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Improve storage of quantized coefficients

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Antoine SOULIER
2022-05-10 13:49:57 +02:00
parent 913ed465f6
commit c4f48f2618
4 changed files with 87 additions and 36 deletions
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78
src/spec.c
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@@ -197,9 +197,13 @@ static float unquantize_gain(int g_int)
* g_int Quantization gain value
* x Spectral coefficients, scaled as output
* xq, nq Output spectral quantized coefficients, and count
*
* The spectral coefficients `xq` are stored as :
* b0 0:positive or zero 1:negative
* b15..b1 Absolute value
*/
LC3_HOT static void quantize(enum lc3_dt dt, enum lc3_srate sr,
int g_int, float *x, int16_t *xq, int *nq)
int g_int, float *x, uint16_t *xq, int *nq)
{
float g_inv = 1 / unquantize_gain(g_int);
int ne = LC3_NE(dt, sr);
@@ -207,15 +211,16 @@ LC3_HOT static void quantize(enum lc3_dt dt, enum lc3_srate sr,
*nq = ne;
for (int i = 0; i < ne; i += 2) {
int16_t x0, x1;
uint16_t x0, x1;
x[i+0] *= g_inv;
x0 = fminf(floorf(fabsf(x[i+0]) + 6.f/16), INT16_MAX);
xq[i+0] = x[i+0] < 0 ? -x0 : x0;
x[i+1] *= g_inv;
x1 = fminf(floorf(fabsf(x[i+1]) + 6.f/16), INT16_MAX);
xq[i+1] = x[i+1] < 0 ? -x1 : x1;
x0 = fminf(fabsf(x[i+0]) + 6.f/16, INT16_MAX);
x1 = fminf(fabsf(x[i+1]) + 6.f/16, INT16_MAX);
xq[i+0] = (x0 << 1) + ((x0 > 0) & (x[i+0] < 0));
xq[i+1] = (x1 << 1) + ((x1 > 0) & (x[i+1] < 0));
*nq = x0 || x1 ? ne : *nq - 2;
}
@@ -266,10 +271,14 @@ static int resolve_high_rate(enum lc3_srate sr, int nbytes)
* nbits_budget Truncate to stay in budget, when not zero
* p_lsb_mode Return True when LSB's are not AC coded, or NULL
* return The number of bits coding the spectrum
*
* The spectral coefficients `x` storage is :
* b0 0:positive or zero 1:negative
* b15..b1 Absolute value
*/
LC3_HOT static int compute_nbits(
enum lc3_dt dt, enum lc3_srate sr, int nbytes,
const int16_t *x, int *n, int nbits_budget, bool *p_lsb_mode)
const uint16_t *x, int *n, int nbits_budget, bool *p_lsb_mode)
{
int ne = LC3_NE(dt, sr);
@@ -295,11 +304,11 @@ LC3_HOT static int compute_nbits(
&& nbits <= nbits_budget; i += 2) {
const uint8_t *lut = lut_coeff[state];
int a = LC3_ABS(x[i]), b = LC3_ABS(x[i+1]);
uint16_t a = x[i] >> 1, b = x[i+1] >> 1;
/* --- Sign values --- */
int s = (a != 0) + (b != 0);
int s = (a > 0) + (b > 0);
nbits += s * 2048;
/* --- LSB values Reduce to 2*2 bits MSB values ---
@@ -312,6 +321,7 @@ LC3_HOT static int compute_nbits(
int m = (a | b) >> 2;
if (m) {
if (lsb_mode) {
nbits += lc3_spectrum_bits[lut[k++]][16] - 2*2048;
nbits_lsb += 2 + (a == 1) + (b == 1);
@@ -362,10 +372,14 @@ LC3_HOT static int compute_nbits(
* dt, sr, nbytes Duration, samplerate and size of the frame
* x Spectral quantized
* nq, lsb_mode Count of significants, and LSB discard indication
*
* The spectral coefficients `x` storage is :
* b0 0:positive or zero 1:negative
* b15..b1 Absolute value
*/
LC3_HOT static void put_quantized(lc3_bits_t *bits,
enum lc3_dt dt, enum lc3_srate sr, int nbytes,
const int16_t *x, int nq, bool lsb_mode)
const uint16_t *x, int nq, bool lsb_mode)
{
int ne = LC3_NE(dt, sr);
bool high_rate = resolve_high_rate(sr, nbytes);
@@ -380,8 +394,7 @@ LC3_HOT static void put_quantized(lc3_bits_t *bits,
for ( ; i < LC3_MIN(nq, (ne + 2) >> (1 - h)); i += 2) {
const uint8_t *lut = lut_coeff[state];
bool a_neg = x[i] < 0, b_neg = x[i+1] < 0;
int a = LC3_ABS(x[i]), b = LC3_ABS(x[i+1]);
uint16_t a = x[i] >> 1, b = x[i+1] >> 1;
/* --- LSB values Reduce to 2*2 bits MSB values ---
* Reduce to 2x2 bits MSB values. The LSB's pair are arithmetic
@@ -413,8 +426,8 @@ LC3_HOT static void put_quantized(lc3_bits_t *bits,
/* --- Sign values --- */
if (a) lc3_put_bit(bits, a_neg);
if (b) lc3_put_bit(bits, b_neg);
if (a) lc3_put_bit(bits, x[i+0] & 1);
if (b) lc3_put_bit(bits, x[i+1] & 1);
/* --- MSB values --- */
@@ -511,18 +524,24 @@ LC3_HOT static int get_quantized(lc3_bits_t *bits,
* Put residual bits of quantization
* bits Bitstream context
* nbits Maximum number of bits to output
* xq, n Spectral quantized, and count of significants
* x, n Spectral quantized, and count of significants
* xf Scaled spectral coefficients
*
* The spectral coefficients `x` storage is :
* b0 0:positive or zero 1:negative
* b15..b1 Absolute value
*/
LC3_HOT static void put_residual(
lc3_bits_t *bits, int nbits, const int16_t *xq, int n, const float *xf)
lc3_bits_t *bits, int nbits, const uint16_t *x, int n, const float *xf)
{
for (int i = 0; i < n && nbits > 0; i++) {
if (xq[i] == 0)
if (x[i] == 0)
continue;
lc3_put_bit(bits, xf[i] >= xq[i]);
float xq = x[i] & 1 ? -(x[i] >> 1) : (x[i] >> 1);
lc3_put_bit(bits, xf[i] >= xq);
nbits--;
}
}
@@ -555,14 +574,17 @@ LC3_HOT static void get_residual(
* bits Bitstream context
* nbits Maximum number of bits to output
* x, n Spectral quantized, and count of significants
*
* The spectral coefficients `x` storage is :
* b0 0:positive or zero 1:negative
* b15..b1 Absolute value
*/
LC3_HOT static void put_lsb(
lc3_bits_t *bits, int nbits, const int16_t *x, int n)
lc3_bits_t *bits, int nbits, const uint16_t *x, int n)
{
for (int i = 0; i < n && nbits > 0; i += 2) {
bool a_neg = x[i] < 0, b_neg = x[i+1] < 0;
int a = LC3_ABS(x[i]), b = LC3_ABS(x[i+1]);
uint16_t a = x[i] >> 1, b = x[i+1] >> 1;
int a_neg = x[i] & 1, b_neg = x[i+1] & 1;
if ((a | b) >> 2 == 0)
continue;
@@ -631,9 +653,13 @@ LC3_HOT static void get_lsb(lc3_bits_t *bits,
* xq, nq Quantized spectral coefficients
* x Quantization scaled spectrum coefficients
* return Noise factor (0 to 7)
*
* The spectral coefficients `x` storage is :
* b0 0:positive or zero 1:negative
* b15..b1 Absolute value
*/
LC3_HOT static int estimate_noise(enum lc3_dt dt, enum lc3_bandwidth bw,
const int16_t *xq, int nq, const float *x)
const uint16_t *xq, int nq, const float *x)
{
int bw_stop = (dt == LC3_DT_7M5 ? 60 : 80) * (1 + bw);
int w = 2 + dt;
@@ -739,7 +765,7 @@ static int get_nbits_ac(enum lc3_dt dt, enum lc3_srate sr, int nbytes)
void lc3_spec_analyze(enum lc3_dt dt, enum lc3_srate sr,
int nbytes, bool pitch, const lc3_tns_data_t *tns,
struct lc3_spec_analysis *spec, float *x,
int16_t *xq, struct lc3_spec_side *side)
uint16_t *xq, struct lc3_spec_side *side)
{
bool reset_off;
@@ -802,7 +828,7 @@ void lc3_spec_put_side(lc3_bits_t *bits,
*/
void lc3_spec_encode(lc3_bits_t *bits,
enum lc3_dt dt, enum lc3_srate sr, enum lc3_bandwidth bw, int nbytes,
const int16_t *xq, const lc3_spec_side_t *side, const float *x)
const uint16_t *xq, const lc3_spec_side_t *side, const float *x)
{
bool lsb_mode = side->lsb_mode;
int nq = side->nq;