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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_enc.c
Contains: ALAC mixing/matrixing encode 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 mix16( int16_t * in, uint32_t stride, int32_t * u, int32_t * v, int32_t numSamples, int32_t mixbits, int32_t mixres )
{
int16_t * ip = in;
int32_t j;
if ( mixres != 0 )
{
int32_t mod = 1 << mixbits;
int32_t m2;
/* matrixed stereo */
m2 = mod - mixres;
for ( j = 0; j < numSamples; j++ )
{
int32_t l, r;
l = (int32_t) ip[0];
r = (int32_t) ip[1];
ip += stride;
u[j] = (mixres * l + m2 * r) >> mixbits;
v[j] = l - r;
}
}
else
{
/* Conventional separated stereo. */
for ( j = 0; j < numSamples; j++ )
{
u[j] = (int32_t) ip[0];
v[j] = (int32_t) ip[1];
ip += 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 mix20( uint8_t * in, uint32_t stride, int32_t * u, int32_t * v, int32_t numSamples, int32_t mixbits, int32_t mixres )
{
int32_t l, r;
uint8_t * ip = in;
int32_t j;
if ( mixres != 0 )
{
/* matrixed stereo */
int32_t mod = 1 << mixbits;
int32_t m2 = mod - mixres;
for ( j = 0; j < numSamples; j++ )
{
l = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
l = (l << 8) >> 12;
ip += 3;
r = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
r = (r << 8) >> 12;
ip += (stride - 1) * 3;
u[j] = (mixres * l + m2 * r) >> mixbits;
v[j] = l - r;
}
}
else
{
/* Conventional separated stereo. */
for ( j = 0; j < numSamples; j++ )
{
l = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
u[j] = (l << 8) >> 12;
ip += 3;
r = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
v[j] = (r << 8) >> 12;
ip += (stride - 1) * 3;
}
}
}
// 24-bit routines
// - the 24 bits of data are right-justified in the input/output predictor buffers
void mix24( uint8_t * in, uint32_t stride, int32_t * u, int32_t * v, int32_t numSamples,
int32_t mixbits, int32_t mixres, uint16_t * shiftUV, int32_t bytesShifted )
{
int32_t l, r;
uint8_t * ip = in;
int32_t shift = bytesShifted * 8;
uint32_t mask = (1ul << shift) - 1;
int32_t j, k;
if ( mixres != 0 )
{
/* matrixed stereo */
int32_t mod = 1 << mixbits;
int32_t m2 = mod - mixres;
if ( bytesShifted != 0 )
{
for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
{
l = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
l = (l << 8) >> 8;
ip += 3;
r = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
r = (r << 8) >> 8;
ip += (stride - 1) * 3;
shiftUV[k + 0] = (uint16_t)(l & mask);
shiftUV[k + 1] = (uint16_t)(r & mask);
l >>= shift;
r >>= shift;
u[j] = (mixres * l + m2 * r) >> mixbits;
v[j] = l - r;
}
}
else
{
for ( j = 0; j < numSamples; j++ )
{
l = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
l = (l << 8) >> 8;
ip += 3;
r = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
r = (r << 8) >> 8;
ip += (stride - 1) * 3;
u[j] = (mixres * l + m2 * r) >> mixbits;
v[j] = l - r;
}
}
}
else
{
/* Conventional separated stereo. */
if ( bytesShifted != 0 )
{
for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
{
l = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
l = (l << 8) >> 8;
ip += 3;
r = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
r = (r << 8) >> 8;
ip += (stride - 1) * 3;
shiftUV[k + 0] = (uint16_t)(l & mask);
shiftUV[k + 1] = (uint16_t)(r & mask);
l >>= shift;
r >>= shift;
u[j] = l;
v[j] = r;
}
}
else
{
for ( j = 0; j < numSamples; j++ )
{
l = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
u[j] = (l << 8) >> 8;
ip += 3;
r = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
v[j] = (r << 8) >> 8;
ip += (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 mix32( int32_t * in, uint32_t stride, int32_t * u, int32_t * v, int32_t numSamples,
int32_t mixbits, int32_t mixres, uint16_t * shiftUV, int32_t bytesShifted )
{
int32_t * ip = in;
int32_t shift = bytesShifted * 8;
uint32_t mask = (1ul << shift) - 1;
int32_t l, r;
int32_t j, k;
if ( mixres != 0 )
{
int32_t mod = 1 << mixbits;
int32_t m2;
//Assert( bytesShifted != 0 );
/* matrixed stereo with shift */
m2 = mod - mixres;
for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
{
l = ip[0];
r = ip[1];
ip += stride;
shiftUV[k + 0] = (uint16_t)(l & mask);
shiftUV[k + 1] = (uint16_t)(r & mask);
l >>= shift;
r >>= shift;
u[j] = (mixres * l + m2 * r) >> mixbits;
v[j] = l - r;
}
}
else
{
if ( bytesShifted == 0 )
{
/* de-interleaving w/o shift */
for ( j = 0; j < numSamples; j++ )
{
u[j] = ip[0];
v[j] = ip[1];
ip += stride;
}
}
else
{
/* de-interleaving with shift */
for ( j = 0, k = 0; j < numSamples; j++, k += 2 )
{
l = ip[0];
r = ip[1];
ip += stride;
shiftUV[k + 0] = (uint16_t)(l & mask);
shiftUV[k + 1] = (uint16_t)(r & mask);
l >>= shift;
r >>= shift;
u[j] = l;
v[j] = r;
}
}
}
}
// 20/24-bit <-> 32-bit helper routines (not really matrixing but convenient to put here)
void copy20ToPredictor( uint8_t * in, uint32_t stride, int32_t * out, int32_t numSamples )
{
uint8_t * ip = in;
int32_t j;
for ( j = 0; j < numSamples; j++ )
{
int32_t val;
// 20-bit values are left-aligned in the 24-bit input buffer but right-aligned in the 32-bit output buffer
val = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
out[j] = (val << 8) >> 12;
ip += stride * 3;
}
}
void copy24ToPredictor( uint8_t * in, uint32_t stride, int32_t * out, int32_t numSamples )
{
uint8_t * ip = in;
int32_t j;
for ( j = 0; j < numSamples; j++ )
{
int32_t val;
val = (int32_t)( ((uint32_t)ip[HBYTE] << 16) | ((uint32_t)ip[MBYTE] << 8) | (uint32_t)ip[LBYTE] );
out[j] = (val << 8) >> 8;
ip += stride * 3;
}
}
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