1 /* 2 * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef AUDIO_UTILITY_AUDIO_FRAME_OPERATIONS_H_ 12 #define AUDIO_UTILITY_AUDIO_FRAME_OPERATIONS_H_ 13 14 #include <stddef.h> 15 #include <stdint.h> 16 17 #include "api/audio/audio_frame.h" 18 #include "rtc_base/deprecation.h" 19 20 namespace webrtc { 21 22 // TODO(andrew): consolidate this with utility.h and audio_frame_manipulator.h. 23 // Change reference parameters to pointers. Consider using a namespace rather 24 // than a class. 25 class AudioFrameOperations { 26 public: 27 // Add samples in |frame_to_add| with samples in |result_frame| 28 // putting the results in |results_frame|. The fields 29 // |vad_activity_| and |speech_type_| of the result frame are 30 // updated. If |result_frame| is empty (|samples_per_channel_|==0), 31 // the samples in |frame_to_add| are added to it. The number of 32 // channels and number of samples per channel must match except when 33 // |result_frame| is empty. 34 static void Add(const AudioFrame& frame_to_add, AudioFrame* result_frame); 35 36 // |frame.num_channels_| will be updated. This version checks for sufficient 37 // buffer size and that |num_channels_| is mono. Use UpmixChannels 38 // instead. TODO(bugs.webrtc.org/8649): remove. 39 RTC_DEPRECATED static int MonoToStereo(AudioFrame* frame); 40 41 // |frame.num_channels_| will be updated. This version checks that 42 // |num_channels_| is stereo. Use DownmixChannels 43 // instead. TODO(bugs.webrtc.org/8649): remove. 44 RTC_DEPRECATED static int StereoToMono(AudioFrame* frame); 45 46 // Downmixes 4 channels |src_audio| to stereo |dst_audio|. This is an in-place 47 // operation, meaning |src_audio| and |dst_audio| may point to the same 48 // buffer. 49 static void QuadToStereo(const int16_t* src_audio, 50 size_t samples_per_channel, 51 int16_t* dst_audio); 52 53 // |frame.num_channels_| will be updated. This version checks that 54 // |num_channels_| is 4 channels. 55 static int QuadToStereo(AudioFrame* frame); 56 57 // Downmixes |src_channels| |src_audio| to |dst_channels| |dst_audio|. 58 // This is an in-place operation, meaning |src_audio| and |dst_audio| 59 // may point to the same buffer. Supported channel combinations are 60 // Stereo to Mono, Quad to Mono, and Quad to Stereo. 61 static void DownmixChannels(const int16_t* src_audio, 62 size_t src_channels, 63 size_t samples_per_channel, 64 size_t dst_channels, 65 int16_t* dst_audio); 66 67 // |frame.num_channels_| will be updated. This version checks that 68 // |num_channels_| and |dst_channels| are valid and performs relevant downmix. 69 // Supported channel combinations are N channels to Mono, and Quad to Stereo. 70 static void DownmixChannels(size_t dst_channels, AudioFrame* frame); 71 72 // |frame.num_channels_| will be updated. This version checks that 73 // |num_channels_| and |dst_channels| are valid and performs relevant 74 // downmix. Supported channel combinations are Mono to N 75 // channels. The single channel is replicated. 76 static void UpmixChannels(size_t target_number_of_channels, 77 AudioFrame* frame); 78 79 // Swap the left and right channels of |frame|. Fails silently if |frame| is 80 // not stereo. 81 static void SwapStereoChannels(AudioFrame* frame); 82 83 // Conditionally zero out contents of |frame| for implementing audio mute: 84 // |previous_frame_muted| && |current_frame_muted| - Zero out whole frame. 85 // |previous_frame_muted| && !|current_frame_muted| - Fade-in at frame start. 86 // !|previous_frame_muted| && |current_frame_muted| - Fade-out at frame end. 87 // !|previous_frame_muted| && !|current_frame_muted| - Leave frame untouched. 88 static void Mute(AudioFrame* frame, 89 bool previous_frame_muted, 90 bool current_frame_muted); 91 92 // Zero out contents of frame. 93 static void Mute(AudioFrame* frame); 94 95 // Halve samples in |frame|. 96 static void ApplyHalfGain(AudioFrame* frame); 97 98 static int Scale(float left, float right, AudioFrame* frame); 99 100 static int ScaleWithSat(float scale, AudioFrame* frame); 101 }; 102 103 } // namespace webrtc 104 105 #endif // AUDIO_UTILITY_AUDIO_FRAME_OPERATIONS_H_ 106