ref: 9d1decd1bbdd0eba00697bee95d53d7e0d454c57
parent: 12b22484e2b994a21b5e2ee4f36eecf22c448424
author: Jean-Marc Valin <[email protected]>
date: Tue Jun 17 09:28:13 EDT 2008
short-block MDCT
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -44,6 +44,7 @@
static void dctIV(float *X, int len, int dim)
{+ return;
int d, n, k;
for (d=0;d<dim;d++)
{@@ -388,7 +389,7 @@
for (i=0;i<len-5;i++)
stereo_mode[i] = 0;
for (;i<len;i++)
- stereo_mode[i] = 1;
+ stereo_mode[i] = 0;
}
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -159,16 +159,18 @@
}
/** Apply window and compute the MDCT for all sub-frames and all channels in a frame */
-static void compute_mdcts(const CELTMode *mode, const celt_word16_t * restrict window, celt_sig_t * restrict in, celt_sig_t * restrict out)
+static void compute_mdcts(const CELTMode *mode, int shortBlocks, celt_sig_t * restrict in, celt_sig_t * restrict out)
{- const mdct_lookup *lookup = MDCT(mode);
- const int N = FRAMESIZE(mode);
const int C = CHANNELS(mode);
- const int overlap = OVERLAP(mode);
- if (C==1)
+ if (C==1 && !shortBlocks)
{- mdct_forward(lookup, in, out, window, overlap);
- } else {+ const mdct_lookup *lookup = MDCT(mode);
+ const int overlap = OVERLAP(mode);
+ mdct_forward(lookup, in, out, mode->window, overlap);
+ } else if (!shortBlocks) {+ const mdct_lookup *lookup = MDCT(mode);
+ const int overlap = OVERLAP(mode);
+ const int N = FRAMESIZE(mode);
int c;
VARDECL(celt_word32_t, x);
VARDECL(celt_word32_t, tmp);
@@ -180,21 +182,45 @@
int j;
for (j=0;j<N+overlap;j++)
x[j] = in[C*j+c];
- mdct_forward(lookup, x, tmp, window, overlap);
+ mdct_forward(lookup, x, tmp, mode->window, overlap);
/* Interleaving the sub-frames */
for (j=0;j<N;j++)
out[C*j+c] = tmp[j];
}
RESTORE_STACK;
+ } else {+ const mdct_lookup *lookup = &mode->shortMdct;
+ const int overlap = mode->shortMdctSize;
+ const int N = mode->shortMdctSize;
+ int b, c;
+ VARDECL(celt_word32_t, x);
+ VARDECL(celt_word32_t, tmp);
+ SAVE_STACK;
+ ALLOC(x, N+overlap, celt_word32_t);
+ ALLOC(tmp, N, celt_word32_t);
+ for (c=0;c<C;c++)
+ {+ int B = mode->nbShortMdcts;
+ for (b=0;b<B;b++)
+ {+ int j;
+ for (j=0;j<N+overlap;j++)
+ x[j] = in[C*(b*N+j)+c];
+ mdct_forward(lookup, x, tmp, mode->window, overlap);
+ /* Interleaving the sub-frames */
+ for (j=0;j<N;j++)
+ out[C*(j*B+b)+c] = tmp[j];
+ }
+ }
+ RESTORE_STACK;
}
}
/** Compute the IMDCT and apply window for all sub-frames and all channels in a frame */
-static void compute_inv_mdcts(const CELTMode *mode, const celt_word16_t * restrict window, celt_sig_t *X, int transient_time, float transient_gain, celt_sig_t * restrict out_mem)
+static void compute_inv_mdcts(const CELTMode *mode, int shortBlocks, celt_sig_t *X, int transient_time, float transient_gain, celt_sig_t * restrict out_mem)
{int c, N4;
const int C = CHANNELS(mode);
- const mdct_lookup *lookup = MDCT(mode);
const int N = FRAMESIZE(mode);
const int overlap = OVERLAP(mode);
N4 = (N-overlap)>>1;
@@ -201,9 +227,11 @@
for (c=0;c<C;c++)
{int j;
- if (transient_time<0 && C==1) {- mdct_backward(lookup, X, out_mem+C*(MAX_PERIOD-N-N4), window, overlap);
- } else {+ if (transient_time<0 && C==1 && !shortBlocks) {+ const mdct_lookup *lookup = MDCT(mode);
+ mdct_backward(lookup, X, out_mem+C*(MAX_PERIOD-N-N4), mode->window, overlap);
+ } else if (!shortBlocks) {+ const mdct_lookup *lookup = MDCT(mode);
VARDECL(celt_word32_t, x);
VARDECL(celt_word32_t, tmp);
SAVE_STACK;
@@ -214,7 +242,7 @@
tmp[j] = X[C*j+c];
/* Prevents problems from the imdct doing the overlap-add */
CELT_MEMSET(x+N4, 0, overlap);
- mdct_backward(lookup, tmp, x, window, overlap);
+ mdct_backward(lookup, tmp, x, mode->window, overlap);
if (transient_time >= 0)
{for (j=0;j<16;j++)
@@ -231,6 +259,41 @@
for (j=0;j<2*N4;j++)
out_mem[C*(MAX_PERIOD-N)+C*(j+overlap)+c] = x[j+N4+overlap];
RESTORE_STACK;
+ } else {+ int b;
+ const int N2 = mode->shortMdctSize;
+ const int B = mode->nbShortMdcts;
+ const mdct_lookup *lookup = &mode->shortMdct;
+ VARDECL(celt_word32_t, x);
+ VARDECL(celt_word32_t, tmp);
+ SAVE_STACK;
+ ALLOC(x, 2*N, celt_word32_t);
+ ALLOC(tmp, N, celt_word32_t);
+ /* Prevents problems from the imdct doing the overlap-add */
+ CELT_MEMSET(x+N4, 0, overlap);
+ for (b=0;b<B;b++)
+ {+ /* De-interleaving the sub-frames */
+ for (j=0;j<N2;j++)
+ tmp[j] = X[C*(j*B+b)+c];
+ mdct_backward(lookup, tmp, x+N4+N2*b, mode->window, overlap);
+ }
+ if (transient_time >= 0)
+ {+ for (j=0;j<16;j++)
+ x[N4+transient_time+j-16] *= 1+gainWindow[j]*(transient_gain-1);
+ for (j=transient_time;j<N+overlap;j++)
+ x[N4+j] *= transient_gain;
+ }
+ /* The first and last part would need to be set to zero if we actually
+ wanted to use them. */
+ for (j=0;j<overlap;j++)
+ out_mem[C*(MAX_PERIOD-N)+C*j+c] += x[j+N4];
+ for (j=0;j<overlap;j++)
+ out_mem[C*(MAX_PERIOD)+C*(overlap-j-1)+c] = x[2*N-j-N4-1];
+ for (j=0;j<2*N4;j++)
+ out_mem[C*(MAX_PERIOD-N)+C*(j+overlap)+c] = x[j+N4+overlap];
+ RESTORE_STACK;
}
}
}
@@ -251,7 +314,7 @@
#ifdef EXP_PSY
VARDECL(celt_word32_t, mask);
#endif
- int time_domain=0;
+ int shortBlocks=0;
int transient_time;
float transient_gain;
const int C = CHANNELS(st->mode);
@@ -297,7 +360,7 @@
{float diff = sqrt(sqrt(end[i]/(C*len-i)))-sqrt(sqrt(begin[i]/(i)));
float ratio = ((1000+end[i])*i)/((1000+begin[i])*(C*len-i));
- if (diff > maxD)
+ if (diff > maxD && end[i] > .5*begin[i])
{maxD = diff;
maxR = ratio;
@@ -310,12 +373,13 @@
transient_time = -1;
maxR = 0;
}
- if (maxR > 20)
+ if (maxR > 10)
{float gain_1;
ec_enc_bits(&st->enc, 1, 1);
if (maxR < 30)
{+ transient_time = 16;
transient_gain = 1;
ec_enc_bits(&st->enc, 0, 2);
} else if (maxR < 100)
@@ -339,16 +403,16 @@
for (c=0;c<C;c++)
for (i=transient_time;i<len;i++)
in[C*i+c] *= gain_1;
- time_domain = 1;
+ shortBlocks = 1;
} else {ec_enc_bits(&st->enc, 0, 1);
transient_time = -1;
transient_gain = 1;
- time_domain = 0;
+ shortBlocks = 0;
}
}
/* Pitch analysis: we do it early to save on the peak stack space */
- if (!time_domain)
+ if (!shortBlocks)
find_spectral_pitch(st->mode, st->mode->fft, &st->mode->psy, in, st->out_mem, st->mode->window, 2*N-2*N4, MAX_PERIOD-(2*N-2*N4), &pitch_index);
ALLOC(freq, C*N, celt_sig_t); /**< Interleaved signal MDCTs */
@@ -355,7 +419,7 @@
/*for (i=0;i<(B+1)*C*N;i++) printf ("%f(%d) ", in[i], i); printf ("\n");*//* Compute MDCTs */
- compute_mdcts(st->mode, st->mode->window, in, freq);
+ compute_mdcts(st->mode, shortBlocks, in, freq);
#ifdef EXP_PSY
CELT_MOVE(st->psy_mem, st->out_mem+N, MAX_PERIOD+st->overlap-N);
@@ -396,8 +460,8 @@
/*for (i=0;i<N*B*C;i++)printf("%f ", X[i]);printf("\n");*//* Compute MDCTs of the pitch part */
- if (!time_domain)
- compute_mdcts(st->mode, st->mode->window, st->out_mem+pitch_index*C, freq);
+ if (!shortBlocks)
+ compute_mdcts(st->mode, 0, st->out_mem+pitch_index*C, freq);
{/* Normalise the pitch vector as well (discard the energies) */
@@ -409,7 +473,7 @@
}
curr_power = bandE[0]+bandE[1]+bandE[2];
/* Check if we can safely use the pitch (i.e. effective gain isn't too high) */
- if (!time_domain && (MULT16_32_Q15(QCONST16(.1f, 15),curr_power) + QCONST32(10.f,ENER_SHIFT) < pitch_power))
+ if (!shortBlocks && (MULT16_32_Q15(QCONST16(.1f, 15),curr_power) + QCONST32(10.f,ENER_SHIFT) < pitch_power))
{/* Simulates intensity stereo */
/*for (i=30;i<N*B;i++)
@@ -438,7 +502,7 @@
/*for (i=0;i<B*N;i++) printf("%f ",P[i]);printf("\n");*//* Residual quantisation */
- quant_bands(st->mode, X, P, NULL, bandE, stereo_mode, nbCompressedBytes*8, time_domain, &st->enc);
+ quant_bands(st->mode, X, P, NULL, bandE, stereo_mode, nbCompressedBytes*8, shortBlocks, &st->enc);
if (C==2)
{@@ -450,7 +514,7 @@
CELT_MOVE(st->out_mem, st->out_mem+C*N, C*(MAX_PERIOD+st->overlap-N));
- compute_inv_mdcts(st->mode, st->mode->window, freq, transient_time, transient_gain, st->out_mem);
+ compute_inv_mdcts(st->mode, shortBlocks, freq, transient_time, transient_gain, st->out_mem);
/* De-emphasis and put everything back at the right place in the synthesis history */
#ifndef SHORTCUTS
for (c=0;c<C;c++)
@@ -608,7 +672,7 @@
offset = MAX_PERIOD-pitch_index;
while (offset+len >= MAX_PERIOD)
offset -= pitch_index;
- compute_mdcts(st->mode, st->mode->window, st->out_mem+offset*C, freq);
+ compute_mdcts(st->mode, 0, st->out_mem+offset*C, freq);
for (i=0;i<N;i++)
freq[i] = MULT16_32_Q15(QCONST16(.9f,15),freq[i]);
#endif
@@ -617,7 +681,7 @@
CELT_MOVE(st->out_mem, st->out_mem+C*N, C*(MAX_PERIOD+st->mode->overlap-N));
/* Compute inverse MDCTs */
- compute_inv_mdcts(st->mode, st->mode->window, freq, -1, 1, st->out_mem);
+ compute_inv_mdcts(st->mode, 0, freq, -1, 1, st->out_mem);
for (c=0;c<C;c++)
{@@ -646,7 +710,7 @@
VARDECL(celt_ener_t, bandE);
VARDECL(celt_pgain_t, gains);
VARDECL(int, stereo_mode);
- int time_domain;
+ int shortBlocks;
int transient_time;
float transient_gain;
const int C = CHANNELS(st->mode);
@@ -679,8 +743,8 @@
ec_byte_readinit(&buf,data,len);
ec_dec_init(&dec,&buf);
- time_domain = ec_dec_bits(&dec, 1);
- if (time_domain)
+ shortBlocks = ec_dec_bits(&dec, 1);
+ if (shortBlocks)
{int gainid = ec_dec_bits(&dec, 2);
switch(gainid) {@@ -720,7 +784,7 @@
unquant_energy(st->mode, bandE, st->oldBandE, 20*C+len*8/5, st->mode->prob, &dec);
/* Pitch MDCT */
- compute_mdcts(st->mode, st->mode->window, st->out_mem+pitch_index*C, freq);
+ compute_mdcts(st->mode, 0, st->out_mem+pitch_index*C, freq);
{VARDECL(celt_ener_t, bandEp);
@@ -735,7 +799,7 @@
pitch_quant_bands(st->mode, P, gains);
/* Decode fixed codebook and merge with pitch */
- unquant_bands(st->mode, X, P, bandE, stereo_mode, len*8, time_domain, &dec);
+ unquant_bands(st->mode, X, P, bandE, stereo_mode, len*8, shortBlocks, &dec);
if (C==2)
{@@ -747,7 +811,7 @@
CELT_MOVE(st->out_mem, st->out_mem+C*N, C*(MAX_PERIOD+st->overlap-N));
/* Compute inverse MDCTs */
- compute_inv_mdcts(st->mode, st->mode->window, freq, transient_time, transient_gain, st->out_mem);
+ compute_inv_mdcts(st->mode, shortBlocks, freq, transient_time, transient_gain, st->out_mem);
for (c=0;c<C;c++)
{--- a/libcelt/modes.c
+++ b/libcelt/modes.c
@@ -380,6 +380,11 @@
mdct_init(&mode->mdct, 2*mode->mdctSize);
mode->fft = pitch_state_alloc(MAX_PERIOD);
+ mode->nbShortMdcts = 4;
+ mode->shortMdctSize = mode->mdctSize/mode->nbShortMdcts;
+ mdct_init(&mode->shortMdct, 2*mode->shortMdctSize);
+ mode->shortWindow = mode->window;
+
mode->prob = quant_prob_alloc(mode);
compute_energy_allocation_table(mode);
--- a/libcelt/modes.h
+++ b/libcelt/modes.h
@@ -97,6 +97,11 @@
const celt_word16_t *window;
+ int nbShortMdcts;
+ int shortMdctSize;
+ mdct_lookup shortMdct;
+ const celt_word16_t *shortWindow;
+
struct PsyDecay psy;
int *prob;