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 "absl/base/attributes.h" 18 #include "api/audio/audio_frame.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 ABSL_DEPRECATED("bugs.webrtc.org/8649") 40 static int MonoToStereo(AudioFrame* frame); 41 42 // `frame.num_channels_` will be updated. This version checks that 43 // `num_channels_` is stereo. Use DownmixChannels 44 // instead. TODO(bugs.webrtc.org/8649): remove. 45 ABSL_DEPRECATED("bugs.webrtc.org/8649") 46 static int StereoToMono(AudioFrame* frame); 47 48 // Downmixes 4 channels `src_audio` to stereo `dst_audio`. This is an in-place 49 // operation, meaning `src_audio` and `dst_audio` may point to the same 50 // buffer. 51 static void QuadToStereo(const int16_t* src_audio, 52 size_t samples_per_channel, 53 int16_t* dst_audio); 54 55 // `frame.num_channels_` will be updated. This version checks that 56 // `num_channels_` is 4 channels. 57 static int QuadToStereo(AudioFrame* frame); 58 59 // Downmixes `src_channels` `src_audio` to `dst_channels` `dst_audio`. 60 // This is an in-place operation, meaning `src_audio` and `dst_audio` 61 // may point to the same buffer. Supported channel combinations are 62 // Stereo to Mono, Quad to Mono, and Quad to Stereo. 63 static void DownmixChannels(const int16_t* src_audio, 64 size_t src_channels, 65 size_t samples_per_channel, 66 size_t dst_channels, 67 int16_t* dst_audio); 68 69 // `frame.num_channels_` will be updated. This version checks that 70 // `num_channels_` and `dst_channels` are valid and performs relevant downmix. 71 // Supported channel combinations are N channels to Mono, and Quad to Stereo. 72 static void DownmixChannels(size_t dst_channels, AudioFrame* frame); 73 74 // `frame.num_channels_` will be updated. This version checks that 75 // `num_channels_` and `dst_channels` are valid and performs relevant 76 // downmix. Supported channel combinations are Mono to N 77 // channels. The single channel is replicated. 78 static void UpmixChannels(size_t target_number_of_channels, 79 AudioFrame* frame); 80 81 // Swap the left and right channels of `frame`. Fails silently if `frame` is 82 // not stereo. 83 static void SwapStereoChannels(AudioFrame* frame); 84 85 // Conditionally zero out contents of `frame` for implementing audio mute: 86 // `previous_frame_muted` && `current_frame_muted` - Zero out whole frame. 87 // `previous_frame_muted` && !`current_frame_muted` - Fade-in at frame start. 88 // !`previous_frame_muted` && `current_frame_muted` - Fade-out at frame end. 89 // !`previous_frame_muted` && !`current_frame_muted` - Leave frame untouched. 90 static void Mute(AudioFrame* frame, 91 bool previous_frame_muted, 92 bool current_frame_muted); 93 94 // Zero out contents of frame. 95 static void Mute(AudioFrame* frame); 96 97 // Halve samples in `frame`. 98 static void ApplyHalfGain(AudioFrame* frame); 99 100 static int Scale(float left, float right, AudioFrame* frame); 101 102 static int ScaleWithSat(float scale, AudioFrame* frame); 103 }; 104 105 } // namespace webrtc 106 107 #endif // AUDIO_UTILITY_AUDIO_FRAME_OPERATIONS_H_ 108