vad : add initial Voice Activity Detection (VAD) support

.github/workflows/build.yml

@@ -1253,3 +1253,23 @@ jobs:
           source venv/bin/activate
           pip install ane_transformers openai-whisper coremltools
           ./models/generate-coreml-model.sh ${{ env.MODEL_NAME }}
+
+  vad:
+    if: ${{ github.event_name == 'push' || github.event_name == 'pull_request' ||
+            github.event.inputs.run_type == 'full-ci' }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build
+        shell: bash
+        run: |
+          cmake -B build
+          cmake --build build --config Release
+
+      - name: Test
+        shell: bash
+        run: |
+          ctest -R ^test-vad$ --test-dir build --output-on-failure -VV

README.md

@@ -25,6 +25,7 @@ High-performance inference of [OpenAI's Whisper](https://github.com/openai/whisp
 - [Ascend NPU Support](#ascend-npu-support)
 - [Moore Threads GPU Support](#moore-threads-gpu-support)
 - [C-style API](https://github.com/ggml-org/whisper.cpp/blob/master/include/whisper.h)
+- [Voice Activity Detection (VAD)](#voice-activity-detection-vad)
 
 Supported platforms:
 
@@ -732,6 +733,64 @@ let package = Package(
 )
 ```
 
+### Voice Activity Detection (VAD)
+Support for Voice Activity Detection (VAD) can be enabled using the `--vad`
+argument to `whisper-cli`. In addition to this option a VAD model is also
+required.
+
+The way this works is that first the audio samples are passed through
+the VAD model which will detect speech segments. Using this information the
+only the speech segments that are detected are extracted from the original audio
+input and passed to whisper for processing. This reduces the amount of audio
+data that needs to be processed by whisper and can significantly speed up the
+transcription process.
+
+The following VAD models are currently supported:
+
+#### Silero-VAD
+[Silero-vad](https://github.com/snakers4/silero-vad) is a lightweight VAD model
+written in Python that is fast and accurate.
+
+This model can be converted to ggml using the following command:
+```console
+$ python3 -m venv venv && source venv/bin/activate
+$ (venv) pip install silero-vad
+$ (venv) $ python models/convert-silero-vad-to-ggml.py --output models/silero.bin
+Saving GGML Silero-VAD model to models/silero-v5.1.2-ggml.bin
+```
+And it can then be used with whisper as follows:
+```console
+$ ./build/bin/whisper-cli \
+   --file ./samples/jfk.wav \
+   --model ./models/ggml-base.en.bin \
+   --vad \
+   --vad-model ./models/silero-v5.1.2-ggml.bin
+```
+
+#### VAD Options
+
+* --vad-threshold: Threshold probability for speech detection. A probability
+for a speech segment/frame above this threshold will be considered as speech.
+
+* --vad-min-speech-duration-ms: Minimum speech duration in milliseconds. Speech
+segments shorter than this value will be discarded to filter out brief noise or
+false positives.
+
+* --vad-min-silence-duration-ms: Minimum silence duration in milliseconds. Silence
+periods must be at least this long to end a speech segment. Shorter silence
+periods will be ignored and included as part of the speech.
+
+* --vad-max-speech-duration-s: Maximum speech duration in seconds. Speech segments
+longer than this will be automatically split into multiple segments at silence
+points exceeding 98ms to prevent excessively long segments.
+
+* --vad_speech_pad_ms: Speech padding in milliseconds. Adds this amount of padding
+before and after each detected speech segment to avoid cutting off speech edges.
+
+* --vad_samples_overlap: Amount of audio to extend from each speech segment into
+the next one, in seconds (e.g., 0.10 = 100ms overlap). This ensures speech isn't
+cut off abruptly between segments when they're concatenated together.
+
 ## Examples
 
 There are various examples of using the library for different projects in the [examples](examples) folder.

examples/cli/cli.cpp

@@ -11,6 +11,7 @@
 #include <thread>
 #include <vector>
 #include <cstring>
+#include <cfloat>
 
 #if defined(_WIN32)
 #ifndef NOMINMAX
@@ -97,6 +98,16 @@ struct whisper_params {
     std::vector<std::string> fname_out = {};
 
     grammar_parser::parse_state grammar_parsed;
+
+    // Voice Activity Detection (VAD) parameters
+    bool        vad           = false;
+    std::string vad_model     = "";
+    float       vad_threshold = 0.5f;
+    int         vad_min_speech_duration_ms = 250;
+    int         vad_min_silence_duration_ms = 100;
+    float       vad_max_speech_duration_s = FLT_MAX;
+    int         vad_speech_pad_ms = 30;
+    float       vad_samples_overlap = 0.1f;
 };
 
 static void whisper_print_usage(int argc, char ** argv, const whisper_params & params);
@@ -185,6 +196,15 @@ static bool whisper_params_parse(int argc, char ** argv, whisper_params & params
         else if (                  arg == "--grammar")         { params.grammar         = ARGV_NEXT; }
         else if (                  arg == "--grammar-rule")    { params.grammar_rule    = ARGV_NEXT; }
         else if (                  arg == "--grammar-penalty") { params.grammar_penalty = std::stof(ARGV_NEXT); }
+        // Voice Activity Detection (VAD)
+        else if (arg == "-v"    || arg == "--vad")                         { params.vad                         = true; }
+        else if (arg == "-vm"   || arg == "--vad-model")                   { params.vad_model                   = ARGV_NEXT; }
+        else if (arg == "-vt"   || arg == "--vad-threshold")               { params.vad_threshold               = std::stof(ARGV_NEXT); }
+        else if (arg == "-vsd"  || arg == "--vad-min-speech-duration-ms")  { params.vad_min_speech_duration_ms  = std::stoi(ARGV_NEXT); }
+        else if (arg == "-vsd"  || arg == "--vad-min-silence-duration-ms") { params.vad_min_speech_duration_ms  = std::stoi(ARGV_NEXT); }
+        else if (arg == "-vmsd" || arg == "--vad-max-speech-duration-s")   { params.vad_max_speech_duration_s   = std::stof(ARGV_NEXT); }
+        else if (arg == "-vp"   || arg == "--vad-speech-pad-ms")           { params.vad_speech_pad_ms           = std::stoi(ARGV_NEXT); }
+        else if (arg == "-vo"   || arg == "--vad-samples-overlap")         { params.vad_samples_overlap         = std::stof(ARGV_NEXT); }
         else {
             fprintf(stderr, "error: unknown argument: %s\n", arg.c_str());
             whisper_print_usage(argc, argv, params);
@@ -254,6 +274,18 @@ static void whisper_print_usage(int /*argc*/, char ** argv, const whisper_params
     fprintf(stderr, "  --grammar GRAMMAR              [%-7s] GBNF grammar to guide decoding\n",                 params.grammar.c_str());
     fprintf(stderr, "  --grammar-rule RULE            [%-7s] top-level GBNF grammar rule name\n",               params.grammar_rule.c_str());
     fprintf(stderr, "  --grammar-penalty N            [%-7.1f] scales down logits of nongrammar tokens\n",      params.grammar_penalty);
+    // Voice Activity Detection (VAD) parameters
+    fprintf(stderr, "\nVoice Activity Detection (VAD) options:\n");
+    fprintf(stderr, "  -v,        --vad                           [%-7s] enable Voice Activity Detection (VAD)\n",            params.vad ? "true" : "false");
+    fprintf(stderr, "  -vm FNAME, --vad-model FNAME               [%-7s] VAD model path\n",                                   params.vad_model.c_str());
+    fprintf(stderr, "  -vt N,     --vad-threshold N               [%-7.2f] VAD threshold for speech recognition\n",           params.vad_threshold);
+    fprintf(stderr, "  -vspd N,   --vad-min-speech-duration-ms  N [%-7d] VAD min speech duration (0.0-1.0)\n",                params.vad_min_speech_duration_ms);
+    fprintf(stderr, "  -vsd N,    --vad-min-silence-duration-ms N [%-7d] VAD min silence duration (to split segments)\n",      params.vad_min_silence_duration_ms);
+    fprintf(stderr, "  -vmsd N,   --vad-max-speech-duration-s   N [%-7s] VAD max speech duration (auto-split longer)\n",      params.vad_max_speech_duration_s == FLT_MAX ?
+                                                                                                                                  std::string("FLT_MAX").c_str() :
+                                                                                                                                  std::to_string(params.vad_max_speech_duration_s).c_str());
+    fprintf(stderr, "  -vp N,     --vad_speech_pad_ms           N [%-7d] VAD speech padding (extend segments)\n",             params.vad_speech_pad_ms);
+    fprintf(stderr, "  -vo N,     --vad_samples_overlap         N [%-7.2f] VAD samples overlap (seconds between segments)\n", params.vad_samples_overlap);
     fprintf(stderr, "\n");
 }
 
@@ -1131,6 +1163,16 @@ int main(int argc, char ** argv) {
 
             wparams.suppress_nst     = params.suppress_nst;
 
+            wparams.vad            = params.vad;
+            wparams.vad_model_path = params.vad_model.c_str();
+
+            wparams.vad_params.threshold               = params.vad_threshold;
+            wparams.vad_params.min_speech_duration_ms  = params.vad_min_speech_duration_ms;
+            wparams.vad_params.min_silence_duration_ms = params.vad_min_silence_duration_ms;
+            wparams.vad_params.max_speech_duration_s   = params.vad_max_speech_duration_s;
+            wparams.vad_params.speech_pad_ms           = params.vad_speech_pad_ms;
+            wparams.vad_params.samples_overlap         = params.vad_samples_overlap;
+
             whisper_print_user_data user_data = { &params, &pcmf32s, 0 };
 
             const auto & grammar_parsed = params.grammar_parsed;

include/whisper.h

@@ -189,6 +189,15 @@ extern "C" {
         uint32_t             value; // Unicode code point or rule ID
     } whisper_grammar_element;
 
+    typedef struct whisper_vad_params {
+        float threshold;               // Probability threshold to consider as speech.
+        int   min_speech_duration_ms;  // Min duration for a valid speech segment.
+        int   min_silence_duration_ms; // Min silence duration to consider speech as ended.
+        float max_speech_duration_s;   // Max duration of a speech segment before forcing a new segment.
+        int   speech_pad_ms;           // Padding added before and after speech segments.
+        float samples_overlap;         // Overlap in seconds when copying audio samples from speech segment.
+    } whisper_vad_params;
+
     // Various functions for loading a ggml whisper model.
     // Allocate (almost) all memory needed for the model.
     // Return NULL on failure
@@ -570,11 +579,18 @@ extern "C" {
         size_t                           n_grammar_rules;
         size_t                           i_start_rule;
         float                            grammar_penalty;
+
+        // Voice Activity Detection (VAD) params
+        bool         vad;                         // Enable VAD
+        const char * vad_model_path;              // Path to VAD model
+
+        whisper_vad_params vad_params;
     };
 
     // NOTE: this function allocates memory, and it is the responsibility of the caller to free the pointer - see whisper_free_context_params & whisper_free_params()
     WHISPER_API struct whisper_context_params * whisper_context_default_params_by_ref(void);
     WHISPER_API struct whisper_context_params   whisper_context_default_params       (void);
+
     WHISPER_API struct whisper_full_params * whisper_full_default_params_by_ref(enum whisper_sampling_strategy strategy);
     WHISPER_API struct whisper_full_params   whisper_full_default_params       (enum whisper_sampling_strategy strategy);
 
@@ -652,6 +668,53 @@ extern "C" {
     WHISPER_API float whisper_full_get_token_p           (struct whisper_context * ctx, int i_segment, int i_token);
     WHISPER_API float whisper_full_get_token_p_from_state(struct whisper_state * state, int i_segment, int i_token);
 
+    //
+    // Voice Activity Detection (VAD)
+    //
+
+    struct whisper_vad_context;
+
+    WHISPER_API struct whisper_vad_params whisper_vad_default_params(void);
+
+    struct whisper_vad_context_params {
+        int   n_threads;  // The number of threads to use for processing.
+        bool  use_gpu;
+        int   gpu_device; // CUDA device
+    };
+
+    WHISPER_API struct whisper_vad_context_params whisper_vad_default_context_params(void);
+
+    WHISPER_API struct whisper_vad_context * whisper_vad_init_from_file_with_params(const char * path_model,              struct whisper_vad_context_params params);
+    WHISPER_API struct whisper_vad_context * whisper_vad_init_with_params          (struct whisper_model_loader * loader, struct whisper_vad_context_params params);
+
+    WHISPER_API bool whisper_vad_detect_speech(
+            struct whisper_vad_context * vctx,
+                           const float * samples,
+                                   int   n_samples);
+
+    WHISPER_API int     whisper_vad_n_probs(struct whisper_vad_context * vctx);
+    WHISPER_API float * whisper_vad_probs  (struct whisper_vad_context * vctx);
+
+    struct whisper_vad_segments;
+
+    WHISPER_API struct whisper_vad_segments * whisper_vad_segments_from_probs(
+            struct whisper_vad_context * vctx,
+            struct whisper_vad_params    params);
+
+    WHISPER_API struct whisper_vad_segments * whisper_vad_segments_from_samples(
+            struct whisper_vad_context * vctx,
+            struct whisper_vad_params    params,
+                           const float * samples,
+                                   int   n_samples);
+
+    WHISPER_API int whisper_vad_segments_n_segments(struct whisper_vad_segments * segments);
+
+    WHISPER_API float whisper_vad_segments_get_segment_t0(struct whisper_vad_segments * segments, int i_segment);
+    WHISPER_API float whisper_vad_segments_get_segment_t1(struct whisper_vad_segments * segments, int i_segment);
+
+    WHISPER_API void whisper_vad_free_segments(struct whisper_vad_segments * segments);
+    WHISPER_API void whisper_vad_free         (struct whisper_vad_context  * ctx);
+
     ////////////////////////////////////////////////////////////////////////////
 
     // Temporary helpers needed for exposing ggml interface