🇫🇷 Version française : LISEZMOI.md
Slow Scan Television (SSTV) in the browser: encode an image into an audio file, decode a file or live sound, diagnose a recording. Three standalone HTML files, no library, no installation. User interfaces in French (diagnostic tool in French or English, after the browser).
| Tool | Launch |
|---|---|
| SSTV multi-mode transmitter v4 | |
| SSTV Decoder Ultimate | |
| SSTV Diagnostic |
| Feature | Description |
|---|---|
| Image | Image loading, scaled to the chosen mode |
| Modes | Robot36 colour and B&W, Robot72, Martin M1 / M2, Scottie S1 / S2, PD90, PD120, PD160, PD180, PD240 (duration shown) |
| Signal | PCM 16-bit mono 44.1 kHz WAV, sample-accurate timing (Robot36 line = 150.000 ms) |
| Header | Standard VIS code (start bit, 7 bits, even parity, stop bit), optional 1 s calibration tone at 1,900 Hz |
| Output | Downloaded WAV file, to be played through a transmitter or a loudspeaker |
| Feature | Description |
|---|---|
| Sources | WAV file (8 / 16 / 24 / 32-bit or float, mono or stereo, any sample rate), or live audio from the microphone at its native sample rate (smartphone friendly, screen kept awake) |
| Modes | Automatic detection by VIS code, or forced: Robot36 / 72, Martin M1 / M2, Scottie S1 / S2, PD90 to PD240 |
| Synchronisation | All modes: sync tracked line by line and measured clock (no slant); automatic frequency correction (AFC) measured on the VIS leader and the sync pulses, up to ±250 Hz |
| WAV file | Opening a file runs the built-in diagnostic (VIS, sync measurements, clock error, drift, sync deviation and frequency plots) and decodes at once when the mode is known |
| Microphone | Family selector (Robot, Martin, Scottie, PD); reception starts on START; the last 5 minutes are kept and tapping the image decodes them again in the next sub-mode, even after STOP |
| Output | PNG export of the decoded image; WAV recording of the microphone capture |
| Feature | Description |
|---|---|
| Input | Any WAV file (8 / 16 / 24 / 32-bit or float, mono or stereo, any sample rate) |
| Measurements | Standard VIS, all 11 modes, sync pulses measured line by line: line period, clock error (ppm), cumulative drift (ms and pixels), sync duration and frequency |
| Plots | Sync deviation from nominal timing (a clock error shows as a slope); instantaneous frequency with zoom and A / B measurement on click |
| Language | French or English, after the browser |
The tools at the root of the repository are the approved version. Work in progress lives in the dev/ folder, same file names, online at tx-4.2, rx-1.8, diag-2.0…).
SSTV is used by radio amateurs to send images over HF / VHF. These tools let you experiment without a transmitter, through an audio cable or acoustic coupling; transmitting on amateur bands still requires a licence.
| Version | Change |
|---|---|
| 2026-10-17 | Files renamed without copy suffix, header blocks, home page fixed, README / LISEZMOI rewritten |
| 2026-10-17 | Transmitter 4.1: standard VIS, exact timing, Robot36 fixed. Decoder 1.1: VIS detection, any WAV format, Robot36 sync tracking. Validated against an external decoder and ARISS / PySSTV recordings (Robot36 only) |
| 2026-10-17 | Decoder 1.2: live microphone reception on the same decoding chain as files (Robot36 VIS, sync tracking, measured clock), tested on simulated acoustic coupling |
| 2026-10-17 | Decoder 1.3: microphone left at its default settings (browser processing off only on request), level meter in dBFS, recording of the microphone capture to WAV |
| 2026-10-17 | Decoder 1.4: no log displayed; microphone tab simplified: Robot36 only, start on regular sync pulses (VIS optional), touch-friendly audio processing toggle usable during capture, level meter -90 to 0 dBFS, capture recording below the image |
| 2026-10-17 | Decoder 1.5: microphone reception starts on START without waiting for VIS or sync, runs continuously until STOP (images follow one another), locks on the first sync found; a Robot36 VIS realigns the image to the top |
| 2026-10-17 | Decoder 1.6: microphone with echo cancellation and noise suppression off, automatic gain (preamp) on with a button to turn it off; PNG and WAV downloads fixed on Chrome Android |
| 2026-10-18 | Approved: transmitter 4.1, decoder 1.6. In progress in dev/: transmitter 4.2 (Robot72 fixed, PD90 / PD160 / PD240), decoder 1.7 (all modes with sync tracking, microphone family selector, 5-minute buffer re-decoded by tapping the image) |
| 2026-10-18 | Approved: diagnostic 2.0 |
| 2026-10-18 | In progress in dev/: decoder 1.8, file tab with the built-in diagnostic: opening a WAV runs the measurements and decodes at once when the mode is known (VIS or chosen); automatic frequency correction (AFC) measured on the VIS leader and the sync pulses, up to ±250 Hz; Analyse / Decode buttons, manual Doppler, waveform and spectrogram removed |
| 2026-10-18 | Approved: transmitter 4.2, decoder 1.8 |
| 2026-10-18 | In progress in dev/: decoder 1.9, microphone with all browser processing off, automatic gain (preamp) included; preamp button removed |
| 2026-10-18 | In progress in dev/: decoder 1.10, B&W variant of every mode (same signal, luminance only: transmitted Y for Robot and PD, BT.601 luminance of R, G, B for Martin and Scottie), each mode followed by its B&W variant when tapping the image, B&W variants in the file mode selector; transmitter 4.3, non-standard "Robot36 B&W" removed |
| 2026-10-18 | In progress in dev/: decoder 1.11, microphone state checked without a permission prompt: START greyed out when no microphone, access denied or non-secure page, reason shown on click and on start failure; capture falls back to ScriptProcessor when the AudioWorklet cannot load (page opened as a local file) |
| 2026-10-18 | In progress in dev/: decoder 1.12 and transmitter 4.4, interface in French or English after the browser language (no setting); transmitter layout adapted to phones |
| 2026-10-18 | AZS visual identity on all pages (stable and dev/): slate / amber / cyan palette, AZS band linking back to www.azs.fr, system fonts; no functional change; screenshots refreshed |
Free for non-commercial use — CC BY-NC 4.0, with mandatory credit of the source and the author:
sstv — Eric PERRET — https://github.com/ericperret/sstv
Any commercial use is forbidden without the author's written permission, requested by e-mail: eperret@azs.fr. Full terms (French / English): LICENSE.
Eric PERRET — GitHub