FreeCalypso > hg > gsm-codec-lib
view libgsmfr2/tfo_dtxd.c @ 585:3c6bf0d26ee7 default tip
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 | 5a3535470c95 |
children |
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line source
/* * The function implemented in this module is a post-processor to be invoked * after Rx DTX preproc functions if the Rx DTX handler block is used as a * TFO transform with DTXd enabled. It selectively transforms certain * preproc output frames (CN and silence frames specifically) into SID, * thereby allowing the network operator to reap the benefits of DTX on * the radio downlink leg. */ #include <stdint.h> #include "tw_gsmfr.h" #include "pp_state.h" int gsmfr_tfo_xfrm_dtxd(struct gsmfr_preproc_state *st, uint8_t *frame) { uint8_t *p, sub; if (!st->dtxd_sid_flag) return 1; /* SP=1: output is a speech frame */ /* turn the output frame into SID */ p = frame + 5; /* skip magic+LARc */ for (sub = 0; sub < 4; sub++) { *p++ = 0; *p++ &= 0x1F; /* upper 5 bits of Xmaxc field */ *p++ &= 0x80; /* and the lsb spilling into the next byte */ *p++ = 0; *p++ = 0; *p++ = 0; *p++ = 0; } return 0; /* SP=0: output is SID */ }