Files
llama.cpp/tools/server/server-realtime.cpp
Tarek DakhranandXuan Son Nguyen 8ca4060b7e server : add realtime conversation and transcription on /v1/realtime (#31269)
* server : add realtime conversation and transcription on /v1/realtime

Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
Assisted-by: Claude Opus 5.5

* examples : default the realtime client to the server port 9931

Assisted-by: Claude Opus 5.5

* server : sample realtime responses right after their own decode

Slots respond in turns on one context: sampling at the start of the next step read the logits of whichever slot decoded last, so concurrent sessions mixed their outputs.

Assisted-by: Claude Opus 5.5

* move more stuff to server-realtime, making it self-contained

* examples : fix the type check of the realtime client

Assisted-by: Claude Opus 5.5

* examples : use the model card prompts in the realtime client

Assisted-by: Claude Opus 5.5

---------

Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
2026-10-28 01:26:12 +01:00

950 lines
37 KiB
C++

#include "server-realtime.h"
#include "server-common.h"
#include "server-context.h"
#include "server-task.h"
#include "base64.hpp"
#include "chat.h"
#include "common.h"
#include "mtmd.h"
#include "mtmd-helper.h"
#include <algorithm>
#include <atomic>
#include <climits>
#include <cmath>
#include <cstring>
#include <mutex>
#include <thread>
//
// a realtime conversation, modeled after the OpenAI realtime API (GA)
//
// one slot holds the conversation for the whole session: text and audio go into it as they arrive, so a response
// starts right after the last audio. session.type "realtime" holds a conversation, "transcription" transcribes each
// committed audio buffer on its own.
//
namespace {
// output_modalities of a response, unset: the model switches between text and audio itself
bool parse_output_modalities(const json & j, mtmd_helper_gen_audio_out_mode & mode, std::string & err) {
if (j.is_null()) {
mode = MTMD_HELPER_GEN_AUDIO_OUT_AUTO;
return true;
}
if (!j.is_array() || j.empty()) {
err = "output_modalities must be a non-empty array";
return false;
}
bool text = false;
bool audio = false;
for (const auto & m : j) {
if (m == "text") {
text = true;
} else if (m == "audio") {
audio = true;
} else {
err = "output_modalities: unknown modality " + m.dump();
return false;
}
}
if (text && audio) {
mode = MTMD_HELPER_GEN_AUDIO_OUT_MIXED;
} else {
mode = audio ? MTMD_HELPER_GEN_AUDIO_OUT_AUDIO : MTMD_HELPER_GEN_AUDIO_OUT_TEXT;
}
return true;
}
bool parse_max_output_tokens(const json & j, int32_t & n) {
if (j == "inf") {
n = -1;
return true;
}
if (!j.is_number_integer() || j.get<int64_t>() < 1) {
return false;
}
n = (int32_t) std::min<int64_t>(j.get<int64_t>(), INT32_MAX);
return true;
}
json output_modalities_json(mtmd_helper_gen_audio_out_mode mode) {
switch (mode) {
case MTMD_HELPER_GEN_AUDIO_OUT_TEXT: return json::array({"text"});
case MTMD_HELPER_GEN_AUDIO_OUT_AUDIO: return json::array({"audio"});
case MTMD_HELPER_GEN_AUDIO_OUT_MIXED: return json::array({"text", "audio"});
default: return nullptr;
}
}
struct realtime_conversation {
const server_realtime_deps & deps;
server_http_context::ws_conn & conn;
std::string id = "sess_" + random_string();
// session config
std::string type = "realtime";
std::string instructions;
std::string language; // transcription
mtmd_helper_gen_audio_out_mode out_mode = MTMD_HELPER_GEN_AUDIO_OUT_AUTO;
int32_t max_output_tokens = -1; // "inf"
int input_rate = 16000;
int output_rate = 24000;
// the text around a turn, from the chat template
std::string first_header; // system prompt + first user header
std::string user_header;
std::string user_footer;
std::string assistant_header;
std::string assistant_footer;
// conversation state, owned by the reader thread
bool started = false; // something went into the slot, the session config is fixed
bool turn_open = false; // a user turn is being filled
bool has_audio = false; // the open turn has audio not committed yet
int n_turns = 0;
std::string next_header; // text that goes in before the next user turn
// the item or response the results belong to, shared with the result loop
std::mutex mutex;
std::string last_item_id;
std::string transcribe_item_id; // transcription: the item being transcribed
std::string transcript;
std::string response_id;
std::string response_item_id;
std::string response_text;
int idx_text = -1;
int idx_audio = -1;
json parts = json::array();
std::atomic<bool> closed{false};
realtime_conversation(const server_realtime_deps & deps, server_http_context::ws_conn & conn) : deps(deps), conn(conn) {}
//
// events
//
void send_event(json ev) {
ev["event_id"] = "event_" + random_string();
conn.send(safe_json_to_str(ev));
}
void send_error(const std::string & message, const std::string & type_err = "invalid_request_error") {
send_event({
{"type", "error"},
{"error", {{"type", type_err}, {"code", nullptr}, {"message", message}, {"param", nullptr}}},
});
}
json session_json() const {
json audio_in = {{"format", {{"type", "audio/pcm"}, {"rate", input_rate}}}, {"turn_detection", nullptr}};
if (type == "transcription") {
audio_in["transcription"] = {{"model", deps.meta.model_name}, {"language", language.empty() ? json(nullptr) : json(language)}};
return {
{"id", id},
{"object", "realtime.transcription_session"},
{"type", "transcription"},
{"audio", {{"input", audio_in}}},
};
}
json audio = {{"input", audio_in}};
if (deps.cap.audio_gen) {
audio["output"] = {{"format", {{"type", "audio/pcm"}, {"rate", output_rate}}}};
}
return {
{"id", id},
{"object", "realtime.session"},
{"type", "realtime"},
{"model", deps.meta.model_name},
{"instructions", instructions},
{"output_modalities", output_modalities_json(out_mode)},
{"max_output_tokens", max_output_tokens < 0 ? json("inf") : json(max_output_tokens)},
{"audio", audio},
};
}
//
// slot controls, run on the slot in the order they are posted
//
bool control(server_control_action action, std::string text = {}, std::vector<float> audio = {},
server_control_response response = {}) {
server_response_reader ctl(deps.queue_tasks, deps.queue_results, 1);
server_task task(SERVER_TASK_TYPE_CONTROL);
task.id = ctl.get_new_id();
task.params.control_action = action;
task.params.control_cmpl_id = id;
task.params.control_text = std::move(text);
task.params.control_audio = std::move(audio);
task.params.control_response = response;
ctl.post_task(std::move(task));
auto result = ctl.next([this]() { return closed.load() || !conn.is_open(); });
auto * res = result ? dynamic_cast<server_task_result_control *>(result.get()) : nullptr;
return res && res->success;
}
//
// chat template
//
std::string render(const std::vector<common_chat_msg> & messages, bool add_generation_prompt = false) const {
const auto & chat = deps.meta.chat_params;
common_chat_templates_inputs inputs;
inputs.messages = messages;
inputs.add_generation_prompt = add_generation_prompt;
inputs.use_jinja = chat.use_jinja;
inputs.enable_thinking = false;
inputs.chat_template_kwargs = chat.chat_template_kwargs;
return common_chat_templates_apply(chat.tmpls.get(), inputs).prompt.str();
}
// the text around a user and an assistant turn, from placeholder messages
bool derive_turn_text() {
const std::string user = "@@USER@@";
const std::string reply = "@@REPLY@@";
auto msg = [](const char * role, const std::string & content) {
common_chat_msg m;
m.role = role;
m.content = content;
return m;
};
std::vector<common_chat_msg> sys;
if (!instructions.empty()) {
sys.push_back(msg("system", instructions));
}
auto with = [&](std::vector<common_chat_msg> rest, bool add_generation_prompt = false) {
std::vector<common_chat_msg> all = sys;
all.insert(all.end(), rest.begin(), rest.end());
return render(all, add_generation_prompt);
};
const std::string a = with({msg("user", user)});
const std::string g = with({msg("user", user)}, true);
const std::string c = with({msg("user", user), msg("assistant", reply)});
const std::string d = with({msg("user", user), msg("assistant", reply), msg("user", user)});
const size_t pa = a.find(user);
const size_t pc = c.find(reply);
const size_t pd = d.find(user, c.size());
if (pa == std::string::npos || pc == std::string::npos || pd == std::string::npos ||
c.compare(0, a.size(), a) != 0 || d.compare(0, c.size(), c) != 0 || g.compare(0, a.size(), a) != 0 || pc < a.size()) {
return false;
}
// the response opens with the generation prompt, a past turn may render differently (e.g. its think block)
first_header = a.substr(0, pa);
user_footer = a.substr(pa + user.size());
assistant_header = g.substr(a.size());
assistant_footer = c.substr(pc + reply.size());
user_header = d.substr(c.size(), pd - c.size());
return true;
}
//
// conversation
//
// the header of a user turn goes in before its first audio or text
bool ensure_turn() {
if (turn_open) {
return true;
}
const std::string header = n_turns == 0 ? first_header : next_header + user_header;
if (!control(SERVER_CONTROL_ACTION_TEXT_APPEND, header)) {
return false;
}
next_header.clear();
started = true;
turn_open = true;
return true;
}
void on_append(const json & ev) {
std::string pcm;
try {
pcm = base64::decode(json_value(ev, "audio", std::string()));
} catch (const std::exception &) {
send_error("invalid base64 audio");
return;
}
std::vector<float> samples(pcm.size() / 2);
for (size_t i = 0; i < samples.size(); i++) {
int16_t v;
memcpy(&v, pcm.data() + 2 * i, sizeof(v));
samples[i] = v / 32768.0f;
}
if (samples.empty() || !ensure_turn()) {
return;
}
if (control(SERVER_CONTROL_ACTION_AUDIO_APPEND, {}, std::move(samples))) {
has_audio = true;
}
}
// ends the audio of the open turn, it becomes a user item
bool commit() {
if (!has_audio) {
send_error("input_audio_buffer.commit: the buffer is empty", "input_audio_buffer_commit_empty");
return false;
}
if (!control(SERVER_CONTROL_ACTION_AUDIO_END)) {
return false;
}
has_audio = false;
std::lock_guard<std::mutex> lock(mutex);
const json prev = last_item_id.empty() ? json(nullptr) : json(last_item_id);
last_item_id = "item_" + random_string();
send_event({{"type", "input_audio_buffer.committed"}, {"previous_item_id", prev}, {"item_id", last_item_id}});
const json item = {{"id", last_item_id}, {"object", "realtime.item"}, {"type", "message"}, {"role", "user"},
{"status", "completed"}, {"content", json::array({{{"type", "input_audio"}}})}};
send_event({{"type", "conversation.item.added"}, {"previous_item_id", prev}, {"item", item}});
send_event({{"type", "conversation.item.done"}, {"previous_item_id", prev}, {"item", item}});
return true;
}
void on_commit() {
if (!commit() || type != "transcription") {
return;
}
// transcription: the committed audio is transcribed on its own, then the slot is cleared for the next one
{
std::lock_guard<std::mutex> lock(mutex);
transcribe_item_id = last_item_id;
transcript.clear();
}
server_control_response response;
response.n_predict = max_output_tokens;
response.out_mode = MTMD_HELPER_GEN_AUDIO_OUT_TEXT;
if (!control(SERVER_CONTROL_ACTION_RESPONSE_CREATE, user_footer + assistant_header, {}, response)) {
return;
}
control(SERVER_CONTROL_ACTION_CLEAR);
turn_open = false;
n_turns = 0;
}
void on_item_create(const json & ev) {
if (type == "transcription") {
send_error("conversation.item.create: not supported in a transcription session");
return;
}
const json item = ev.value("item", json::object());
if (json_value(item, "type", std::string()) != "message" || json_value(item, "role", std::string()) != "user") {
send_error("conversation.item.create: only user messages are supported");
return;
}
std::string text;
for (const auto & part : item.value("content", json::array())) {
const std::string t = json_value(part, "type", std::string());
if (t != "input_text") {
send_error("conversation.item.create: unsupported content type: " + t);
return;
}
text += json_value(part, "text", std::string());
}
if (!ensure_turn() || !control(SERVER_CONTROL_ACTION_TEXT_APPEND, text)) {
return;
}
std::lock_guard<std::mutex> lock(mutex);
const json prev = last_item_id.empty() ? json(nullptr) : json(last_item_id);
last_item_id = item.contains("id") && item["id"].is_string() ? item["id"].get<std::string>() : "item_" + random_string();
const json out = {{"id", last_item_id}, {"object", "realtime.item"}, {"type", "message"}, {"role", "user"},
{"status", "completed"}, {"content", json::array({{{"type", "input_text"}, {"text", text}}})}};
send_event({{"type", "conversation.item.added"}, {"previous_item_id", prev}, {"item", out}});
send_event({{"type", "conversation.item.done"}, {"previous_item_id", prev}, {"item", out}});
}
void on_response_create(const json & ev) {
if (type == "transcription") {
send_error("response.create: not supported in a transcription session");
return;
}
if (!turn_open) {
send_error("response.create: commit audio or create a message first", "conversation_empty");
return;
}
mtmd_helper_gen_audio_out_mode mode = out_mode;
const json resp = ev.value("response", json::object());
if (resp.contains("output_modalities")) {
std::string err;
if (!parse_output_modalities(resp["output_modalities"], mode, err)) {
send_error("response.create: " + err);
return;
}
}
if (!deps.cap.audio_gen && mode != MTMD_HELPER_GEN_AUDIO_OUT_TEXT && mode != MTMD_HELPER_GEN_AUDIO_OUT_AUTO) {
send_error("response.create: the model cannot generate audio");
return;
}
if (!deps.cap.text_gen && mode != MTMD_HELPER_GEN_AUDIO_OUT_AUDIO && mode != MTMD_HELPER_GEN_AUDIO_OUT_AUTO) {
send_error("response.create: the model cannot generate text");
return;
}
// audio not committed yet belongs to this turn
if (has_audio && !commit()) {
return;
}
// the gen-audio pipeline opens the response in the asked mode
const std::string prompt = user_footer + assistant_header;
server_control_response response;
response.n_predict = max_output_tokens;
if (resp.contains("max_output_tokens") && !parse_max_output_tokens(resp["max_output_tokens"], response.n_predict)) {
send_error("response.create: max_output_tokens must be an integer or \"inf\"");
return;
}
response.out_mode = mode;
{
std::lock_guard<std::mutex> lock(mutex);
response_id = "resp_" + random_string();
response_item_id = "item_" + random_string();
response_text.clear();
parts = json::array();
idx_text = -1;
idx_audio = -1;
send_event({{"type", "response.created"}, {"response", {{"id", response_id}, {"object", "realtime.response"},
{"status", "in_progress"}, {"output_modalities", output_modalities_json(mode)}, {"output", json::array()}}}});
send_event({{"type", "response.output_item.added"}, {"response_id", response_id}, {"output_index", 0},
{"item", {{"id", response_item_id}, {"object", "realtime.item"}, {"type", "message"}, {"role", "assistant"},
{"status", "in_progress"}, {"content", json::array()}}}});
}
if (!control(SERVER_CONTROL_ACTION_RESPONSE_CREATE, prompt, {}, response)) {
return;
}
// the response ends the turn, its tokens are in the slot; the footer goes in before the next turn
next_header = assistant_footer;
turn_open = false;
n_turns++;
}
void on_session_update(const json & ev) {
const json session = ev.value("session", json::object());
if (session.contains("type") && session["type"].is_string() && session["type"] != type) {
const std::string t = session["type"];
if (t != "realtime" && t != "transcription") {
send_error("session.update: unknown session type " + t);
return;
}
if (started) {
send_error("session.update: the session type cannot change after the first audio or message");
return;
}
type = t;
}
if (session.contains("instructions") && session["instructions"].is_string()) {
if (started) {
send_error("session.update: instructions cannot change after the first audio or message");
} else {
instructions = session["instructions"];
}
}
if (session.contains("output_modalities")) {
std::string err;
if (!parse_output_modalities(session["output_modalities"], out_mode, err)) {
send_error("session.update: " + err);
return;
}
}
if (session.contains("max_output_tokens") && !parse_max_output_tokens(session["max_output_tokens"], max_output_tokens)) {
send_error("session.update: max_output_tokens must be an integer or \"inf\"");
return;
}
const json audio = session.value("audio", json::object());
const json in = audio.value("input", json::object());
if (in.contains("format") && in["format"].is_object() && json_value(in["format"], "rate", input_rate) != input_rate) {
send_error("session.update: the input audio must be PCM16 at " + std::to_string(input_rate) + " Hz");
}
if (in.contains("transcription") && in["transcription"].is_object()) {
language = json_value(in["transcription"], "language", language);
}
if (!started && !configure()) {
send_error("the chat template does not fit the realtime turn format", "server_error");
return;
}
send_event({{"type", "session.updated"}, {"session", session_json()}});
}
// turn text of the session type, before anything went into the slot
bool configure() {
const std::string saved = instructions;
if (type == "transcription") {
const auto preset = common_chat_get_asr_prompt(deps.meta.chat_params.tmpls.get(), language);
instructions = preset.system;
}
const bool ok = derive_turn_text();
instructions = saved;
return ok;
}
void handle(const std::string & msg) {
json ev;
try {
ev = json::parse(msg);
} catch (const std::exception &) {
send_error("invalid JSON");
return;
}
const std::string t = json_value(ev, "type", std::string());
if (t == "session.update" || t == "transcription_session.update") {
on_session_update(ev);
} else if (t == "input_audio_buffer.append") {
on_append(ev);
} else if (t == "input_audio_buffer.commit") {
on_commit();
} else if (t == "input_audio_buffer.clear") {
// the audio already went into the conversation
send_event({{"type", "input_audio_buffer.cleared"}});
} else if (t == "conversation.item.create") {
on_item_create(ev);
} else if (t == "response.create") {
on_response_create(ev);
} else if (t == "response.cancel") {
control(SERVER_CONTROL_ACTION_RESPONSE_CANCEL);
} else {
send_error("unknown event type: " + t);
}
}
//
// results of the slot
//
static std::string encode_pcm16(const std::vector<float> & samples) {
std::string bytes(samples.size() * sizeof(int16_t), '\0');
for (size_t i = 0; i < samples.size(); i++) {
const int16_t v = (int16_t) std::lround(std::max(-1.0f, std::min(1.0f, samples[i])) * 32767.0f);
memcpy(&bytes[2 * i], &v, sizeof(v));
}
return base64::encode(bytes);
}
// a part of the response is opened on its first delta, in order of appearance
int open_part(const char * part_type) {
json part = std::string(part_type) == "output_text" ? json{{"type", part_type}, {"text", ""}} : json{{"type", part_type}, {"transcript", ""}};
parts.push_back(part);
send_event({{"type", "response.content_part.added"}, {"response_id", response_id}, {"item_id", response_item_id},
{"output_index", 0}, {"content_index", parts.size() - 1}, {"part", part}});
return (int) parts.size() - 1;
}
void on_result(const server_task_result_realtime & res) {
std::lock_guard<std::mutex> lock(mutex);
if (!transcribe_item_id.empty()) {
if (!res.text.empty()) {
transcript += res.text;
send_event({{"type", "conversation.item.input_audio_transcription.delta"}, {"item_id", transcribe_item_id},
{"content_index", 0}, {"delta", res.text}});
}
if (res.response_done) {
send_event({{"type", "conversation.item.input_audio_transcription.completed"}, {"item_id", transcribe_item_id},
{"content_index", 0}, {"transcript", transcript}});
transcribe_item_id.clear();
}
return;
}
const json base = {{"response_id", response_id}, {"item_id", response_item_id}, {"output_index", 0}};
if (!res.text.empty()) {
if (idx_text < 0) {
idx_text = open_part("output_text");
}
response_text += res.text;
json ev = base;
ev["type"] = "response.output_text.delta";
ev["content_index"] = idx_text;
ev["delta"] = res.text;
send_event(ev);
}
if (!res.audio.empty()) {
if (idx_audio < 0) {
idx_audio = open_part("output_audio");
}
json ev = base;
ev["type"] = "response.output_audio.delta";
ev["content_index"] = idx_audio;
ev["delta"] = encode_pcm16(res.audio);
send_event(ev);
}
if (!res.response_done) {
return;
}
const std::string status = res.cancelled ? "cancelled" : "completed";
for (size_t i = 0; i < parts.size(); i++) {
json ev = base;
ev["content_index"] = i;
if ((int) i == idx_text) {
parts[i]["text"] = response_text;
ev["type"] = "response.output_text.done";
ev["text"] = response_text;
} else {
ev["type"] = "response.output_audio.done";
}
send_event(ev);
ev.erase("text");
ev["type"] = "response.content_part.done";
ev["part"] = parts[i];
send_event(ev);
}
const json item = {{"id", response_item_id}, {"object", "realtime.item"}, {"type", "message"}, {"role", "assistant"},
{"status", status}, {"content", parts}};
send_event({{"type", "response.output_item.done"}, {"response_id", response_id}, {"output_index", 0}, {"item", item}});
send_event({{"type", "response.done"}, {"response", {{"id", response_id}, {"object", "realtime.response"}, {"status", status},
{"output", json::array({item})}, {"usage", {{"output_tokens", res.n_decoded}}}}}});
last_item_id = response_item_id;
}
//
// session
//
void run() {
input_rate = mtmd_get_audio_sample_rate(deps.mctx);
if (deps.cap.audio_gen) {
output_rate = mtmd_gen_audio_get_info(deps.mctx).sample_rate;
}
if (!configure()) {
send_error("the chat template does not fit the realtime turn format", "server_error");
conn.close();
return;
}
server_response_reader rd(deps.queue_tasks, deps.queue_results, 1);
{
server_task task(SERVER_TASK_TYPE_REALTIME);
task.id = rd.get_new_id();
task.params.sampling = deps.sampling;
task.params.stream = true;
task.params.oaicompat_cmpl_id = id;
task.params.oaicompat_model = deps.meta.model_name;
rd.post_task(std::move(task));
}
// the slot answers once it holds the session
{
auto result = rd.next([this]() { return !conn.is_open(); });
if (!result || result->is_error()) {
if (result) {
send_error(json_value(result->to_json(), "message", std::string("server error")), "server_error");
}
conn.close();
return;
}
}
send_event({{"type", "session.created"}, {"session", session_json()}});
// client events are handled on this thread, results are sent from the loop below
std::thread reader([this]() {
std::string msg;
while (conn.read(msg) != 0) {
handle(msg);
}
closed = true;
conn.close();
});
while (true) {
auto result = rd.next([this]() { return !conn.is_open(); });
if (!result) {
break;
}
if (result->is_error()) {
send_error(json_value(result->to_json(), "message", std::string("server error")), "server_error");
break;
}
if (auto * res = dynamic_cast<server_task_result_realtime *>(result.get())) {
on_result(*res);
}
}
closed = true;
conn.close();
reader.join();
}
};
} // namespace
void server_realtime_conversation(const server_realtime_deps & deps, server_http_context::ws_conn & conn) {
realtime_conversation session(deps, conn);
session.run();
}
//
// server_realtime_slot
//
server_realtime_slot::server_realtime_slot(llama_context * ctx, mtmd_context * mctx, llama_seq_id seq_id, int32_t n_ctx,
const common_params_sampling & sampling, server_response & queue_results, int id_task, int index)
: ctx(ctx), model(llama_get_model(ctx)), vocab(llama_model_get_vocab(llama_get_model(ctx))), mctx(mctx), seq_id(seq_id),
n_ctx(n_ctx), sampling(sampling), queue_results(queue_results), id_task(id_task), index(index) {
if (mtmd_gen_audio_get_info(mctx).type != MTMD_GEN_AUDIO_TYPE_NONE) {
gen.init(ctx, mctx);
}
}
void server_realtime_slot::push(server_realtime_op && op) {
ops.push_back(std::move(op));
}
void server_realtime_slot::cancel() {
cancelled = responding;
}
bool server_realtime_slot::is_idle() const {
return ops.empty() && !responding;
}
bool server_realtime_slot::fail(const std::string & msg, enum error_type type) {
error = msg;
error_type = type;
return false;
}
void server_realtime_slot::send_result(std::string text, std::vector<float> audio, bool response_done) {
auto res = std::make_unique<server_task_result_realtime>();
res->id = id_task;
res->index = index;
res->text = std::move(text);
res->audio = std::move(audio);
res->response_done = response_done;
res->cancelled = response_done && cancelled;
res->n_decoded = n_decoded;
queue_results.send(std::move(res));
}
// appends tokens or embedding rows to the conversation, logits of the last one if asked
bool server_realtime_slot::decode(const llama_token * tokens, const float * rows, int32_t n, bool logits_last) {
const int32_t n_embd = llama_model_n_embd_inp(model);
const int32_t n_batch = llama_n_batch(ctx);
if (n_past + n >= n_ctx) {
return fail("the conversation does not fit in the context", ERROR_TYPE_EXCEED_CONTEXT_SIZE);
}
for (int32_t i0 = 0; i0 < n; i0 += n_batch) {
const int32_t n_cur = std::min(n_batch, n - i0);
llama_batch b = llama_batch_init(n_cur, rows ? n_embd : 0, 1);
for (int32_t i = 0; i < n_cur; i++) {
if (rows) {
memcpy(b.embd + (size_t) i * n_embd, rows + (size_t) (i0 + i) * n_embd, n_embd * sizeof(float));
} else {
b.token[i] = tokens[i0 + i];
}
b.pos[i] = n_past + i0 + i;
b.n_seq_id[i] = 1;
b.seq_id[i][0] = seq_id;
b.logits[i] = logits_last && i0 + i == n - 1;
}
b.n_tokens = n_cur;
const int ret = llama_decode(ctx, b);
llama_batch_free(b);
if (ret != 0) {
return fail("failed to decode the conversation");
}
}
n_past += n;
return true;
}
// decodes the rows the audio stream has ready
bool server_realtime_slot::audio_rows() {
while (true) {
const int32_t n = mtmd_audio_stream_step(stream.get(), LLAMA_TOKEN_NULL);
if (n == -2) {
return fail("audio stream error");
}
if (n <= 0) {
return true;
}
if (!decode(nullptr, mtmd_audio_stream_get_output_embd(stream.get()), n, false)) {
return false;
}
}
}
// samples the next text token of a response from the logits of the slot's own last decode; several slots
// respond in turns on the same context, so this runs before any other slot decodes
void server_realtime_slot::sample_next() {
sampled = LLAMA_TOKEN_NULL;
if (gen.valid() && !gen.next_is_text()) {
return;
}
sampled = common_sampler_sample(smpl.get(), ctx, -1);
common_sampler_accept(smpl.get(), sampled, true);
}
bool server_realtime_slot::response_start(const server_realtime_op & op) {
auto sparams = sampling;
n_predict = op.response.n_predict;
n_decoded = 0;
cancelled = false;
if (gen.valid()) {
// the gen-audio pipeline continues the conversation and follows the model's text/audio switching
mtmd_helper::gen_audio::inp inp;
inp.set_prompt(op.text);
inp.data.seq_id = seq_id;
inp.data.n_past = n_past;
inp.data.seed = sampling.seed;
inp.data.stream = true;
inp.data.out_type = MTMD_HELPER_GEN_AUDIO_OUTTYPE_PCM;
inp.data.out_mode = op.response.out_mode;
if (gen.set_input(inp.get()) != 0) {
return fail("failed to start the response");
}
// the pipeline may bias some text tokens, e.g. the switch to audio of a text-only response
for (const auto & b : gen.logit_bias()) {
sparams.logit_bias.push_back(b);
}
int32_t ret;
while ((ret = gen.step_prompt(llama_n_batch(ctx))) > 0) {
}
if (ret < 0) {
return fail("failed to start the response");
}
const float * h = llama_get_embeddings_ith(ctx, -1);
h_state.assign(h, h + llama_model_n_embd(model));
} else {
const llama_tokens toks = common_tokenize(vocab, op.text, false, true);
if (toks.empty()) {
return fail("failed to start the response");
}
if (!decode(toks.data(), nullptr, (int32_t) toks.size(), true)) {
return false;
}
}
smpl.reset(common_sampler_init(model, sparams));
// the logits of the last decode are this slot's only until another slot decodes
sample_next();
responding = true;
return true;
}
// one text token or audio frame of the response being generated
bool server_realtime_slot::response_step() {
bool stop = false;
std::string text;
std::vector<float> audio;
if (gen.valid()) {
const float * h_next = nullptr;
if (gen.step_gen(sampled, h_state.data(), &h_next, &stop) != 0) {
return fail("response generation failed");
}
if (sampled != LLAMA_TOKEN_NULL && !stop && !llama_vocab_is_control(vocab, sampled)) {
text = common_token_to_piece(vocab, sampled, false);
}
if (h_next) {
h_state.assign(h_next, h_next + llama_model_n_embd(model));
}
} else {
stop = llama_vocab_is_eog(vocab, sampled);
if (!stop) {
if (!llama_vocab_is_control(vocab, sampled)) {
text = common_token_to_piece(vocab, sampled, false);
}
if (!decode(&sampled, nullptr, 1, true)) {
return false;
}
}
}
n_decoded++;
// the pipeline decodes on its own, the response ends before the context is full
const bool ctx_full = gen.valid() ?
llama_memory_seq_pos_max(llama_get_memory(ctx), seq_id) + 2 >= n_ctx :
n_past + 1 >= n_ctx;
const bool done = stop || cancelled || ctx_full || (n_predict > 0 && n_decoded >= n_predict);
if (!done) {
sample_next();
}
if (gen.valid()) {
if (done) {
gen.flush();
}
int32_t sample_rate = 0;
const char * data = nullptr;
size_t data_len = 0;
if (gen.get_output(&sample_rate, &data, &data_len) == 0 && data_len > 0) {
audio.assign((const float *) data, (const float *) data + data_len / sizeof(float));
}
}
if (!text.empty() || !audio.empty()) {
send_result(std::move(text), std::move(audio));
}
if (done) {
if (gen.valid()) {
// the pipeline decoded the response, the sequence ends where it stopped
n_past = llama_memory_seq_pos_max(llama_get_memory(ctx), seq_id) + 1;
}
send_result({}, {}, true);
responding = false;
cancelled = false;
}
return true;
}
bool server_realtime_slot::update() {
llama_set_embeddings(ctx, true);
if (responding) {
return response_step();
}
while (!ops.empty() && !responding) {
server_realtime_op op = std::move(ops.front());
ops.pop_front();
switch (op.action) {
case SERVER_CONTROL_ACTION_TEXT_APPEND:
{
const llama_tokens toks = common_tokenize(vocab, op.text, false, true);
if (!toks.empty() && !decode(toks.data(), nullptr, (int32_t) toks.size(), false)) {
return false;
}
} break;
case SERVER_CONTROL_ACTION_AUDIO_APPEND:
{
if (!stream) {
stream.reset(mtmd_audio_stream_init(mctx, mtmd_audio_stream_params_default()));
if (!stream) {
return fail("failed to initialize the audio stream");
}
}
mtmd_audio_stream_push(stream.get(), op.audio.data(), op.audio.size());
if (!audio_rows()) {
return false;
}
} break;
case SERVER_CONTROL_ACTION_AUDIO_COMMIT:
case SERVER_CONTROL_ACTION_AUDIO_END:
{
// the end of the audio of a turn
if (stream) {
mtmd_audio_stream_flush(stream.get(), true);
if (!audio_rows()) {
return false;
}
stream.reset();
}
} break;
case SERVER_CONTROL_ACTION_RESPONSE_CREATE:
{
if (!response_start(op)) {
return false;
}
} break;
case SERVER_CONTROL_ACTION_CLEAR:
{
llama_memory_seq_rm(llama_get_memory(ctx), seq_id, -1, -1);
stream.reset();
n_past = 0;
} break;
default:
break;
}
}
return true;
}