Reland "Refactoring of the noise suppressor and adding true multichannel support"
This is a reland of 87a7b82520b83a6cf42da27cdc46142c2eb6248c
Original change's description:
> Refactoring of the noise suppressor and adding true multichannel support
>
> This CL adds proper multichannel support to the noise suppressor.
> To accomplish that in a safe way, a full refactoring of the noise
> suppressor code has been done.
>
> Due to floating point precision, the changes made are not entirely
> bitexact. They are, however, very close to being bitexact.
>
> As a safety measure, the former noise suppressor code is preserved
> and a kill-switch is added to allow revering to the legacy noise
> suppressor in case issues arise.
>
> Bug: webrtc:10895, b/143344262
> Change-Id: I0b071011b23265ac12e6d4b3956499d122286657
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158407
> Commit-Queue: Per Åhgren <peah@webrtc.org>
> Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#29646}
Bug: webrtc:10895, b/143344262
Change-Id: I236f1e67bb0baa4e30908a4cf7a8a7bb55fbced3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158747
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29663}
diff --git a/modules/audio_processing/legacy_ns/noise_suppression.h b/modules/audio_processing/legacy_ns/noise_suppression.h
new file mode 100644
index 0000000..01f04cc
--- /dev/null
+++ b/modules/audio_processing/legacy_ns/noise_suppression.h
@@ -0,0 +1,134 @@
+/*
+ * 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.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_LEGACY_NS_NOISE_SUPPRESSION_H_
+#define MODULES_AUDIO_PROCESSING_LEGACY_NS_NOISE_SUPPRESSION_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef struct NsHandleT NsHandle;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * This function creates an instance of the floating point Noise Suppression.
+ */
+NsHandle* WebRtcNs_Create(void);
+
+/*
+ * This function frees the dynamic memory of a specified noise suppression
+ * instance.
+ *
+ * Input:
+ * - NS_inst : Pointer to NS instance that should be freed
+ */
+void WebRtcNs_Free(NsHandle* NS_inst);
+
+/*
+ * This function initializes a NS instance and has to be called before any other
+ * processing is made.
+ *
+ * Input:
+ * - NS_inst : Instance that should be initialized
+ * - fs : sampling frequency
+ *
+ * Output:
+ * - NS_inst : Initialized instance
+ *
+ * Return value : 0 - Ok
+ * -1 - Error
+ */
+int WebRtcNs_Init(NsHandle* NS_inst, uint32_t fs);
+
+/*
+ * This changes the aggressiveness of the noise suppression method.
+ *
+ * Input:
+ * - NS_inst : Noise suppression instance.
+ * - mode : 0: Mild, 1: Medium , 2: Aggressive
+ *
+ * Output:
+ * - NS_inst : Updated instance.
+ *
+ * Return value : 0 - Ok
+ * -1 - Error
+ */
+int WebRtcNs_set_policy(NsHandle* NS_inst, int mode);
+
+/*
+ * This functions estimates the background noise for the inserted speech frame.
+ * The input and output signals should always be 10ms (80 or 160 samples).
+ *
+ * Input
+ * - NS_inst : Noise suppression instance.
+ * - spframe : Pointer to speech frame buffer for L band
+ *
+ * Output:
+ * - NS_inst : Updated NS instance
+ */
+void WebRtcNs_Analyze(NsHandle* NS_inst, const float* spframe);
+
+/*
+ * This functions does Noise Suppression for the inserted speech frame. The
+ * input and output signals should always be 10ms (80 or 160 samples).
+ *
+ * Input
+ * - NS_inst : Noise suppression instance.
+ * - spframe : Pointer to speech frame buffer for each band
+ * - num_bands : Number of bands
+ *
+ * Output:
+ * - NS_inst : Updated NS instance
+ * - outframe : Pointer to output frame for each band
+ */
+void WebRtcNs_Process(NsHandle* NS_inst,
+ const float* const* spframe,
+ size_t num_bands,
+ float* const* outframe);
+
+/* Returns the internally used prior speech probability of the current frame.
+ * There is a frequency bin based one as well, with which this should not be
+ * confused.
+ *
+ * Input
+ * - handle : Noise suppression instance.
+ *
+ * Return value : Prior speech probability in interval [0.0, 1.0].
+ * -1 - NULL pointer or uninitialized instance.
+ */
+float WebRtcNs_prior_speech_probability(NsHandle* handle);
+
+/* Returns a pointer to the noise estimate per frequency bin. The number of
+ * frequency bins can be provided using WebRtcNs_num_freq().
+ *
+ * Input
+ * - handle : Noise suppression instance.
+ *
+ * Return value : Pointer to the noise estimate per frequency bin.
+ * Returns NULL if the input is a NULL pointer or an
+ * uninitialized instance.
+ */
+const float* WebRtcNs_noise_estimate(const NsHandle* handle);
+
+/* Returns the number of frequency bins, which is the length of the noise
+ * estimate for example.
+ *
+ * Return value : Number of frequency bins.
+ */
+size_t WebRtcNs_num_freq(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // MODULES_AUDIO_PROCESSING_LEGACY_NS_NOISE_SUPPRESSION_H_