FreeCalypso > hg > gsm-codec-lib

comparison doc/EFR-rationale @ 313:69b9a1eeb5a2

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
doc/EFR-rationale: update future roadmap
author Mychaela Falconia <falcon@freecalypso.org>
date Wed, 17 Apr 2024 22:45:27 +0000
parents 3a0ee08a3b9d
children
comparison
equal deleted inserted replaced
312:78739fda2856 313:69b9a1eeb5a2
82 now. 82 now.
83 83
84 Future roadmap 84 Future roadmap
85 ============== 85 ==============
86 86
87 If someone is implementing a DSP vocoder block for a GSM MS or a network-side 87 When this article was originally written in late 2022, my thoughts were that we
88 speech transcoder that needs to support all standard GSM codecs, at some point 88 would go in the direction of a single library supporting both AMR and EFR,
89 they will need to implement both EFR and AMR. Given the close relation between 89 sharing most code in common and handling the differences between EFR and MR122
90 these two codecs (they are not perfectly compatible as we started out saying, 90 similarly to how most proprietary implementations have done it, following the
91 but they are still very closely related), keeping two entirely separate library 91 "alternative" of GSM 06.54 chapter 10. However, that plan has been revised;
92 implementations for AMR and EFR will be very inefficient in the long run, and a 92 our current approach (as of 2024-04) is that we are developing a separate
93 nightmare to get them to perform equally well. It seems to me (Mother Mychaela) 93 library for AMR (libtwamr, librifying 3GPP AMR code in the same way how we
94 that the correct solution will be to produce a single codec library that 94 librified ETSI EFR in libgsmefr), while libgsmefr remains as it is, a pristine
95 implements both AMR and EFR, probably by starting with an AMR library and 95 implementation of GSM-EFR in its *original* bit-exact form.
96 extending it with special modes to handle those aspects where EFR differs. It 96
97 is my forecast that we are going to end up doing something along these lines in 97 Please refer to AMR-EFR-philosophy article for more information.
98 Themyscira - but it will be much later down the road; for the time being, our
99 initial version of ThemWi will only support FR and EFR, but not AMR.