FreeCalypso > hg > gsm-codec-lib

annotate doc/Codec-utils @ 218:f4f68c652e98

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
doc: document AMR study utilities
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 21 Apr 2023 23:41:56 +0000
parents 04936af99fc8
children a053cf0bac04
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
136
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 Standalone command line utilities for FR and EFR codecs
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 =======================================================
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 The pre-existing FOSS opencore-amr package includes amrnb-enc and amrnb-dec test
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 programs: the first reads linear PCM from a WAV file and emits AMR encoder
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 output in a .amr file (RFC 4867 AMR storage format), the second reads this .amr
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 format and emits AMR decoder output as WAV. Inspired by these simple test
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 programs, the present package offers equivalent command line utilities for GSM
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 FR and EFR codecs. Here they are:
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 gsmfr-encode This utility reads linear PCM from a WAV file, runs libgsm
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 06.10 encoder and writes the output in the classic .gsm format
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 (directly abutted FR codec frames of 33 bytes each). We don't
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 currently have a Tx-side DTX implementation (VAD etc) for GSM
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 FR, hence the output from gsmfr-encode will always consist of
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 good speech frames only.
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 gsmfr-decode This utility reads our gsmx format (see Binary-file-format
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 article), which is a superset of the classic libgsm format.
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 The input to gsmfr-decode may be a pure .gsm recording as
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 produced by gsmfr-encode or toast from libgsm package, or it
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22 can also contain SID frames and/or BFI markers. The processing
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
23 performed by gsmfr-decode begins with our FR1 Rx DTX handler
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 preprocessor, which will be an identity transform for pure .gsm
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
25 input but becomes important for real-world input containing SIDs
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26 and BFIs, and is followed by gsm_decode() from libgsm. The
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 decoded output is written as WAV.
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29 gsmefr-encode This utility reads linear PCM from a WAV file, runs our EFR
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 encoder (Themyscira libgsmefr) and writes the output in our gsmx
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31 format. There is an option to enable or disable DTX: -d enables
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 DTX, otherwise it is disabled. (This option mirrors amrnb-enc.)
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34 gsmefr-decode This utility reads our gsmx format (which must be EFR, not FR1)
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 and feeds all frames and BFIs to our EFR decoder. The decoded
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 output is written as WAV.
8eb0e7a39409 doc: document command line utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37
157
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
38 The above are original programs that read WAV input for encoding and write WAV
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
39 output from decoding. We now also have raw versions that read and write our
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
40 "robe" (raw big-endian) format instead:
144
30c7bc064218 doc/Codec-utils: add note about PCM file format issue
Mychaela Falconia <falcon@freecalypso.org>
parents: 136
diff changeset
41
157
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
42 gsmfr-encode-r Just like gsm[e]fr-encode, but reading "robe" instead of WAV.
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
43 gsmefr-encode-r
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
44
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
45 gsmfr-decode-r Just like gsm[e]fr-decode, but writing "robe" instead of WAV.
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
46 gsmefr-decode-r
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
47
04936af99fc8 document gsm[e]fr-{en,de}code-r utilities
Mychaela Falconia <falcon@freecalypso.org>
parents: 144
diff changeset
48 Please see PCM-file-formats article for the rationale.