One scan line is one major frame of 12375 bytes, consisting of 15 minor frames of 825 bytes each. Minor frames have a 9 byte header plus 816 bytes of video data, except the last minor frame in each major frame which has only 384 bytes of video data with the rest being calibration data.
Major frames are ingested with each byte stored in a 16-bit word plus each major frame is padded to 25600 bytes. However frames are packed back into 12375 bytes when stored on disk.
| Byte offset | Contents |
|---|---|
| 0 | Sync 10110010 = 0xB2 = 178 |
| 1 | Sync 00011110 = 0x1E = 30 |
| 2 | Sync 01011001 = 0x59 = 89 |
| 3 | Frame number 1010nnnn = 0xAn = 160+ |
| 4 | Time code is 5 bytes transmitted as one byte per minor frame and repeated 3 times, ie. only changes once per scan line. The 5 words are BCD seconds, minutes, hours, day, day (2 bits)+update flag. |
| 5 | Fill word 01010101 = 0x55 = 85 |
| 6 | Fill word 01010101 = 0x55 = 85 |
| 7 | Fill word 01010101 = 0x55 = 85 |
| 8 | Fill word 01010101 = 0x55 = 85 |
| 9 | Video data, six channels, for 1968 pixels |
Unpacked back to 12375-byte records.
SeaDAS requires level 1 data. No further information on this format is available.
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