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 // MSVC++ requires this to be set before any other includes to get M_PI. 6 #define _USE_MATH_DEFINES 7 8 #include <cmath> 9 10 #include "media/base/fake_audio_render_callback.h" 11 12 namespace media { 13 14 FakeAudioRenderCallback::FakeAudioRenderCallback(double step) 15 : half_fill_(false), 16 step_(step), 17 last_audio_delay_milliseconds_(-1), 18 volume_(1) { 19 reset(); 20 } 21 22 FakeAudioRenderCallback::~FakeAudioRenderCallback() {} 23 24 int FakeAudioRenderCallback::Render(AudioBus* audio_bus, 25 int audio_delay_milliseconds) { 26 last_audio_delay_milliseconds_ = audio_delay_milliseconds; 27 int number_of_frames = audio_bus->frames(); 28 if (half_fill_) 29 number_of_frames /= 2; 30 31 // Fill first channel with a sine wave. 32 for (int i = 0; i < number_of_frames; ++i) 33 audio_bus->channel(0)[i] = sin(2 * M_PI * (x_ + step_ * i)); 34 x_ += number_of_frames * step_; 35 36 // Copy first channel into the rest of the channels. 37 for (int i = 1; i < audio_bus->channels(); ++i) 38 memcpy(audio_bus->channel(i), audio_bus->channel(0), 39 number_of_frames * sizeof(*audio_bus->channel(i))); 40 41 return number_of_frames; 42 } 43 44 double FakeAudioRenderCallback::ProvideInput(AudioBus* audio_bus, 45 base::TimeDelta buffer_delay) { 46 Render(audio_bus, buffer_delay.InMillisecondsF() + 0.5); 47 return volume_; 48 } 49 50 } // namespace media 51
