6 Jul
2012
6 Jul
'12
11:30 a.m.
Hi List!
I am studying the AMR codec in GSM.but I met some problem.
I use burst_id to capture TCH in my test network,and in my programmm,
I use the firsrt 8 bits of a TCH block to decide whether it is a tch or
not
and also get the codec mode of a AFS,and than other operations,but it is
not to work , I am struggled to this, any one can help me?
this is my code:
static void process_tch_amr(struct osmocom_ms *ms,struct l1ctl_burst_ind
*bi)
{
int16_t rx_dbm;
uint16_t arfcn;
uint32_t fn,B;
uint8_t cbits, tn, lch_idx;
int ul, bid, i, k, length;
sbit_t *bursts, mC[456];
ubit_t steal_bit[2],
bt[114],convu[260],convd[260],EFRBits[244],EFRAMR[8 + 244];
pbit_t voice[33];
unsigned char mode;
arfcn = ntohs(bi->band_arfcn);
rx_dbm = rxlev2dbm(bi->rx_level);
fn = ntohl(bi->frame_nr);
ul = !!(arfcn & ARFCN_UPLINK);
cbits = bi->chan_nr >> 3;
tn = bi->chan_nr & 7;
B = -1;
if((fn%13)%4 == 0) flag= 1;
if(!flag) return;
B = count_tch % 8;
if (B == -1)
return;
if (B == 0){
for(i=0; i<4; i++){
memset(app_state.mI[i], 0x00, 114);
}
}else if(B == 4){
for(i=4; i<8; i++){
memset(app_state.mI[i], 0x00, 114);
}
}
/* Unpack (ignore hu/hl) */
osmo_pbit2ubit_ext(bt, 0, bi->bits, 0, 57, 0);
osmo_pbit2ubit_ext(bt, 57, bi->bits, 57, 57, 0);
/* Convert to softbits */
for (i=0; i<114; i++)
app_state.mI[B][i] = bt[i] ? - (bi->snr >> 1) : (bi->snr >> 1);
count_tch++;
// Deinterleaves i[] to c[]
if((B % 4 ==3)&&(count_tch >= 7)){
if(B == 3)
{
tch_deinterleave(mC, 4);
}else{
tch_deinterleave(mC, 0);
}
//abstract the codec mode
for(i = 0;i<8;i++)
{
//printf("%x ",mC[i]);
if(mC[i] < 0)
mode = ( mode | (1 << i));
else
mode = ( mode & (~(1 << i)));
}
//printf("mode %x\n",mode);
switch(mode){
case CODEC_MODE_1:
printf("codec 1\n");
i = find_speech_mode(app_state.amr_arg.amr_acs, 1);
break;
case CODEC_MODE_2:
printf("codec 2\n");
i = find_speech_mode(app_state.amr_arg.amr_acs, 2);
break;
case CODEC_MODE_3:
printf("codec 3\n");
i = find_speech_mode(app_state.amr_arg.amr_acs, 3);
break;
case CODEC_MODE_4:
printf("codec 4\n");
i = find_speech_mode(app_state.amr_arg.amr_acs, 4);
break;
default:
{
//printf("unkown codec\n");
return;
}
}
memset(voice,0,32);
switch( 1 << i ){
case gsm690_4_75:
printf("codec gsm690_4_75\n");
osmo_conv_decode(&conv_tch_afs_4_75, &mC[8], convu);
memcpy(convd,convu,39);
memcpy(convd,&convu[45],56);
tch_map(gsm690_4_75_bitorder, gsm690_4_75_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x04, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_4_75_len, 1);
break;
case gsm690_5_15:
printf("codec gsm690_5_15\n");
osmo_conv_decode(&conv_tch_afs_5_15, &mC[8], convu);
memcpy(convd,convu,49);
memcpy(convd,&convu[55],54);
tch_map(gsm690_5_15_bitorder, gsm690_5_15_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x0c, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_5_15_len, 1);
break;
case gsm690_5_90:
printf("codec gsm690_5_90\n");
osmo_conv_decode(&conv_tch_afs_5_9, &mC[8], convu);
memcpy(convd,convu,55);
memcpy(convd,&convu[61],63);
tch_map(gsm690_5_9_bitorder, gsm690_5_90_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x14, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_5_90_len, 1);
break;
case gsm690_6_70:
printf("codec gsm690_6_70\n");
osmo_conv_decode(&conv_tch_afs_6_7, &mC[8], convu);
memcpy(convd,convu,55);
memcpy(convd,&convu[61],79);
tch_map(gsm690_6_7_bitorder, gsm690_6_70_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x1c, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_6_70_len, 1);
break;
case gsm690_7_40:
printf("codec gsm690_7_40\n");
osmo_conv_decode(&conv_tch_afs_7_4, &mC[8], convu);
memcpy(convd,convu,61);
memcpy(convd,&convu[67],87);
tch_map(gsm690_7_4_bitorder, gsm690_7_40_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x24, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_7_40_len, 1);
break;
case gsm690_7_95:
printf("codec gsm690_7_95\n");
osmo_conv_decode(&conv_tch_afs_7_95, &mC[8], convu);
memcpy(convd,convu,75);
memcpy(convd,&convu[81],84);
tch_map(gsm690_7_95_bitorder, gsm690_7_95_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x2c, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_7_95_len, 1);
break;
case gsm690_10_2:
printf("codec gsm690_10_2\n");
osmo_conv_decode(&conv_tch_afs_10_2, &mC[8], convu);
memcpy(convd,convu,65);
memcpy(convd,&convu[71],139);
tch_map(gsm690_10_2_bitorder, gsm690_10_2_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x34, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_10_2_len, 1);
break;
case gsm690_12_2:
printf("codec gsm690_12_2\n");
osmo_conv_decode(&conv_tch_afs_12_2, &mC[8], convu);
memcpy(convd,convu,81);
memcpy(convd,&convu[87],163);
tch_map(gsm690_12_2_bitorder, gsm690_12_2_len, EFRAMR +
8,convd);
fillField(EFRAMR, 0, 0x3c, 8);
length = osmo_ubit2pbit_ext(voice, 0, EFRAMR, 0, 8 +
gsm690_12_2_len, 1);
break;
default:
{
printf("unkown gsm690 codec\n");
return;
}
}
printf("length is %d\n",length);
printf("voice[0] is %x\n",voice[0]);
fwrite(voice, 1, length, d_speech_file);
}