Martin mode
Martin 4
M4 is a reference-only analog SSTV row with 29 s duration, 320 x 128 raster, RGB color model, and VIS 32.
Reference onlyMode sample
BBC-style colour test card and app-generated audio
The image is generated locally for this mode's raster. For supported modes, the audio sample is encoded from that image with the SSTV Signal Desk transmitter code, then published as lossless FLAC for static playback.
No app-generated audio sample is published for this reference-only mode because no matching transmitter entry exists in the app code.
Mode spec
| Short name | M4 |
|---|---|
| Support status | Reference only |
| Spec status | Reference timing row from the OK2MNM SSTV mode-list PDF. |
| Duration | 29 s |
| Frame | 320 x 128 |
| Data lines | 128 |
| Public VIS | VIS 32 |
| Standard VIS code | 0x20 (32) |
| Extended/N-VIS | No |
| Color model | RGB |
| Component sequence | G-B-R |
| Line rate | 264.553 lpm |
| Public timing profile | Mode-list row gives 29 s total duration, 128 scan lines, 320 columns, and 264.553 lpm; line-level porch timing is not part of this catalog row. |
Strengths
- M4 has a concrete catalogue row: 29 s, 320 x 128, RGB, VIS 32.
- M4's G-B-R component order and 264.553 lpm line rate make it useful for comparing airtime, raster, and colour structure against related modes.
Tradeoffs
- M4 is not app-supported yet, so the 29 s / 320 x 128 row should be treated as reference data rather than a verified transmit preset.
- M4 still needs implementation-grade porch, sync, and pixel timing before an app-generated WAV/FLAC sample can be published with the same confidence as supported modes.
Source notes
OK2MNM SSTV Handbook chapter 5 lists M4 as RGB, VIS 32, 29 s, 128 lines, 320 columns, 264.553 lpm. Less common Martin family variant beyond the app-supported M1 and M2 modes.
- SSTV Handbook Chapter 5: List of SSTV modesSSTV Handbook - accessed 2026-08-24Reference for analog SSTV mode names, VIS codes, durations, line counts, column counts, and line rates.