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README: add libgsmhr1
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 20 Mar 2026 04:50:08 +0000
parents 614ae8dc6807
children
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636:76c6fa603370 637:d71ef85036e4
19 code from ETSI (GSM 06.53). The bit-exact version of GSM-EFR 19 code from ETSI (GSM 06.53). The bit-exact version of GSM-EFR
20 implemented here is the original one, not the AMR-EFR hybrid 20 implemented here is the original one, not the AMR-EFR hybrid
21 that was made into a permissible implementation option after 21 that was made into a permissible implementation option after
22 the development of AMR. 22 the development of AMR.
23 23
24 libgsmhr1 This library implements GSM-HR codec, based on the reference
25 code from ETSI (GSM 06.06). In addition to standard speech
26 encoder and decoder functions, our library includes many
27 supporting utility functions and a TFO transform implementation.
28
24 libtwamr This library implements 3GPP AMR-NB codec, based on the official 29 libtwamr This library implements 3GPP AMR-NB codec, based on the official
25 reference code (TS 26.073). Both VAD versions are included, 30 reference code (TS 26.073). Both VAD versions are included,
26 selected by the user application at run time, and I/O functions 31 selected by the user application at run time, and I/O functions
27 are provided for both 3GPP test sequence format and the more 32 are provided for both 3GPP test sequence format and the more
28 practical format of IETF RFC 4867. This library can also be 33 practical format of IETF RFC 4867. This library can also be
29 used to implement AMR-EFR hybrid operation if no DTX is needed 34 used to implement AMR-EFR hybrid operation if no DTX is needed
30 in the encoder and if the input to the decoder contains no SID 35 in the encoder and if the input to the decoder contains no SID
31 frames. 36 frames.
32 37
33 The only GSM codec for which no implementation library is currently provided is 38 The libraries provided here are intended for multiple purposes - here are some
34 GSM-HR, also known as HRv1. Librification of HRv1 reference code from ETSI is 39 of them:
35 a planned work item for future development.
36 40
37 The libraries provided here are intended for two primary purposes: 41 * They are used as part of Themyscira Wireless MGW (media gateway)
42 implementation, providing the necessary speech transcoder between a GSM
43 network and G.711-based PSTN.
38 44
39 1) They are used as part of Themyscira Wireless MGW (media gateway) 45 * TFO transforms implemented in these libraries are needed in order to make a
40 implementation, providing the necessary speech transcoder between a GSM 46 proper interface from an incoming RTP stream to an Abis-DL link driving a
41 network and G.711-based PSTN. 47 traditional E1 BTS.
42 48
43 2) They are useful in many varied study and exploration workings, as part of 49 * They are useful in many varied study and exploration workings, as part of
44 experiments where it becomes necessary to model, simulate or replicate 50 experiments where it becomes necessary to model, simulate or replicate
45 bit-exact operation of someone else's network element. 51 bit-exact operation of someone else's network element.
46 52
47 Each of our Themyscira core libraries is free-standing and independent of the 53 Each of our Themyscira core libraries is free-standing and independent of the
48 others. The dependency on classic libgsm (by way of <gsm.h> header file) that 54 others. The dependency on classic libgsm (by way of <gsm.h> header file) that
49 existed in previous versions of Themyscira gsm-codec-lib suite has been 55 existed in previous versions of Themyscira gsm-codec-lib suite has been
50 eliminated; the present version has zero dependencies. 56 eliminated; the present version has zero dependencies.