doc: lc3: doc review

Created a readme file with changelog included.
Moved the API PDF to FTP and included link in the readme.
Moved legal files to top folder.
Deleted original doc files.

Signed-off-by: Grzegorz Ferenc <Grzegorz.Ferenc@nordicsemi.no>

doc/links.txt

@@ -63,6 +63,9 @@
 .. _`ZBOSS API documentation`:
 .. _`ZBOSS stack release notes`: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/zboss/index.html
 
+.. _`LC3 API documentation document`: https://developer.nordicsemi.com/nRF_Connect_SDK/nrf5340_audio/lc3_api/T2_LC3_API_Documentation_1.5.pdf
+.. _`Bluetooth® LE Audio specifications`: https://www.bluetooth.com/learn-about-bluetooth/recent-enhancements/le-audio/le-audio-specifications/
+
 .. _`certification policy`: https://zigbeealliance.org/wp-content/uploads/2021/04/07-4842-13-Zigbee-certification-policy.pdf
 
 .. _`Mbed TLS backend`: https://tls.mbed.org/

lc3/README.rst

@@ -0,0 +1,186 @@
+.. _lc3:
+
+Low Complexity Communication Codec (LC3)
+########################################
+
+.. contents::
+   :local:
+   :depth: 2
+
+Low Complexity Communication Codec (LC3) is the default software codec for the :ref:`nrf53_audio_app` application, conformant to the `Bluetooth® LE Audio specifications`_ (Bluetooth 5.2, QDID #156294).
+It is used only by this application for encoding and decoding purposes, but can be used with any other audio application developed with the nRF5340 Audio DK.
+For more information about the codec usage in the application, see the application documentation page in the |NCS| documentation.
+
+The nrfxlib module includes the :file:`lc3/include/sw_codec_lc3.h` and :file:`lc3/src/sw_codec_lc3.c` files that form a translation layer for using a standardized API in the nRF5340 Audio application.
+
+.. _lc3_legal:
+
+License and attribution
+***********************
+
+For the terms and conditions for using the LC3 codec, see :file:`license.txt` and :file:`attiribution.txt` at :file:`lc3/`.
+
+.. _lc3_api:
+
+API documentation
+*****************
+
+For API documenation, check the `LC3 API documentation document`_.
+
+.. _lc3_changelog:
+
+Changelog
+*********
+
+All notable changes to this project are documented in this section.
+
+main branch
+===========
+
+Initial release.
+This release includes the following changes to the codec.
+
+LC3 v1.0.4
+----------
+
+Build information:
+
+* Platform: ARM Cortex-M33, Cortex-M44
+* Compiler: ARM v6, -Ofast
+* Hard floating point, fixed point
+
+Changes:
+
+* Replaced floating point stdlib dependencies in data path with T2 functions.
+* Optimized the LTPF decoder, fixed point.
+
+LC3 v1.0.3
+----------
+
+Changes:
+
+* MDCT optimizations.
+* LTPF optimizations.
+* Arithmetic encoding optimizations.
+
+LC3 v1.0.2
+----------
+
+Changes:
+
+* Platform-specific optimizations.
+
+LC3 v1.0.1
+----------
+
+Changes:
+
+* Fixed point optimizations.
+
+LC3 v1.0.0
+----------
+
+Changes:
+
+* ARC LTPF SIMD optimizations.
+
+LC3 v0.9.14
+-----------
+
+Changes:
+
+* ARM optimizations.
+
+LC3 v0.9.13
+-----------
+
+Changes:
+
+* Added compile option to separate encode/decode memory.
+
+LC3 v0.9.12
+-----------
+
+Changes:
+
+* ARM optimizations.
+
+LC3 v0.9.11
+-----------
+
+Changes:
+
+* ARM optimizations.
+
+LC3 v0.9.10
+-----------
+
+Changes:
+
+* Incorporated all technical errata up to 15138.
+
+LC3 v0.9.9
+----------
+
+Changes:
+
+* Non-functional changes.
+
+LC3 v0.9.8
+----------
+
+Changes:
+
+* Fixed point memory optimizations.
+* Fixed point 7.5 ms frame size conformance improvements, meets stricter 0.06 ODG threshold in conformance tests.
+* Fixed scaling for > 16 bit PCM output in fixed point.
+
+LC3 v0.9.7
+----------
+
+Changes:
+
+* Fixed Glockenspiel 24 kHz / 48 kbps / 7.5 ms exceeding 0.06 ODG in floating point encode/decode test.
+* Performance optimizations.
+
+LC3 v0.9.6
+----------
+
+Changes:
+
+* Added 7.5 ms support for floating point.
+
+LC3 v0.9.5
+----------
+
+Changes:
+
+* Fixed point memory optimizations.
+
+LC3 v0.9.4
+----------
+
+Changes:
+
+* Added 24 and 32 bit PCM input and output to T2_LC3.
+* Optimizations in pitch lag detection.
+* Added API for amount of packet loss correction (PLC) applied.
+* Added API for providing static buffers.
+* Added error code offset to avoid value conflict with other modules.
+* Added API for the number of bytes read from encoder input.
+
+LC3 v0.9.3
+----------
+
+Changes:
+
+* Fixed an issue in T2_LC3 where decoding a single frame resulted in 1/4 frame of additional PCM output.
+
+LC3 v0.9.2
+----------
+
+Changes:
+
+* Added x64 Linux build T2_LC3.
+* Added support for multi-channel WAV files to T2_LC3 application.
+* Removed a DLL dependency from T2_LC3 Windows build.