FreeCalypso > hg > freecalypso-docs

annotate Voice-memo-feature @ 106:28c1cb869d91

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
TCH-tap-modes: updates for TCH/HS
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 22 Jul 2024 22:36:29 +0000
parents 80f0996bfd16
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
96
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 The full Calypso hw+fw solution as delivered by TI (the relevant components here
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 are the DSP, the official L1 code and RiViera Audio Service) implements an
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 interesting feature called voice memos. It is actually two paired features:
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 * Voice memo recording: in almost all states of the MS (no GSM network at all,
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 or idle mode, or in an active call) it is possible to activate an extra
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 instance of GSM 06.10 encoder that takes input from the microphone (and also
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 from the active call downlink if invoked during a speech call) and writes its
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 output into an otherwise-unused DSP buffer. The combination of L1 and RiViera
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 Audio Service then writes this speech recording into a file in FFS.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 * Voice memo playback: voice memo files recorded with the just-described VM
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 record feature can be played into the phone's speaker output. The operation
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 of playing a previously recorded voice memo is conceptually no different from
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 playing tones or melodies, and can likewise be done in any state: with no GSM
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 network at all, in idle mode, or in an active call.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 VM recording and VM playback cannot be active at the same time: they use the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 same DSP buffer, and likely other mutually exclusive DSP resources too.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 Furthermore, the same DSP buffer that is used for these VM features is also
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 used for TCH UL substitution debug/test feature described in the TCH-tap-modes
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22 article - therefore, all 3 features (VM record, VM play and TCH UL play) need
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
23 to be treated as mutually exclusive in time. However, aside from this mutual
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 exclusion, it is very remarkable that VM recording or VM playback can be invoked
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
25 during an active speech call (which can use any codec!), and the extra instance
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26 of FR1 encoder or decoder (always FR1) invoked by VM features is essentially
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 independent from the main TCH encoder and the main TCH decoder, all of which
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28 run simultaneously. It is worth noting that all newer GSM speech codecs (HR1,
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29 EFR and AMR) are much more computationally intensive than FR1, thus given that
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 the DSP has the necessary horsepower to run any one of those "heavy" codecs, it
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31 probably isn't too much extra work to also run a simultaneous instance of
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 unidirectional (encoder only or decoder only) FR1.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34 The entire voice memo facility was already fully implemented in the TCS211 code
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 delivery from TI, but prior to FreeCalypso there was no way to exercise it. In
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 order to exercise VM functionality in TCS211, one needs to invoke these RiViera
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 Audio Service API functions:
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
38
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39 audio_vm_record_start()
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40 audio_vm_record_stop()
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41 audio_vm_play_start()
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42 audio_vm_play_stop()
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 In FreeCalypso we've added some simple AT commands that call the just-listed API
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 functions, and the facility that has been there all along is now accessible to
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46 play - it is the same situation as with Melody E1.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48 FreeCalypso AT commands for voice memo testing
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 ==============================================
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
51 AT@VMR="/pathname",dur,dtx
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
52
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
53 This command initiates VM recording. The FFS pathname into which the recording
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
54 should be written must be given as a quoted string (and as a reminder, all FFS
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
55 pathnames must be absolute - there are no current directories in the firmware
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
56 architecture), and there is a second required argument that sets the maximum
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
57 size of the recording. The duration argument is a decimal integer, and it is
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
58 reckoned in 1000-word units: if you specify duration as 1, the maximum recording
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
59 size is 1000 words (2000 bytes), if you specify duration as 2, the maximum
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
60 recording size is 2000 words (4000 bytes), and so forth. If you record with DTX
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
61 disabled, each block of 1000 words corresponds to 1 second in time (every 20 ms
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
62 frame turns into a block of 20 words), thus with DTX disabled the duration
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
63 argument becomes the actual duration in seconds. However, if you record with
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
64 DTX enabled, then periods of silence will be written in a compressed format
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
65 described later in this article, and the time duration of the recording will
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
66 depend on how much silence there is.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
67
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
68 The dtx argument is 1 to enable DTX or 0 to disable it; the default is DTX
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
69 disabled. The employed FR1 DTX algorithm appears to be the same as would be
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
70 used for TCH/FS uplink, except that an "artificial" (there is no SACCH with
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
71 independent-of-GSM voice memos) TAF position is generated on every 16th audio
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
72 frame, i.e., every 320 ms. (Note the shortening of this SID interval compared
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
73 to official TCH, where it is 24 frames or 480 ms.)
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
74
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
75 AT@VMRS
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
76
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
77 This command stops any VM recording in progress, but it is rarely needed - the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
78 recording will stop automatically when the size limit is reached.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
79
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
80 AT@VMP="/pathname"
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
81
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
82 This command initiates playback of the VM recording contained in the named file
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
83 in FFS. The FFS pathname is the only argument.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
84
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
85 AT@VMPS
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
86
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
87 This command stops any VM playback in progress, but it is rarely needed - the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
88 playback will stop automatically when the end-marker is read from the file.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
89
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
90 Voice memo file format
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
91 ======================
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
92
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
93 Using fc-fsio, you can read out voice memo files written by the VM record
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
94 facility, and you can likewise construct your own memo files externally, upload
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
95 them into FC device FFS and then play them via the VM play facility. The format
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
96 of these files is determined by TI's firmware stack (RV Audio Service on top of
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
97 L1 on top of the DSP), but is fundamentally based on a DSP buffer that is just
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
98 like those used for TCH. The companion TCH-tap-modes article describes the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
99 format of the DSP buffer from which TCH DL bits can be read out; in the present
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
100 article we are going to cover the differences specific to the voice memo
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
101 facility.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
102
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
103 When VM recording is done with DTX disabled, every 20 ms speech frame turns into
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
104 a block of 40 bytes in the memo file. This block of 40 bytes is produced from
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
105 20 16-bit words in the DSP buffer, each word turned into two bytes in LE order
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
106 by the ARM part of Calypso. The DSP buffer used for the VM facility has the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
107 same overall format as the one used for TCH DL, described in the TCH-tap-modes
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
108 article - 3 status or header words followed by 17 words of payload, with the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
109 latter words carrying a 260-bit FR1 codec frame in the bit order of GSM 05.03
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
110 interface 1. As explained in the TCH-tap-modes article, speech codec payload
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
111 words are filled in the msb-to-lsb direction by the DSP, thus the natural byte-
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
112 oriented representation would be big-endian - but because the little-endian ARM
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
113 core sits in between the DSP and the on-media file format, the byte order in
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
114 voice memo files comes out "wrong". Oh well - it is what it is.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
115
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
116 Of the 3 header words that precede every 20 ms speech frame, words 1 and 2
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
117 appear to be dummies - they have meaning related to the channel decoder block
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
118 in the case of TCH DL, but in the case of isolated-from-GSM voice memos, there
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
119 does not seem to be any meaning. However, header or status word 0, consisting
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
120 of bit flags, is still important, but the bit flags for the VM facility are
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
121 different from those of TCH DL.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
122
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
123 When VM recording is done with DTX disabled, status word 0 is observed to always
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
124 equal 0xC400 on every frame. However, when DTX is enabled, the following bits
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
125 are seen in status word 0:
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
126
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
127 * Bit 15 will be set if this frame needs to be saved in its entirety, or cleared
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
128 if it is to be skipped. When VM recording code in L1S sees that the DSP has
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
129 delivered a frame with this status bit cleared, it will save only this status
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
130 word 0, i.e., 2 bytes will be written into the memo file instead of 40 bytes
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
131 for this 20 ms frame. On VM playback, the code likewise checks this bit to
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
132 see how many words need to be read from the file, so synchronization is
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
133 maintained.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
134
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
135 * Bit 14 appears to be the SP flag of GSM 06.31 section 5.1: set when a speech
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
136 frame has been generated, or cleared when a SID frame has been generated
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
137 instead.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
138
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
139 * Bit 11 is a TAF-like flag: when DTX is enabled, this bit is set in every 16th
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
140 frame generated by the DSP in the VM recording session, otherwise it is
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
141 cleared.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
142
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
143 * Bit 10 will always be set in every status word 0 that gets written to voice
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
144 memo files: this bit is set by the DSP when it has finished encoding a 20 ms
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
145 audio frame and is checked by L1S on every TDMA frame, serving as a
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
146 synchronization mechanism telling L1S when it needs to copy a speech frame
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
147 from the DSP to the memo file.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
148
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
149 When VM recording is done with DTX enabled, the recorded memo file will consist
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
150 of speech frames (header word 0xC400 or 0xCC00), SID frames (header word 0x8400
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
151 or 0x8C00) and skipped frames consisting of only the header word 0x0400, with
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
152 the remaining words omitted. There will always be a present (not skipped) frame
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
153 in every 16th position (0xCC00 or 0x8C00), thus no 0x0C00 frames are ever seen.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
154
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
155 Every voice memo binary file ends with a 0xFBFF end-marker word; this end-marker
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
156 is needed because TCS211 fw architecture exhibits a separation between the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
157 actual data reading and writing processes in L1S and the FFS read/write
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
158 interface provided by RiViera Audio Service, and because of this separation the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
159 operational code in L1S can't "see" an EOF condition at the file system level.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
160
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
161 FreeCalypso tools for decoding voice memo files
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
162 ===============================================
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
163
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
164 If you have recorded a voice memo with AT@VMR and then read it out with fc-fsio,
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
165 you can use additional FC tools to analyze it. The following tools are
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
166 available, split between FC host tools and GSM codec libs & utilities packages:
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
167
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
168 * fc-vm2hex converts a binary VM recording into ASCII hex format, similar to
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
169 the old (2016) TCH DL recording format before it was extended in late 2022.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
170 Every fully-written frame is emitted in the hex output as 3 space-separated
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
171 hex status words followed by a block of 66 hex digits giving the FR1 codec
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
172 frame in the unchanged bit order of TI's DSP, and every skipped frame (one
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
173 for which only status word 0 was written into the memo file) is emitted in
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
174 the hex output as just that one word.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
175
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
176 * gsmfr-dlcap-parse utility, originally written for parsing TCH DL capture
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
177 files, accepts TCH DL recording files in both old and new formats, and it also
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
178 accepts the output from fc-vm2hex as its input. The combination of fc-vm2hex
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
179 and gsmfr-dlcap-parse allows a developer or tinkerer to do thorough human
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
180 analysis of TCS211 VM recordings in both DTX-disabled and DTX-enabled modes.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
181
97
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
182 * As of fc-host-tools-r18 there is a new fc-vm2gsmx utility that reads binary VM
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
183 recording files (as you would read out with fc-fsio) and converts them into
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
184 extended-libgsm (gsmx) format defined in our GSM codec libraries & utilities
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
185 package. This gsmx format is an extension of the classic libgsm (GSM 06.10)
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
186 format, adding the possibility of SID frames and BFI markers (frame gaps) in
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
187 addition to regular speech frames, thus it can represent the content of a
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
188 voice memo recording made in DTX mode. These gsmx files can then be decoded
80f0996bfd16 Voice-memo-feature: fc-vm2gsmx utility is here
Mychaela Falconia <falcon@freecalypso.org>
parents: 96
diff changeset
189 into playable WAV with our gsmfr-decode utility.
96
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
190
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
191 FreeCalypso tools for external generation of voice memo files
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
192 =============================================================
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
193
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
194 Using FreeCalypso tools, you can produce an external speech recording in GSM
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
195 06.10 FR1 codec format, convert it into TCS211 VM format, upload it into FC
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
196 device FFS with fc-fsio, and then play these externally-produced voice memos
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
197 with AT@VMP. The steps are as follows:
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
198
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
199 1) You can use gsmfr-encode to FR1-encode a speech sample from WAV into classic
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
200 .gsm format, or gsmfr-encode-r if the source is raw BE instead of WAV.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
201 Alternatively, you can use any other off-the-shelf software that can encode
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
202 FR1 and write libgsm format; SoX shipped with Slackware includes the
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
203 necessary support.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
204
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
205 2) fc-gsm2vm converts a .gsm recording into non-DTX TCS211 VM format.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
206
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
207 At the present time we don't have any tools for producing external DTX-enabled
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
208 VM recordings: the main limitation is that at least to this Mother's knowledge,
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
209 the published source software community does not currently possess a GSM 06.10
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
210 encoding library that has been extended with VAD and DTX functions. There is
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
211 classic libgsm from 1990s, used by everyone in the FOSS community who needs a
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
212 GSM 06.10 encoder or decoder, but it doesn't do DTX; we (FreeCalypso and
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
213 Themyscira Wireless) have produced our own libgsmfrp front-end that implements
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
214 Rx DTX handler functions (that's how we can properly decode FR1 streams that
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
215 contain SIDs and/or missing frames), but it doesn't help with DTX encoding.
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
216 Therefore, our ability to produce TCS211-compatible VM recordings externally is
69061d044f05 Voice-memo-feature: new article
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
217 currently limited to non-DTX mode.