实时音频处理

uint32_t streamStateChangeCount;
game_chat_stream_state_change_array streamStateChanges;
chat_manager::singleton_instance().start_processing_stream_state_changes(&streamStateChangeCount, &streamStateChanges);

for (uint32_t streamStateChangeIndex = 0; streamStateChangeIndex < streamStateChangeCount; ++streamStateChangeIndex)
{
    switch (streamStateChanges[streamStateChangeIndex]->state_change_type)
    {
        case game_chat_stream_state_change_type::pre_encode_audio_stream_created:
        {
            HandlePreEncodeAudioStreamCreated(streamStateChanges[streamStateChangeIndex].pre_encode_audio_stream);
            break;
        }

        case Xs::game_chat_2::game_chat_stream_state_change_type::pre_encode_audio_stream_closed:
        {
            HandlePreEncodeAudioStreamClosed(streamStateChanges[streamStateChangeIndex].pre_encode_audio_stream);
            break;
        }

        ...
    }
}
chat_manager::singleton_instance().finish_processing_stream_state_changes(streamStateChanges);

uint32_t streamStateChangeCount;
game_chat_stream_state_change_array streamStateChanges;
chat_manager::singleton_instance().start_processing_stream_state_changes(&streamStateChangeCount, &streamStateChanges);

for (uint32_t streamStateChangeIndex = 0; streamStateChangeIndex < streamStateChangeCount; ++streamStateChangeIndex)
{
    switch (streamStateChanges[streamStateChangeIndex]->state_change_type)
    {
        case game_chat_stream_state_change_type::pre_encode_audio_stream_created:
        {
            pre_encode_audio_stream* stream = streamStateChanges[streamStateChangeIndex]->pre_encode_audio_stream;
            stream->set_processed_audio_format(...);
            stream->set_custom_stream_context(...);
            HandlePreEncodeAudioStreamCreated(stream);
            break;
        }

        case game_chat_2::game_chat_stream_state_change_type::pre_encode_audio_stream_closed:
        {
            HandlePreEncodeAudioStreamClosed(streamStateChanges[streamStateChangeIndex].pre_encode_audio_stream);
            break;
        }

        case game_chat_2::game_chat_stream_state_change_type::pre_encode_audio_stream_destroyed:
        {
            HandlePreEncodeAudioStreamDestroyed(streamStateChanges[streamStateChangeIndex].pre_encode_audio_stream);
            break;
        }

        ...
    }
}
chat_manager::singleton_instance().finish_processing_stream_state_changes(streamStateChanges);

uint32_t preEncodeAudioStreamCount;
pre_encode_audio_stream_array preEncodeAudioStreams;
chat_manager::singleton_instance().get_pre_encode_audio_streams(&preEncodeAudioStreamCount, &preEncodeAudioStreams);
for (uint32_t preEncodeAudioStreamIndex = 0; preEncodeAudioStreamIndex < preEncodeAudioStreamCount; ++preEncodeAudioStreamIndex)
{
    pre_encode_audio_stream* stream = preEncodeAudioStreams[preEncodeAudioStreamIndex];
    StreamContext* context = reinterpret_cast<StreamContext*>(stream->custom_stream_context());

    game_chat_audio_format audio_format = stream->get_pre_processed_format();

    uint32_t preProcessedBufferByteCount;
    void* preProcessedBuffer;
    stream->get_next_buffer(&preProcessedBufferByteCount, &preProcessedBuffer);

    while (preProcessedBuffer != nullptr)
    {
        void* processedBuffer = nullptr;
        switch (audio_format.bits_per_sample)
        {
            case 16:
            {
                assert (audio_format.sample_type == game_chat_sample_type::integer);
                processedBuffer = ManipulateChatBuffer<int16_t>(preProcessedBufferByteCount, preProcessedBuffer, context);
                break;
            }

            case 32:
            {
                switch (audio_format.sample_type)
                {
                    case game_chat_sample_type::integer:
                    {
                        processedBuffer = ManipulateChatBuffer<int32_t>(preProcessedBufferByteCount, preProcessedBuffer, context);
                        break;
                    }

                    case game_chat_sample_type::ieee_float:
                    {
                        processedBuffer = ManipulateChatBuffer<float>(preProcessedBufferByteCount, preProcessedBuffer, context);
                        break;
                    }

                    default:
                    {
                        assert(false);
                        break;
                    }
                }
                break;
            }

            default:
            {
                assert(false);
                break;
            }
        }
        // processedBuffer can be the same as preProcessedBuffer (in-place manipulation) or it can be a buffer of
        // memory not managed by Game Chat 2 (out-of-place manipulation).
        stream->submit_buffer(processedBuffer);
        // Only return buffers retrieved from Game Chat 2. Don't return foreign memory to return_buffer.
        stream->return_buffer(preProcessedBuffer);
        stream->get_next_buffer(&preProcessedBufferByteCount, &preProcessedBuffer);
    }
}

Sleep(audioProcessingPeriodInMilliseconds);

uint32_t streamStateChangeCount;
game_chat_stream_state_change_array streamStateChanges;
chat_manager::singleton_instance().start_processing_stream_state_changes(&streamStateChangeCount, &streamStateChanges);

for (uint32_t streamStateChangeIndex = 0; streamStateChangeIndex < streamStateChangeCount; ++streamStateChangeIndex)
{
    switch (streamStateChanges[streamStateChangeIndex]->state_change_type)
    {
        case game_chat_stream_state_change_type::post_decode_audio_source_stream_created:
        {
            post_decode_audio_source_stream* stream = streamStateChanges[streamStateChangeIndex]->post_decode_audio_source_stream;
            stream->set_custom_stream_context(...);
            HandlePostDecodeAudioSourceStreamCreated(stream);
            break;
        }

        case game_chat_stream_state_change_type::post_decode_audio_source_stream_closed:
        {
            HandlePostDecodeAudioSourceStreamClosed(stream);
            break;
        }

        case game_chat_stream_state_change_type::post_decode_audio_source_stream_destroyed:
        {
            HandlePostDecodeAudioSourceStreamDestroyed(stream);
            break;
        }

        case game_chat_stream_state_change_type::post_decode_audio_sink_stream_created:
        {
            post_decode_audio_sink_stream* stream = streamStateChanges[streamStateChangeIndex]->post_decode_audio_sink_stream;
            stream->set_custom_stream_context(...);
            stream->set_processed_format(...);
            HandlePostDecodeAudioSinkStreamCreated(stream);
            break;
        }

        case game_chat_stream_state_change_type::post_decode_audio_sink_stream_closed:
        {
            HandlePostDecodeAudioSinkStreamClosed(stream);
            break;
        }

        case game_chat_stream_state_change_type::post_decode_audio_sink_stream_destroyed:
        {
            HandlePostDecodeAudioSinkStreamDestroyed(stream);
            break;
        }

        ...
    }
}

chat_manager::singleton_instance().finish_processing_stream_state_changes(streamStateChanges);

uint32_t sourceStreamCount;
post_decode_audio_source_stream_array sourceStreams;
chatManager::singleton_instance().get_post_decode_audio_source_streams(&sourceStreamCount, &sourceStreams);

uint32_t sinkStreamCount;
post_decode_audio_sink_stream_array sinkStreams;
chatManager::singleton_instance().get_post_decode_audio_sink_streams(&sinkStreamCount, &sinkStreams);

//
// MixBuffer is a custom type defined as:
// struct MixBuffer
// {
//     uint32_t bufferByteCount;
//     void* buffer;
// };
//
std::vector<std::pair<post_decode_audio_source_stream*, MixBuffer>> cachedSourceBuffers;

for (uint32_t sourceStreamIndex = 0; sourceStreamIndex < sourceStreamCount; ++sourceStreamIndex)
{
    post_decode_audio_source_stream* sourceStream = sourceStreams[sourceStreamIndex];

    MixBuffer mixBuffer;
    sourceStream->get_next_buffer(&mixBuffer.bufferByteCount, &mixBuffer.buffer);
    if (buffer != nullptr)
    {
        // Stash the buffer to return after we're done with mixing. If this program was using audio middleware, now
        // would be an appropriate time to plumb the buffer through the middleware.
        cachedSourceBuffer.push_back(std::pair<post_decode_audio_source_stream*, MixBuffer>{sourceStream, mixBuffer});
    }
}

// Loop over each sink stream, perform mixing, and submit.
for (uint32_t sinkStreamIndex = 0; sinkStreamIndex < sinkStreamCount; ++sinkStreamIndex)
{
    post_decode_audio_sink_stream* sinkStream = sinkStreams[sinkStreamIndex];

    if (sinkStream->is_open())
    {
        std::vector<std::pair<MixBuffer, float>> buffersToMixForThisStream;

        for (const std::pair<post_decode_audio_source_stream, MixBuffer>& sourceBufferPair : cachedSourceBuffers)
        {
            float volume;
            if (sinkStream->can_receive_audio_from_source_stream(sourceBufferPair.first, &volume))
            {
                buffersToMixForThisStream.push_back(std::pair<MixBuffer, float>{sourceBufferPair.second, volume});
            }
        }

        if (buffersToMixForThisStream.size() > 0)
        {
            uint32_t mixedBufferByteCount;
            uint8_t* mixedBuffer;
            MixPostDecodeBuffers(buffersToMixForThisStream, &mixedBufferByteCount, &mixedBuffer);
            sinkStream->submit_mixed_buffer(mixedBufferByteCount, mixedBuffer);
        }
    }
}

// Return buffers after mix and submission.
for (const std::pair<post_decode_audio_source_stream*, MixBuffer>& cachedSourceBuffer : cachedSourceBuffers)
{
    post_decode_audio_source_stream* sourceStream = cachedSourceBuffer.first;
    void* bufferToReturn = cachedSourceBuffer.second.buffer;
    sourceStream->return_buffer(bufferToReturn);
}

Sleep(audioProcessingPeriodInMilliseconds);

// At some point, a chat user, chatUserX, leaves the game session.
chat_manager::singleton_instance().remove_user(chatUserX);

// chatUserX is still valid, but to avoid further synchronization, prevent non-audio-stream use of chatUserX.
chatUserX = nullptr;

// On the audio processing thread...
uint32_t streamStateChangeCount;
game_chat_stream_state_change_array streamStateChanges;
chat_manager::singleton_instance().start_processing_stream_state_changes(&streamStateChangeCount, &streamStateChanges);
for (uint32_t streamStateChangeIndex = 0; streamStateChangeIndex < streamStateChangeCount; ++streamStateChangeIndex)
{
    switch (streamStateChanges[streamStateChangeIndex]->state_change_type)
    {
        ...

        // All the streams that are associated with chatUserX will close.
        case Xs::game_chat_2::game_chat_stream_state_change_type::pre_encode_audio_stream_closed:
        {
            CleanupPreEncodeAudioStreamResources(streamStateChanges[streamStateChangeIndex].pre_encode_audio_stream);
            break;
        }

        ...
    }
}
chat_manager::singleton_instance().finish_processing_stream_state_changes(streamStateChanges);

// The next time the app processes stream state changes...
uint32_t streamStateChangeCount;
game_chat_stream_state_change_array streamStateChanges;
chat_manager::singleton_instance().start_processing_stream_state_changes(&streamStateChangeCount, &streamStateChanges);
for (uint32_t streamStateChangeIndex = 0; streamStateChangeIndex < streamStateChangeCount; ++streamStateChangeIndex)
{
    switch (streamStateChanges[streamStateChangeIndex]->state_change_type)
    {
        ...

        case Xs::game_chat_2::game_chat_stream_state_change_type::pre_encode_audio_stream_destroyed:
        {
            uint32_t chatUserCount;
            Xs::game_chat_2::chat_user_array chatUsers;
            streamStateChanges[streamStateChangeIndex].pre_encode_audio_stream->get_users(&chatUserCount, &chatUsers);
            assert(chatUserCount != 0);
            for (uint32_t chatUserIndex = 0; chatUserIndex < chatUserCount; ++chatUserIndex)
            {
                // chat_user objects such as chatUserX will still be valid while the destroyed state change is being processed.
                Log(chatUsers[chatUserIndex]->xbox_user_id());
            }
            break;
        }

        ...
    }
}
chat_manager::singleton_instance().finish_processing_stream_state_changes(streamStateChanges);
// After the all destroyed state changes have been processed for all streams associated with chatUserX, its memory will be invalidated.
// Don't call methods on chatUserX. For example, chatUserX->xbox_user_id()