*Assempix* decodes COFDMTV encoded audio signals to images and is based on open-source software.<br><br>COFDMTV is based on COFDM (coded orthogonal frequency-division multiplexing) technology:<br>- 160 ms long OFDM symbols<br>- 6.25 Hz per sub-carrier<br>- 1/8 guard interval<br>- differentially encoded PSK (phase-shift keying) modulation<br>- systematic polar codes for forward error correction<br><br>Following modes are supported:<br><br>Using SPC(64800, 43072):<br>Mode 6: 8PSK, 2700 Hz BW and about 10 seconds long<br>Mode 7: 8PSK, 2500 Hz BW and about 11 seconds long<br>Mode 8: QPSK, 2500 Hz BW and about 16 seconds long<br>Mode 9: QPSK, 2250 Hz BW and about 18 seconds long<br><br>Using SPC(64512, 43072):<br>Mode 10: 8PSK, 3200 Hz BW and about 9 seconds long<br>Mode 11: 8PSK, 2400 Hz BW and about 11 seconds long<br>Mode 12: QPSK, 2400 Hz BW and about 16 seconds long<br>Mode 13: QPSK, 1600 Hz BW and about 24 seconds long<br><br>Payload must be smaller or equal to 5380 bytes.<br>JPEG, PNG and WebP image formats are supported.<br>Width and height are limited to between 16 and 1024 pixels.<br>