🇫🇷 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 English).
| 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, PD120, PD180 (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 and default settings (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 | Robot36: sync tracked line by line and measured clock (no slant); automatic AFC, manual Doppler offset |
| Analysis | Signal analysis, image displayed as it decodes |
| Output | PNG export of the decoded image; WAV recording of the microphone capture |
| Feature | Description |
|---|---|
| Input | WAV file |
| Searches | VIS code, sync pulses, line duration measurement |
| Plot | Instantaneous frequency, measurement on click |
| Results | Detected markers, timing analysis, log |
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 |
CC BY-NC 4.0 — see LICENSE (CC BY-NC 4.0).
Eric PERRET — GitHub