diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9fbbab3..e4e177f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -42,15 +42,23 @@ set(MUMLIB_SRC
         src/Audio.cpp
         )
 
+set(SPEEX_LIBRARIES
+        speex
+        speexdsp
+        )
+
 PROTOBUF_GENERATE_CPP(PROTO_SRCS PROTO_HDRS Mumble.proto)
 
 add_library(mumlib SHARED ${MUMLIB_SRC} ${MUMLIB_PUBLIC_HEADERS} ${MUMLIB_PRIVATE_HEADERS} ${PROTO_SRCS} ${PROTO_HDRS})
-target_link_libraries(mumlib ${PROTOBUF_LIBRARIES})
-target_link_libraries(mumlib ${Boost_LIBRARIES})
-target_link_libraries(mumlib ${OPENSSL_LIBRARIES})
-target_link_libraries(mumlib ${LOG4CPP_LIBRARIES})
-target_link_libraries(mumlib ${OPUS_LIBRARIES})
+target_link_libraries(mumlib 
+        ${SPEEX_LIBRARIES}
+        ${PROTOBUF_LIBRARIES}
+        ${Boost_LIBRARIES}
+        ${OPENSSL_LIBRARIES}
+        ${LOG4CPP_LIBRARIES}
+        ${OPUS_LIBRARIES})
 
+# add_executable(mumlib_example mumlib_example.cpp)
+# target_link_libraries(mumlib_example mumlib)
 
-add_executable(mumlib_example mumlib_example.cpp)
-target_link_libraries(mumlib_example mumlib)
+install(TARGETS mumlib LIBRARY DESTINATION lib)
diff --git a/Mumble.proto b/Mumble.proto
index 92b8737..a74f247 100644
--- a/Mumble.proto
+++ b/Mumble.proto
@@ -1,3 +1,10 @@
+// Copyright 2005-2018 The Mumble Developers. All rights reserved.
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file at the root of the
+// Mumble source tree or at <https://www.mumble.info/LICENSE>.
+
+syntax = "proto2";
+
 package MumbleProto;
 
 option optimize_for = SPEED;
@@ -63,7 +70,8 @@ message Ping {
 // Sent by the server when it rejects the user connection.
 message Reject {
 	enum RejectType {
-		// TODO ??
+		// The rejection reason is unknown (details should be available
+		// in Reject.reason).
 		None = 0;
 		// The client attempted to connect with an incompatible version.
 		WrongVersion = 1;
@@ -98,7 +106,7 @@ message ServerSync {
 	optional uint32 max_bandwidth = 2;
 	// Server welcome text.
 	optional string welcome_text = 3;
-	// Current user permissions TODO: Confirm??
+	// Current user permissions in the root channel.
 	optional uint64 permissions = 4;
 }
 
@@ -134,6 +142,10 @@ message ChannelState {
 	optional int32 position = 9 [default = 0];
 	// SHA1 hash of the description if the description is 128 bytes or more.
 	optional bytes description_hash = 10;
+	// Maximum number of users allowed in the channel. If this value is zero,
+	// the maximum number of users allowed in the channel is given by the
+	// server's "usersperchannel" setting.
+	optional uint32 max_users = 11;
 }
 
 // Used to communicate user leaving or being kicked. May be sent by the client
@@ -180,9 +192,14 @@ message UserState {
 	optional bool self_deaf = 10;
 	// User image if it is less than 128 bytes.
 	optional bytes texture = 11;
-	// TODO ??
+	// The positional audio plugin identifier.
+	// Positional audio information is only sent to users who share
+	// identical plugin contexts.
+	//
+	// This value is not trasmitted to clients.
 	optional bytes plugin_context = 12;
-	// TODO ??
+	// The user's plugin-specific identity.
+	// This value is not transmitted to clients.
 	optional string plugin_identity = 13;
 	// User comment if it is less than 128 bytes.
 	optional string comment = 14;
@@ -209,7 +226,7 @@ message BanList {
 		required uint32 mask = 2;
 		// User name for identification purposes (does not affect the ban).
 		optional string name = 3;
-		// TODO ??
+		// The certificate hash of the banned user.
 		optional string hash = 4;
 		// Reason for the ban (does not affect the ban).
 		optional string reason = 5;
@@ -403,9 +420,9 @@ message VoiceTarget {
 	message Target {
 		// Users that are included as targets.
 		repeated uint32 session = 1;
-		// Channels that are included as targets.
+		// Channel that is included as a target.
 		optional uint32 channel_id = 2;
-		// TODO ??
+		// ACL group that is included as a target.
 		optional string group = 3;
 		// True if the voice should follow links from the specified channel.
 		optional bool links = 4 [default = false];
@@ -529,6 +546,8 @@ message ServerConfig {
 	optional uint32 message_length = 4;
 	// Maximum image message length.
 	optional uint32 image_message_length = 5;
+	// The maximum number of users allowed on the server.
+	optional uint32 max_users = 6;
 }
 
 // Sent by the server to inform the clients of suggested client configuration
@@ -541,4 +560,4 @@ message SuggestConfig {
 	optional bool positional = 2;
 	// True if the administrator suggests push to talk to be used on this server.
 	optional bool push_to_talk = 3;
-}
+}
\ No newline at end of file
diff --git a/include/mumlib.hpp b/include/mumlib.hpp
index 95afe02..08297d1 100644
--- a/include/mumlib.hpp
+++ b/include/mumlib.hpp
@@ -11,6 +11,8 @@
 namespace mumlib {
 
     constexpr int DEFAULT_OPUS_ENCODER_BITRATE = 16000;
+    constexpr int DEFAULT_OPUS_SAMPLE_RATE = 48000;
+    constexpr int DEFAULT_OPUS_NUM_CHANNELS = 1;
 
     using namespace std;
     using namespace boost::asio;
@@ -22,15 +24,28 @@ namespace mumlib {
 
     struct MumlibConfiguration {
         int opusEncoderBitrate = DEFAULT_OPUS_ENCODER_BITRATE;
+        int opusSampleRate = DEFAULT_OPUS_SAMPLE_RATE;
+        int opusChannels = DEFAULT_OPUS_NUM_CHANNELS;
         // additional fields will be added in the future
     };
 
+    struct MumbleUser {
+        int32_t sessionId;
+        string name;
+    };
+
+    struct MumbleChannel {
+        int32_t channelId;
+        string name;
+        string description;
+    };
+
     struct _Mumlib_Private;
 
 
     class Mumlib : boost::noncopyable {
     public:
-        Mumlib(Callback &callback);
+        explicit Mumlib(Callback &callback);
 
         Mumlib(Callback &callback, io_service &ioService);
 
@@ -48,13 +63,39 @@ namespace mumlib {
 
         ConnectionState getConnectionState();
 
+        int getChannelId();
+
+        vector<MumbleUser> getListAllUser();
+
+        vector<MumbleChannel> getListAllChannel();
+
         void sendAudioData(int16_t *pcmData, int pcmLength);
 
+        void sendAudioDataTarget(int targetId, int16_t *pcmData, int pcmLength);
+
         void sendTextMessage(std::string message);
 
         void joinChannel(int channelId);
 
+        void joinChannel(std::string channelName);
+
+        void sendVoiceTarget(int targetId, mumlib::VoiceTargetType type, int sessionId);
+
+        void sendVoiceTarget(int targetId, mumlib::VoiceTargetType type, std::string name, int &error);
+
+        void sendUserState(mumlib::UserState state, bool val);
+
+        void sendUserState(mumlib::UserState state, std::string value);
+        
     private:
         _Mumlib_Private *impl;
+
+        int getChannelIdBy(std::string channelName);
+
+        int getUserIdBy(std::string userName);
+
+        bool isSessionIdValid(int sessionId);
+
+        bool isChannelIdValid(int channelId);
     };
 }
diff --git a/include/mumlib/Audio.hpp b/include/mumlib/Audio.hpp
index d98f41a..862eeef 100644
--- a/include/mumlib/Audio.hpp
+++ b/include/mumlib/Audio.hpp
@@ -2,19 +2,19 @@
 
 #include "Transport.hpp"
 
-#include <opus.h>
+#include <opus/opus.h>
+
+#include <speex/speex_jitter.h>
 
 #include <chrono>
 
 namespace mumlib {
 
-    constexpr int SAMPLE_RATE = 48000;
-
     class MumlibException;
 
     class AudioException : public MumlibException {
     public:
-        AudioException(string message) : MumlibException(message) { }
+        explicit AudioException(string message) : MumlibException(message) { }
     };
 
     struct IncomingAudioPacket {
@@ -28,17 +28,30 @@ namespace mumlib {
 
     class Audio : boost::noncopyable {
     public:
-        Audio(int opusEncoderBitrate = DEFAULT_OPUS_ENCODER_BITRATE);
+        explicit Audio(int sampleRate=DEFAULT_OPUS_SAMPLE_RATE,
+                       int bitrate=DEFAULT_OPUS_ENCODER_BITRATE,
+                       int channels=DEFAULT_OPUS_NUM_CHANNELS);
 
         virtual ~Audio();
 
         IncomingAudioPacket decodeIncomingAudioPacket(uint8_t *inputBuffer, int inputBufferLength);
 
+        void addFrameToBuffer(uint8_t *inputBuffer, int inputLength, int sequence);
+
+        // todo: mix audio
+        void mixAudio(uint8_t *dest, uint8_t *src, int bufferOffset, int inputLength);
+
+        void resizeBuffer();
+
+        std::pair<int, bool> decodeOpusPayload(int16_t *pcmBuffer,
+                                               int pcmBufferSize);
+        
         std::pair<int, bool> decodeOpusPayload(uint8_t *inputBuffer,
                                                int inputLength,
                                                int16_t *pcmBuffer,
                                                int pcmBufferSize);
 
+
         int encodeAudioPacket(
                 int target,
                 int16_t *inputPcmBuffer,
@@ -52,14 +65,25 @@ namespace mumlib {
 
         void resetEncoder();
 
+        void resetJitterBuffer();
+
     private:
         log4cpp::Category &logger;
 
         OpusDecoder *opusDecoder;
         OpusEncoder *opusEncoder;
+        JitterBuffer *jbBuffer;
 
         int64_t outgoingSequenceNumber;
 
+        unsigned int iSampleRate;
+        unsigned int iChannels;
+        unsigned int iFrameSize;
+        unsigned int iAudioBufferSize;
+
+        float *fFadeIn;
+        float *fFadeOut;
+
         std::chrono::time_point<std::chrono::system_clock> lastEncodedAudioPacketTimestamp;
     };
 }
\ No newline at end of file
diff --git a/include/mumlib/Callback.hpp b/include/mumlib/Callback.hpp
index a11b7b4..3e3ac4c 100644
--- a/include/mumlib/Callback.hpp
+++ b/include/mumlib/Callback.hpp
@@ -153,7 +153,7 @@ namespace mumlib {
 
         ~BasicCallback();
 
-        virtual void version(
+        void version(
                 uint16_t major,
                 uint8_t minor,
                 uint8_t patch,
@@ -161,29 +161,29 @@ namespace mumlib {
                 string os,
                 string os_version) override;
 
-        virtual void audio(
+        void audio(
                 int target,
                 int sessionId,
                 int sequenceNumber,
                 int16_t *pcm_data,
                 uint32_t pcm_data_size) override;
 
-        virtual void unsupportedAudio(
+        void unsupportedAudio(
                 int target,
                 int sessionId,
                 int sequenceNumber,
                 uint8_t *encoded_audio_data,
                 uint32_t encoded_audio_data_size) override;
 
-        virtual void serverSync(
+        void serverSync(
                 string welcome_text,
                 int32_t session,
                 int32_t max_bandwidth,
                 int64_t permissions) override;
 
-        virtual void channelRemove(uint32_t channel_id) override;
+        void channelRemove(uint32_t channel_id) override;
 
-        virtual void channelState(
+        void channelState(
                 string name,
                 int32_t channel_id,
                 int32_t parent,
@@ -194,13 +194,13 @@ namespace mumlib {
                 bool temporary,
                 int32_t position) override;
 
-        virtual void userRemove(
+        void userRemove(
                 uint32_t session,
                 int32_t actor,
                 string reason,
                 bool ban) override;
 
-        virtual void userState(
+        void userState(
                 int32_t session,
                 int32_t actor,
                 string name,
@@ -215,7 +215,7 @@ namespace mumlib {
                 int32_t priority_speaker,
                 int32_t recording) override;
 
-        virtual void banList(
+        void banList(
                 const uint8_t *ip_data,
                 uint32_t ip_data_size,
                 uint32_t mask,
@@ -225,14 +225,14 @@ namespace mumlib {
                 string start,
                 int32_t duration) override;
 
-        virtual void textMessage(
+        void textMessage(
                 uint32_t actor,
                 std::vector<uint32_t> session,
                 std::vector<uint32_t> channel_id,
                 std::vector<uint32_t> tree_id,
                 string message) override;
 
-        virtual void permissionDenied(
+        void permissionDenied(
                 int32_t permission,
                 int32_t channel_id,
                 int32_t session,
@@ -240,48 +240,48 @@ namespace mumlib {
                 int32_t deny_type,
                 string name) override;
 
-        virtual void queryUsers(
+        void queryUsers(
                 uint32_t n_ids,
                 uint32_t *ids,
                 uint32_t n_names,
                 string *names) override;
 
-        virtual void contextActionModify(
+        void contextActionModify(
                 string action,
                 string text,
                 uint32_t m_context,
                 uint32_t operation) override;
 
-        virtual void contextAction(
+        void contextAction(
                 int32_t session,
                 int32_t channel_id,
                 string action) override;
 
-        virtual void userList(
+        void userList(
                 uint32_t user_id,
                 string name,
                 string last_seen,
                 int32_t last_channel) override;
 
-        virtual void permissionQuery(
+        void permissionQuery(
                 int32_t channel_id,
                 uint32_t permissions,
                 int32_t flush) override;
 
-        virtual void codecVersion(
+        void codecVersion(
                 int32_t alpha,
                 int32_t beta,
                 uint32_t prefer_alpha,
                 int32_t opus) override;
 
-        virtual void serverConfig(
+        void serverConfig(
                 uint32_t max_bandwidth,
                 string welcome_text,
                 uint32_t allow_html,
                 uint32_t message_length,
                 uint32_t image_message_length) override;
 
-        virtual void suggestConfig(
+        void suggestConfig(
                 uint32_t version,
                 uint32_t positional,
                 uint32_t push_to_talk) override;
diff --git a/include/mumlib/CryptState.hpp b/include/mumlib/CryptState.hpp
index cf5b61f..5d53c73 100644
--- a/include/mumlib/CryptState.hpp
+++ b/include/mumlib/CryptState.hpp
@@ -36,7 +36,7 @@
 namespace mumlib {
 
     class CryptState : boost::noncopyable {
-    public:
+    private:
         unsigned char raw_key[AES_BLOCK_SIZE];
         unsigned char encrypt_iv[AES_BLOCK_SIZE];
         unsigned char decrypt_iv[AES_BLOCK_SIZE];
@@ -56,14 +56,19 @@ namespace mumlib {
         AES_KEY decrypt_key;
         bool bInit;
 
+    public:
         CryptState();
 
         bool isValid() const;
 
+        void genKey();
+
         void setKey(const unsigned char *rkey, const unsigned char *eiv, const unsigned char *div);
 
         void setDecryptIV(const unsigned char *iv);
 
+        const unsigned char* getEncryptIV() const;
+
         void ocb_encrypt(const unsigned char *plain, unsigned char *encrypted, unsigned int len,
                          const unsigned char *nonce,
                          unsigned char *tag);
diff --git a/include/mumlib/Transport.hpp b/include/mumlib/Transport.hpp
index ccf94a7..346728b 100644
--- a/include/mumlib/Transport.hpp
+++ b/include/mumlib/Transport.hpp
@@ -14,6 +14,7 @@
 #include <google/protobuf/message.h>
 
 #include <chrono>
+#include <utility>
 
 namespace mumlib {
 
@@ -30,7 +31,7 @@ namespace mumlib {
 
     class TransportException : public MumlibException {
     public:
-        TransportException(string message) : MumlibException(message) { }
+        TransportException(string message) : MumlibException(std::move(message)) { }
     };
 
     class Transport : boost::noncopyable {
diff --git a/include/mumlib/VarInt.hpp b/include/mumlib/VarInt.hpp
index 451c61e..7e301c7 100644
--- a/include/mumlib/VarInt.hpp
+++ b/include/mumlib/VarInt.hpp
@@ -29,6 +29,6 @@ namespace mumlib {
     private:
         const int64_t value;
 
-        int64_t parseVariant(uint8_t *buffer);
+        int64_t parseVariant(const uint8_t *buffer);
     };
 }
\ No newline at end of file
diff --git a/include/mumlib/enums.hpp b/include/mumlib/enums.hpp
index b4a9b43..740d83b 100644
--- a/include/mumlib/enums.hpp
+++ b/include/mumlib/enums.hpp
@@ -45,4 +45,19 @@ namespace mumlib {
         OPUS
     };
 
+    enum class UserState {
+        MUTE,
+        DEAF,
+        SUPPRESS,
+        SELF_MUTE,
+        SELF_DEAF,
+        COMMENT,
+        PRIORITY_SPEAKER,
+        RECORDING
+    };
+
+    enum class VoiceTargetType {
+        CHANNEL,
+        USER
+    };
 }
\ No newline at end of file
diff --git a/src/Audio.cpp b/src/Audio.cpp
index 3ce7594..393b674 100644
--- a/src/Audio.cpp
+++ b/src/Audio.cpp
@@ -4,29 +4,69 @@
 
 static boost::posix_time::seconds RESET_SEQUENCE_NUMBER_INTERVAL(5);
 
-mumlib::Audio::Audio(int opusEncoderBitrate)
+mumlib::Audio::Audio(int sampleRate, int bitrate, int channels)
         : logger(log4cpp::Category::getInstance("mumlib.Audio")),
           opusDecoder(nullptr),
           opusEncoder(nullptr),
-          outgoingSequenceNumber(0) {
+          outgoingSequenceNumber(0),
+          iSampleRate(sampleRate),
+          iChannels(channels) {
 
-    int error;
+    int error, ret;
+    iFrameSize = sampleRate / 100;
+    iAudioBufferSize = iFrameSize;
+    iAudioBufferSize *= 12;
 
-    opusDecoder = opus_decoder_create(SAMPLE_RATE, 1, &error);
+    opusDecoder = opus_decoder_create(sampleRate, channels, &error);
     if (error != OPUS_OK) {
         throw AudioException((boost::format("failed to initialize OPUS decoder: %s") % opus_strerror(error)).str());
     }
 
-    opusEncoder = opus_encoder_create(SAMPLE_RATE, 1, OPUS_APPLICATION_VOIP, &error);
+    opusEncoder = opus_encoder_create(sampleRate, channels, OPUS_APPLICATION_VOIP, &error);
     if (error != OPUS_OK) {
         throw AudioException((boost::format("failed to initialize OPUS encoder: %s") % opus_strerror(error)).str());
     }
 
-    opus_encoder_ctl(opusEncoder, OPUS_SET_VBR(0));
-
-    setOpusEncoderBitrate(opusEncoderBitrate);
+    ret = opus_encoder_ctl(opusEncoder, OPUS_SET_BITRATE(bitrate));
+    if (ret != OPUS_OK) {
+        throw AudioException((boost::format("failed to initialize transmission bitrate to %d B/s: %s")
+                            % bitrate % opus_strerror(ret)).str());
+    }
+    ret = opus_encoder_ctl(opusEncoder, OPUS_SET_VBR(0));
+    if (ret != OPUS_OK) {
+        throw AudioException((boost::format("failed to initialize variable bitrate: %s") 
+                            % opus_strerror(ret)).str());
+    }
+    ret = opus_encoder_ctl(opusEncoder, OPUS_SET_VBR_CONSTRAINT(0));
+    if (ret != OPUS_OK) {
+        throw AudioException((boost::format("failed to initialize variable bitrate constraint: %s") 
+                            % opus_strerror(ret)).str());
+    }
+    ret = opus_encoder_ctl(opusEncoder, OPUS_SET_BANDWIDTH(OPUS_BANDWIDTH_NARROWBAND));
+    if (ret != OPUS_OK) {
+        throw AudioException((boost::format("failed to initialize bandwidth narrow: %s") 
+                            % opus_strerror(ret)).str());
+    }
+    ret = opus_encoder_ctl(opusEncoder, OPUS_SET_MAX_BANDWIDTH(OPUS_BANDWIDTH_NARROWBAND));
+    if (ret != OPUS_OK) {
+        throw AudioException((boost::format("failed to initialize maximum bandwidth narrow: %s") 
+                            % opus_strerror(ret)).str());
+    }
 
     resetEncoder();
+
+    jbBuffer = jitter_buffer_init(iFrameSize);
+    int margin = 10 * iFrameSize;
+    jitter_buffer_ctl(jbBuffer, JITTER_BUFFER_SET_MARGIN, &margin);
+
+    fFadeIn = new float[iFrameSize];
+    fFadeOut = new float[iFrameSize];
+
+    // Sine function to represent fade in/out. Period is FRAME_SIZE.
+    float mul = static_cast<float>(M_PI / 2.0 * static_cast<double>(iFrameSize));
+    for(unsigned int i = 0; i < iFrameSize; i++) {
+        fFadeIn[i] = fFadeOut[iFrameSize - 1 - 1] = sinf(static_cast<float>(i) * mul);
+    }
 }
 
 mumlib::Audio::~Audio() {
@@ -37,6 +77,11 @@ mumlib::Audio::~Audio() {
     if (opusEncoder) {
         opus_encoder_destroy(opusEncoder);
     }
+
+    jitter_buffer_destroy(jbBuffer);
+
+    delete[] fFadeIn;
+    delete[] fFadeOut;
 }
 
 void mumlib::Audio::setOpusEncoderBitrate(int bitrate) {
@@ -56,6 +101,105 @@ int mumlib::Audio::getOpusEncoderBitrate() {
     return bitrate;
 }
 
+void mumlib::Audio::addFrameToBuffer(uint8_t *inputBuffer, int inputLength, int sequence) {
+    int dataPointer = 0;
+    VarInt varInt(inputBuffer);
+    int opusDataLength = varInt.getValue();
+    dataPointer += varInt.getEncoded().size();
+    bool lastPacket = (opusDataLength & 0x2000) != 0;
+    opusDataLength &= 0x1fff;
+
+    auto *packet = reinterpret_cast<const unsigned char *>(&inputBuffer[dataPointer]);
+    int frame = opus_packet_get_nb_frames(packet, opusDataLength);
+    int samples = frame * opus_packet_get_samples_per_frame(packet, iSampleRate);
+    int channel = opus_packet_get_nb_channels(packet);
+
+    if(not sequence) {
+        resetJitterBuffer();
+    }
+
+    logger.info("Opus packet, frame: %d, samples: %d, channel: %d", frame, samples, channel);
+
+    JitterBufferPacket jbPacket;
+    jbPacket.data = reinterpret_cast<char *>(&inputBuffer[dataPointer]);
+    jbPacket.len = opusDataLength;
+    jbPacket.span = samples;
+    jbPacket.timestamp = iFrameSize * sequence;
+    jbPacket.user_data = lastPacket;
+        
+    jitter_buffer_put(jbBuffer, &jbPacket);
+}
+
+std::pair<int, bool> mumlib::Audio::decodeOpusPayload(int16_t *pcmBuffer, int pcmBufferSize) {
+    int avail = 0;
+    spx_uint32_t remaining = 0;
+    jitter_buffer_ctl(jbBuffer, JITTER_BUFFER_GET_AVAILABLE_COUNT, &avail);
+    jitter_buffer_remaining_span(jbBuffer, remaining);
+    int timestamp = jitter_buffer_get_pointer_timestamp(jbBuffer);
+
+    logger.warn("jbBufer, avail: %d, remain: %d, timestamp: %d", avail, remaining, timestamp);
+
+    char data[4096];
+    JitterBufferPacket jbPacket;
+    jbPacket.data = data;
+    jbPacket.len = 4096;
+
+    spx_int32_t startofs = 0;
+    int opusDataLength;
+    int outputSize;
+    spx_uint32_t lastPacket;
+
+    if(jitter_buffer_get(jbBuffer, &jbPacket, iFrameSize, &startofs) == JITTER_BUFFER_OK) {
+        opusDataLength = jbPacket.len;
+        lastPacket = jbPacket.user_data;
+    } else {
+        jitter_buffer_update_delay(jbBuffer, &jbPacket, NULL);
+    }
+    
+    if(opusDataLength) {
+        outputSize = opus_decode(opusDecoder, 
+                                    reinterpret_cast<const unsigned char *>(jbPacket.data),
+                                    jbPacket.len, 
+                                    pcmBuffer, 
+                                    pcmBufferSize, 0);
+    } else {
+        outputSize = opus_decode(opusDecoder, 
+                                    NULL, 0, pcmBuffer, pcmBufferSize, 0);        
+    }
+
+    if(outputSize < 0) {
+        outputSize = iFrameSize;
+        memset(pcmBuffer, 0, iFrameSize * sizeof(float));
+    }
+
+    if(lastPacket) {
+        for(unsigned int i = 0; i < iFrameSize; i++)
+            pcmBuffer[i] *= fFadeOut[i];
+    }
+
+    for (int i = outputSize / iFrameSize; i > 0; --i) {
+        jitter_buffer_tick(jbBuffer);
+    }
+    
+    logger.debug("%d B of Opus data decoded to %d PCM samples, last packet: %d.",
+                 opusDataLength, outputSize, lastPacket);
+
+    return std::make_pair(outputSize, lastPacket);
+}
+
+void mumlib::Audio::mixAudio(uint8_t *dest, uint8_t *src, int bufferOffset, int inputLength) {
+    for(int i = 0; i < inputLength; i++) {
+        float mix = 0;
+
+        // Clip to [-1,1]
+        if(mix > 1)
+            mix = 1;
+        else if(mix < -1)
+            mix = -1;
+        dest[i + bufferOffset] = mix;
+    }
+}
+
 std::pair<int, bool>  mumlib::Audio::decodeOpusPayload(uint8_t *inputBuffer,
                                                        int inputLength,
                                                        int16_t *pcmBuffer,
@@ -75,8 +219,18 @@ std::pair<int, bool>  mumlib::Audio::decodeOpusPayload(uint8_t *inputBuffer,
                               % inputLength % dataPointer % opusDataLength).str());
     }
 
+    // Issue #3 (Users speaking simultaneously)
+    // https://mf4.xiph.org/jenkins/view/opus/job/opus/ws/doc/html/group__opus__decoder.html
+    // Opus is a stateful codec with overlapping blocks and as a result Opus packets are not coded independently of each other. 
+    // Packets must be passed into the decoder serially and in the correct order for a correct decode. 
+    // Lost packets can be replaced with loss concealment by calling the decoder with a null pointer and zero length for the missing packet.
+    // A single codec state may only be accessed from a single thread at a time and any required locking must be performed by the caller. 
+    // Separate streams must be decoded with separate decoder states and can be decoded in parallel unless the library was compiled with NONTHREADSAFE_PSEUDOSTACK defined.
+    auto *packet = reinterpret_cast<const unsigned char *>(&inputBuffer[dataPointer]);
+    int frame = opus_packet_get_nb_frames(packet, opusDataLength);
+    int samples = frame * opus_packet_get_samples_per_frame(packet, iSampleRate);
     int outputSize = opus_decode(opusDecoder,
-                                 reinterpret_cast<const unsigned char *>(&inputBuffer[dataPointer]),
+                                 packet,
                                  opusDataLength,
                                  pcmBuffer,
                                  pcmBufferSize,
@@ -108,7 +262,7 @@ int mumlib::Audio::encodeAudioPacket(int target, int16_t *inputPcmBuffer, int in
 
     std::vector<uint8_t> header;
 
-    header.push_back(0x80 | target);
+    header.push_back(static_cast<unsigned char &&>(0x80 | target));
 
     auto sequenceNumberEnc = VarInt(outgoingSequenceNumber).getEncoded();
     header.insert(header.end(), sequenceNumberEnc.begin(), sequenceNumberEnc.end());
@@ -130,15 +284,15 @@ int mumlib::Audio::encodeAudioPacket(int target, int16_t *inputPcmBuffer, int in
     header.insert(header.end(), outputSizeEnc.begin(), outputSizeEnc.end());
 
     memcpy(outputBuffer, &header[0], header.size());
-    memcpy(outputBuffer + header.size(), tmpOpusBuffer, outputSize);
+    memcpy(outputBuffer + header.size(), tmpOpusBuffer, (size_t) outputSize);
 
-    int incrementNumber = 100 * inputLength / SAMPLE_RATE;
+    int incrementNumber = 100 * inputLength / iSampleRate;
 
     outgoingSequenceNumber += incrementNumber;
 
     lastEncodedAudioPacketTimestamp = std::chrono::system_clock::now();
 
-    return outputSize + header.size();
+    return static_cast<int>(outputSize + header.size());
 }
 
 void mumlib::Audio::resetEncoder() {
@@ -151,8 +305,13 @@ void mumlib::Audio::resetEncoder() {
     outgoingSequenceNumber = 0;
 }
 
+void mumlib::Audio::resetJitterBuffer() {
+    logger.debug("Last audio packet, resetting jitter buffer");
+    jitter_buffer_reset(jbBuffer);
+}
+
 mumlib::IncomingAudioPacket mumlib::Audio::decodeIncomingAudioPacket(uint8_t *inputBuffer, int inputBufferLength) {
-    mumlib::IncomingAudioPacket incomingAudioPacket;
+    mumlib::IncomingAudioPacket incomingAudioPacket{};
 
     incomingAudioPacket.type = static_cast<AudioPacketType >((inputBuffer[0] & 0xE0) >> 5);
     incomingAudioPacket.target = inputBuffer[0] & 0x1F;
diff --git a/src/Callback.cpp b/src/Callback.cpp
index ea8fb80..5bc69e3 100644
--- a/src/Callback.cpp
+++ b/src/Callback.cpp
@@ -35,7 +35,7 @@ void mumlib::BasicCallback::version(
                        os_version.c_str());
 }
 
-void mumlib::BasicCallback::audio(
+void BasicCallback::audio(
         int target,
         int sessionId,
         int sequenceNumber,
diff --git a/src/CryptState.cpp b/src/CryptState.cpp
index 9c5937a..e1763c3 100644
--- a/src/CryptState.cpp
+++ b/src/CryptState.cpp
@@ -40,6 +40,7 @@
 
 #include "mumlib/CryptState.hpp"
 
+#include <openssl/rand.h>
 #include <cstring>
 #include <cstdint>
 
@@ -57,6 +58,15 @@ bool mumlib::CryptState::isValid() const {
     return bInit;
 }
 
+void mumlib::CryptState::genKey() {
+	RAND_bytes(raw_key, AES_BLOCK_SIZE);
+	RAND_bytes(encrypt_iv, AES_BLOCK_SIZE);
+	RAND_bytes(decrypt_iv, AES_BLOCK_SIZE);
+	AES_set_encrypt_key(raw_key, 128, &encrypt_key);
+	AES_set_decrypt_key(raw_key, 128, &decrypt_key);
+	bInit = true;
+}
+
 void mumlib::CryptState::setKey(const unsigned char *rkey, const unsigned char *eiv, const unsigned char *div) {
     memcpy(raw_key, rkey, AES_BLOCK_SIZE);
     memcpy(encrypt_iv, eiv, AES_BLOCK_SIZE);
@@ -70,6 +80,10 @@ void mumlib::CryptState::setDecryptIV(const unsigned char *iv) {
     memcpy(decrypt_iv, iv, AES_BLOCK_SIZE);
 }
 
+const unsigned char* mumlib::CryptState::getEncryptIV() const {
+	return encrypt_iv;
+}
+
 void mumlib::CryptState::encrypt(const unsigned char *source, unsigned char *dst, unsigned int plain_length) {
     unsigned char tag[AES_BLOCK_SIZE];
 
diff --git a/src/Transport.cpp b/src/Transport.cpp
index f134512..83a383a 100644
--- a/src/Transport.cpp
+++ b/src/Transport.cpp
@@ -32,15 +32,15 @@ mumlib::Transport::Transport(
         bool noUdp) :
         logger(log4cpp::Category::getInstance("mumlib.Transport")),
         ioService(ioService),
-        processMessageFunction(processMessageFunc),
-        processEncodedAudioPacketFunction(processEncodedAudioPacketFunction),
+        processMessageFunction(std::move(processMessageFunc)),
+        processEncodedAudioPacketFunction(std::move(processEncodedAudioPacketFunction)),
         noUdp(noUdp),
         state(ConnectionState::NOT_CONNECTED),
         udpSocket(ioService),
         sslContext(ssl::context::sslv23),
         sslSocket(ioService, sslContext),
         pingTimer(ioService, PING_INTERVAL),
-        asyncBufferPool(max(MAX_UDP_LENGTH, MAX_TCP_LENGTH)) {
+        asyncBufferPool(static_cast<const unsigned long>(max(MAX_UDP_LENGTH, MAX_TCP_LENGTH))) {
 
     sslIncomingBuffer = new uint8_t[MAX_TCP_LENGTH];
 
@@ -81,7 +81,7 @@ void mumlib::Transport::connect(
 
             doReceiveUdp();
         }
-
+        
         ip::tcp::resolver resolverTcp(ioService);
         ip::tcp::resolver::query queryTcp(host, to_string(port));
 
@@ -118,7 +118,6 @@ void mumlib::Transport::disconnect() {
     }
 }
 
-
 void mumlib::Transport::sendVersion() {
     MumbleProto::Version version;
 
@@ -185,10 +184,10 @@ void mumlib::Transport::doReceiveUdp() {
                         }
 
                         uint8_t plainBuffer[1024];
-                        const int plainBufferLength = bytesTransferred - 4;
+                        const int plainBufferLength = static_cast<const int>(bytesTransferred - 4);
 
                         bool success = cryptState.decrypt(
-                                udpIncomingBuffer, plainBuffer, bytesTransferred);
+                                udpIncomingBuffer, plainBuffer, static_cast<unsigned int>(bytesTransferred));
 
                         if (not success) {
                             throwTransportException("UDP packet decryption failed");
@@ -263,12 +262,12 @@ void mumlib::Transport::sendUdpAsync(uint8_t *buff, int length) {
     auto *encryptedMsgBuff = asyncBufferPool.malloc();
     const int encryptedMsgLength = length + 4;
 
-    cryptState.encrypt(buff, reinterpret_cast<uint8_t *>(encryptedMsgBuff), length);
+    cryptState.encrypt(buff, reinterpret_cast<uint8_t *>(encryptedMsgBuff), static_cast<unsigned int>(length));
 
     logger.debug("Sending %d B of data UDP asynchronously.", encryptedMsgLength);
 
     udpSocket.async_send_to(
-            boost::asio::buffer(encryptedMsgBuff, length + 4),
+            boost::asio::buffer(encryptedMsgBuff, static_cast<size_t>(length + 4)),
             udpReceiverEndpoint,
             [this, encryptedMsgBuff](const boost::system::error_code &ec, size_t bytesTransferred) {
                 asyncBufferPool.free(encryptedMsgBuff);
@@ -318,7 +317,7 @@ void mumlib::Transport::doReceiveSsl() {
                     processMessageInternal(
                             static_cast<MessageType>(messageType),
                             &sslIncomingBuffer[6],
-                            bytesTransferred - 6);
+                            static_cast<int>(bytesTransferred - 6));
 
                     doReceiveSsl();
                 } else {
@@ -438,10 +437,10 @@ void mumlib::Transport::sendUdpPing() {
     vector<uint8_t> message;
     message.push_back(0x20);
 
-    auto timestampVarint = VarInt(time(nullptr)).getEncoded();
+    auto timestampVarint = VarInt(static_cast<int64_t>(time(nullptr))).getEncoded();
     message.insert(message.end(), timestampVarint.begin(), timestampVarint.end());
 
-    sendUdpAsync(&message[0], message.size());
+    sendUdpAsync(&message[0], static_cast<int>(message.size()));
 }
 
 void mumlib::Transport::sendSsl(uint8_t *buff, int length) {
@@ -453,7 +452,7 @@ void mumlib::Transport::sendSsl(uint8_t *buff, int length) {
     logger.debug("Sending %d bytes of data.", length);
 
     try {
-        write(sslSocket, boost::asio::buffer(buff, length));
+        write(sslSocket, boost::asio::buffer(buff, static_cast<size_t>(length)));
     } catch (boost::system::system_error &err) {
         throwTransportException(std::string("SSL send failed: ") + err.what());
     }
@@ -467,13 +466,13 @@ void mumlib::Transport::sendSslAsync(uint8_t *buff, int length) {
 
     auto *asyncBuff = asyncBufferPool.malloc();
 
-    memcpy(asyncBuff, buff, length);
+    memcpy(asyncBuff, buff, static_cast<size_t>(length));
 
     logger.debug("Sending %d B of data asynchronously.", length);
 
     async_write(
             sslSocket,
-            boost::asio::buffer(asyncBuff, length),
+            boost::asio::buffer(asyncBuff, static_cast<size_t>(length)),
             [this, asyncBuff](const boost::system::error_code &ec, size_t bytesTransferred) {
                 asyncBufferPool.free(asyncBuff);
                 logger.debug("Sent %d B.", bytesTransferred);
@@ -499,7 +498,7 @@ void mumlib::Transport::sendControlMessagePrivate(MessageType type, google::prot
     const uint16_t type_network = htons(static_cast<uint16_t>(type));
 
     const int size = message.ByteSize();
-    const uint32_t size_network = htonl(size);
+    const uint32_t size_network = htonl((uint32_t) size);
 
     const int length = sizeof(type_network) + sizeof(size_network) + size;
 
@@ -517,7 +516,7 @@ void mumlib::Transport::sendControlMessagePrivate(MessageType type, google::prot
 void mumlib::Transport::throwTransportException(string message) {
     state = ConnectionState::FAILED;
 
-    throw TransportException(message);
+    throw TransportException(std::move(message));
 }
 
 void mumlib::Transport::sendEncodedAudioPacket(uint8_t *buffer, int length) {
@@ -534,7 +533,7 @@ void mumlib::Transport::sendEncodedAudioPacket(uint8_t *buffer, int length) {
 
         const uint16_t netUdptunnelType = htons(static_cast<uint16_t>(MessageType::UDPTUNNEL));
 
-        const uint32_t netLength = htonl(length);
+        const uint32_t netLength = htonl(static_cast<uint32_t>(length));
 
         const int packet = sizeof(netUdptunnelType) + sizeof(netLength) + length;
 
@@ -542,14 +541,14 @@ void mumlib::Transport::sendEncodedAudioPacket(uint8_t *buffer, int length) {
 
         memcpy(packetBuff, &netUdptunnelType, sizeof(netUdptunnelType));
         memcpy(packetBuff + sizeof(netUdptunnelType), &netLength, sizeof(netLength));
-        memcpy(packetBuff + sizeof(netUdptunnelType) + sizeof(netLength), buffer, length);
+        memcpy(packetBuff + sizeof(netUdptunnelType) + sizeof(netLength), buffer, static_cast<size_t>(length));
 
         sendSslAsync(packetBuff, length + sizeof(netUdptunnelType) + sizeof(netLength));
     }
 }
 
 void mumlib::Transport::processAudioPacket(uint8_t *buff, int length) {
-    AudioPacketType type = static_cast<AudioPacketType >((buff[0] & 0xE0) >> 5);
+    auto type = static_cast<AudioPacketType >((buff[0] & 0xE0) >> 5);
     switch (type) {
         case AudioPacketType::CELT_Alpha:
         case AudioPacketType::Speex:
diff --git a/src/VarInt.cpp b/src/VarInt.cpp
index 2eeebf8..bd489da 100644
--- a/src/VarInt.cpp
+++ b/src/VarInt.cpp
@@ -12,7 +12,7 @@ mumlib::VarInt::VarInt(std::vector<uint8_t> encoded) : value(parseVariant(&encod
  * This code was taken from Mumble source code
  * https://github.com/mumble-voip/mumble/blob/master/src/PacketDataStream.h
  */
-int64_t mumlib::VarInt::parseVariant(uint8_t *buffer) {
+int64_t mumlib::VarInt::parseVariant(const uint8_t *buffer) {
     int64_t v = buffer[0];
     if ((v & 0x80) == 0x00) {
         return (v & 0x7F);
@@ -36,6 +36,7 @@ int64_t mumlib::VarInt::parseVariant(uint8_t *buffer) {
         return (v & 0x1F) << 16 | buffer[1] << 8 | buffer[2];
     }
 
+
     throw VarIntException("invalid varint");
 }
 
@@ -46,7 +47,7 @@ std::vector<uint8_t> mumlib::VarInt::getEncoded() const {
     if ((i & 0x8000000000000000LL) && (~i < 0x100000000LL)) {
         i = ~i;
         if (i <= 0x3) {
-            encoded.push_back(0xFC | i);
+            encoded.push_back(static_cast<unsigned char &&>(0xFC | i));
             return encoded;
         } else {
             encoded.push_back(0xF8);
@@ -54,29 +55,29 @@ std::vector<uint8_t> mumlib::VarInt::getEncoded() const {
     }
 
     if (i < 0x80) {
-        encoded.push_back(i);
+        encoded.push_back(static_cast<unsigned char &&>(i));
     } else if (i < 0x4000) {
-        encoded.push_back(0x80 | (i >> 8));
-        encoded.push_back(i & 0xFF);
+        encoded.push_back(static_cast<unsigned char &&>(0x80 | (i >> 8)));
+        encoded.push_back(static_cast<unsigned char &&>(i & 0xFF));
     } else if (i < 0x200000) {
-        encoded.push_back(0xC0 | (i >> 16));
-        encoded.push_back((i >> 8) & 0xFF);
-        encoded.push_back(i & 0xFF);
+        encoded.push_back(static_cast<unsigned char &&>(0xC0 | (i >> 16)));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 8) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>(i & 0xFF));
     } else if (i < 0x10000000) {
-        encoded.push_back(0xE0 | (i >> 24));
-        encoded.push_back((i >> 16) & 0xFF);
-        encoded.push_back((i >> 8) & 0xFF);
-        encoded.push_back(i & 0xFF);
+        encoded.push_back(static_cast<unsigned char &&>(0xE0 | (i >> 24)));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 16) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 8) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>(i & 0xFF));
     } else {
         encoded.push_back(0xF4);
-        encoded.push_back((i >> 56) & 0xFF);
-        encoded.push_back((i >> 48) & 0xFF);
-        encoded.push_back((i >> 40) & 0xFF);
-        encoded.push_back((i >> 32) & 0xFF);
-        encoded.push_back((i >> 24) & 0xFF);
-        encoded.push_back((i >> 16) & 0xFF);
-        encoded.push_back((i >> 8) & 0xFF);
-        encoded.push_back(i & 0xFF);
+        encoded.push_back(static_cast<unsigned char &&>((i >> 56) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 48) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 40) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 32) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 24) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 16) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>((i >> 8) & 0xFF));
+        encoded.push_back(static_cast<unsigned char &&>(i & 0xFF));
     }
 
     return encoded;
diff --git a/src/mumlib.cpp b/src/mumlib.cpp
index 08197d1..3c85cec 100644
--- a/src/mumlib.cpp
+++ b/src/mumlib.cpp
@@ -8,6 +8,7 @@
 
 #include <boost/asio.hpp>
 #include <boost/bind.hpp>
+#include <openssl/sha.h>
 #include <log4cpp/Category.hh>
 
 #include <Mumble.pb.h>
@@ -32,6 +33,10 @@ namespace mumlib {
 
         int sessionId = 0;
         int channelId = 0;
+        int64_t seq = 0;
+
+        std::vector<MumbleUser> listMumbleUser;
+        std::vector<MumbleChannel> listMumbleChannel;
 
         _Mumlib_Private(Callback &callback, MumlibConfiguration &configuration)
                 : _Mumlib_Private(callback, *(new io_service()), configuration) {
@@ -43,7 +48,8 @@ namespace mumlib {
                   ioService(ioService),
                   externalIoService(true),
                   transport(ioService, boost::bind(&_Mumlib_Private::processIncomingTcpMessage, this, _1, _2, _3),
-                            boost::bind(&_Mumlib_Private::processAudioPacket, this, _1, _2, _3)) {
+                            boost::bind(&_Mumlib_Private::processAudioPacket, this, _1, _2, _3)),
+                  audio(configuration.opusSampleRate, configuration.opusEncoderBitrate, configuration.opusChannels) {
 
             audio.setOpusEncoderBitrate(configuration.opusEncoderBitrate);
         }
@@ -61,16 +67,26 @@ namespace mumlib {
 
                 if (type == AudioPacketType::OPUS) {
                     int16_t pcmData[5000];
-                    auto status = audio.decodeOpusPayload(incomingAudioPacket.audioPayload,
-                                                          incomingAudioPacket.audioPayloadLength,
-                                                          pcmData,
-                                                          5000);
+
+                    audio.addFrameToBuffer(incomingAudioPacket.audioPayload, 
+                                        incomingAudioPacket.audioPayloadLength,
+                                        seq);
+
+                    auto status = audio.decodeOpusPayload(pcmData, 5000);
+
+                    // auto status = audio.decodeOpusPayload(incomingAudioPacket.audioPayload,
+                    //                                       incomingAudioPacket.audioPayloadLength,
+                    //                                       pcmData,
+                    //                                       5000);
+
+                    if(status.second) seq = 0; else seq++;
 
                     callback.audio(incomingAudioPacket.target,
-                                   incomingAudioPacket.sessionId,
-                                   incomingAudioPacket.sequenceNumber,
-                                   pcmData,
-                                   status.first);
+                                incomingAudioPacket.sessionId,
+                                incomingAudioPacket.sequenceNumber,
+                                pcmData,
+                                status.first);
+                    
                 } else {
                     logger.warn("Incoming audio packet doesn't contain Opus data, calling unsupportedAudio callback.");
                     callback.unsupportedAudio(incomingAudioPacket.target,
@@ -122,6 +138,11 @@ namespace mumlib {
                 case MessageType::CHANNELREMOVE: {
                     MumbleProto::ChannelRemove channelRemove;
                     channelRemove.ParseFromArray(buffer, length);
+                    
+                    if(isListChannelContains(channelRemove.channel_id())) {
+                        listChannelRemovedBy(channelRemove.channel_id());
+                    }
+
                     callback.channelRemove(channelRemove.channel_id());
                 }
                     break;
@@ -152,7 +173,14 @@ namespace mumlib {
                         links_remove.push_back(channelState.links_remove(i));
                     }
 
-                    this->channelId = channel_id;
+                    MumbleChannel mumbleChannel;
+                    mumbleChannel.channelId = channel_id;
+                    mumbleChannel.name = channelState.name();
+                    mumbleChannel.description = channelState.description();
+
+                    if(not isListChannelContains(channel_id)) {
+                        listMumbleChannel.push_back(mumbleChannel);
+                    } 
 
                     callback.channelState(
                             channelState.name(),
@@ -175,6 +203,10 @@ namespace mumlib {
                     bool ban = user_remove.has_ban() ? user_remove.ban()
                                                      : false; //todo make sure it's correct to assume it's false
 
+                    if(isListUserContains(user_remove.session())) {
+                        listUserRemovedBy(user_remove.session());
+                    }
+
                     callback.userRemove(
                             user_remove.session(),
                             actor,
@@ -200,6 +232,18 @@ namespace mumlib {
                     int32_t priority_speaker = userState.has_priority_speaker() ? userState.priority_speaker() : -1;
                     int32_t recording = userState.has_recording() ? userState.recording() : -1;
 
+                    if(session == this->sessionId) {
+                        this->channelId = channel_id;
+                    }
+
+                    MumbleUser mumbleUser;
+                    mumbleUser.name = userState.name();
+                    mumbleUser.sessionId = session;
+
+                    if(not isListUserContains(session)) {
+                        listMumbleUser.push_back(mumbleUser);
+                    }
+
                     callback.userState(session,
                                        actor,
                                        userState.name(),
@@ -334,7 +378,37 @@ namespace mumlib {
             return true;
         }
 
+        bool isListUserContains(int sessionId) {
+            for(int i = 0; i < listMumbleUser.size(); i++)
+                if(listMumbleUser[i].sessionId == sessionId) 
+                    return true;
+            return false;
+        }
 
+        void listUserRemovedBy(int sessionId) {
+            for(int i = 0; i < listMumbleUser.size(); i++) {
+                if(listMumbleUser[i].sessionId == sessionId) {
+                    listMumbleUser.erase(listMumbleUser.begin() + i);
+                    return;
+                }
+            }
+        }
+
+        bool isListChannelContains(int channelId) {
+            for(int i = 0; i < listMumbleChannel.size(); i++)
+                if(listMumbleChannel[i].channelId == channelId)
+                    return true;
+            return false;
+        }
+
+        void listChannelRemovedBy(int channelId) {
+            for(int i = 0; i < listMumbleChannel.size(); i++) {
+                if(listMumbleChannel[i].channelId == channelId) {
+                    listMumbleChannel.erase(listMumbleChannel.begin() + i);
+                    return;
+                }
+            }
+        }
     };
 
     Mumlib::Mumlib(Callback &callback) {
@@ -363,13 +437,25 @@ namespace mumlib {
         return impl->transport.getConnectionState();
     }
 
+    int Mumlib::getChannelId() {
+        return impl->channelId;
+    }
+
+    vector<mumlib::MumbleUser> Mumlib::getListAllUser() {
+        return impl->listMumbleUser;
+    }
+
+    vector<mumlib::MumbleChannel> Mumlib::getListAllChannel() {
+        return impl->listMumbleChannel;
+    }
+
     void Mumlib::connect(string host, int port, string user, string password) {
         impl->transport.connect(host, port, user, password);
     }
 
     void Mumlib::disconnect() {
         if (not impl->externalIoService) {
-            impl->ioService.reset();
+            impl->ioService.stop();
         }
         if (impl->transport.getConnectionState() != ConnectionState::NOT_CONNECTED) {
             impl->transport.disconnect();
@@ -385,8 +471,12 @@ namespace mumlib {
     }
 
     void Mumlib::sendAudioData(int16_t *pcmData, int pcmLength) {
+        Mumlib::sendAudioDataTarget(0, pcmData, pcmLength);
+    }
+
+    void Mumlib::sendAudioDataTarget(int targetId, int16_t *pcmData, int pcmLength) {
         uint8_t encodedData[5000];
-        int length = impl->audio.encodeAudioPacket(0, pcmData, pcmLength, encodedData, 5000);
+        int length = impl->audio.encodeAudioPacket(targetId, pcmData, pcmLength, encodedData, 5000);
         impl->transport.sendEncodedAudioPacket(encodedData, length);
     }
 
@@ -399,9 +489,146 @@ namespace mumlib {
     }
 
     void Mumlib::joinChannel(int channelId) {
+        if(!isChannelIdValid(channelId)) // when channel has not been registered / create
+            return;
         MumbleProto::UserState userState;
         userState.set_channel_id(channelId);
         impl->transport.sendControlMessage(MessageType::USERSTATE, userState);
         impl->channelId = channelId;
     }
+
+    void Mumlib::joinChannel(string name) {
+        int channelId = Mumlib::getChannelIdBy(name);
+        Mumlib::joinChannel(channelId);
+    }
+
+    void Mumlib::sendVoiceTarget(int targetId, VoiceTargetType type, int id) {
+        MumbleProto::VoiceTarget voiceTarget;
+        MumbleProto::VoiceTarget_Target voiceTargetTarget;
+        switch(type) {
+            case VoiceTargetType::CHANNEL: {
+                voiceTargetTarget.set_channel_id(id);
+                voiceTargetTarget.set_children(true);
+            }
+            break;
+            case VoiceTargetType::USER: {
+                voiceTargetTarget.add_session(id);
+            }
+            break;
+            default:
+                return;
+        }
+        voiceTarget.set_id(targetId);
+        voiceTarget.add_targets()->CopyFrom(voiceTargetTarget);
+        impl->transport.sendControlMessage(MessageType::VOICETARGET, voiceTarget);
+    }
+
+    void Mumlib::sendVoiceTarget(int targetId, VoiceTargetType type, string name, int &error) {
+        int id;
+        switch(type) {
+            case VoiceTargetType::CHANNEL: 
+                id = getChannelIdBy(name);
+                break;
+            case VoiceTargetType::USER:
+                id = getUserIdBy(name);
+                break;
+            default:
+                break;
+        }        
+        error = id < 0 ? 1: 0;
+        if(error) return;
+        sendVoiceTarget(targetId, type, id);
+    }
+
+    void Mumlib::sendUserState(mumlib::UserState field, bool val) {
+        MumbleProto::UserState userState;
+
+        switch (field) {
+            case UserState::MUTE:
+                userState.set_mute(val);
+                break;
+            case UserState::DEAF:
+                userState.set_deaf(val);
+                break;
+            case UserState::SUPPRESS:
+                userState.set_suppress(val);
+                break;
+            case UserState::SELF_MUTE:
+                userState.set_self_mute(val);
+                break;
+            case UserState::SELF_DEAF:
+                userState.set_self_deaf(val);
+                break;
+            case UserState::PRIORITY_SPEAKER:
+                userState.set_priority_speaker(val);
+                break;
+            case UserState::RECORDING:
+                userState.set_recording(val);
+                break;
+            default:
+                // in any other case, just ignore the command
+                return;
+        }
+
+        impl->transport.sendControlMessage(MessageType::USERSTATE, userState);
+    }
+
+    void Mumlib::sendUserState(mumlib::UserState field, std::string val) {
+        MumbleProto::UserState userState;
+        
+        // if comment longer than 128 bytes, we need to set the SHA1 hash
+        // http://www.askyb.com/cpp/openssl-sha1-hashing-example-in-cpp/
+        unsigned char digest[SHA_DIGEST_LENGTH];
+        char mdString[SHA_DIGEST_LENGTH * 2 + 1];
+
+        SHA1((unsigned char*) val.c_str(), val.size(), digest);
+        for(int i = 0; i < SHA_DIGEST_LENGTH; i++)
+            sprintf(&mdString[i*2], "%02x", (unsigned int) digest[i]);
+	
+        switch (field) {
+            case UserState::COMMENT:
+                if(val.size() < 128)
+                    userState.set_comment(val);
+                else
+                    userState.set_comment_hash(mdString);
+                break;
+            default:
+                // in any other case, just ignore the command
+                return;
+        }
+
+        impl->transport.sendControlMessage(MessageType::USERSTATE, userState);
+    }
+
+    int Mumlib::getChannelIdBy(string name) {
+        vector<mumlib::MumbleChannel> listMumbleChannel = impl->listMumbleChannel;
+        for(int i = 0; i < listMumbleChannel.size(); i++)
+            if(listMumbleChannel[i].name == name)
+                return listMumbleChannel[i].channelId;
+        return -1;
+    }
+
+    int Mumlib::getUserIdBy(string name) {
+        vector<mumlib::MumbleUser> listMumbleUser = impl->listMumbleUser;
+        for(int i = 0; i < listMumbleUser.size(); i++)
+            if(listMumbleUser[i].name == name)
+                return listMumbleUser[i].sessionId;
+        return -1;
+    }
+
+    bool Mumlib::isSessionIdValid(int sessionId) {
+        vector<mumlib::MumbleUser> listMumbleUser = impl->listMumbleUser;
+        for(int i = 0; i < listMumbleUser.size(); i++)
+            if(listMumbleUser[i].sessionId == sessionId)
+                return true;
+        return false;
+    }
+
+    bool Mumlib::isChannelIdValid(int channelId) {
+        vector<mumlib::MumbleChannel> listMumbleChannel = impl->listMumbleChannel;
+        for(int i = 0; i < listMumbleChannel.size(); i++)
+            if(listMumbleChannel[i].channelId == channelId)
+                return true;
+        return false;
+    }
 }