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Diffstat (limited to 'third_party/libwebrtc/common_audio/vad/vad_filterbank.h')
| -rw-r--r-- | third_party/libwebrtc/common_audio/vad/vad_filterbank.h | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/third_party/libwebrtc/common_audio/vad/vad_filterbank.h b/third_party/libwebrtc/common_audio/vad/vad_filterbank.h new file mode 100644 index 0000000000..205eac832c --- /dev/null +++ b/third_party/libwebrtc/common_audio/vad/vad_filterbank.h @@ -0,0 +1,45 @@ +/* + * Copyright (c) 2012 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. + */ + +/* + * This file includes feature calculating functionality used in vad_core.c. + */ + +#ifndef COMMON_AUDIO_VAD_VAD_FILTERBANK_H_ +#define COMMON_AUDIO_VAD_VAD_FILTERBANK_H_ + +#include "common_audio/vad/vad_core.h" + +// Takes `data_length` samples of `data_in` and calculates the logarithm of the +// energy of each of the `kNumChannels` = 6 frequency bands used by the VAD: +// 80 Hz - 250 Hz +// 250 Hz - 500 Hz +// 500 Hz - 1000 Hz +// 1000 Hz - 2000 Hz +// 2000 Hz - 3000 Hz +// 3000 Hz - 4000 Hz +// +// The values are given in Q4 and written to `features`. Further, an approximate +// overall energy is returned. The return value is used in +// WebRtcVad_GmmProbability() as a signal indicator, hence it is arbitrary above +// the threshold `kMinEnergy`. +// +// - self [i/o] : State information of the VAD. +// - data_in [i] : Input audio data, for feature extraction. +// - data_length [i] : Audio data size, in number of samples. +// - features [o] : 10 * log10(energy in each frequency band), Q4. +// - returns : Total energy of the signal (NOTE! This value is not +// exact. It is only used in a comparison.) +int16_t WebRtcVad_CalculateFeatures(VadInstT* self, + const int16_t* data_in, + size_t data_length, + int16_t* features); + +#endif // COMMON_AUDIO_VAD_VAD_FILTERBANK_H_ |