add detected language callback

include/whisper.h

@@ -415,6 +415,9 @@ extern "C" {
     WHISPER_API float * whisper_get_logits           (struct whisper_context * ctx);
     WHISPER_API float * whisper_get_logits_from_state(struct whisper_state * state);
 
+    WHISPER_API int whisper_get_lang_id_from_state(struct whisper_state * state);
+    WHISPER_API float whisper_get_lang_prob_from_state(struct whisper_state * state);
+
     // Token Id -> String. Uses the vocabulary in the provided context
     WHISPER_API const char * whisper_token_to_str(struct whisper_context * ctx, whisper_token token);
     WHISPER_API const char * whisper_model_type_readable(struct whisper_context * ctx);
@@ -465,6 +468,9 @@ extern "C" {
     // Progress callback
     typedef void (*whisper_progress_callback)(struct whisper_context * ctx, struct whisper_state * state, int progress, void * user_data);
 
+    // Detected language callback
+    typedef void (*whisper_detected_language_callback)(struct whisper_context * ctx, struct whisper_state * state, void * user_data);
+
     // Encoder begin callback
     // If not NULL, called before the encoder starts
     // If it returns false, the computation is aborted
@@ -562,6 +568,10 @@ extern "C" {
         whisper_new_segment_callback new_segment_callback;
         void * new_segment_callback_user_data;
 
+        // called on detected language
+        whisper_detected_language_callback detected_language_callback;
+        void * detected_language_callback_user_data;
+
         // called on each progress update
         whisper_progress_callback progress_callback;
         void * progress_callback_user_data;

src/whisper.cpp

@@ -892,6 +892,7 @@ struct whisper_state {
     std::vector<whisper_token>   prompt_past1; // dynamic context from decoded output
 
     int lang_id = 0; // english by default
+    float lang_prob = 0.0f; // probability of the detected language
 
     std::string path_model; // populated by whisper_init_from_file_with_params()
 
@@ -4198,6 +4199,14 @@ float * whisper_get_logits_from_state(struct whisper_state * state) {
     return state->logits.data();
 }
 
+int whisper_get_lang_id_from_state(struct whisper_state * state) {
+    return state->lang_id;
+}
+
+float whisper_get_lang_prob_from_state(struct whisper_state * state) {
+    return state->lang_prob;
+}
+
 const char * whisper_token_to_str(struct whisper_context * ctx, whisper_token token) {
     return ctx->vocab.id_to_token.at(token).c_str();
 }
@@ -5968,6 +5977,9 @@ struct whisper_full_params whisper_full_default_params(enum whisper_sampling_str
         /*.new_segment_callback           =*/ nullptr,
         /*.new_segment_callback_user_data =*/ nullptr,
 
+        /*.detected_language_callback           =*/ nullptr,
+        /*.detected_language_callback_user_data =*/ nullptr,
+
         /*.progress_callback           =*/ nullptr,
         /*.progress_callback_user_data =*/ nullptr,
 
@@ -6818,9 +6830,15 @@ int whisper_full_with_state(
             return -3;
         }
         state->lang_id = lang_id;
+        state->lang_prob = probs[lang_id];
         params.language = whisper_lang_str(lang_id);
 
-        WHISPER_LOG_INFO("%s: auto-detected language: %s (p = %f)\n", __func__, params.language, probs[whisper_lang_id(params.language)]);
+        WHISPER_LOG_INFO("%s: auto-detected language: %s (p = %f)\n", __func__, params.language, probs[lang_id]);
+
+        if (params.detected_language_callback) {
+            params.detected_language_callback(ctx, state, params.detected_language_callback_user_data);
+        }
+
         if (params.detect_language) {
             return 0;
         }