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comparison doc/Binary-file-format @ 133:b4b1c3a192c7

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doc/Binary-file-format: document gsmrec-dump
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 11 Dec 2022 05:24:11 +0000
parents 598ee3ce238b
children 7e490a8efe8a
comparison
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132:3fd48946dcb8 133:b4b1c3a192c7
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14 File reading functions begin by reading only one byte; this byte, once decoded, 14 File reading functions begin by reading only one byte; this byte, once decoded,
15 tells us how many more bytes need to be read, and frame synchronization is thus 15 tells us how many more bytes need to be read, and frame synchronization is thus
16 maintained. 16 maintained.
17 17
18 FR and EFR frames are not expected to be mixed in the same stream recording;
19 our low-level binary file reading function will grok such mixing just fine, but
20 each higher-level test program is expected to be written for only one codec,
21 either FR or EFR.
22
23 The recommended filename suffix for extended-libgsm binary files in the present 18 The recommended filename suffix for extended-libgsm binary files in the present
24 format is .gsmx; of course dot-separated filename suffixes hold absolutely no 19 format is .gsmx; of course dot-separated filename suffixes hold absolutely no
25 special meaning on Unix systems, but many developers still strongly prefer to 20 special meaning on Unix systems, but many developers still strongly prefer to
26 have them for psychological comfort. 21 have them for psychological comfort.
22
23 Any gsmx file (FR or EFR) can be dumped in human-readable form with our
24 gsmrec-dump utility. This utility turns every read frame from bytes into codec
25 parameters with gsm_explode() or EFR_frame2params(), and then displays those
26 parameters in a sensible manner, with a per-frame header line followed by 4
27 lines of subframe parameters.
28
29 FR and EFR frames are not expected to be mixed in the same stream recording;
30 our low-level binary file reading function and gsmrec-dump will grok such mixing
31 just fine, but each higher-level test program (beyond gsmrec-dump) is expected
32 to be written for only one codec, either FR or EFR.