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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_CAST_TEST_AUDIO_UTILITY_H_
#define MEDIA_CAST_TEST_AUDIO_UTILITY_H_
#include "media/audio/simple_sources.h"
namespace base {
class TimeDelta;
}
namespace media {
class AudioBus;
}
namespace media {
namespace cast {
struct PcmAudioFrame;
// Produces AudioBuses of varying duration where each successive output contains
// the continuation of a single sine wave.
class TestAudioBusFactory {
public:
TestAudioBusFactory(int num_channels, int sample_rate,
float sine_wave_frequency, float volume);
~TestAudioBusFactory();
// Creates a new AudioBus of the given |duration|, filled with the next batch
// of sine wave samples.
scoped_ptr<AudioBus> NextAudioBus(const base::TimeDelta& duration);
// A reasonable test tone.
static const int kMiddleANoteFreq = 440;
private:
const int num_channels_;
const int sample_rate_;
const float volume_;
SineWaveAudioSource source_;
DISALLOW_COPY_AND_ASSIGN(TestAudioBusFactory);
};
// Convenience function to convert an |audio_bus| to its equivalent
// PcmAudioFrame.
// TODO(miu): Remove this once all code has migrated to use AudioBus. See
// comment in media/cast/cast_config.h.
scoped_ptr<PcmAudioFrame> ToPcmAudioFrame(const AudioBus& audio_bus,
int sample_rate);
// Assuming |samples| contains a single-frequency sine wave (and maybe some
// low-amplitude noise), count the number of times the sine wave crosses
// zero.
int CountZeroCrossings(const std::vector<int16>& samples);
} // namespace cast
} // namespace media
#endif // MEDIA_CAST_TEST_AUDIO_UTILITY_H_
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