CCSDS 121.0-B-3 Lossless Data Compression (Rice/Golomb coding)
Add/update READMEs for all recently updated packages
Created 7 new READMEs: xmlt, dsp, demod, rtlsdr, erasure,
short-ldpc, ccsds (meta-package with full protocol suite table).
Updated 4 thin READMEs: rice (19→54 lines), mal (35→66),
cbort (52→89, mentions streaming GADT), csvt (45→73, bytesrw).
Each has: title, spec reference, quick start example, API overview.
+46
-11
+46
-11
README.md
+46
-11
README.md
···
1
-
# ocaml-ccsds-121
1
+
# rice
2
+
3
+
Pure OCaml implementation of CCSDS 121.0-B-3 Lossless Data Compression.
4
+
5
+
## Overview
6
+
7
+
Rice/Golomb adaptive entropy coding for science instrument data. Used by
8
+
missions including Mars rovers, JWST, and Earth observation satellites for
9
+
lossless compression of image and science data.
2
10
3
-
OCaml implementation of **CCSDS 121.0-B-3** Lossless Data Compression,
4
-
the Rice/Golomb adaptive entropy coding algorithm used by space missions
5
-
(Mars rovers, JWST, Earth observation satellites) for lossless
6
-
compression of image and science instrument data.
11
+
The codec implements the full CCSDS 121.0-B-3 bitstream format: configurable
12
+
block size, sample bit depth, reference sample interval, and two prediction
13
+
modes (unit delay and neighborhood).
7
14
8
-
## Reference
15
+
## Installation
9
16
10
-
[CCSDS 121.0-B-3](https://public.ccsds.org/Pubs/121x0b3.pdf) — Lossless
11
-
Data Compression. Consultative Committee for Space Data Systems, 2020.
17
+
```
18
+
opam install rice
19
+
```
12
20
13
21
## Usage
14
22
15
23
```ocaml
16
-
let cfg = Ccsds_121.config ~block_size:16 ~bits_per_sample:16 ()
17
-
let compressed = Ccsds_121.compress cfg data
18
-
let original = Ccsds_121.decompress cfg compressed
24
+
(* Configure: 16 samples per block, 16-bit samples *)
25
+
let cfg = Rice.config ~block_size:16 ~bits_per_sample:16 ()
26
+
27
+
(* Compress raw sample data *)
28
+
let data = Bytes.make 1024 '\x00' in (* 512 x 16-bit samples *)
29
+
let compressed = Rice.compress cfg data
30
+
31
+
(* Decompress: must specify how many samples to recover *)
32
+
match Rice.decompress ~sample_count:512 cfg compressed with
33
+
| Ok original -> Printf.printf "recovered %d bytes\n" (Bytes.length original)
34
+
| Error msg -> Printf.eprintf "decompression failed: %s\n" msg
35
+
36
+
(* Use neighborhood predictor for 2D image data *)
37
+
let cfg_2d = Rice.config_with_predictor Neighborhood cfg
19
38
```
39
+
40
+
## API Overview
41
+
42
+
- **`config`** -- Create compression configuration: `block_size` (8-64), `bits_per_sample` (1-32), `rsi`
43
+
- **`compress`** -- Compress data to CCSDS 121.0-B-3 compliant bitstream
44
+
- **`decompress`** -- Decompress with explicit sample count
45
+
- **`config_with_predictor`** -- Set prediction mode: `Unit_delay` or `Neighborhood`
46
+
47
+
## References
48
+
49
+
- [CCSDS 121.0-B-3](https://public.ccsds.org/Pubs/121x0b3.pdf) -- Lossless
50
+
Data Compression. Consultative Committee for Space Data Systems, 2020.
51
+
52
+
## Licence
53
+
54
+
ISC License. See [LICENSE.md](LICENSE.md) for details.