/* | |
** Copyright 2003-2010, VisualOn, Inc. | |
** | |
** Licensed under the Apache License, Version 2.0 (the "License"); | |
** you may not use this file except in compliance with the License. | |
** You may obtain a copy of the License at | |
** | |
** http://www.apache.org/licenses/LICENSE-2.0 | |
** | |
** Unless required by applicable law or agreed to in writing, software | |
** distributed under the License is distributed on an "AS IS" BASIS, | |
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
** See the License for the specific language governing permissions and | |
** limitations under the License. | |
*/ | |
/************************************************************************** | |
* File: gpclip.c * | |
* * | |
* Description:To avoid unstable synthesis on frame erasure, the gain * | |
* need to be limited(gain pitch < 1.0) when the following * | |
* case occurs * | |
* a resonance on LPC filter(lp_disp < 60Hz) * | |
* a good pitch prediction (lp_gp > 0.95) * | |
* * | |
***************************************************************************/ | |
#include "typedef.h" | |
#include "basic_op.h" | |
#define DIST_ISF_MAX 307 /* 120 Hz (6400Hz=16384) */ | |
#define DIST_ISF_THRES 154 /* 60 (6400Hz=16384) */ | |
#define GAIN_PIT_THRES 14746 /* 0.9 in Q14 */ | |
#define GAIN_PIT_MIN 9830 /* 0.6 in Q14 */ | |
#define M 16 | |
void Init_gp_clip( | |
Word16 mem[] /* (o) : memory of gain of pitch clipping algorithm */ | |
) | |
{ | |
mem[0] = DIST_ISF_MAX; | |
mem[1] = GAIN_PIT_MIN; | |
} | |
Word16 Gp_clip( | |
Word16 mem[] /* (i/o) : memory of gain of pitch clipping algorithm */ | |
) | |
{ | |
Word16 clip = 0; | |
if ((mem[0] < DIST_ISF_THRES) && (mem[1] > GAIN_PIT_THRES)) | |
clip = 1; | |
return (clip); | |
} | |
void Gp_clip_test_isf( | |
Word16 isf[], /* (i) : isf values (in frequency domain) */ | |
Word16 mem[] /* (i/o) : memory of gain of pitch clipping algorithm */ | |
) | |
{ | |
Word16 dist, dist_min; | |
Word32 i; | |
dist_min = vo_sub(isf[1], isf[0]); | |
for (i = 2; i < M - 1; i++) | |
{ | |
dist = vo_sub(isf[i], isf[i - 1]); | |
if(dist < dist_min) | |
{ | |
dist_min = dist; | |
} | |
} | |
dist = extract_h(L_mac(vo_L_mult(26214, mem[0]), 6554, dist_min)); | |
if (dist > DIST_ISF_MAX) | |
{ | |
dist = DIST_ISF_MAX; | |
} | |
mem[0] = dist; | |
return; | |
} | |
void Gp_clip_test_gain_pit( | |
Word16 gain_pit, /* (i) Q14 : gain of quantized pitch */ | |
Word16 mem[] /* (i/o) : memory of gain of pitch clipping algorithm */ | |
) | |
{ | |
Word16 gain; | |
Word32 L_tmp; | |
L_tmp = (29491 * mem[1])<<1; | |
L_tmp += (3277 * gain_pit)<<1; | |
gain = extract_h(L_tmp); | |
if(gain < GAIN_PIT_MIN) | |
{ | |
gain = GAIN_PIT_MIN; | |
} | |
mem[1] = gain; | |
return; | |
} | |