Examples: Add save audio to file option in stream.cpp (#1310)

* save the recorded audio to a file

* Alignment -help

* Save the correct audio

* chage to a consistent coding style

* Correct typo

* Update examples/stream/stream.cpp

* Update examples/stream/stream.cpp

* Correct variable misuse

* Update examples/stream/stream.cpp

* Update examples/stream/stream.cpp

* Update examples/stream/stream.cpp

* Update examples/stream/stream.cpp

---------

Co-authored-by: bobqianic <[email protected]>

examples/stream/stream.cpp

@@ -2,7 +2,7 @@
 //
 // A very quick-n-dirty implementation serving mainly as a proof of concept.
 //
-
+#include <fstream>
 #include "common-sdl.h"
 #include "common.h"
 #include "whisper.h"
@@ -13,7 +13,60 @@
 #include <thread>
 #include <vector>
 #include <fstream>
+#include <ctime>
+
+class SimpleWavWriter {
+private:
+    std::ofstream file;
+    int32_t dataSize = 0;
+
+public:
+    SimpleWavWriter(const std::string &filename, int sampleRate, int bitsPerSample, int channels) {
+        file.open(filename, std::ios::binary);
+
+        file.write("RIFF", 4);
+        file.write("\0\0\0\0", 4);    // Placeholder for file size
+        file.write("WAVE", 4);
+        file.write("fmt ", 4);
+
+        int32_t subChunkSize = 16;
+        int16_t audioFormat = 1;      // PCM format
+        int32_t byteRate = sampleRate * channels * bitsPerSample / 8;
+        int16_t blockAlign = channels * bitsPerSample / 8;
+
+        file.write(reinterpret_cast<char *>(&subChunkSize), 4);
+        file.write(reinterpret_cast<char *>(&audioFormat), 2);
+        file.write(reinterpret_cast<char *>(&channels), 2);
+        file.write(reinterpret_cast<char *>(&sampleRate), 4);
+        file.write(reinterpret_cast<char *>(&byteRate), 4);
+        file.write(reinterpret_cast<char *>(&blockAlign), 2);
+        file.write(reinterpret_cast<char *>(&bitsPerSample), 2);
+        file.write("data", 4);
+        file.write("\0\0\0\0", 4);    // Placeholder for data size
+    }
+
+    void writeData(const float *data, size_t length) {
+        for (size_t i = 0; i < length; ++i) {
+            int16_t intSample = static_cast<int16_t>(data[i] * 32767);
+            file.write(reinterpret_cast<char *>(&intSample), sizeof(int16_t));
+            dataSize += sizeof(int16_t);
+        }
+        if (file.is_open()) {
+            file.seekp(4, std::ios::beg);
+            int32_t fileSize = 36 + dataSize;
+            file.write(reinterpret_cast<char *>(&fileSize), 4);
+            file.seekp(40, std::ios::beg);
+            file.write(reinterpret_cast<char *>(&dataSize), 4);
+            file.seekp(0, std::ios::end);
+        }
+    }
 
+    ~SimpleWavWriter() {
+        if (file.is_open()) {
+            file.close();
+        }
+    }
+};
 //  500 -> 00:05.000
 // 6000 -> 01:00.000
 std::string to_timestamp(int64_t t) {
@@ -52,6 +105,7 @@ struct whisper_params {
     std::string language  = "en";
     std::string model     = "models/ggml-base.en.bin";
     std::string fname_out;
+    bool save_audio = false; // save audio to wav file
 };
 
 void whisper_print_usage(int argc, char ** argv, const whisper_params & params);
@@ -82,6 +136,7 @@ bool whisper_params_parse(int argc, char ** argv, whisper_params & params) {
         else if (arg == "-m"   || arg == "--model")         { params.model         = argv[++i]; }
         else if (arg == "-f"   || arg == "--file")          { params.fname_out     = argv[++i]; }
         else if (arg == "-tdrz" || arg == "--tinydiarize")  { params.tinydiarize   = true; }
+        else if (arg == "-sa"  || arg == "--save-audio")    { params.save_audio    = true; }
 
         else {
             fprintf(stderr, "error: unknown argument: %s\n", arg.c_str());
@@ -117,6 +172,7 @@ void whisper_print_usage(int /*argc*/, char ** argv, const whisper_params & para
     fprintf(stderr, "  -m FNAME, --model FNAME   [%-7s] model path\n",                                     params.model.c_str());
     fprintf(stderr, "  -f FNAME, --file FNAME    [%-7s] text output file name\n",                          params.fname_out.c_str());
     fprintf(stderr, "  -tdrz,     --tinydiarize  [%-7s] enable tinydiarize (requires a tdrz model)\n",     params.tinydiarize ? "true" : "false");
+    fprintf(stderr, "  -sa,      --save-audio    [%-7s] save the recorded audio to a file\n",              params.save_audio ? "true" : "false");
     fprintf(stderr, "\n");
 }
 
@@ -154,7 +210,6 @@ int main(int argc, char ** argv) {
     audio.resume();
 
     // whisper init
-
     if (params.language != "auto" && whisper_lang_id(params.language.c_str()) == -1){
         fprintf(stderr, "error: unknown language '%s'\n", params.language.c_str());
         whisper_print_usage(argc, argv, params);
@@ -211,15 +266,28 @@ int main(int argc, char ** argv) {
             return 1;
         }
     }
-
-    printf("[Start speaking]");
+    // save wav file
+    SimpleWavWriter *wavWriter = nullptr;
+    if (params.save_audio) {
+        // Get current date/time for filename
+        time_t now = time(0);
+        char buffer[80];
+        strftime(buffer, sizeof(buffer), "%Y%m%d%H%M%S", localtime(&now));
+        std::string filename = std::string(buffer) + ".wav";
+
+        wavWriter = new SimpleWavWriter(filename, WHISPER_SAMPLE_RATE, 16, 1);
+    }
+    printf("[Start speaking]\n");
     fflush(stdout);
 
-          auto t_last  = std::chrono::high_resolution_clock::now();
+    auto t_last  = std::chrono::high_resolution_clock::now();
     const auto t_start = t_last;
 
     // main audio loop
     while (is_running) {
+        if (params.save_audio && wavWriter) {
+            wavWriter->writeData(pcmf32_new.data(), pcmf32_new.size());
+        }
         // handle Ctrl + C
         is_running = sdl_poll_events();
 
@@ -371,7 +439,7 @@ int main(int argc, char ** argv) {
                     fout << std::endl;
                 }
 
-                if (use_vad){
+                if (use_vad) {
                     printf("\n");
                     printf("### Transcription %d END\n", n_iter);
                 }
@@ -408,4 +476,4 @@ int main(int argc, char ** argv) {
     whisper_free(ctx);
 
     return 0;
-}
+}