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- /*
- * 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;
- }
- }
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