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doc/AMR-EFR-philosophy: document implemented solution
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 10 May 2024 18:20:06 +0000
parents f4f68c652e98
children e26b974f7ba3
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f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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1 As of this writing (2023-04), the main emphasis here at Themyscira Wireless is
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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2 on classic FR and EFR codecs, particularly the latter, rather than AMR.
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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3 However, given the close relation between GSM EFR and the highest MR122 mode of
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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4 AMR, we are starting to explore AMR a little too, focusing on the reference C
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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5 implementation and various published test sequences. Working in this direction,
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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6 we have developed the following AMR study and exploration utilities:
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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7
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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8 amr-cod-parse This utility reads the *.cod binary file format used by 3GPP
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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9 reference code and test sequences for AMR-encoded speech, groks
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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10 every frame and dumps all recorded parameters in human-readable
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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11 form.
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
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12
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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13 amr-ietf-parse A similar AMR parse/dump utility to amr-cod-parse, but reading
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
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14 the more common IETF RFC 4867 *.amr binary file format instead.
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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16 amr-cod2ietf These two utilities convert between 3GPP *.cod and IETF *.amr
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
parents:
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17 amr-ietf2cod formats. amr-cod2ietf converts from *.cod to *.amr;
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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18 amr-ietf2cod converts in the opposite direction.
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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19
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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20 Just like ETSI *.cod and *.dec formats for EFR, 3GPP *.cod format for AMR is
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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21 endian-dependent. Our amr-cod-parse and amr-cod2ietf utilities expect LE byte
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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22 order by default, matching the official test sequences in
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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23 ts_126074v170001p0.zip; they also support BE byte order with -b option.
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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24 However, our amr-ietf2cod utility (rarely needed) emits its cod-format output
f4f68c652e98 doc: document AMR study utilities
Mychaela Falconia <falcon@freecalypso.org>
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25 in the local machine's native byte order.