experiments with websocket-stream [Review required]

CMakeLists.txt

@@ -83,6 +83,7 @@ option(WHISPER_BUILD_SERVER   "whisper: build server example" ${WHISPER_STANDALO
 # 3rd party libs
 option(WHISPER_CURL "whisper: use libcurl to download model from an URL" OFF)
 option(WHISPER_SDL2 "whisper: support for libSDL2" OFF)
+option(WEBSOCKET "whisper: support for websocket" OFF)
 
 if (CMAKE_SYSTEM_NAME MATCHES "Linux")
     option(WHISPER_FFMPEG "whisper: support building and linking with ffmpeg libs (avcodec, swresample, ...)" OFF)

examples/CMakeLists.txt

@@ -100,8 +100,10 @@ if (EMSCRIPTEN)
     add_subdirectory(bench.wasm)
 elseif(CMAKE_JS_VERSION)
     add_subdirectory(addon.node)
-else()
-    add_subdirectory(cli)
+else() 
+    if (WEBSOCKET)
+	add_subdirectory(cli)
+    endif()
     add_subdirectory(bench)
     add_subdirectory(server)
     add_subdirectory(quantize)

examples/websocket-stream/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(TARGET whisper-websocket-stream)
+add_executable(${TARGET} main.cpp whisper-server.cpp message-buffer.cpp)
+find_package(ixwebsocket)
+find_package(CURL REQUIRED)
+include(DefaultTargetOptions)
+target_link_libraries(${TARGET} PRIVATE common whisper ixwebsocket z CURL::libcurl ${CMAKE_THREAD_LIBS_INIT})
+
+install(TARGETS ${TARGET} RUNTIME)

examples/websocket-stream/README.md

@@ -0,0 +1,90 @@
+# WebSocket Whisper Stream Example
+
+This example demonstrates a WebSocket-based real-time audio transcription service using the Whisper model. The server captures audio from clients, processes it using the Whisper model, and sends transcriptions back through WebSocket connections.
+
+## Features
+
+- Real-time audio transcription
+- WebSocket communication for audio and transcription data
+- Configurable parameters for model, language, and processing settings
+- Integration with backend services via HTTP requests
+
+## Usage
+
+Run the server with the following command:
+
+```bash
+./build/bin/whisper-websocket-stream -m ./models/ggml-large-v3-turbo.bin -t 8 --host 0.0.0.0 --port 9002 --forward-url http://localhost:8080/completion
+```
+
+### Parameters
+
+- `-m` or `--model`: Path to the Whisper model file.
+- `-t` or `--threads`: Number of threads for processing.
+- `-H` or `--host`: Hostname or IP address to bind the server to.
+- `-p` or `--port`: Port number for the server.
+- `-f` or `--forward-url`: URL to forward transcriptions to a backend service.
+- `-nm` or `--max-messages`: Maximum number of messages before sending to the backend.
+- `-l` or `--language`: Spoken language for transcription.
+- `-vth` or `--vad-thold`: Voice activity detection threshold.
+- `-tr` or `--translate`: Enable translation to English.
+- `-ng` or `--no-gpu`: Disable GPU usage.
+- `-bs` or `--beam-size`: Beam size for beam search.
+
+## Building
+
+To build the server, follow these steps:
+
+```bash
+# Install dependencies
+git clone --depth 1 https://github.com/machinezone/IXWebSocket/
+cd IXWebSocket
+mkdir -p build && cd build && cmake -GNinja .. && sudo ninja -j$((npoc)) install
+# Build the project
+#cuda is optional
+git clone --depth 1 https://github.com/ggml-org/whisper.cpp
+cd whisper.cpp
+mkdir -p build && cd build
+cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DWEBSOCKET=ON -DGGML_CUDA ..
+ninja -j$((npoc))
+
+# Run the server
+./bin/whisper-websocket-stream --help
+```
+
+## Client Integration
+
+Clients can connect to the WebSocket server and send audio data. The server processes the audio and sends transcriptions back through the WebSocket connection.
+
+### Example Client Code (JavaScript)
+
+```javascript
+const socket = new WebSocket('ws://localhost:9002');
+
+socket.onopen = () => {
+    console.log('Connected to WebSocket server');
+};
+
+socket.onmessage = (event) => {
+    console.log('Transcription:', event.data);
+};
+
+socket.onclose = () => {
+    console.log('Disconnected from WebSocket server');
+};
+
+// Function to send audio data to the server
+function sendAudioData(audioData) {
+    socket.send(audioData);
+}
+```
+
+## Backend Integration
+
+The server can forward transcriptions to a backend service via HTTP requests. Configure the `forward_url` parameter to specify the backend service URL.
+
+## Dependencies
+- whisper.cpp
+- ixwebsocket for WebSocket communication
+- libcurl for HTTP requests
+```

examples/websocket-stream/client-session.h

@@ -0,0 +1,15 @@
+#ifndef CLIENT_SESSION_H
+#define CLIENT_SESSION_H
+#include <vector>
+#include <mutex>
+#include <atomic>
+#include "ixwebsocket/IXWebSocketServer.h"
+#include "message-buffer.h"
+struct ClientSession {
+    std::vector<float> pcm_buffer;
+    std::mutex mtx;
+    std::atomic<bool> active{true};
+    ix::WebSocket *connection;
+    MessageBuffer buffToBackend;
+};
+#endif

examples/websocket-stream/index.html

@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>Mic to WebSocket</title>
+</head>
+<body>
+    <button id="startBtn">Start Mic</button>
+    <div id="status"></div>
+
+    <script>
+        const startBtn = document.getElementById('startBtn');
+        const statusDiv = document.getElementById('status');
+        let isRecording = false;
+        let socket;
+
+        startBtn.addEventListener('click', async () => {
+            if (!isRecording) {
+                try {
+                    socket = new WebSocket('ws://192.168.2.109:9002');
+
+                    const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
+			const audioContext = new AudioContext({sampleRate: 16000});
+                    const source = audioContext.createMediaStreamSource(stream);
+
+                    const processor = audioContext.createScriptProcessor(1024, 1, 1);
+
+                    source.connect(processor);
+                    processor.connect(audioContext.destination);
+                    function floatTo16BitPCM(input) {
+			    const output = new Int16Array(input.length);
+			    for (let i = 0; i < input.length; i++) {
+				output[i] = Math.max(-1, Math.min(1, input[i])) * 0x7FFF;
+			    }
+			    return output;
+			}
+                    processor.onaudioprocess = (e) => {
+                        const input = e.inputBuffer.getChannelData(0);
+    			const int16Data = floatTo16BitPCM(input);
+
+                        if (socket.readyState === WebSocket.OPEN) {
+                            socket.send(int16Data.buffer);
+                        }
+                    };
+
+                    statusDiv.textContent = 'Recording...';
+                    startBtn.textContent = 'Stop';
+                    isRecording = true;
+                } catch (err) {
+                    console.error('Error accessing microphone:', err);
+                    statusDiv.textContent = 'Error accessing microphone';
+                }
+            } else {
+                if (socket) socket.close();
+                statusDiv.textContent = 'Stopped';
+                startBtn.textContent = 'Start Mic';
+                isRecording = false;
+            }
+        });
+    </script>
+</body>
+</html>

examples/websocket-stream/main.cpp

@@ -0,0 +1,74 @@
+#include <string>
+#include "whisper.h"
+#include "server-params.h"
+#include "whisper-server.h"
+
+#define CONVERT_FROM_PCM_16
+std::string forward_url = "http://127.0.0.1:8080/completion";
+size_t max_messages = 1000;
+
+void print_usage(int argc, char** argv, const ServerParams& params) {
+    fprintf(stderr, "\n");
+    fprintf(stderr, "usage: %s [options]\n", argv[0]);
+    fprintf(stderr, "\n");
+    fprintf(stderr, "options:\n");
+    fprintf(stderr, "  -h,       --help          show this help message and exit\n");
+    fprintf(stderr, "  -H HOST,  --host HOST     [%-7s] hostname or ip\n", params.host.c_str());
+    fprintf(stderr, "  -p PORT,  --port PORT     [%-7d] server port\n", params.port);
+    fprintf(stderr, "  -f FORWARD_URL,  --forward-url FORWARD_URL     [%-7s] forward url\n", forward_url.c_str());
+    fprintf(stderr, "  -t N,     --threads N     [%-7d] number of threads\n", params.n_threads);
+    fprintf(stderr, "  -nm max_messages,    --max-messages max_messages     [%-7d] max messages before send to backend\n", max_messages);
+    fprintf(stderr, "  -m FNAME, --model FNAME   [%-7s] model path\n", params.model.c_str());
+    fprintf(stderr, "  -l LANG,  --language LANG [%-7s] spoken language\n", params.language.c_str());
+    fprintf(stderr, "  -vth N,   --vad-thold N   [%-7.2f] voice activity threshold\n", params.vad_thold);
+    fprintf(stderr, "  -tr,      --translate     [%-7s] translate to english\n", params.translate ? "true" : "false");
+    fprintf(stderr, "  -ng,      --no-gpu        [%-7s] disable GPU\n", params.use_gpu ? "false" : "true");
+    fprintf(stderr, "  -bs N,    --beam-size N   [%-7d] beam size for beam search\n", params.beam_size);
+    fprintf(stderr, "\n");
+}
+
+bool parse_params(int argc, char** argv, ServerParams& params) {
+    for (int i = 1; i < argc; i++) {
+        std::string arg = argv[i];
+
+        if (arg == "-h" || arg == "--help") {
+            print_usage(argc, argv, params);
+            exit(0);
+        }
+        else if (arg == "-H" || arg == "--host")      { params.host = argv[++i]; }
+        else if (arg == "-p" || arg == "--port")      { params.port = std::stoi(argv[++i]); }
+        else if (arg == "-f" || arg == "--forward-url")      { forward_url = argv[++i]; }
+        else if (arg == "-t" || arg == "--threads")   { params.n_threads = std::stoi(argv[++i]); }
+        else if (arg == "-nm" || arg == "--max-messages")   { max_messages = std::stoi(argv[++i]); }
+        else if (arg == "-m" || arg == "--model")     { params.model = argv[++i]; }
+        else if (arg == "-l" || arg == "--language")  { params.language = argv[++i]; }
+        else if (arg == "-vth" || arg == "--vad-thold") { params.vad_thold = std::stof(argv[++i]); }
+        else if (arg == "-tr" || arg == "--translate")  { params.translate = true; }
+        else if (arg == "-bs" || arg == "--beam-size")  { params.beam_size = std::stoi(argv[++i]); }
+        else if (arg == "-ng" || arg == "--no-gpu")     { params.use_gpu = false; }
+        else {
+            fprintf(stderr, "error: unknown argument: %s\n", arg.c_str());
+            print_usage(argc, argv, params);
+            return false;
+        }
+    }
+    return true;
+}
+
+int main(int argc, char** argv) {
+    ServerParams params;
+    if (!parse_params(argc, argv, params)) {
+        return 1;
+    }
+    if (params.port < 1 || params.port > 65535) {
+        throw std::invalid_argument("Invalid port number");
+    }
+    if (params.language != "auto" && whisper_lang_id(params.language.c_str()) == -1) {
+        fprintf(stderr, "error: unknown language '%s'\n", params.language.c_str());
+        return 1;
+    }
+
+    WhisperServer server(params);
+    server.run();
+    return 0;
+}

examples/websocket-stream/message-buffer.cpp

@@ -0,0 +1,79 @@
+#include <sstream>
+#include <mutex>
+#include <curl/curl.h>
+
+#include "message-buffer.h"
+extern std::string forward_url;
+extern size_t max_messages;
+namespace {
+    std::stringstream ss;
+    std::mutex mtx;
+    size_t current_count = 0;
+    static size_t write_callback(char* ptr, size_t size, size_t nmemb, void* userdata) {
+        ((std::string*)userdata)->append(ptr, size * nmemb);
+        return size * nmemb;
+    }
+}
+
+void MessageBuffer::add_message(const char* msg) {
+    std::lock_guard<std::mutex> lock(mtx);
+    ss << std::string(msg) << '\n';
+    if (++current_count >= max_messages) {
+        flush();
+    }
+}
+
+std::string MessageBuffer::get_payload() {
+    std::lock_guard<std::mutex> lock(mtx);
+    return ss.str();
+}
+
+void MessageBuffer::flush() {
+    std::string payload = get_payload();
+    if (!payload.empty()) {
+        send_via_http(payload);
+        ss.str("");  //clear string stream
+        current_count = 0;
+    }
+}
+
+void MessageBuffer::send_via_http(const std::string& data) {
+    CURL* curl = curl_easy_init();
+    if (!curl) {
+        printf("CURL init failed");
+        return;
+    }
+
+    //make headers
+    struct curl_slist* headers = NULL;
+    headers = curl_slist_append(headers, "Content-Type: text/plain");
+    std::string cid_header = "X-Connection-ID: " + connection_id;
+    headers = curl_slist_append(headers, cid_header.c_str());
+
+    //config curl
+    std::string response;
+    printf("sending to %s\n", forward_url.c_str());
+    curl_easy_setopt(curl, CURLOPT_URL, forward_url.c_str());
+    curl_easy_setopt(curl, CURLOPT_POST, 1L);
+    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
+    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data.c_str());
+    curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, data.size());
+    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
+    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);
+    curl_easy_setopt(curl, CURLOPT_TIMEOUT, 5L);
+    curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 2L);
+
+    //run curl
+    for (int retry = 0; retry < 3; ++retry) {
+        CURLcode res = curl_easy_perform(curl);
+        if (res == CURLE_OK) {
+             printf("[Response (%s): %s\n", connection_id.c_str(), response.c_str());
+             break;
+        }
+        printf("[CURL error:  %s\n", curl_easy_strerror(res));
+    }
+
+    //clean
+    curl_slist_free_all(headers);
+    curl_easy_cleanup(curl);
+}

examples/websocket-stream/message-buffer.h

@@ -0,0 +1,14 @@
+#ifndef MESSAGE_BUFFER_H
+#define MESSAGE_BUFFER_H
+class MessageBuffer {
+public:
+    std::string connection_id;
+    void add_message(const char* msg);
+
+    std::string get_payload();
+
+    void flush();
+
+    void send_via_http(const std::string& data);
+};
+#endif

examples/websocket-stream/server-params.h

@@ -0,0 +1,23 @@
+#ifndef SERVER_PARAMS_H
+#define SERVER_PARAMS_H
+#include <thread>
+struct ServerParams {
+    int32_t port = 9002;
+    int32_t n_threads = std::min(4, (int32_t)std::thread::hardware_concurrency());
+    int32_t audio_ctx = 0;
+    int32_t beam_size = -1;
+
+    float vad_thold = 0.6f;
+
+    bool translate = false;
+    bool print_special = false;
+    bool no_timestamps = true;
+    bool tinydiarize = false;
+    bool use_gpu = true;
+    bool flash_attn = true;
+
+    std::string language = "en";
+    std::string model = "ggml-large-v3-turbo.bin";
+    std::string host = "0.0.0.0";
+};
+#endif