AudioDecoder.hpp

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/*
    MIT License
 
    DiscordCoreAPI, A bot library for Discord, written in C++, and featuring explicit multithreading through the usage of custom, asynchronous C++ CoRoutines.
 
    Copyright 2022, 2023 Chris M. (RealTimeChris)
 
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
 
    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.
 
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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*/
/// AudioDecoder.hpp - Header for the audio decoder class.
/// Jul 29, 2021
/// https://discordcoreapi.com
/// \file AudioDecoder.hpp
#pragma once
 
#include <discordcoreapi/FoundationEntities.hpp>
#include <opus/opus.h>
 
namespace discord_core_api {
 
    namespace discord_core_internal {
 
        /**
         * \addtogroup discord_core_internal
         * @{
         */
 
 
        /// @brief A wrapper class for the opus audio decoder.
        struct opus_decoder_wrapper {
            /// @brief Deleter foropus_decoder instances.
            struct opus_decoder_deleter {
                /// @brief Operator to destroy an OpusDecoder instance.
                /// @param other the OpusDecoder pointer to be deleted.
                DCA_INLINE void operator()(OpusDecoder* other) {
                    if (other) {
                        opus_decoder_destroy(other);
                        other = nullptr;
                    }
                }
            };
 
            /// @brief Constructor for opus_decoder_wrapper. initializes and configures the opus decoder.
            DCA_INLINE opus_decoder_wrapper() {
                int32_t error{};
 
                // ensure data vector has minimum size
                if (data.size() < 23040) {
                    data.resize(23040);
                }
 
                // create OpusDecoder instance
                ptr.reset(opus_decoder_create(48000, 2, &error));
 
                // check for initialization errors
                if (error != OPUS_OK) {
                    throw dca_exception{ "Failed to create the opus decoder, reason: " + jsonifier::string{ opus_strerror(error) } };
                }
            }
 
            /// @brief Decode opus audio data.
            /// @param dataToDecode the opus-encoded audio data to decode.
            /// @return a basic_string_view containing the decoded audio samples.
            /// @throws dca_exception if decoding fails.
            DCA_INLINE jsonifier::string_view_base<opus_int16> decodeData(jsonifier::string_view_base<uint8_t> dataToDecode) {
                const int32_t sampleCount = opus_decode(ptr.get(), dataToDecode.data(), static_cast<opus_int32>(dataToDecode.size() & 0x7FFFFFFF), data.data(), 5760, 0);
 
                // check for successful decoding
                if (sampleCount > 0) {
                    return jsonifier::string_view_base<opus_int16>{ data.data(), static_cast<uint64_t>(sampleCount) * 2ULL };
                } else {
                    throw dca_exception{ "Failed to decode a user's voice payload, reason: " + jsonifier::string{ opus_strerror(sampleCount) } };
                }
            }
 
          protected:
            unique_ptr<OpusDecoder, opus_decoder_deleter> ptr{};///< Unique pointer to OpusDecoder instance.
            jsonifier::vector<opus_int16> data{};///< Buffer for decoded audio samples.
        };
 
        /**@}*/
 
    }
 
}