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TW-TS-005 reader: fix maximum line length bug TW-TS-005 section 4.1 states: The maximum allowed length of each line is 80 characters, not including the OS-specific newline encoding. The implementation of this line length limit in the TW-TS-005 hex file reader function in the present suite was wrong, such that lines of the full maximum length could not be read. Fix it. Note that this bug affects comment lines too, not just actual RTP payloads. Neither Annex A nor Annex B features an RTP payload format that goes to the maximum of 40 bytes, but if a comment line goes to the maximum allowed length of 80 characters not including the terminating newline, the bug will be triggered, necessitating the present fix.
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 25 Feb 2025 07:49:28 +0000
parents e26b974f7ba3
children
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1 Historical article from 2023-04
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2 ===============================
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4 The following article was written in 2023-04, a year before the introduction of
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5 libtwamr. All of the utilities described in this article, plus even older
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6 gsm-amr2efr and gsm-efr2amr utilities described in AMR-EFR-conversion article,
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7 are implemented in amrconv subdirectory of the present source package, and are
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8 entirely independent of libtwamr - they predate this library.
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10 Original article follows; the utilities described therein are still useful:
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12 As of this writing (2023-04), the main emphasis here at Themyscira Wireless is
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13 on classic FR and EFR codecs, particularly the latter, rather than AMR.
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14 However, given the close relation between GSM EFR and the highest MR122 mode of
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15 AMR, we are starting to explore AMR a little too, focusing on the reference C
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16 implementation and various published test sequences. Working in this direction,
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17 we have developed the following AMR study and exploration utilities:
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19 amr-cod-parse This utility reads the *.cod binary file format used by 3GPP
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20 reference code and test sequences for AMR-encoded speech, groks
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21 every frame and dumps all recorded parameters in human-readable
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22 form.
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24 amr-ietf-parse A similar AMR parse/dump utility to amr-cod-parse, but reading
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25 the more common IETF RFC 4867 *.amr binary file format instead.
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27 amr-cod2ietf These two utilities convert between 3GPP *.cod and IETF *.amr
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28 amr-ietf2cod formats. amr-cod2ietf converts from *.cod to *.amr;
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29 amr-ietf2cod converts in the opposite direction.
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31 Just like ETSI *.cod and *.dec formats for EFR, 3GPP *.cod format for AMR is
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32 endian-dependent. Our amr-cod-parse and amr-cod2ietf utilities expect LE byte
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33 order by default, matching the official test sequences in
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34 ts_126074v170001p0.zip; they also support BE byte order with -b option.
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35 However, our amr-ietf2cod utility (rarely needed) emits its cod-format output
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36 in the local machine's native byte order.