1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MEDIA_BASE_VECTOR_MATH_H_ 6 #define MEDIA_BASE_VECTOR_MATH_H_ 7 8 #include <utility> 9 10 #include "media/base/media_export.h" 11 12 namespace media { 13 namespace vector_math { 14 15 // Required alignment for inputs and outputs to all vector math functions 16 enum { kRequiredAlignment = 16 }; 17 18 // Selects runtime specific optimizations such as SSE. Must be called prior to 19 // calling FMAC() or FMUL(). Called during media library initialization; most 20 // users should never have to call this. 21 MEDIA_EXPORT void Initialize(); 22 23 // Multiply each element of |src| (up to |len|) by |scale| and add to |dest|. 24 // |src| and |dest| must be aligned by kRequiredAlignment. 25 MEDIA_EXPORT void FMAC(const float src[], float scale, int len, float dest[]); 26 27 // Multiply each element of |src| by |scale| and store in |dest|. |src| and 28 // |dest| must be aligned by kRequiredAlignment. 29 MEDIA_EXPORT void FMUL(const float src[], float scale, int len, float dest[]); 30 31 // Computes the exponentially-weighted moving average power of a signal by 32 // iterating the recurrence: 33 // 34 // y[-1] = initial_value 35 // y[n] = smoothing_factor * src[n]^2 + (1-smoothing_factor) * y[n-1] 36 // 37 // Returns the final average power and the maximum squared element value. 38 MEDIA_EXPORT std::pair<float, float> EWMAAndMaxPower( 39 float initial_value, const float src[], int len, float smoothing_factor); 40 41 } // namespace vector_math 42 } // namespace media 43 44 #endif // MEDIA_BASE_VECTOR_MATH_H_ 45