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-rw-r--r--media/libstagefright/codecs/amrwbenc/src/levinson.c286
1 files changed, 143 insertions, 143 deletions
diff --git a/media/libstagefright/codecs/amrwbenc/src/levinson.c b/media/libstagefright/codecs/amrwbenc/src/levinson.c
index 4b2f8ed..9d5a3bd 100644
--- a/media/libstagefright/codecs/amrwbenc/src/levinson.c
+++ b/media/libstagefright/codecs/amrwbenc/src/levinson.c
@@ -21,7 +21,7 @@
* *
************************************************************************/
/*---------------------------------------------------------------------------*
- * LEVINSON.C *
+ * LEVINSON.C *
*---------------------------------------------------------------------------*
* *
* LEVINSON-DURBIN algorithm in double precision *
@@ -96,154 +96,154 @@
#define NC (M/2)
void Init_Levinson(
- Word16 * mem /* output :static memory (18 words) */
- )
+ Word16 * mem /* output :static memory (18 words) */
+ )
{
- Set_zero(mem, 18); /* old_A[0..M-1] = 0, old_rc[0..1] = 0 */
- return;
+ Set_zero(mem, 18); /* old_A[0..M-1] = 0, old_rc[0..1] = 0 */
+ return;
}
void Levinson(
- Word16 Rh[], /* (i) : Rh[M+1] Vector of autocorrelations (msb) */
- Word16 Rl[], /* (i) : Rl[M+1] Vector of autocorrelations (lsb) */
- Word16 A[], /* (o) Q12 : A[M] LPC coefficients (m = 16) */
- Word16 rc[], /* (o) Q15 : rc[M] Reflection coefficients. */
- Word16 * mem /* (i/o) :static memory (18 words) */
- )
+ Word16 Rh[], /* (i) : Rh[M+1] Vector of autocorrelations (msb) */
+ Word16 Rl[], /* (i) : Rl[M+1] Vector of autocorrelations (lsb) */
+ Word16 A[], /* (o) Q12 : A[M] LPC coefficients (m = 16) */
+ Word16 rc[], /* (o) Q15 : rc[M] Reflection coefficients. */
+ Word16 * mem /* (i/o) :static memory (18 words) */
+ )
{
- Word32 i, j;
- Word16 hi, lo;
- Word16 Kh, Kl; /* reflection coefficient; hi and lo */
- Word16 alp_h, alp_l, alp_exp; /* Prediction gain; hi lo and exponent */
- Word16 Ah[M + 1], Al[M + 1]; /* LPC coef. in double prec. */
- Word16 Anh[M + 1], Anl[M + 1]; /* LPC coef.for next iteration in double prec. */
- Word32 t0, t1, t2; /* temporary variable */
- Word16 *old_A, *old_rc;
-
- /* Last A(z) for case of unstable filter */
- old_A = mem;
- old_rc = mem + M;
-
- /* K = A[1] = -R[1] / R[0] */
-
- t1 = ((Rh[1] << 16) + (Rl[1] << 1)); /* R[1] in Q31 */
- t2 = L_abs(t1); /* abs R[1] */
- t0 = Div_32(t2, Rh[0], Rl[0]); /* R[1]/R[0] in Q31 */
- if (t1 > 0)
- t0 = -t0; /* -R[1]/R[0] */
-
- Kh = t0 >> 16;
- Kl = (t0 & 0xffff)>>1;
- rc[0] = Kh;
- t0 = (t0 >> 4); /* A[1] in Q27 */
-
- Ah[1] = t0 >> 16;
- Al[1] = (t0 & 0xffff)>>1;
-
- /* Alpha = R[0] * (1-K**2) */
- t0 = Mpy_32(Kh, Kl, Kh, Kl); /* K*K in Q31 */
- t0 = L_abs(t0); /* Some case <0 !! */
- t0 = vo_L_sub((Word32) 0x7fffffffL, t0); /* 1 - K*K in Q31 */
-
- hi = t0 >> 16;
- lo = (t0 & 0xffff)>>1;
-
- t0 = Mpy_32(Rh[0], Rl[0], hi, lo); /* Alpha in Q31 */
-
- /* Normalize Alpha */
- alp_exp = norm_l(t0);
- t0 = (t0 << alp_exp);
-
- alp_h = t0 >> 16;
- alp_l = (t0 & 0xffff)>>1;
- /*--------------------------------------*
- * ITERATIONS I=2 to M *
- *--------------------------------------*/
- for (i = 2; i <= M; i++)
- {
- /* t0 = SUM ( R[j]*A[i-j] ,j=1,i-1 ) + R[i] */
- t0 = 0;
- for (j = 1; j < i; j++)
- t0 = vo_L_add(t0, Mpy_32(Rh[j], Rl[j], Ah[i - j], Al[i - j]));
-
- t0 = t0 << 4; /* result in Q27 -> convert to Q31 */
- /* No overflow possible */
- t1 = ((Rh[i] << 16) + (Rl[i] << 1));
- t0 = vo_L_add(t0, t1); /* add R[i] in Q31 */
-
- /* K = -t0 / Alpha */
- t1 = L_abs(t0);
- t2 = Div_32(t1, alp_h, alp_l); /* abs(t0)/Alpha */
- if (t0 > 0)
- t2 = -t2; /* K =-t0/Alpha */
- t2 = (t2 << alp_exp); /* denormalize; compare to Alpha */
-
- Kh = t2 >> 16;
- Kl = (t2 & 0xffff)>>1;
-
- rc[i - 1] = Kh;
- /* Test for unstable filter. If unstable keep old A(z) */
- if (abs_s(Kh) > 32750)
- {
- A[0] = 4096; /* Ai[0] not stored (always 1.0) */
- for (j = 0; j < M; j++)
- {
- A[j + 1] = old_A[j];
- }
- rc[0] = old_rc[0]; /* only two rc coefficients are needed */
- rc[1] = old_rc[1];
- return;
- }
- /*------------------------------------------*
- * Compute new LPC coeff. -> An[i] *
- * An[j]= A[j] + K*A[i-j] , j=1 to i-1 *
- * An[i]= K *
- *------------------------------------------*/
- for (j = 1; j < i; j++)
- {
- t0 = Mpy_32(Kh, Kl, Ah[i - j], Al[i - j]);
- t0 = vo_L_add(t0, ((Ah[j] << 16) + (Al[j] << 1)));
- Anh[j] = t0 >> 16;
- Anl[j] = (t0 & 0xffff)>>1;
- }
- t2 = (t2 >> 4); /* t2 = K in Q31 ->convert to Q27 */
-
- VO_L_Extract(t2, &Anh[i], &Anl[i]); /* An[i] in Q27 */
-
- /* Alpha = Alpha * (1-K**2) */
- t0 = Mpy_32(Kh, Kl, Kh, Kl); /* K*K in Q31 */
- t0 = L_abs(t0); /* Some case <0 !! */
- t0 = vo_L_sub((Word32) 0x7fffffffL, t0); /* 1 - K*K in Q31 */
- hi = t0 >> 16;
- lo = (t0 & 0xffff)>>1;
- t0 = Mpy_32(alp_h, alp_l, hi, lo); /* Alpha in Q31 */
-
- /* Normalize Alpha */
- j = norm_l(t0);
- t0 = (t0 << j);
- alp_h = t0 >> 16;
- alp_l = (t0 & 0xffff)>>1;
- alp_exp += j; /* Add normalization to alp_exp */
-
- /* A[j] = An[j] */
- for (j = 1; j <= i; j++)
- {
- Ah[j] = Anh[j];
- Al[j] = Anl[j];
- }
- }
- /* Truncate A[i] in Q27 to Q12 with rounding */
- A[0] = 4096;
- for (i = 1; i <= M; i++)
- {
- t0 = (Ah[i] << 16) + (Al[i] << 1);
- old_A[i - 1] = A[i] = vo_round((t0 << 1));
- }
- old_rc[0] = rc[0];
- old_rc[1] = rc[1];
-
- return;
+ Word32 i, j;
+ Word16 hi, lo;
+ Word16 Kh, Kl; /* reflection coefficient; hi and lo */
+ Word16 alp_h, alp_l, alp_exp; /* Prediction gain; hi lo and exponent */
+ Word16 Ah[M + 1], Al[M + 1]; /* LPC coef. in double prec. */
+ Word16 Anh[M + 1], Anl[M + 1]; /* LPC coef.for next iteration in double prec. */
+ Word32 t0, t1, t2; /* temporary variable */
+ Word16 *old_A, *old_rc;
+
+ /* Last A(z) for case of unstable filter */
+ old_A = mem;
+ old_rc = mem + M;
+
+ /* K = A[1] = -R[1] / R[0] */
+
+ t1 = ((Rh[1] << 16) + (Rl[1] << 1)); /* R[1] in Q31 */
+ t2 = L_abs(t1); /* abs R[1] */
+ t0 = Div_32(t2, Rh[0], Rl[0]); /* R[1]/R[0] in Q31 */
+ if (t1 > 0)
+ t0 = -t0; /* -R[1]/R[0] */
+
+ Kh = t0 >> 16;
+ Kl = (t0 & 0xffff)>>1;
+ rc[0] = Kh;
+ t0 = (t0 >> 4); /* A[1] in Q27 */
+
+ Ah[1] = t0 >> 16;
+ Al[1] = (t0 & 0xffff)>>1;
+
+ /* Alpha = R[0] * (1-K**2) */
+ t0 = Mpy_32(Kh, Kl, Kh, Kl); /* K*K in Q31 */
+ t0 = L_abs(t0); /* Some case <0 !! */
+ t0 = vo_L_sub((Word32) 0x7fffffffL, t0); /* 1 - K*K in Q31 */
+
+ hi = t0 >> 16;
+ lo = (t0 & 0xffff)>>1;
+
+ t0 = Mpy_32(Rh[0], Rl[0], hi, lo); /* Alpha in Q31 */
+
+ /* Normalize Alpha */
+ alp_exp = norm_l(t0);
+ t0 = (t0 << alp_exp);
+
+ alp_h = t0 >> 16;
+ alp_l = (t0 & 0xffff)>>1;
+ /*--------------------------------------*
+ * ITERATIONS I=2 to M *
+ *--------------------------------------*/
+ for (i = 2; i <= M; i++)
+ {
+ /* t0 = SUM ( R[j]*A[i-j] ,j=1,i-1 ) + R[i] */
+ t0 = 0;
+ for (j = 1; j < i; j++)
+ t0 = vo_L_add(t0, Mpy_32(Rh[j], Rl[j], Ah[i - j], Al[i - j]));
+
+ t0 = t0 << 4; /* result in Q27 -> convert to Q31 */
+ /* No overflow possible */
+ t1 = ((Rh[i] << 16) + (Rl[i] << 1));
+ t0 = vo_L_add(t0, t1); /* add R[i] in Q31 */
+
+ /* K = -t0 / Alpha */
+ t1 = L_abs(t0);
+ t2 = Div_32(t1, alp_h, alp_l); /* abs(t0)/Alpha */
+ if (t0 > 0)
+ t2 = -t2; /* K =-t0/Alpha */
+ t2 = (t2 << alp_exp); /* denormalize; compare to Alpha */
+
+ Kh = t2 >> 16;
+ Kl = (t2 & 0xffff)>>1;
+
+ rc[i - 1] = Kh;
+ /* Test for unstable filter. If unstable keep old A(z) */
+ if (abs_s(Kh) > 32750)
+ {
+ A[0] = 4096; /* Ai[0] not stored (always 1.0) */
+ for (j = 0; j < M; j++)
+ {
+ A[j + 1] = old_A[j];
+ }
+ rc[0] = old_rc[0]; /* only two rc coefficients are needed */
+ rc[1] = old_rc[1];
+ return;
+ }
+ /*------------------------------------------*
+ * Compute new LPC coeff. -> An[i] *
+ * An[j]= A[j] + K*A[i-j] , j=1 to i-1 *
+ * An[i]= K *
+ *------------------------------------------*/
+ for (j = 1; j < i; j++)
+ {
+ t0 = Mpy_32(Kh, Kl, Ah[i - j], Al[i - j]);
+ t0 = vo_L_add(t0, ((Ah[j] << 16) + (Al[j] << 1)));
+ Anh[j] = t0 >> 16;
+ Anl[j] = (t0 & 0xffff)>>1;
+ }
+ t2 = (t2 >> 4); /* t2 = K in Q31 ->convert to Q27 */
+
+ VO_L_Extract(t2, &Anh[i], &Anl[i]); /* An[i] in Q27 */
+
+ /* Alpha = Alpha * (1-K**2) */
+ t0 = Mpy_32(Kh, Kl, Kh, Kl); /* K*K in Q31 */
+ t0 = L_abs(t0); /* Some case <0 !! */
+ t0 = vo_L_sub((Word32) 0x7fffffffL, t0); /* 1 - K*K in Q31 */
+ hi = t0 >> 16;
+ lo = (t0 & 0xffff)>>1;
+ t0 = Mpy_32(alp_h, alp_l, hi, lo); /* Alpha in Q31 */
+
+ /* Normalize Alpha */
+ j = norm_l(t0);
+ t0 = (t0 << j);
+ alp_h = t0 >> 16;
+ alp_l = (t0 & 0xffff)>>1;
+ alp_exp += j; /* Add normalization to alp_exp */
+
+ /* A[j] = An[j] */
+ for (j = 1; j <= i; j++)
+ {
+ Ah[j] = Anh[j];
+ Al[j] = Anl[j];
+ }
+ }
+ /* Truncate A[i] in Q27 to Q12 with rounding */
+ A[0] = 4096;
+ for (i = 1; i <= M; i++)
+ {
+ t0 = (Ah[i] << 16) + (Al[i] << 1);
+ old_A[i - 1] = A[i] = vo_round((t0 << 1));
+ }
+ old_rc[0] = rc[0];
+ old_rc[1] = rc[1];
+
+ return;
}
generated by cgit v1.1 at 2024-05-07 16:49:13 +0000