source/application/api/use_case/noise_reduction/include/RNNoiseModel.hpp

/*
 * Copyright (c) 2021 Arm Limited. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef RNNOISE_MODEL_HPP
#define RNNOISE_MODEL_HPP

#include "Model.hpp"

namespace arm {
namespace app {
    namespace rnn {
        extern const uint32_t g_NumInputFeatures;
        extern const uint32_t g_FrameLength;
        extern const uint32_t g_FrameStride;
    } /* namespace rnn */

    class RNNoiseModel : public Model {
    public:
        /**
         * @brief Runs inference for RNNoise model.
         *
         * Call CopyGruStates so GRU state outputs are copied to GRU state inputs before the inference run.
         * Run ResetGruState() method to set states to zero before starting processing logically related data.
         * @return True if inference succeeded, False - otherwise
         */
        bool RunInference() override;

        /**
         * @brief Sets GRU input states to zeros.
         * Call this method before starting processing the new sequence of logically related data.
         */
        void ResetGruState();

        /**
        * @brief Copy current GRU output states to input states.
        * Call this method before starting processing the next sequence of logically related data.
         */
        bool CopyGruStates();

        /* Which index of model outputs does the main output (gains) come from. */
        const size_t m_indexForModelOutput = 1;

    protected:
        /** @brief   Gets the reference to op resolver interface class. */
        const tflite::MicroOpResolver& GetOpResolver() override;

        /** @brief   Adds operations to the op resolver instance. */
        bool EnlistOperations() override;

        /*
        Each inference after the first needs to copy 3 GRU states from a output index to input index (model dependent):
        0 -> 3, 2 -> 2, 3 -> 1
        */
        const std::vector<std::pair<size_t, size_t>> m_gruStateMap = {{0,3}, {2, 2}, {3, 1}};
    private:
        /* Maximum number of individual operations that can be enlisted. */
        static constexpr int ms_maxOpCnt = 15;

        /* A mutable op resolver instance. */
        tflite::MicroMutableOpResolver<ms_maxOpCnt> m_opResolver;
    };

} /* namespace app */
} /* namespace arm */

#endif /* RNNOISE_MODEL_HPP */