diff --git a/examples/main/main.cpp b/examples/main/main.cpp
index 591a09f8f57..1b7fc9c78c4 100644
--- a/examples/main/main.cpp
+++ b/examples/main/main.cpp
@@ -72,7 +72,6 @@ struct whisper_params {
     float no_speech_thold =  0.60f;
 
     bool speed_up        = false;
-    bool debug_mode      = false;
     bool translate       = false;
     bool detect_language = false;
     bool diarize         = false;
@@ -92,6 +91,7 @@ struct whisper_params {
     bool print_progress  = false;
     bool no_timestamps   = false;
     bool suppress_nst    = true;  // suppress non speech tokens
+    bool heuristic       = true;
     bool log_score       = false;
     bool use_gpu         = true;
 
@@ -143,8 +143,8 @@ bool whisper_params_parse(int argc, const char ** argv, whisper_params & params)
         else if (arg == "-lpt"  || arg == "--logprob-thold")   { params.logprob_thold   = std::stof(argv[++i]); }
         else if (arg == "-nst"  || arg == "--nospeech-thold")  { params.no_speech_thold = std::stof(argv[++i]); }
         // else if (arg == "-su"   || arg == "--speed-up")        { params.speed_up        = true; }
-        else if (arg == "-debug"|| arg == "--debug-mode")      { params.debug_mode      = true; }
-        else if (arg == "-snst" || arg == "--suppress-nst")    { params.suppress_nst    = true; }
+        else if (arg == "-nsnst"|| arg == "--no-suppress-nst") { params.suppress_nst    = false; }
+        else if (arg == "-nh"   || arg == "--no-heuristic")    { params.heuristic       = false; }
         else if (arg == "-tr"   || arg == "--translate")       { params.translate       = true; }
         else if (arg == "-di"   || arg == "--diarize")         { params.diarize         = true; }
         else if (arg == "-tdrz" || arg == "--tinydiarize")     { params.tinydiarize     = true; }
@@ -202,8 +202,8 @@ void whisper_print_usage(int /*argc*/, const char ** argv, const whisper_params
     fprintf(stderr, "  -lpt N,    --logprob-thold N   [%-7.2f] log probability threshold for decoder fail\n",   params.logprob_thold);
     fprintf(stderr, "  -nst N,    --nospeech-thold N  [%-7.2f] no-speech threshold for decoder fail\n",         params.no_speech_thold);
     // fprintf(stderr, "  -su,       --speed-up          [%-7s] speed up audio by x2 (reduced accuracy)\n",        params.speed_up ? "true" : "false");
-    fprintf(stderr, "  -debug,    --debug-mode        [%-7s] enable debug mode (eg. dump log_mel)\n",           params.debug_mode ? "true" : "false");
-    fprintf(stderr, "  -snst,     --suppress-nst      [%-7s] suppress non-speech tokens\n",                     params.suppress_nst ? "true" : "false");
+    fprintf(stderr, "  -nsnst,    --no-suppress-nst   [%-7s] do not suppress non-speech tokens\n",              params.suppress_nst ? "false" : "true");
+    fprintf(stderr, "  -nh,       --no-heuristic      [%-7s] do not use heuristic while decoding\n",            params.heuristic ? "false" : "true");
     fprintf(stderr, "  -tr,       --translate         [%-7s] translate from source language to english\n",      params.translate ? "true" : "false");
     fprintf(stderr, "  -di,       --diarize           [%-7s] stereo audio diarization\n",                       params.diarize ? "true" : "false");
     fprintf(stderr, "  -tdrz,     --tinydiarize       [%-7s] enable tinydiarize (requires a tdrz model)\n",     params.tinydiarize ? "true" : "false");
@@ -1014,7 +1014,7 @@ int run(int argc, const char ** argv) {
             wparams.max_len          = params.output_wts && params.max_len == 0 ? 60 : params.max_len;
 
             wparams.speed_up         = params.speed_up;
-            wparams.debug_mode       = params.debug_mode;
+            wparams.heuristic        = params.heuristic;
 
             wparams.tdrz_enable      = params.tinydiarize; // [TDRZ]
 
diff --git a/examples/server/server.cpp b/examples/server/server.cpp
index b9c566a3a68..cf0157d4a58 100644
--- a/examples/server/server.cpp
+++ b/examples/server/server.cpp
@@ -68,7 +68,6 @@ struct whisper_params {
     float temperature_inc =  0.20f;
 
     bool speed_up        = false;
-    bool debug_mode      = false;
     bool translate       = false;
     bool detect_language = false;
     bool diarize         = false;
@@ -141,7 +140,6 @@ void whisper_print_usage(int /*argc*/, char ** argv, const whisper_params & para
     fprintf(stderr, "  -et N,     --entropy-thold N   [%-7.2f] entropy threshold for decoder fail\n",           params.entropy_thold);
     fprintf(stderr, "  -lpt N,    --logprob-thold N   [%-7.2f] log probability threshold for decoder fail\n",   params.logprob_thold);
     // fprintf(stderr, "  -su,       --speed-up          [%-7s] speed up audio by x2 (reduced accuracy)\n",        params.speed_up ? "true" : "false");
-    fprintf(stderr, "  -debug,    --debug-mode        [%-7s] enable debug mode (eg. dump log_mel)\n",           params.debug_mode ? "true" : "false");
     fprintf(stderr, "  -tr,       --translate         [%-7s] translate from source language to english\n",      params.translate ? "true" : "false");
     fprintf(stderr, "  -di,       --diarize           [%-7s] stereo audio diarization\n",                       params.diarize ? "true" : "false");
     fprintf(stderr, "  -tdrz,     --tinydiarize       [%-7s] enable tinydiarize (requires a tdrz model)\n",     params.tinydiarize ? "true" : "false");
@@ -186,7 +184,6 @@ bool whisper_params_parse(int argc, char ** argv, whisper_params & params, serve
         else if (arg == "-et"   || arg == "--entropy-thold")   { params.entropy_thold   = std::stof(argv[++i]); }
         else if (arg == "-lpt"  || arg == "--logprob-thold")   { params.logprob_thold   = std::stof(argv[++i]); }
         // else if (arg == "-su"   || arg == "--speed-up")        { params.speed_up        = true; }
-        else if (arg == "-debug"|| arg == "--debug-mode")      { params.debug_mode      = true; }
         else if (arg == "-tr"   || arg == "--translate")       { params.translate       = true; }
         else if (arg == "-di"   || arg == "--diarize")         { params.diarize         = true; }
         else if (arg == "-tdrz" || arg == "--tinydiarize")     { params.tinydiarize     = true; }
@@ -443,10 +440,6 @@ void get_req_parameters(const Request & req, whisper_params & params)
     {
         params.logprob_thold = std::stof(req.get_file_value("logprob_thold").content);
     }
-    if (req.has_file("debug_mode"))
-    {
-        params.debug_mode = parse_str_to_bool(req.get_file_value("debug_mode").content);
-    }
     if (req.has_file("translate"))
     {
         params.translate = parse_str_to_bool(req.get_file_value("translate").content);
@@ -733,7 +726,6 @@ int main(int argc, char ** argv) {
             wparams.max_len          = params.max_len == 0 ? 60 : params.max_len;
 
             wparams.speed_up         = params.speed_up;
-            wparams.debug_mode       = params.debug_mode;
 
             wparams.tdrz_enable      = params.tinydiarize; // [TDRZ]
 
diff --git a/whisper.cpp b/whisper.cpp
index 79e0e5eb092..dbea6058cd9 100644
--- a/whisper.cpp
+++ b/whisper.cpp
@@ -2845,7 +2845,6 @@ static bool log_mel_spectrogram(
               const int   n_mel,
               const int   n_threads,
               const whisper_filters & filters,
-              const bool   debug,
               whisper_mel & mel) {
     const int64_t t_start_us = ggml_time_us();
 
@@ -2917,17 +2916,6 @@ static bool log_mel_spectrogram(
 
     wstate.t_mel_us += ggml_time_us() - t_start_us;
 
-    // Dump log_mel_spectrogram
-    if (debug) {
-        std::ofstream outFile("log_mel_spectrogram.json");
-        outFile << "[";
-        for (uint64_t i = 0; i < mel.data.size() - 1; i++) {
-            outFile << mel.data[i] << ", ";
-        }
-        outFile << mel.data[mel.data.size() - 1] << "]";
-        outFile.close();
-    }
-
     return true;
 }
 
@@ -3598,7 +3586,7 @@ void whisper_free_params(struct whisper_full_params * params) {
 }
 
 int whisper_pcm_to_mel_with_state(struct whisper_context * ctx, struct whisper_state * state, const float * samples, int n_samples, int n_threads) {
-    if (!log_mel_spectrogram(*state, samples, n_samples, WHISPER_SAMPLE_RATE, WHISPER_N_FFT, WHISPER_HOP_LENGTH, ctx->model.filters.n_mel, n_threads, ctx->model.filters, false, state->mel)) {
+    if (!log_mel_spectrogram(*state, samples, n_samples, WHISPER_SAMPLE_RATE, WHISPER_N_FFT, WHISPER_HOP_LENGTH, ctx->model.filters.n_mel, n_threads, ctx->model.filters, state->mel)) {
         WHISPER_LOG_ERROR("%s: failed to compute mel spectrogram\n", __func__);
         return -1;
     }
@@ -3612,7 +3600,7 @@ int whisper_pcm_to_mel(struct whisper_context * ctx, const float * samples, int
 
 // same as whisper_pcm_to_mel, but applies a Phase Vocoder to speed up the audio x2 (PV without phase lock is not good)
 int whisper_pcm_to_mel_phase_vocoder_with_state(struct whisper_context * ctx, struct whisper_state * state, const float * samples, int n_samples, int n_threads) {
-    if (!log_mel_spectrogram(*state, samples, n_samples, WHISPER_SAMPLE_RATE, 2 * WHISPER_N_FFT, 2 * WHISPER_HOP_LENGTH, ctx->model.filters.n_mel, n_threads, ctx->model.filters, false, state->mel)) {
+    if (!log_mel_spectrogram(*state, samples, n_samples, WHISPER_SAMPLE_RATE, 2 * WHISPER_N_FFT, 2 * WHISPER_HOP_LENGTH, ctx->model.filters.n_mel, n_threads, ctx->model.filters, state->mel)) {
         WHISPER_LOG_ERROR("%s: failed to compute mel spectrogram\n", __func__);
         return -1;
     }
@@ -4530,7 +4518,6 @@ struct whisper_full_params whisper_full_default_params(enum whisper_sampling_str
         /*.max_tokens        =*/ 0,
 
         /*.speed_up          =*/ false,
-        /*.debug_mode        =*/ false,
         /*.audio_ctx         =*/ 0,
 
         /*.tdrz_enable       =*/ false,
@@ -4544,6 +4531,7 @@ struct whisper_full_params whisper_full_default_params(enum whisper_sampling_str
 
         /*.suppress_blank    =*/ true,
         /*.suppress_non_speech_tokens =*/ true,
+        /*.heuristic         =*/ true,
 
         /*.temperature       =*/  0.0f,
         /*.max_initial_ts    =*/  1.0f,
@@ -4785,7 +4773,7 @@ static void whisper_no_speech_probs(
 }
 
 static const std::vector<std::string> non_speech_tokens = {
-    "\"", "#", "(", ")", "*", "+", "/", ":", ";", "<", "=", ">", "@", "[", "\\", "]", "^",
+    "\"", "#", "*", "+", "/", ":", ";", "<", "=", ">", "@", "\\", "^",
     "_", "`", "{", "|", "}", "~", "「", "」", "『", "』", "<<", ">>", "<<<", ">>>", "--",
     "---", "-(", "-[", "('", "(\"", "((", "))", "(((", ")))", "[[", "]]", "{{", "}}", "♪♪",
     "♪♪♪","♩", "♪", "♫", "♬", "♭", "♮", "♯"
@@ -5435,6 +5423,7 @@ int whisper_full_with_state(
     }
 
     int seek = seek_start;
+    bool fast_forward = false;
 
     std::vector<whisper_token> prompt;
     prompt.reserve(whisper_n_text_ctx(ctx));
@@ -5991,6 +5980,42 @@ int whisper_full_with_state(
             if (best_decoder.sequence.no_speech_probs > params.no_speech_thold) {
                 if (best_decoder.sequence.avg_logprobs < params.logprob_thold) {
                     // fast-forward to the next segment boundary
+                    prompt_past.clear();
+                    fast_forward = true;
+                    seek += std::min(3000, state->mel.n_len_org - seek);
+                    continue;
+                }
+            }
+        }
+
+        // repetition check
+        {
+            if (!params.no_timestamps && params.heuristic) {
+                const auto & best_decoder = state->decoders[best_decoder_id];
+                const auto & tokens_cur = best_decoder.sequence.tokens;
+
+                std::set<std::string> table;
+                std::string text;
+                int timestamp_token_counter = 0;
+                int max_length = 0;
+
+                for (auto & token : tokens_cur) {
+                    if (token.id < whisper_token_beg(ctx)) {
+                        text += ctx->vocab.id_to_token[token.id];
+                    } else {
+                        timestamp_token_counter++;
+                    }
+                    if (timestamp_token_counter % 2 == 0) {
+                        if (text.length() > max_length) {max_length = text.length();}
+                        table.insert(text);
+                        text.clear();
+                    }
+                }
+
+                if ((static_cast<float>(table.size()) / static_cast<float>(timestamp_token_counter)) < 0.25 || max_length <= 4) {
+                    // fast-forward to the next segment boundary
+                    prompt_past.clear();
+                    fast_forward = true;
                     seek += std::min(3000, state->mel.n_len_org - seek);
                     continue;
                 }
@@ -6113,6 +6138,8 @@ int whisper_full_with_state(
                 }
             }
 
+            fast_forward = false;
+
             // update audio window
             // https://github.com/openai/whisper/blob/ba3f3cd54b0e5b8ce1ab3de13e32122d0d5f98ab/whisper/transcribe.py#L353-L361
             {
diff --git a/whisper.h b/whisper.h
index f9bdf36a0ce..137ecc8b9bf 100644
--- a/whisper.h
+++ b/whisper.h
@@ -457,7 +457,6 @@ extern "C" {
         // [EXPERIMENTAL] speed-up techniques
         // note: these can significantly reduce the quality of the output
         bool speed_up;          // speed-up the audio by 2x using Phase Vocoder
-        bool debug_mode;        // enable debug_mode provides extra info (eg. Dump log_mel)
         int  audio_ctx;         // overwrite the audio context size (0 = use default)
 
         // [EXPERIMENTAL] [TDRZ] tinydiarize
@@ -476,6 +475,7 @@ extern "C" {
         // common decoding parameters:
         bool suppress_blank;    // ref: https://github.com/openai/whisper/blob/f82bc59f5ea234d4b97fb2860842ed38519f7e65/whisper/decoding.py#L89
         bool suppress_non_speech_tokens; // ref: https://github.com/openai/whisper/blob/7858aa9c08d98f75575035ecd6481f462d66ca27/whisper/tokenizer.py#L224-L253
+        bool heuristic;
 
         float temperature;      // initial decoding temperature, ref: https://ai.stackexchange.com/a/32478
         float max_initial_ts;   // ref: https://github.com/openai/whisper/blob/f82bc59f5ea234d4b97fb2860842ed38519f7e65/whisper/decoding.py#L97