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Very basic packet loss concealment code

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This commit is contained in:
Jean-Marc Valin 2007-12-08 00:56:04 +11:00
parent aa5bd61cb7
commit fb83fb422f
2 changed files with 61 additions and 1 deletions
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57
libcelt/celt.c
View file

@ -330,6 +330,8 @@ struct CELTDecoder {
float *out_mem;
float *oldBandE;
int last_pitch_index;
};
CELTDecoder *celt_decoder_new(const CELTMode *mode)
@ -355,6 +357,8 @@ CELTDecoder *celt_decoder_new(const CELTMode *mode)
st->oldBandE = celt_alloc(mode->nbEBands*sizeof(float));
st->preemph = 0.8;
st->last_pitch_index = 0;
return st;
}
@ -376,6 +380,51 @@ void celt_decoder_destroy(CELTDecoder *st)
celt_free(st);
}
int celt_decode_lost(CELTDecoder *st, short *pcm)
{
int i, N, B;
N = st->block_size;
B = st->nb_blocks;
float X[B*N]; /**< Interleaved signal MDCTs */
float P[B*N]; /**< Interleaved pitch MDCTs*/
float bandE[st->mode->nbEBands];
float gains[st->mode->nbPBands];
int pitch_index;
pitch_index = st->last_pitch_index;
/* Pitch MDCT */
compute_mdcts(&st->mdct_lookup, st->window, st->out_mem+pitch_index, X, N, B);
CELT_MOVE(st->out_mem, st->out_mem+B*N, MAX_PERIOD-B*N);
/* Compute inverse MDCTs */
for (i=0;i<B;i++)
{
int j;
float x[2*N];
float tmp[N];
/* De-interleaving the sub-frames */
for (j=0;j<N;j++)
tmp[j] = X[B*j+i];
mdct_backward(&st->mdct_lookup, tmp, x);
for (j=0;j<2*N;j++)
x[j] = st->window[j]*x[j];
for (j=0;j<N;j++)
st->out_mem[MAX_PERIOD+(i-B)*N+j] = x[j]+st->mdct_overlap[j];
for (j=0;j<N;j++)
st->mdct_overlap[j] = x[N+j];
for (j=0;j<N;j++)
{
float tmp = st->out_mem[MAX_PERIOD+(i-B)*N+j] + st->preemph*st->preemph_memD;
st->preemph_memD = tmp;
pcm[i*N+j] = (short)floor(.5+tmp);
}
}
}
int celt_decode(CELTDecoder *st, char *data, int len, short *pcm)
{
int i, N, B;
@ -390,11 +439,18 @@ int celt_decode(CELTDecoder *st, char *data, int len, short *pcm)
ec_dec dec;
ec_byte_buffer buf;
if (data == NULL)
{
celt_decode_lost(st, pcm);
return 0;
}
ec_byte_readinit(&buf,data,len);
ec_dec_init(&dec,&buf);
/* Get the pitch index */
pitch_index = ec_dec_uint(&dec, MAX_PERIOD-(B+1)*N);;
st->last_pitch_index = pitch_index;
/* Get band energies */
unquant_energy(st->mode, bandE, st->oldBandE, &dec);
@ -449,6 +505,7 @@ int celt_decode(CELTDecoder *st, char *data, int len, short *pcm)
pcm[i*N+j] = (short)floor(.5+tmp);
}
}
return 0;
//printf ("\n");
}

3
libcelt/testcelt.c
View file

@ -60,6 +60,9 @@ int main(int argc, char *argv[])
celt_encode(enc, in);
data = celt_encoder_get_bytes(enc, &len);
//printf ("%d\n", len);
if (rand()%100==-1)
celt_decode(dec, NULL, len, in);
else
celt_decode(dec, data, len, in);
fwrite(in, sizeof(short), FRAME_SIZE, fout);
}