1 /* 2 * Copyright (C) 2017 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 LB2_SOUND_SYSTEM_H_ 18 #define LB2_SOUND_SYSTEM_H_ 19 20 #include <functional> 21 22 #include "lb2/audio_buffer.h" 23 #include "lb2/test_context.h" // for PerformanceMode 24 25 // Interface for sound systems. 26 // It is assumed that "pull" model (callback) is used for providing 27 // sound data to the system, and "push" model (sync read) is used 28 // for sound input. 29 class SoundSystem { 30 public: 31 // The memory region pointed by this buffer must remain 32 // valid until the write callback is called the next time, 33 // or until 'shutdown' is called. 34 using WriteCallback = std::function<AudioBufferView<sample_t>(size_t expectedFrames)>; 35 36 SoundSystem() = default; 37 SoundSystem(const SoundSystem&) = delete; 38 SoundSystem& operator=(const SoundSystem&) = delete; 39 virtual ~SoundSystem() {} 40 41 // Probes the output hardware for the recommended parameters for input 42 // and output streams. Returns 'false' if probing is impossible or has failed. 43 // Note that this is a separate use case for the sound system. After commencing 44 // probing, the instance of the sound system used for probing must be shut down. 45 virtual bool probeDefaultSettings(PerformanceMode /*performanceMode*/, int* /*samplingRate*/, 46 int* /*playerBufferFrameCount*/, int* /*recorderBufferFrameCount*/) { return false; } 47 // Initializes the sound system for the regular testing scenario. 48 // Returns 'true' if initialization was successful, 'false' otherwise. 49 virtual bool init(WriteCallback callback) = 0; 50 // Make sure the buffer of the input stream is empty, so fresh audio data 51 // can be received immediately on the next call to 'readAudio'. 52 // Returns 'true' if there were no errors, 'false' otherwise. 53 virtual bool drainInput() = 0; 54 // Reads from audio input into the provided buffer. A non-negative result value 55 // indicates success, a negative return value indicates an error. 56 virtual ssize_t readAudio(AudioBufferView<sample_t> buffer) = 0; 57 // Shuts the sound system down. 58 virtual void shutdown() = 0; 59 }; 60 61 #endif // LB2_SOUND_SYSTEM_H_ 62
