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Diffstat (limited to 'third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor.h')
-rw-r--r-- | third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor.h b/third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor.h new file mode 100644 index 0000000000..14612508c0 --- /dev/null +++ b/third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor.h @@ -0,0 +1,62 @@ +/* + * Copyright (c) 2021 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_PROCESSING_AGC2_CLIPPING_PREDICTOR_H_ +#define MODULES_AUDIO_PROCESSING_AGC2_CLIPPING_PREDICTOR_H_ + +#include <memory> +#include <vector> + +#include "absl/types/optional.h" +#include "modules/audio_processing/include/audio_frame_view.h" +#include "modules/audio_processing/include/audio_processing.h" + +namespace webrtc { + +// Frame-wise clipping prediction and clipped level step estimation. Analyzes +// 10 ms multi-channel frames and estimates an analog mic level decrease step +// to possibly avoid clipping when predicted. `Analyze()` and +// `EstimateClippedLevelStep()` can be called in any order. +class ClippingPredictor { + public: + virtual ~ClippingPredictor() = default; + + virtual void Reset() = 0; + + // Analyzes a 10 ms multi-channel audio frame. + virtual void Analyze(const AudioFrameView<const float>& frame) = 0; + + // Predicts if clipping is going to occur for the specified `channel` in the + // near-future and, if so, it returns a recommended analog mic level decrease + // step. Returns absl::nullopt if clipping is not predicted. + // `level` is the current analog mic level, `default_step` is the amount the + // mic level is lowered by the analog controller with every clipping event and + // `min_mic_level` and `max_mic_level` is the range of allowed analog mic + // levels. + virtual absl::optional<int> EstimateClippedLevelStep( + int channel, + int level, + int default_step, + int min_mic_level, + int max_mic_level) const = 0; +}; + +// Creates a ClippingPredictor based on the provided `config`. When enabled, +// the following must hold for `config`: +// `window_length < reference_window_length + reference_window_delay`. +// Returns `nullptr` if `config.enabled` is false. +std::unique_ptr<ClippingPredictor> CreateClippingPredictor( + int num_channels, + const AudioProcessing::Config::GainController1::AnalogGainController:: + ClippingPredictor& config); + +} // namespace webrtc + +#endif // MODULES_AUDIO_PROCESSING_AGC2_CLIPPING_PREDICTOR_H_ |