FreeCalypso > hg > gsm-codec-lib

view CHANGES @ 581:e2d5cad04cbf

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
libgsmhr1 RxFE: store CN R0+LPC separately from speech In the original GSM 06.06 code the ECU for speech mode is entirely separate from the CN generator, maintaining separate state. (The main intertie between them is the speech vs CN state variable, distinguishing between speech and CN BFIs, in addition to the CN-specific function of distinguishing between initial and update SIDs.) In the present RxFE implementation I initially thought that we could use the same saved_frame buffer for both ECU and CN, overwriting just the first 4 params (R0 and LPC) when a valid SID comes in. However, I now realize it was a bad idea: the original code has a corner case (long sequence of speech-mode BFIs to put the ECU in state 6, then SID and CN-mode BFIs, then a good speech frame) that would be broken by that buffer reuse approach. We could eliminate this corner case by resetting the ECU state when passing through a CN insertion period, but doing so would needlessly increase the behavioral diffs between GSM 06.06 and our version. Solution: use a separate CN-specific buffer for CN R0+LPC parameters, and match the behavior of GSM 06.06 code in this regard.
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 13 Feb 2025 10:02:45 +0000
parents b66fb6be73c3
children
line wrap: on
line source

Changes from gsm-codec-lib-r3 to gsm-codec-lib-r4:

* Libgsmfr2 evolved from version 2.0.0 to version 2.1.0: see
  doc/FR1-library-history for the details.

* Libgsmefr evolved from version 1.1.0 to version 1.2.0: see
  doc/EFR-library-history for the details.

* Command line utilities support the new hexadecimal file format of TW-TS-005
  Annex A for FR and EFR codecs (see doc/TW-TS-005 article):

  + tw5a-dump parses TW-TS-005 Annex A files in the same way how gsmrec-dump
    parses gsmx binary files;

  + gsm[e]fr-decode-tw5[-r] are new speech decoder utilities that read their
    input from TW-TS-005 Annex A files;

  + gsmx-to-tw5a and tw5a-to-gsmx conversion utilities should be sufficient for
    most other use cases.

* New command line utility gsmfr-tfo-xfrm exercises TFO transform addition to
  libgsmfr2.

Changes from gsm-codec-lib-r2 to gsm-codec-lib-r3:

* Libgsmfrp has been replaced with libgsmfr2, a major version change per SemVer.

* The former dependency on historical libgsm has been eliminated; the
  functionality of libgsm (GSM 06.10 encoder and decoder implementation) has
  been absorbed into libgsmfr2.

* Libgsmefr version 1.1.0 exhibits approximately 2x performance improvement
  over the original version, and also exhibits a small addition to the public
  API: the RTP-encoded form of the standard EFR DHF is now provided as a const
  datum.

* New library added: libtwamr for 3GPP AMR-NB codec, serving as a replacement
  for libopencore-amrnb in Themyscira GSM codec exploration workflows.

* New command line utilities:

  + amrefr-* and twamr-* related to libtwamr: see doc/Codec-utils,
    doc/AMR-EFR-hybrid-emu and doc/AMR-library-tests articles.

  + amrts-pcm8-compact: see doc/Utils-overview article.

  + gsmfr-* updates for libgsmfr2: see doc/Codec-utils article.

  + gsm[e]fr-dlcap-sync: see doc/Calypso-TCH-downlink article.

* gsmfr-* utilities set: gsmfr-hand-test and gsmfr-max-out hack programs have
  been dropped.  These hack programs were never properly documented and were
  written only as part of a debug chase, in pursuit of a bug that ultimately
  turned out to be in our then-hacky patch to osmo-bts-sysmo.

* gsmrec-dump now prints the bit-counting SID classification for both FRv1 and
  EFR codecs, and also identifies bit patterns that match the official DHF
  (decoder homing frame) for each codec.

* The configuration and build process has been revamped: the full suite of
  libraries and utilities can now be installed in any desired file system
  location without contortions.

Changes from gsm-codec-lib-r1 to gsm-codec-lib-r2:

* Libgsmfrp evolved from version 1.0.0 to version 1.0.2; please see
  doc/FR1-Rx-DTX for a detailing listing of libgsmfrp changes.

* Some new utilities have been developed for studying AMR: see
  doc/AMR-study-utils for more information.

* The subject of conversions between 16-bit 2's complement linear PCM and 8-bit
  A-law and mu-law PCM formats (G.711) has been thoroughly studied, the findings
  have been documented in doc/PCM8-conversions, and some new command line
  utilities have been added, described in the same article.

* Many new table generators have been added to the dev subdirectory; some of
  them may be useful to other software developers.

* pcap utilities have been split off to a separate rtp-debug-utils repository;
  this split was made so that those utilities can be developed freely while the
  gsm-codec-lib repository remains under strict release process control.