| /* |
| * Copyright (c) 2011 Apple Inc. All rights reserved. |
| * |
| * @APPLE_APACHE_LICENSE_HEADER_START@ |
| * |
| * 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. |
| * |
| * @APPLE_APACHE_LICENSE_HEADER_END@ |
| */ |
| |
| /* |
| File: matrix_dec.c |
| |
| Contains: ALAC mixing/matrixing decode routines. |
| |
| Copyright: (c) 2004-2011 Apple, Inc. |
| */ |
| |
| #include "matrixlib.h" |
| #include "ALACAudioTypes.h" |
| |
| // up to 24-bit "offset" macros for the individual bytes of a 20/24-bit word |
| #if TARGET_RT_BIG_ENDIAN |
| #define LBYTE 2 |
| #define MBYTE 1 |
| #define HBYTE 0 |
| #else |
| #define LBYTE 0 |
| #define MBYTE 1 |
| #define HBYTE 2 |
| #endif |
| |
| /* |
| There is no plain middle-side option; instead there are various mixing |
| modes including middle-side, each lossless, as embodied in the mix() |
| and unmix() functions. These functions exploit a generalized middle-side |
| transformation: |
| |
| u := [(rL + (m-r)R)/m]; |
| v := L - R; |
| |
| where [ ] denotes integer floor. The (lossless) inverse is |
| |
| L = u + v - [rV/m]; |
| R = L - v; |
| */ |
| |
| // 16-bit routines |
| |
| void unmix16( int32_t * u, int32_t * v, int16_t * out, uint32_t stride, int32_t numSamples, int32_t mixbits, int32_t mixres ) |
| { |
| int16_t * op = out; |
| int32_t j; |
| |
| if ( mixres != 0 ) |
| { |
| /* matrixed stereo */ |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| int32_t l, r; |
| |
| l = u[j] + v[j] - ((mixres * v[j]) >> mixbits); |
| r = l - v[j]; |
| |
| op[0] = (int16_t) l; |
| op[1] = (int16_t) r; |
| op += stride; |
| } |
| } |
| else |
| { |
| /* Conventional separated stereo. */ |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| op[0] = (int16_t) u[j]; |
| op[1] = (int16_t) v[j]; |
| op += stride; |
| } |
| } |
| } |
| |
| // 20-bit routines |
| // - the 20 bits of data are left-justified in 3 bytes of storage but right-aligned for input/output predictor buffers |
| |
| void unmix20( int32_t * u, int32_t * v, uint8_t * out, uint32_t stride, int32_t numSamples, int32_t mixbits, int32_t mixres ) |
| { |
| uint8_t * op = out; |
| int32_t j; |
| |
| if ( mixres != 0 ) |
| { |
| /* matrixed stereo */ |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| int32_t l, r; |
| |
| l = u[j] + v[j] - ((mixres * v[j]) >> mixbits); |
| r = l - v[j]; |
| |
| l <<= 4; |
| r <<= 4; |
| |
| op[HBYTE] = (uint8_t)((l >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((l >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((l >> 0) & 0xffu); |
| op += 3; |
| |
| op[HBYTE] = (uint8_t)((r >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((r >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((r >> 0) & 0xffu); |
| |
| op += (stride - 1) * 3; |
| } |
| } |
| else |
| { |
| /* Conventional separated stereo. */ |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| int32_t val; |
| |
| val = u[j] << 4; |
| op[HBYTE] = (uint8_t)((val >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((val >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((val >> 0) & 0xffu); |
| op += 3; |
| |
| val = v[j] << 4; |
| op[HBYTE] = (uint8_t)((val >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((val >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((val >> 0) & 0xffu); |
| |
| op += (stride - 1) * 3; |
| } |
| } |
| } |
| |
| // 24-bit routines |
| // - the 24 bits of data are right-justified in the input/output predictor buffers |
| |
| void unmix24( int32_t * u, int32_t * v, uint8_t * out, uint32_t stride, int32_t numSamples, |
| int32_t mixbits, int32_t mixres, uint16_t * shiftUV, int32_t bytesShifted ) |
| { |
| uint8_t * op = out; |
| int32_t shift = bytesShifted * 8; |
| int32_t l, r; |
| int32_t j, k; |
| |
| if ( mixres != 0 ) |
| { |
| /* matrixed stereo */ |
| if ( bytesShifted != 0 ) |
| { |
| for ( j = 0, k = 0; j < numSamples; j++, k += 2 ) |
| { |
| l = u[j] + v[j] - ((mixres * v[j]) >> mixbits); |
| r = l - v[j]; |
| |
| l = (l << shift) | (uint32_t) shiftUV[k + 0]; |
| r = (r << shift) | (uint32_t) shiftUV[k + 1]; |
| |
| op[HBYTE] = (uint8_t)((l >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((l >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((l >> 0) & 0xffu); |
| op += 3; |
| |
| op[HBYTE] = (uint8_t)((r >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((r >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((r >> 0) & 0xffu); |
| |
| op += (stride - 1) * 3; |
| } |
| } |
| else |
| { |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| l = u[j] + v[j] - ((mixres * v[j]) >> mixbits); |
| r = l - v[j]; |
| |
| op[HBYTE] = (uint8_t)((l >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((l >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((l >> 0) & 0xffu); |
| op += 3; |
| |
| op[HBYTE] = (uint8_t)((r >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((r >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((r >> 0) & 0xffu); |
| |
| op += (stride - 1) * 3; |
| } |
| } |
| } |
| else |
| { |
| /* Conventional separated stereo. */ |
| if ( bytesShifted != 0 ) |
| { |
| for ( j = 0, k = 0; j < numSamples; j++, k += 2 ) |
| { |
| l = u[j]; |
| r = v[j]; |
| |
| l = (l << shift) | (uint32_t) shiftUV[k + 0]; |
| r = (r << shift) | (uint32_t) shiftUV[k + 1]; |
| |
| op[HBYTE] = (uint8_t)((l >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((l >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((l >> 0) & 0xffu); |
| op += 3; |
| |
| op[HBYTE] = (uint8_t)((r >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((r >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((r >> 0) & 0xffu); |
| |
| op += (stride - 1) * 3; |
| } |
| } |
| else |
| { |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| int32_t val; |
| |
| val = u[j]; |
| op[HBYTE] = (uint8_t)((val >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((val >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((val >> 0) & 0xffu); |
| op += 3; |
| |
| val = v[j]; |
| op[HBYTE] = (uint8_t)((val >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((val >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((val >> 0) & 0xffu); |
| |
| op += (stride - 1) * 3; |
| } |
| } |
| } |
| } |
| |
| // 32-bit routines |
| // - note that these really expect the internal data width to be < 32 but the arrays are 32-bit |
| // - otherwise, the calculations might overflow into the 33rd bit and be lost |
| // - therefore, these routines deal with the specified "unused lower" bytes in the "shift" buffers |
| |
| void unmix32( int32_t * u, int32_t * v, int32_t * out, uint32_t stride, int32_t numSamples, |
| int32_t mixbits, int32_t mixres, uint16_t * shiftUV, int32_t bytesShifted ) |
| { |
| int32_t * op = out; |
| int32_t shift = bytesShifted * 8; |
| int32_t l, r; |
| int32_t j, k; |
| |
| if ( mixres != 0 ) |
| { |
| //Assert( bytesShifted != 0 ); |
| |
| /* matrixed stereo with shift */ |
| for ( j = 0, k = 0; j < numSamples; j++, k += 2 ) |
| { |
| int32_t lt, rt; |
| |
| lt = u[j]; |
| rt = v[j]; |
| |
| l = lt + rt - ((mixres * rt) >> mixbits); |
| r = l - rt; |
| |
| op[0] = (l << shift) | (uint32_t) shiftUV[k + 0]; |
| op[1] = (r << shift) | (uint32_t) shiftUV[k + 1]; |
| op += stride; |
| } |
| } |
| else |
| { |
| if ( bytesShifted == 0 ) |
| { |
| /* interleaving w/o shift */ |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| op[0] = u[j]; |
| op[1] = v[j]; |
| op += stride; |
| } |
| } |
| else |
| { |
| /* interleaving with shift */ |
| for ( j = 0, k = 0; j < numSamples; j++, k += 2 ) |
| { |
| op[0] = (u[j] << shift) | (uint32_t) shiftUV[k + 0]; |
| op[1] = (v[j] << shift) | (uint32_t) shiftUV[k + 1]; |
| op += stride; |
| } |
| } |
| } |
| } |
| |
| // 20/24-bit <-> 32-bit helper routines (not really matrixing but convenient to put here) |
| |
| void copyPredictorTo24( int32_t * in, uint8_t * out, uint32_t stride, int32_t numSamples ) |
| { |
| uint8_t * op = out; |
| int32_t j; |
| |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| int32_t val = in[j]; |
| |
| op[HBYTE] = (uint8_t)((val >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((val >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((val >> 0) & 0xffu); |
| op += (stride * 3); |
| } |
| } |
| |
| void copyPredictorTo24Shift( int32_t * in, uint16_t * shift, uint8_t * out, uint32_t stride, int32_t numSamples, int32_t bytesShifted ) |
| { |
| uint8_t * op = out; |
| int32_t shiftVal = bytesShifted * 8; |
| int32_t j; |
| |
| //Assert( bytesShifted != 0 ); |
| |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| int32_t val = in[j]; |
| |
| val = (val << shiftVal) | (uint32_t) shift[j]; |
| |
| op[HBYTE] = (uint8_t)((val >> 16) & 0xffu); |
| op[MBYTE] = (uint8_t)((val >> 8) & 0xffu); |
| op[LBYTE] = (uint8_t)((val >> 0) & 0xffu); |
| op += (stride * 3); |
| } |
| } |
| |
| void copyPredictorTo20( int32_t * in, uint8_t * out, uint32_t stride, int32_t numSamples ) |
| { |
| uint8_t * op = out; |
| int32_t j; |
| |
| // 32-bit predictor values are right-aligned but 20-bit output values should be left-aligned |
| // in the 24-bit output buffer |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| int32_t val = in[j]; |
| |
| op[HBYTE] = (uint8_t)((val >> 12) & 0xffu); |
| op[MBYTE] = (uint8_t)((val >> 4) & 0xffu); |
| op[LBYTE] = (uint8_t)((val << 4) & 0xffu); |
| op += (stride * 3); |
| } |
| } |
| |
| void copyPredictorTo32( int32_t * in, int32_t * out, uint32_t stride, int32_t numSamples ) |
| { |
| int32_t i, j; |
| |
| // this is only a subroutine to abstract the "iPod can only output 16-bit data" problem |
| for ( i = 0, j = 0; i < numSamples; i++, j += stride ) |
| out[j] = in[i]; |
| } |
| |
| void copyPredictorTo32Shift( int32_t * in, uint16_t * shift, int32_t * out, uint32_t stride, int32_t numSamples, int32_t bytesShifted ) |
| { |
| int32_t * op = out; |
| uint32_t shiftVal = bytesShifted * 8; |
| int32_t j; |
| |
| //Assert( bytesShifted != 0 ); |
| |
| // this is only a subroutine to abstract the "iPod can only output 16-bit data" problem |
| for ( j = 0; j < numSamples; j++ ) |
| { |
| op[0] = (in[j] << shiftVal) | (uint32_t) shift[j]; |
| op += stride; |
| } |
| } |