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.

/*
 * Table 1 in section 6 of 3GPP TS 46.011 specifies a silence frame
 * in the form of GSM 06.10 parameters; here we implement this exact
 * silence frame in libgsm encoding, which is also RTP encoding.
 */

#include <stdint.h>
#include "tw_gsmfr.h"

const uint8_t gsmfr_preproc_silence_frame[GSMFR_RTP_FRAME_LEN] = {
	0xDA, 0xA7, 0xAA, 0xA5, 0x1A,
	0x50, 0x20, 0x38, 0xE4, 0x6D, 0xB9, 0x1B,
	0x50, 0x20, 0x38, 0xE4, 0x6D, 0xB9, 0x1B,
	0x50, 0x20, 0x38, 0xE4, 0x6D, 0xB9, 0x1B,
	0x50, 0x20, 0x38, 0xE4, 0x6D, 0xB9, 0x1B,
};