FreeCalypso > hg > gsm-codec-lib
view libgsmfr2/dhf.c @ 605:63f774192906
gsmhr_decoder_twts002_in(): set BFI=1 SID=1 for invalid SID
When a received TW-TS-002 RTP payload indicates invalid SID,
which of the 3 possible BFI/SID combinations should we pass to
our internal ETSI-based speech decoder or TFO engine?
Our original code passed BFI=0 SID=1, but upon further reflection,
BFI=1 SID=1 is a better choice. In the corner case where received
invalid SID is fed to a full decoder in homed state, setting BFI=1
allows that decoder to emit zeros on PCM and stay homed, instead of
launching into full decoding.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 04 Dec 2025 21:01:46 +0000 |
| parents | c94d9a336e8f |
| children |
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/* * Implementation of the optional decoder homing feature requires matching * the input RTP-encoded GSM-FR frame against the known decoder homing frame. * This C module provides this DHF as an API-exported const array. */ #include <stdint.h> #include "tw_gsmfr.h" const uint8_t gsmfr_decoder_homing_frame[GSMFR_RTP_FRAME_LEN] = { 0xD2, 0x57, 0x7A, 0x1C, 0xDA, 0x50, 0x00, 0x49, 0x24, 0x92, 0x49, 0x24, 0x50, 0x00, 0x49, 0x24, 0x92, 0x49, 0x24, 0x50, 0x00, 0x49, 0x24, 0x92, 0x49, 0x24, 0x50, 0x00, 0x49, 0x23, 0x92, 0x49, 0x24, };