1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ANDROID_AUDIO_LIMITER_H 18 #define ANDROID_AUDIO_LIMITER_H 19 20 #include <sys/cdefs.h> 21 22 /** \cond */ 23 __BEGIN_DECLS 24 /** \endcond */ 25 26 #ifdef __cplusplus 27 extern "C" { 28 #endif 29 /** 30 * This limiter function is the identity for [-sqrt(0.5), sqrt(0.5)] 31 * and then approximates atan or spline. 32 * \param in input in range [-sqrt(2), sqrt(2)]; out of range, inf, and NaN are not permitted 33 * \return the limited output in range no larger than [-1.0, 1.0]. 34 * The implementation is permitted to limit the output to a slightly smaller range, 35 * so the minimum and maximum outputs may not be achievable. 36 */ 37 extern float limiter(float in); 38 #ifdef __cplusplus 39 } 40 #endif 41 42 /** \cond */ 43 __END_DECLS 44 /** \endcond */ 45 46 #endif /* !ANDROID_AUDIO_LIMITER_H */ 47
