ATTENTION: FlyingFathead/sidpulse-tracker is the one and only official, original source for SIDpulse Tracker. Steer clear of other sources or repositories claiming to be the official project.
SIDpulse Tracker is a desktop music tracker for composing with the Commodore 64's SID sound chip, inspired by Impulse Tracker. Arrange notes across three voices, build instruments with waveform and pitch tables, shape their envelopes and filters, and hear the result through native 6581/8580 emulation as you work.
Save editable songs as .sidpulse projects, export .sid music files or
runnable C64 .prg programs, and render your tracks to WAV or MP3. PCM sample
import and sample-to-SID synthesis are also available alongside the tracker.
Watch Autumn at Five with audio (full song, 1:36)
- Three SID voices: compose for 6581 or 8580, PAL or NTSC, with native reSIDfp playback.
- Sample-to-SID wavetable synthesis: fit a self-contained SID instrument from a sample, compare source/result, then freeze or edit its tables. Preferred C64 workflow.
- Tracker workflow: patterns, orders and instrument editing, with Modern and Classic keyboard layouts.
- Channel automation: W waveform and AR arpeggio controls, sync/ring FX, plus editable/recordable A/D/S/R and pulse width; preserve the instrument settings.
- Flexible editing: select individual columns, copy notes or automation, paste special and undo changes.
- Live feedback: three voice scopes, channel and instrument mute/solo, and audio performance counters.
- C64 exports: SID and runnable PRG files, with four SQUEEZER versions, all-version comparison (optional Top 3) and measured size, RAM and playback cycles.
- PCM samples: F3 import, waveform trim markers, squeezing, and instrument sample overrides.
- WAV/MP3 export: output browser, format choice, and extra loop count (default 0).
- Editable projects:
.sidpulsesaves include version information and compatibility warnings when applicable.
Click the song name in the header to open F12 with Song title highlighted. Click the active instrument to open it in F4. Copy instrument / Paste instrument copy the complete instrument and assigned sample; occupied slots ask before overwriting, and paste is undoable.
F2 now has Select all for the whole current pattern and an Arp button on each channel. The previously unused EX column is now AR: type 0 for OFF, 1 for ON, R for the instrument setting, or . to hold. Commands persist on that channel; existing FX commands keep their meanings. See pattern arpeggio automation.
Current priority: sample-to-SID wavetable synthesis. Our preferred C64 workflow is to import a short sound in F3, fit a SID instrument with Synthesize audio (create wavetable), audition it, then use that instrument in the song. The result uses ordinary SID waveform/pitch tables. Improving these fits, with the included kick and snare as reference sounds, is the priority. How it works and current limits.
F2 now fits all three voice channels by default, scaling only the pattern grid's font and horizontal spacing. Header, toolbar and row spacing keep their normal size. Toggle Settings Menu > UI Settings > Fit 3 voice channels (F2) to keep the chosen grid font size instead. The control/filter column still collapses independently; very small windows retain a minimum font and follow the selected voice. Release notes and checks.
This includes the v0.2.38 CI repair for dialog scaling and layout/preset checks.
The fitter now measures short transients separately from the bass body, solves
a falling-pitch model, and checks native attack energy and snare noise content.
Each candidate chip is settled before measurement. Results remain ordinary,
frozen SID instruments with existing waveform, pitch and envelope programs.
Open examples/synthesized-reference-drums.sidpulse to audition the fitted
reference kick and snare. Method and limits ·
release notes and validation.
Stopped-state CPU is reduced by suspending silent emulation and redundant redraws. Input stays responsive; 2048 remains the default audio buffer and 512 is the stress setting. Performance checks.
The File menu now says Save as .sidpulse.... All four SQUEEZER versions, including v2.0.1 and default v2.0.2, and both DIGI methods remain available. DIGI methods and limits.
Choose either Git or a release ZIP. Both use the same launchers and need
Python 3.10+; Python 3.12 is tested. On first launch, the launcher creates a
local .venv and installs the pinned dependencies, which needs internet access.
git clone https://github.com/FlyingFathead/sidpulse-tracker.git
cd sidpulse-tracker- Linux: run
./run.sh. - Windows: run
run.cmd, or double-click it in the cloned folder.
Download the full ZIP and matching SHA256SUMS file for the release.
For this version, they are sidpulse-tracker-v0.2.39-full.zip and
SHA256SUMS-v0.2.39.txt.
Linux, from the download directory:
sha256sum --check --ignore-missing SHA256SUMS-v0.2.39.txt &&
unzip sidpulse-tracker-v0.2.39-full.zip &&
cd sidpulse-tracker &&
./run.shWindows: verify and extract the full ZIP, then double-click
run.cmd inside sidpulse-tracker. Accept the first-run setup when prompted.
For an existing ZIP installation, use the
v0.2.39 update instructions.
Press F5 to play, F2 to edit patterns, F4 for instruments and F8 to stop. Keep the launcher terminal open while the tracker runs.
The official site of SIDpulse Tracker, a homage to Impulse Tracker, reimagined as a modern SID-native tracker.
Created by FlyingFathead. Runs on native Python + pygame-ce desktop application, with Impulse Tracker and Schism Tracker as the main keyboard keymap and visual reference.
NOTE: This project is more or less a WIP (work-in-progress) at this stage, although the program is fully functional. Still, don't expect too much at this point, because the software hasn't been through years of extensive testing. I needed a SID tracker for my Commodore 64 projects, none of them had the classic Impulse Tracker interface, so I made this. This is a hobby project, and that's it.
Earlier changes: v0.2.35 DIGI method selection, v0.2.34 waveform automation and batch synthesis, v0.2.33 sample tools and wavetable synthesis, and the changelog.
Detailed earlier release descriptions are kept in
docs/ so this page stays focused on installation and current usage.
| Key | Action |
|---|---|
| F5 | Start song; show Info if already playing. Restart on repeated F5 is optional, default OFF. |
| Ctrl+F5 | Restart the complete song. |
| − / + on Info | Previous / next song order during playback; keypad also works. |
| F6 | Loop current pattern from row zero. |
| Shift+F6 | Play song from current order. |
| Ctrl+F6 | Loop current pattern from the current row. |
| Ctrl+F7 | Set/clear the separate playback mark in F2. |
| F7 | Play from that mark, otherwise the current pattern/row. |
| F8 | Stop song and audition. |
| Shift+F8 | Pause/resume. |
| Scroll Lock / Ctrl+F | Toggle tracing in the pattern editor. Default off keeps editing cursor independent. |
F2 returns to the pattern editor while the song keeps playing. The green row
and left > mark indicate playback; the outlined cell remains your edit cursor.
A * in the row gutter marks the F7 playback position. F5 uses the song loop
setting: F11 > Loop song when the playlist ends or F12 > Loop song at end
(on for new songs and First light).
An explicit loop=false in older projects stays off. F6 keeps looping until F8.
An unsequenced pattern selected with F7 plays as a pattern loop.
F4 selects SID instruments. Tab cycles bank/buttons/properties. Enter in the bank opens the instrument chooser; click a yellow parameter field to type its value. Keyboard jazz works while stopped: Caps Lock in F2, or normal note keys in F4. F2 audition uses the selected physical SID voice; F4 allocates three voices. During song playback, note entry edits the source without stealing its voices for separate audition. Use F8 before auditioning instruments.
F10 opens Save; Shift+F10 opens Save As. Ctrl+S/W quick-saves a named project outside the browser. Ctrl+Alt +/- zooms; Ctrl+Enter toggles fullscreen. Schism block keys are Alt+C/Alt+P/Alt+O. Ctrl+C centers the cursor; Ctrl+Backspace undoes and Ctrl+Shift+Backspace redoes.
In F4, switch to properties with Tab, then use PgUp/PgDn or click the General /
Motion tabs. Click a yellow field to type; sliders and envelope handles change
values directly while note keys remain available. Arpeggio and pitch sequences use signed decimal
semitone offsets, e.g. 0 3 7 12; waveform sequences use 10 20 40 80 hex.
An empty sequence disables it. Arps loop at the chosen ticks/step; wave and pitch
sequences advance each tick and hold their last step. Motion parameters use
decimal values; General SID registers use hexadecimal values.
Press Ctrl+Shift+F2 for filter focus, move to a row and press Enter. A row has
six values: cutoff, resonance, routing, mode, volume (hex), then signed cutoff
slide (decimal). A dot keeps the previous value; a zero explicitly sets zero.
Example: 380 A 2 10 F -3 routes voice 2 through a resonant low-pass filter and
lowers cutoff by three units each tick. Tab returns to voice editing. Ctrl+F2
continues to edit pattern length. Alt+Insert/Delete moves all voices and filter
rows together; voice/block editing operates on its selected voice lanes.
Shift+F9 opens song notes. Shift+Enter inserts a line; Enter commits. Notes
remain in .sidpulse, including Unicode and line breaks.
Ctrl+Shift+E, or Escape > File > Export PSID, compiles the current document.
The export-only squeezer starts enabled. Choose S to save .sidpulse and export,
E to export only, or Escape to cancel. A analyzes changed checkbox settings.
An export alone never marks unsaved edits as saved. F12 offers PSID released text
and whole-song loop. Existing export files get an overwrite prompt and backup.
For a command-line export that also saves a native source:
bash run.sh --example --export-sid user_songs/first-light.sid
# Or export an existing project; a sibling .sidpulse is always saved:
python -m sidpulse user_songs/song.sidpulse --export-sid exports/song.sid--save-project PATH changes the native-save destination for a CLI export.
The bundled 6510 player requires no assembler, emulator executable or extra
runtime package on your machine.
Escape > File starts with New project, Clear all pattern data, and Clear all instruments. Each asks for OK / Cancel and defaults to Cancel. Clearing patterns empties their voice cells and filter rows while keeping pattern numbers, names, lengths, the order list, instruments and song notes. Clearing instruments removes the whole bank while retaining patterns and their instrument numbers. Both are single undoable edits. Empty slots play silently until repopulated. PSID export reports an empty bank or a used empty slot instead of silently omitting its notes; native .sidpulse saving remains available.
The file browser's Modified column uses local time, YYYY-MM-DD HH:MM, for files
and folders. Its default is on. Toggle File timestamps in F12, or set
"file_browser_show_modified": false in preferences.json. Narrow views hide the
date column to keep filenames readable. Selected dates stay green on black.
Press Alt+F12, open Escape > Settings > Audio settings, or choose Audio buffer in F12. Select an output, use Test arpeggio to preview it, or Refresh outputs after connecting hardware. Reset defaults stages the three audio defaults without changing appearance or other preferences. Drag the slider from Less delay to More stability, or use Left/Right. The current sample count and milliseconds update as you move. OK applies and saves; Cancel or Escape keeps the original setting. Tab reaches every control; Enter activates the focused control. There is no numeric-entry prompt. Available steps are 256, 512, 1024, 2048, 4096 and 8192 samples. Default: 2048 samples / 42.7 ms per buffer. Existing explicitly saved values are retained; use the slider to change them. Larger values help tolerate busy or slower PCs but add latency. This displayed buffer duration is not total output latency: up to two PCM blocks are queued and the device adds its own buffering.
Applying a buffer setting briefly reopens SDL and resumes from the next generated
position; already queued audio is discarded. The setting persists per machine,
not in your song. --audio-buffer 4096 overrides it for one launch. Linux config
is $XDG_CONFIG_HOME/sidpulse-tracker/preferences.json (normally under ~/.config);
Windows uses %LOCALAPPDATA%/SIDpulse/preferences.json.
The saved Detect audio underruns / warn checkbox defaults to ON. Its config
key is audio_underrun_detection (true/false). Live warnings appear as a small
reddish lower-left footer message for 12 seconds, with Alt+F12 as the shortcut;
they never open a popup or steal focus. A late callback is labeled separately
from a confirmed PCM underrun. Raw counters remain available when warnings are
disabled. Audio settings also show missing frames and callback timing.
The Info page shows Audio gaps: continuous episodes where the SDL callback
requests PCM during playback/audition and none is ready. Each episode counts once,
including a long starvation; normal startup, pauses and idle silence do not count.
The old gaps counter polled short-Sound queue state, so its numbers are not directly
comparable. Counters accumulate until Reset audio counters (Settings); reopening
the device preserves these session counters. Late worker wakes, current/peak render
budget and over-budget blocks help distinguish scheduling and rendering pressure.
These are application measurements, not whole-PC CPU usage or definitive proof
of every driver/hardware underrun. A quiet native emulator startup is explicitly
muted; a 5 Hz DC blocker and 5 ms transport ramps condition host PCM only.
Download the v0.2.39 full ZIP and SHA-256 checksum file from the same release. In PowerShell, verify the ZIP before extracting:
$zip = ".\sidpulse-tracker-v0.2.39-full.zip"
$checksums = ".\SHA256SUMS-v0.2.39.txt"
$lines = @(Get-Content -LiteralPath $checksums -ErrorAction Stop | Where-Object {
$_ -match '^[0-9a-fA-F]{64} [ *]sidpulse-tracker-v0\.2\.36-full\.zip$'
})
if ($lines.Count -ne 1) { throw "Missing or ambiguous full-ZIP checksum." }
$expected = ($lines[0] -split '\s+')[0]
$actual = (Get-FileHash -LiteralPath $zip -Algorithm SHA256 -ErrorAction Stop).Hash
if ($actual -ne $expected) { throw "ZIP checksum mismatch. Do not extract." }
Expand-Archive -LiteralPath $zip -DestinationPath . -ErrorAction StopOpen PowerShell or Command Prompt in the extracted sidpulse-tracker folder
(the one containing run.cmd and run.ps1), then run:
.\run.cmdTo start with First light or open your own project:
.\run.cmd --example
.\run.cmd "C:\Music\My song.sidpulse"run.cmd calls the adjacent run.ps1, forwards arguments, and returns its exit
code. If setup is needed, run.ps1 lists Python, the local environment and the
contents of requirements.txt under "The following Python dependencies are
required and need to be downloaded", then asks Continue? [Y/n] before making
changes. Enter or Y accepts; N cancels installation. Missing 64-bit Python is installed as Python
3.12 through WinGet for the current user; if WinGet is unavailable, the launcher
prints the official Python download address. Packages are installed into .venv.
An internet connection is needed for installation. Later runs reuse the ready
environment and skip the setup prompt. The WinGet options follow Microsoft's
install command documentation.
If calling .\run.ps1 directly reports "running scripts is disabled", use
.\run.cmd. The wrapper starts Windows PowerShell with
-NoProfile -ExecutionPolicy Bypass -File; that override applies only to the
launched process. It does not persistently change your execution policy or need
an administrator terminal. Microsoft documents the process-specific option in
about_PowerShell_exe.
For an existing ZIP installation, close the tracker, back up the folder, verify
the full ZIP as above, then extract it over the installation (use -Force with
Expand-Archive to allow replacement). User songs, autosaves and .venv are not
release contents. Preserve local source edits separately; extraction replaces
files rather than merging them. Git checkouts can update with git pull --ff-only
on main after reviewing and preserving local changes.
If you prefer manual setup:
py -3 -m venv .venv
.\.venv\Scripts\python.exe -m pip install -r requirements.txt
.\.venv\Scripts\python.exe -m sidpulseDirect run.ps1 remains available where script execution is already enabled.
The CI matrix includes Windows/Linux tests and the Windows CMD-to-PowerShell
first-run path. Check the Actions result for the exact release commit; local
validation does not substitute for the remote matrix. The validation procedure
is recorded in VALIDATION.md.
python -m pip install -e '.[dev]'
python -m pytest -q
python -m sidpulse --headless-smoke --example
python -m sidpulse --log-keys keys.logPublic release assets are the full source ZIP and its SHA-256 checksum file. Build them from the checked release tag, not by zipping a working directory. Local cumulative patches are not public release assets. Do not include Git history bundles, private project notes, environments, backups or user projects. Clone the repository for Git history. See RELEASING.md for the commit, CI, tag, archive and release-review sequence, and release notes for the user-facing change summary.
Repository: FlyingFathead/sidpulse-tracker.
See PLACEHOLDERS.md, CHECKPOINT.md, VALIDATION.md, IT_KEY_COMPAT.md, COMMANDS.md, EFFECTS.md, PSID_EXPORT.md, PLAYBACK.md, SIDPULSE_FORMAT.md, DECISIONS.md, and the unchanged v4 roadmap.
Thanks to Lasse Öörni and the GoatTracker contributors for the extensive documentation on storing song data more compactly and optimizing playback routines. The GoatTracker documentation served as a useful reference for SIDpulse Tracker's squeezer. The implementation is independent; no GoatTracker code was incorporated. See the optimization study.
- audio-bitsqueezer — Convert audio into compact 4-bit SID samples and playable C64 programs or EasyFlash cartridges, with a command-line interface and local browser UI.
- c64-3d-toolkit — Compile low-poly wireframe models and Blender scenes, animations and physics into C64 demos, with OBJ/MTL and SVG import support.
SIDpulse Tracker has been made by FlyingFathead. Special thanks to: ChaosWhisperer