead, with the chip "LOOP 4 in 1.4 beats", and on a stopped deck too (it only showed once the deck was in it).
• The strip and the page's sound no longer jump forward by a tenth of a second or so when play or cue is pressed. The answer to a click comes by another road than the stream, and a quicker one moved the page's idea of the bench's clock half way at once. It now moves by 5 ms at most for each state.

The unit's input is one deck

• POST /api/audio/source/<n|all> makes the sound port play only deck n, or all the decks again, while the bench runs (--audio-decks still sets the decks it is started with). The state says which in bench.audio_source, the page's "unit input" chip shows it, and a journal keeps it. The DJS-1000 emulator's deck calls it when the INPUT SOURCE knob of LIVE SAMPLING is turned.

Sent files are kept

• The files the page sends with Browse are kept between runs in ~/.deckbench/tracks (--tracks-dir, $DECKBENCH_TRACKS), named by a hash of their contents, so the same file is one file and a path a session recorded is found again. They used to be in a temporary folder that was only removed when the bench exited by itself, and was left behind when it was stopped (pkill, the emulator's start.py stop).
• Files unused for a month are removed at the start, and the oldest when the folder passes 2 GB. A file a deck has loaded stays. --clear-uploads, POST /api/uploads/clear and a button in the page's Settings empty it, and GET /api/uploads says what it holds.

A journal of a session

• POST /api/journal/start begins keeping every request that changes the decks, with its time, after a baseline of requests that would put the decks where they are. POST /api/journal/stop answers both. A program that records a session (the DJS-1000 emulator's REC) keeps it and sends it again to a bench to play the session back. See docs/link.md.

Tracks of your own

• A deck can play a sound file instead of its drum loop: --track DECK=FILE@BPM[@START], the page's "Load a track" fold, or ?audio= on the load request of the API. You say the BPM it was made at, and the deck plays it at its own tempo. See docs/audio.md.
• A deck that plays a sound file has its waveform behind its strip's beat grid, laid out from the BPM and the first beat you gave, so that a wrong one is seen. It comes from /api/deck/N/waveform.
• The strips no longer jump a few pixels now and then. The page took the bench's clock from each state as it arrived, so the delay of that message (a few milliseconds, more through WSL) moved them. It now follows the quickest messages and ignores the slow ones.
• The waveform is one smooth shape, with the loudness taken between its values, and does not shimmer as the strip scrolls.
• The bench's server keeps a queue of 128 connections instead of 5. A page that opened its event stream and a dozen requests at once, with something else asking too, could have one held back a second, or refused through WSL's forwarding of localhost, and said "The bench does not answer."
• The page's Sound button plays a deck's file when it has one (it played the drums of every deck). It is fetched from /api/deck/N/audio.wav.
• The page's Browse button opens the browser's file picker and sends the file to the bench (/api/upload), so a bench in WSL or on another machine gets a file from the one the browser is on.

Testing from code

• The bench says when every socket it listens on is bound, and start() and the command line wait for that, so a bench is listening when start() returns. The monitor counts the packets it reads, so a test sends a marker on each port and waits for it instead of sleeping.
• A test that is beaten to a port (the system hands the range's ports to client sockets) takes the next range and starts again.
• A player is heard once its keep-alive has come as well as its status. The keep-alive says who it is, comes on another port and can come later.

Fixes

• A DJS-1000 on the link has its beat strip follow the beat of its bar. It sends 0 for the beat in the track, which the page kept as a place, so the strip stood on one beat.
• The state of another device on the link (MASTER, SYNC, ON AIR, LOOP, OFFLINE) is side by side, right under the UNIT UNDER TEST tag, as tall together as the number's box. When there are too many for the width they wrap onto a row under. A flag that comes or goes does not change the card's height.

v0.2.0

Tested on Ubuntu and Windows, with Python 3.8 and 3.12. The GitHub Action passes on all four.

Listen to the network

• The bench now hears other players and mixers on the link and shows each as a read-only card with its model and what it does.
• The Network tab has a log of the Pro DJ Link packets as they come (/api/packets). The bench's own packets, statuses and beats are options. See docs/link.md.
• A synced deck now snaps to the master's beat grid, not only to its tempo.

The page

• New look, the same as commitcollective.cc: black and white, thin lines, square corners. Colour only carries meaning: green for on and on air, blue for sync, amber for the master, purple for a loop, red for beat 1 and for a fault.
• Two looks, each in dark and light, chosen in Settings: Commit (the default) and Classic, the first look.
• Each deck and device has a scrolling strip with a grid of beats and bars. A loop shows where it goes back.
• The tempo slider changes the tempo while you drag it, not on release.
• The Sound button plays each playing deck's beat (kick, snare, hat). With a mixer, only decks on air are heard. Settings choose which decks and devices you hear.
• The page can be hosted on another site and used from a phone. See docs/phone.md.
• ?demo runs a bench made of JavaScript inside the page, with no server.

Safety

• The API now refuses requests from web pages of another origin, since any site could otherwise drive a bench on localhost. --allow-origin lets one in.
• --token makes the API ask for a token.

Releases and hosting

• A tag now makes a GitHub release with the changelog entry as its notes.
• The tests run on Ubuntu and Windows, and the workflow says which test failed.
• The page is served by its own Cloudflare worker, so changing it needs no push to the website. See docs/hosting.md.

Fixes

• UDP sockets are shared with SO_REUSEPORT on macOS.
• The page's server no longer does a reverse lookup at start, which held it up for many seconds on a macOS runner.
• The WSL test of Bench only runs where a WSL distribution starts.
• The mixer's channel rows no longer share a CSS class with the beat strips.

v0.1.0

The first version.

Simulated decks

• Pro DJ Link decks with discovery, status, beats, tempo master, sync and hand-off, loops, and the database server for track titles.
• --profile makes the decks stand in for a CDJ-2000 (nexus), CDJ-2000NXS2, XDJ-1000MK2 or CDJ-3000, with its name, status length and nexus byte.
• A deck can load a track from another deck's database and slot.
• --claim makes a deck do what a real player does when it comes online. A deck that is on defends its number against another device.
• Strict decks behave as a CDJ-2000NXS2 does.
• A simulated DJM mixer (--mixer) announces itself as device 33, reports which channels are on air, and starts and stops players with fader start.
• Each deck has sound.
• Network faults can be simulated, for example 30 % packet loss.

The page and the API

• A card for each deck: switches, beat squares, tempo display and slider, loops, cable, and a track from any deck's database.
• Tabs for events (filter, pause, export), scenarios (editor, examples, saved), the network and the settings. Works in light and dark.
• An HTTP API and a command line drive the same things.
• Some settings change while it runs (/api/settings): strict decks, database refusal and the model name.

Scenarios

• Scenarios script the decks and check what the device under test did.
• expect_unit checks its master role, sync, tempo and lamps. expect_deck checks the decks.
• unit presses its controls, when acts only in a given state, and require says what the scenario needs. A scenario that needs a unit or adapter that is missing is skipped, not failed.
• Matchers: near, min, max, in, not.
• --scenario takes several files or a folder and ends with a summary.
• Examples are in deckbench/examples.

Testing a DJS-1000

• --adapter djs1000-emu reads the emulator's lamps and presses its SYNC and MASTER. The Network tab shows the unit's state with buttons.
• A library of scenarios in deckbench/examples/unit: the unit follows a master deck and its tempo, the master role passes between deck and unit, and it keeps following after a cable pull and with 30 % packet loss. 40-on-air.json checks that the unit says it is on air when the mixer's channel 1 is open.
• More of the unit is heard: synced, playing, on air and the beat, with unit_sync and unit_play events.

Running it

• --port-shift moves every port of the decks. The bench names the port it cannot have when it starts.
• --ready-file, GET /api/ready and deckbench.testing.Bench start a bench from a test without guessing a delay.
• Runs on Linux and Windows with Python 3.8 and later. The tests use ports of their own, so a running bench or rekordbox does not matter.
• Not supported on macOS: the loopback carries no broadcasts, so decks on 127.0.0.n are not heard. Use --bind there.

Fixes

• A title with a percent sign is no longer decoded twice.