diff options
Diffstat (limited to 'media/libstagefright/codecs/amrwbenc/src/deemph.c')
| -rw-r--r-- | media/libstagefright/codecs/amrwbenc/src/deemph.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/amrwbenc/src/deemph.c b/media/libstagefright/codecs/amrwbenc/src/deemph.c new file mode 100644 index 0000000..0c49d6b --- /dev/null +++ b/media/libstagefright/codecs/amrwbenc/src/deemph.c @@ -0,0 +1,117 @@ +/* + ** 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: deemph.c * +* * +* Description:filtering through 1/(1-mu z^ -1) * +* Deemph2 --> signal is divided by 2 * +* Deemph_32 --> for 32 bits signal. * +* * +************************************************************************/ + +#include "typedef.h" +#include "basic_op.h" +#include "math_op.h" + +void Deemph( + Word16 x[], /* (i/o) : input signal overwritten by the output */ + Word16 mu, /* (i) Q15 : deemphasis factor */ + Word16 L, /* (i) : vector size */ + Word16 * mem /* (i/o) : memory (y[-1]) */ + ) +{ + Word32 i; + Word32 L_tmp; + + L_tmp = L_deposit_h(x[0]); + L_tmp = L_mac(L_tmp, *mem, mu); + x[0] = vo_round(L_tmp); + + for (i = 1; i < L; i++) + { + L_tmp = L_deposit_h(x[i]); + L_tmp = L_mac(L_tmp, x[i - 1], mu); + x[i] = voround(L_tmp); + } + + *mem = x[L - 1]; + + return; +} + + +void Deemph2( + Word16 x[], /* (i/o) : input signal overwritten by the output */ + Word16 mu, /* (i) Q15 : deemphasis factor */ + Word16 L, /* (i) : vector size */ + Word16 * mem /* (i/o) : memory (y[-1]) */ + ) +{ + Word32 i; + Word32 L_tmp; + L_tmp = x[0] << 15; + L_tmp += ((*mem) * mu)<<1; + x[0] = (L_tmp + 0x8000)>>16; + for (i = 1; i < L; i++) + { + L_tmp = x[i] << 15; + L_tmp += (x[i - 1] * mu)<<1; + x[i] = (L_tmp + 0x8000)>>16; + } + *mem = x[L - 1]; + return; +} + + +void Deemph_32( + Word16 x_hi[], /* (i) : input signal (bit31..16) */ + Word16 x_lo[], /* (i) : input signal (bit15..4) */ + Word16 y[], /* (o) : output signal (x16) */ + Word16 mu, /* (i) Q15 : deemphasis factor */ + Word16 L, /* (i) : vector size */ + Word16 * mem /* (i/o) : memory (y[-1]) */ + ) +{ + Word16 fac; + Word32 i, L_tmp; + + fac = mu >> 1; /* Q15 --> Q14 */ + + L_tmp = L_deposit_h(x_hi[0]); + L_tmp += (x_lo[0] * 8)<<1; + L_tmp = (L_tmp << 3); + L_tmp += ((*mem) * fac)<<1; + L_tmp = (L_tmp << 1); + y[0] = (L_tmp + 0x8000)>>16; + + for (i = 1; i < L; i++) + { + L_tmp = L_deposit_h(x_hi[i]); + L_tmp += (x_lo[i] * 8)<<1; + L_tmp = (L_tmp << 3); + L_tmp += (y[i - 1] * fac)<<1; + L_tmp = (L_tmp << 1); + y[i] = (L_tmp + 0x8000)>>16; + } + + *mem = y[L - 1]; + + return; +} + + + |