-
-DECLARE_ALIGNED_16(float,sine_window[128]);
-DECLARE_ALIGNED_16(float,tcos[64]);
-DECLARE_ALIGNED_16(float,tsin[64]);
-DECLARE_ALIGNED_16(float,cos_tab[64]);
-
-static inline int signed_shift(int i, int shift) {
- if (shift > 0)
- return i << shift;
- return i >> -shift;
-}
-
-static void antialias(float *buf, float *audio)
-{
- int i, end, mid_hi, mid_lo;
-
- end = NELLY_BUF_LEN-1;
- mid_hi = NELLY_BUF_LEN/2;
- mid_lo = mid_hi-1;
-
- for (i = 0; i < NELLY_BUF_LEN/4; i++) {
- audio[2*i] = buf[2*i ]*tcos[i ] - buf[end-2*i]*tsin[i];
- audio[2*i+1] = -(buf[end-2*i ]*tcos[i ] + buf[2*i ]*tsin[i]);
- audio[end-2*i-1]= buf[end-2*i-1]*tcos[mid_lo-i] - buf[2*i+1 ]*tsin[mid_lo-i];
- audio[end-2*i ]= -(buf[2*i+1 ]*tcos[mid_lo-i] + buf[end-2*i]*tsin[mid_lo-i]);
- }
-}
-
-static void complex2signal(float *audio)
-{
- int i, end, mid_hi, mid_lo;
- float *aptr, *sigptr, a, b, c, d, e, f, g;
-
- end = NELLY_BUF_LEN-1;
- mid_hi = NELLY_BUF_LEN/2;
- mid_lo = mid_hi-1;
-
- a = -audio[end];
- b = audio[end-1];
- c = -audio[1];
- d = cos_tab[0];
- e = audio[0];
- f = cos_tab[mid_lo];
- g = cos_tab[1];
-
- audio[0] = d*e;
- audio[1] = b*g-a*f;
- audio[end-1] = a*g+b*f;
- audio[end] = c*(-d);
-
- aptr = audio+end-2;
- sigptr = cos_tab+mid_hi-1;
-
- for (i = 3; i < NELLY_BUF_LEN/2; i += 2) {
- a = audio[i-1];
- b = -audio[i];
- c = cos_tab[i/2];
- d = *sigptr;
- e = *(aptr-1);
- f = -(*aptr);
-
- audio[i-1] = a*c+b*d;
- *aptr = a*d-b*c;
-
- a = cos_tab[(i/2)+1];
- b = *(sigptr-1);
-
- *(aptr-1) = b*e+a*f;
- audio[i] = a*e-b*f;
-
- sigptr--;
- aptr -= 2;
- }
-}
-
-static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio)
-{
- int bot, mid_up, mid_down, top;
- float s_bot, s_top;
-
- bot = 0;
- top = NELLY_BUF_LEN-1;
- mid_up = NELLY_BUF_LEN/2;
- mid_down = (NELLY_BUF_LEN/2)-1;
-
- while (bot < NELLY_BUF_LEN/4) {
- s_bot = audio[bot];
- s_top = audio[top];
- audio[bot] = (audio[mid_up]*sine_window[bot]-state[bot ]*sine_window[top])/s->scale_bias + s->add_bias;
- audio[top] = (-state[bot ]*sine_window[bot]-audio[mid_up]*sine_window[top])/s->scale_bias + s->add_bias;
- state[bot] = audio[mid_down];
-
- audio[mid_down] = (s_top *sine_window[mid_down]-state[mid_down]*sine_window[mid_up])/s->scale_bias + s->add_bias;
- audio[mid_up ] = (-state[mid_down]*sine_window[mid_down]-s_top *sine_window[mid_up])/s->scale_bias + s->add_bias;
- state[mid_down] = s_bot;
-
- bot++;
- mid_up++;
- mid_down--;
- top--;
- }
-}
-
-static int sum_bits(short *buf, short shift, short off)
-{
- int b, i = 0, ret = 0;
-
- for (i = 0; i < NELLY_FILL_LEN; i++) {
- b = buf[i]-off;
- b = ((b>>(shift-1))+1)>>1;
- ret += av_clip(b, 0, NELLY_BIT_CAP);
- }
-
- return ret;
-}
-
-static int headroom(int *la)
-{
- int l;
- if (*la == 0) {
- return 31;
- }
- l = 30 - av_log2(FFABS(*la));
- *la <<= l;
- return l;
-}
-
-
-static void get_sample_bits(float *buf, int *bits)
-{
- int i, j;
- short sbuf[128];
- int bitsum = 0, last_bitsum, small_bitsum, big_bitsum;
- short shift, shift_saved;
- int max, sum, last_off, tmp;
- int big_off, small_off;
- int off;
-
- max = 0;
- for (i = 0; i < NELLY_FILL_LEN; i++) {
- max = FFMAX(max, buf[i]);
- }
- shift = -16;
- shift += headroom(&max);
-
- sum = 0;
- for (i = 0; i < NELLY_FILL_LEN; i++) {
- sbuf[i] = signed_shift(buf[i], shift);
- sbuf[i] = (3*sbuf[i])>>2;
- sum += sbuf[i];
- }
-
- shift += 11;
- shift_saved = shift;
- sum -= NELLY_DETAIL_BITS << shift;
- shift += headroom(&sum);
- small_off = (NELLY_BASE_OFF * (sum>>16)) >> 15;
- shift = shift_saved - (NELLY_BASE_SHIFT+shift-31);
-
- small_off = signed_shift(small_off, shift);
-
- bitsum = sum_bits(sbuf, shift_saved, small_off);
-
- if (bitsum != NELLY_DETAIL_BITS) {
- shift = 0;
- off = bitsum - NELLY_DETAIL_BITS;
-
- for(shift=0; FFABS(off) <= 16383; shift++)
- off *= 2;
-
- off = (off * NELLY_BASE_OFF) >> 15;
- shift = shift_saved-(NELLY_BASE_SHIFT+shift-15);
-
- off = signed_shift(off, shift);
-
- for (j = 1; j < 20; j++) {
- last_off = small_off;
- small_off += off;
- last_bitsum = bitsum;
-
- bitsum = sum_bits(sbuf, shift_saved, small_off);
-
- if ((bitsum-NELLY_DETAIL_BITS) * (last_bitsum-NELLY_DETAIL_BITS) <= 0)
- break;
- }
-
- if (bitsum > NELLY_DETAIL_BITS) {
- big_off = small_off;
- small_off = last_off;
- big_bitsum=bitsum;
- small_bitsum=last_bitsum;
- } else {
- big_off = last_off;
- big_bitsum=last_bitsum;
- small_bitsum=bitsum;
- }
-
- while (bitsum != NELLY_DETAIL_BITS && j <= 19) {
- off = (big_off+small_off)>>1;
- bitsum = sum_bits(sbuf, shift_saved, off);
- if (bitsum > NELLY_DETAIL_BITS) {
- big_off=off;
- big_bitsum=bitsum;
- } else {
- small_off = off;
- small_bitsum=bitsum;
- }
- j++;
- }
-
- if (abs(big_bitsum-NELLY_DETAIL_BITS) >=
- abs(small_bitsum-NELLY_DETAIL_BITS)) {
- bitsum = small_bitsum;
- } else {
- small_off = big_off;
- bitsum = big_bitsum;
- }
- }
-
- for (i = 0; i < NELLY_FILL_LEN; i++) {
- tmp = sbuf[i]-small_off;
- tmp = ((tmp>>(shift_saved-1))+1)>>1;
- bits[i] = av_clip(tmp, 0, NELLY_BIT_CAP);
- }
-
- if (bitsum > NELLY_DETAIL_BITS) {
- tmp = i = 0;
- while (tmp < NELLY_DETAIL_BITS) {
- tmp += bits[i];
- i++;
- }
-
- bits[i-1] -= tmp - NELLY_DETAIL_BITS;
- for(; i < NELLY_FILL_LEN; i++)
- bits[i] = 0;
- }
-}
-
-void nelly_decode_block(NellyMoserDecodeContext *s, unsigned char block[NELLY_BLOCK_LEN], float audio[NELLY_SAMPLES])