|  | /* | 
|  | *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. | 
|  | * | 
|  | *  Use of this source code is governed by a BSD-style license | 
|  | *  that can be found in the LICENSE file in the root of the source | 
|  | *  tree. An additional intellectual property rights grant can be found | 
|  | *  in the file PATENTS.  All contributing project authors may | 
|  | *  be found in the AUTHORS file in the root of the source tree. | 
|  | */ | 
|  |  | 
|  | #ifndef MODULES_AUDIO_MIXER_AUDIO_FRAME_MANIPULATOR_H_ | 
|  | #define MODULES_AUDIO_MIXER_AUDIO_FRAME_MANIPULATOR_H_ | 
|  |  | 
|  | #include <stddef.h> | 
|  | #include <stdint.h> | 
|  |  | 
|  | #include "api/audio/audio_frame.h" | 
|  |  | 
|  | namespace webrtc { | 
|  |  | 
|  | // Updates the audioFrame's energy (based on its samples). | 
|  | uint32_t AudioMixerCalculateEnergy(const AudioFrame& audio_frame); | 
|  |  | 
|  | // Ramps up or down the provided audio frame. Ramp(0, 1, frame) will | 
|  | // linearly increase the samples in the frame from 0 to full volume. | 
|  | void Ramp(float start_gain, float target_gain, AudioFrame* audio_frame); | 
|  |  | 
|  | // Downmixes or upmixes a frame between stereo and mono. | 
|  | void RemixFrame(size_t target_number_of_channels, AudioFrame* frame); | 
|  |  | 
|  | }  // namespace webrtc | 
|  |  | 
|  | #endif  // MODULES_AUDIO_MIXER_AUDIO_FRAME_MANIPULATOR_H_ |