libgsmefr BFI w/o data: emit zero output after decoder reset In real-life usage, each EFR decoder session will most likely begin with lots of BFI frames before the first real frame arrives. However, because the spec-defined home state of the decoder is speech rather than CN, our regular logic for BFI w/o data would have to feed pseudorandom noise to the decoder (in the "fixed codebook excitation pulses" part), which is silly to do at the beginning of the decoder session right out of reset. Therefore, let's check reset_flag_old, and if we are still in the reset state, simply emit zero output.

/*
 * EFR_insert_sid_codeword() inserts the 95 bit wide SID codeword into
 * an EFR frame in RTP encoding, normally as part of EFR_encode_frame()
 * processing right after EFR_params2frame().
 */

#include "gsm_efr.h"

void EFR_insert_sid_codeword(uint8_t *frame)
{
	frame[6] |= 0x6F;
	frame[7]  = 0xFF;
	frame[8]  = 0xFF;
	frame[9] |= 0x80;
	frame[12] |= 0x3B;
	frame[13]  = 0xFF;
	frame[14]  = 0xFF;
	frame[15] |= 0xE0;
	frame[19]  = 0xFF;
	frame[20]  = 0xFF;
	frame[21]  = 0xFF;
	frame[25]  = 0xFF;
	frame[26] |= 0xFC;
	frame[27]  = 0xFF;
	frame[28] |= 0xC0;
}