391 lines
9.3 KiB
C
391 lines
9.3 KiB
C
/*
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* Copyright (c) 2011 Apple Inc. All rights reserved.
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*
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* @APPLE_APACHE_LICENSE_HEADER_START@
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* @APPLE_APACHE_LICENSE_HEADER_END@
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*/
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/*
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File: matrix_dec.c
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Contains: ALAC mixing/matrixing decode routines.
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Copyright: (c) 2004-2011 Apple, Inc.
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*/
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#include "matrixlib.h"
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#include "ALACAudioTypes.h"
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// up to 24-bit "offset" macros for the individual bytes of a 20/24-bit word
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#if TARGET_RT_BIG_ENDIAN
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#define LBYTE 2
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#define MBYTE 1
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#define HBYTE 0
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#else
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#define LBYTE 0
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#define MBYTE 1
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#define HBYTE 2
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#endif
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/*
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There is no plain middle-side option; instead there are various mixing
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modes including middle-side, each lossless, as embodied in the mix()
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and unmix() functions. These functions exploit a generalized middle-side
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transformation:
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u := [(rL + (m-r)R)/m];
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v := L - R;
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where [ ] denotes integer floor. The (lossless) inverse is
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L = u + v - [rV/m];
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R = L - v;
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*/
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// 16-bit routines
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void unmix16( int32_t * u, int32_t * v, int16_t * out, uint32_t stride, int32_t numSamples, int32_t mixbits, int32_t mixres )
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{
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int16_t * op = out;
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int32_t j;
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if ( mixres != 0 )
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{
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/* matrixed stereo */
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for ( j = 0; j < numSamples; j++ )
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{
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int32_t l, r;
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l = u[j] + v[j] - ((mixres * v[j]) >> mixbits);
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r = l - v[j];
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op[0] = (int16_t) l;
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op[1] = (int16_t) r;
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op += stride;
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}
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}
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else
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{
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/* Conventional separated stereo. */
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for ( j = 0; j < numSamples; j++ )
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{
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op[0] = (int16_t) u[j];
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op[1] = (int16_t) v[j];
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op += stride;
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}
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}
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}
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// 20-bit routines
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// - the 20 bits of data are left-justified in 3 bytes of storage but right-aligned for input/output predictor buffers
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void unmix20( int32_t * u, int32_t * v, uint8_t * out, uint32_t stride, int32_t numSamples, int32_t mixbits, int32_t mixres )
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{
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uint8_t * op = out;
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int32_t j;
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if ( mixres != 0 )
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{
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/* matrixed stereo */
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for ( j = 0; j < numSamples; j++ )
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{
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int32_t l, r;
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l = u[j] + v[j] - ((mixres * v[j]) >> mixbits);
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r = l - v[j];
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l <<= 4;
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r <<= 4;
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op[HBYTE] = (uint8_t)((l >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((l >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((l >> 0) & 0xffu);
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op += 3;
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op[HBYTE] = (uint8_t)((r >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((r >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((r >> 0) & 0xffu);
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op += (stride - 1) * 3;
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}
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}
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else
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{
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/* Conventional separated stereo. */
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for ( j = 0; j < numSamples; j++ )
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{
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int32_t val;
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val = u[j] << 4;
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op[HBYTE] = (uint8_t)((val >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((val >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((val >> 0) & 0xffu);
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op += 3;
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val = v[j] << 4;
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op[HBYTE] = (uint8_t)((val >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((val >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((val >> 0) & 0xffu);
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op += (stride - 1) * 3;
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}
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}
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}
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// 24-bit routines
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// - the 24 bits of data are right-justified in the input/output predictor buffers
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void unmix24( int32_t * u, int32_t * v, uint8_t * out, uint32_t stride, int32_t numSamples,
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int32_t mixbits, int32_t mixres, uint16_t * shiftUV, int32_t bytesShifted )
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{
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uint8_t * op = out;
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int32_t shift = bytesShifted * 8;
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int32_t l, r;
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int32_t j, k;
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if ( mixres != 0 )
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{
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/* matrixed stereo */
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if ( bytesShifted != 0 )
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{
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for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
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{
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l = u[j] + v[j] - ((mixres * v[j]) >> mixbits);
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r = l - v[j];
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l = (l << shift) | (uint32_t) shiftUV[k + 0];
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r = (r << shift) | (uint32_t) shiftUV[k + 1];
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op[HBYTE] = (uint8_t)((l >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((l >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((l >> 0) & 0xffu);
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op += 3;
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op[HBYTE] = (uint8_t)((r >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((r >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((r >> 0) & 0xffu);
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op += (stride - 1) * 3;
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}
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}
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else
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{
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for ( j = 0; j < numSamples; j++ )
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{
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l = u[j] + v[j] - ((mixres * v[j]) >> mixbits);
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r = l - v[j];
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op[HBYTE] = (uint8_t)((l >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((l >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((l >> 0) & 0xffu);
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op += 3;
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op[HBYTE] = (uint8_t)((r >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((r >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((r >> 0) & 0xffu);
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op += (stride - 1) * 3;
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}
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}
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}
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else
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{
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/* Conventional separated stereo. */
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if ( bytesShifted != 0 )
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{
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for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
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{
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l = u[j];
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r = v[j];
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l = (l << shift) | (uint32_t) shiftUV[k + 0];
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r = (r << shift) | (uint32_t) shiftUV[k + 1];
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op[HBYTE] = (uint8_t)((l >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((l >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((l >> 0) & 0xffu);
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op += 3;
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op[HBYTE] = (uint8_t)((r >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((r >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((r >> 0) & 0xffu);
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op += (stride - 1) * 3;
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}
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}
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else
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{
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for ( j = 0; j < numSamples; j++ )
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{
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int32_t val;
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val = u[j];
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op[HBYTE] = (uint8_t)((val >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((val >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((val >> 0) & 0xffu);
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op += 3;
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val = v[j];
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op[HBYTE] = (uint8_t)((val >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((val >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((val >> 0) & 0xffu);
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op += (stride - 1) * 3;
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}
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}
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}
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}
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// 32-bit routines
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// - note that these really expect the internal data width to be < 32 but the arrays are 32-bit
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// - otherwise, the calculations might overflow into the 33rd bit and be lost
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// - therefore, these routines deal with the specified "unused lower" bytes in the "shift" buffers
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void unmix32( int32_t * u, int32_t * v, int32_t * out, uint32_t stride, int32_t numSamples,
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int32_t mixbits, int32_t mixres, uint16_t * shiftUV, int32_t bytesShifted )
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{
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int32_t * op = out;
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int32_t shift = bytesShifted * 8;
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int32_t l, r;
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int32_t j, k;
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if ( mixres != 0 )
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{
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//Assert( bytesShifted != 0 );
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/* matrixed stereo with shift */
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for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
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{
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int32_t lt, rt;
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lt = u[j];
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rt = v[j];
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l = lt + rt - ((mixres * rt) >> mixbits);
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r = l - rt;
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op[0] = (l << shift) | (uint32_t) shiftUV[k + 0];
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op[1] = (r << shift) | (uint32_t) shiftUV[k + 1];
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op += stride;
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}
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}
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else
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{
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if ( bytesShifted == 0 )
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{
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/* interleaving w/o shift */
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for ( j = 0; j < numSamples; j++ )
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{
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op[0] = u[j];
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op[1] = v[j];
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op += stride;
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}
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}
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else
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{
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/* interleaving with shift */
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for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
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{
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op[0] = (u[j] << shift) | (uint32_t) shiftUV[k + 0];
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op[1] = (v[j] << shift) | (uint32_t) shiftUV[k + 1];
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op += stride;
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}
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}
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}
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}
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// 20/24-bit <-> 32-bit helper routines (not really matrixing but convenient to put here)
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void copyPredictorTo24( int32_t * in, uint8_t * out, uint32_t stride, int32_t numSamples )
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{
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uint8_t * op = out;
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int32_t j;
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for ( j = 0; j < numSamples; j++ )
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{
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int32_t val = in[j];
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op[HBYTE] = (uint8_t)((val >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((val >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((val >> 0) & 0xffu);
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op += (stride * 3);
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}
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}
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void copyPredictorTo24Shift( int32_t * in, uint16_t * shift, uint8_t * out, uint32_t stride, int32_t numSamples, int32_t bytesShifted )
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{
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uint8_t * op = out;
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int32_t shiftVal = bytesShifted * 8;
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int32_t j;
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//Assert( bytesShifted != 0 );
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for ( j = 0; j < numSamples; j++ )
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{
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int32_t val = in[j];
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val = (val << shiftVal) | (uint32_t) shift[j];
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op[HBYTE] = (uint8_t)((val >> 16) & 0xffu);
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op[MBYTE] = (uint8_t)((val >> 8) & 0xffu);
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op[LBYTE] = (uint8_t)((val >> 0) & 0xffu);
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op += (stride * 3);
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}
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}
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void copyPredictorTo20( int32_t * in, uint8_t * out, uint32_t stride, int32_t numSamples )
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{
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uint8_t * op = out;
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int32_t j;
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// 32-bit predictor values are right-aligned but 20-bit output values should be left-aligned
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// in the 24-bit output buffer
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for ( j = 0; j < numSamples; j++ )
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{
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int32_t val = in[j];
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op[HBYTE] = (uint8_t)((val >> 12) & 0xffu);
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op[MBYTE] = (uint8_t)((val >> 4) & 0xffu);
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op[LBYTE] = (uint8_t)((val << 4) & 0xffu);
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op += (stride * 3);
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}
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}
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void copyPredictorTo32( int32_t * in, int32_t * out, uint32_t stride, int32_t numSamples )
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{
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int32_t i, j;
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// this is only a subroutine to abstract the "iPod can only output 16-bit data" problem
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for ( i = 0, j = 0; i < numSamples; i++, j += stride )
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out[j] = in[i];
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}
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void copyPredictorTo32Shift( int32_t * in, uint16_t * shift, int32_t * out, uint32_t stride, int32_t numSamples, int32_t bytesShifted )
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{
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int32_t * op = out;
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uint32_t shiftVal = bytesShifted * 8;
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int32_t j;
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//Assert( bytesShifted != 0 );
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// this is only a subroutine to abstract the "iPod can only output 16-bit data" problem
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for ( j = 0; j < numSamples; j++ )
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{
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op[0] = (in[j] << shiftVal) | (uint32_t) shift[j];
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op += stride;
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}
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}
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