1135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent/* //device/include/server/AudioFlinger/AudioCoefInterpolator.h 2135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** 3135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** Copyright 2007, The Android Open Source Project 4135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** 5135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** Licensed under the Apache License, Version 2.0 (the "License"); 6135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** you may not use this file except in compliance with the License. 7135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** You may obtain a copy of the License at 8135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** 9135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** http://www.apache.org/licenses/LICENSE-2.0 10135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** 11135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** Unless required by applicable law or agreed to in writing, software 12135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** distributed under the License is distributed on an "AS IS" BASIS, 13135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** See the License for the specific language governing permissions and 15135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent ** limitations under the License. 16135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent */ 17135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 18135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent#ifndef ANDROID_AUDIO_COEF_INTERPOLATOR_H 19135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent#define ANDROID_AUDIO_COEF_INTERPOLATOR_H 20135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 21135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent#include "AudioCommon.h" 22135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 23135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurentnamespace android { 24135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 25135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// A helper class for linear interpolation of N-D -> M-D coefficient tables. 26135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// This class provides support for out-of-range indexes. 27135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// Details: 28135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// The purpose is efficient approximation of a N-dimensional vector to 29135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// M-dimensional function. The approximation is based on a table of output 30135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// values on a uniform grid of the input values. Values not on the grid are 31135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// linearly interpolated. 32135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// Access to values are done by specifying input values in table index units, 33135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// having an integer and a fractional part, e.g. retrieving a value from index 34135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent// 1.4 will result in linear interpolation between index 1 and index 2. 35135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurentclass AudioCoefInterpolator { 36135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurentpublic: 37135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Constructor. 38135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // nInDims Number of input dimensions (limited to MAX_IN_DIMS). 39135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // inDims An array of size nInDims with the size of the table on each 40135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // respective dimension. 41135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // nOutDims Number of output dimensions (limited to MAX_OUT_DIMS). 42135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // table The coefficient table. Should be of size: 43135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // inDims[0]*inDims[1]*...*inDims[nInDims-1]*nOutDims, where 44135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // func([i,j,k]) = table(i,j,k,:) 45135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent AudioCoefInterpolator(size_t nInDims, const size_t inDims[], 46135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent size_t nOutDims, const audio_coef_t * table); 47135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 48135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Get the value of the approximated function at a given point. 49135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // intCoord The integer part of the input value. Should be an array of 50135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // size nInDims. 51135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // fracCoord The fractional part of the input value. Should be an array 52135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // of size nInDims. This value is in 32-bit precision. 53135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // out An array for the output value. Should be of size nOutDims. 54135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent void getCoef(const int intCoord[], uint32_t fracCoord[], audio_coef_t out[]); 55135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 56135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurentprivate: 57135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Maximum allowed number of input dimensions. 58135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent static const size_t MAX_IN_DIMS = 8; 59135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Maximum allowed number of output dimensions. 60135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent static const size_t MAX_OUT_DIMS = 8; 61135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 62135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Number of input dimensions. 63135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent size_t mNumInDims; 64135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Number of input dimensions. 65135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent size_t mInDims[MAX_IN_DIMS]; 66135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // The offset between two consecutive indexes of each dimension. This is in 67135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // fact a cumulative product of mInDims (done in reverse). 68135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent size_t mInDimOffsets[MAX_IN_DIMS]; 69135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Number of output dimensions. 70135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent size_t mNumOutDims; 71135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // The coefficient table. 72135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent const audio_coef_t * mTable; 73135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 74135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // A recursive function for getting an interpolated coefficient value. 75135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // The recursion depth is the number of input dimensions. 76135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // At each step, we fetch two interpolated values of the current dimension, 77135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // by two recursive calls to this method for the next dimensions. We then 78135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // linearly interpolate these values over the current dimension. 79135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // index The linear integer index of the value we need to interpolate. 80135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // fracCoord A vector of fractional coordinates for each of the input 81135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // dimensions. 82135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // out Where the output should be written. Needs to be of size 83135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // mNumOutDims. 84135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // dim The input dimensions we are currently interpolating. This 85135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // value will be increased on recursive calls. 86135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent void getCoefRecurse(size_t index, const uint32_t fracCoord[], 87135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent audio_coef_t out[], size_t dim); 88135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 89135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // Scalar interpolation of two data points. 90135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // lo The first data point. 91135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // hi The second data point. 92135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent // frac A 32-bit fraction designating the weight of the second point. 93135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent static audio_coef_t interp(audio_coef_t lo, audio_coef_t hi, uint32_t frac); 94135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent}; 95135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 96135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent} 97135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent 98135ad07e33d30e5202deb21061a0e3ecf0ffad35Eric Laurent#endif // ANDROID_AUDIO_COEF_INTERPOLATOR_H 99