diff --git a/src/whisper.cpp b/src/whisper.cpp index 05f35028..df60466a 100644 --- a/src/whisper.cpp +++ b/src/whisper.cpp @@ -8948,164 +8948,138 @@ static void whisper_exp_compute_token_level_timestamps_dtw( } } - // adjust timestamps - const int64_t min_dur = 5; + // DTW timestamp refinement constants (in centiseconds, 1 cs = 10ms) + // These values are tuned for natural speech at ~150 WPM + static const int64_t DTW_MIN_TOKEN_DUR = 5; // 50ms absolute minimum + static const int DTW_ONSET_VOWEL = 15; // 150ms for vowels/plosives (anticipate burst) + static const int DTW_ONSET_CONSONANT = 8; // 80ms for other consonants + static const int DTW_DUR_PER_CHAR = 2; // 20ms per character for min duration + static const int DTW_MAX_DUR_PER_CHAR = 15; // 150ms per character for max duration + static const int64_t DTW_MAX_DUR_BASE = 10; // 100ms base max duration + // vowels + plosives benefit from earlier onset to match perceived speech start + static const char * DTW_ONSET_PHONEMES = "aeiouywbcdgkpqt"; + + // helper: get previous token's end time + auto get_prev_end = [&](size_t seg_idx, int tok_idx) -> int64_t { + auto & seg = state->result_all[seg_idx]; + for (int t2 = tok_idx - 1; t2 >= 0; --t2) { + if (seg.tokens[t2].id < whisper_token_eot(ctx)) { + return seg.tokens[t2].t_dtw; + } + } + if (seg_idx > 0 && !state->result_all[seg_idx - 1].tokens.empty()) { + return state->result_all[seg_idx - 1].tokens.back().t_dtw; + } + return 0; + }; + + // helper: get next token's start time + auto get_next_start = [&](size_t seg_idx, int tok_idx, int64_t fallback) -> int64_t { + auto & seg = state->result_all[seg_idx]; + const int n = seg.tokens.size(); + for (int t2 = tok_idx + 1; t2 < n; ++t2) { + if (seg.tokens[t2].id < whisper_token_eot(ctx)) { + return seg.tokens[t2].t_dtw; + } + } + if (seg_idx + 1 < state->result_all.size()) { + for (const auto & ntok : state->result_all[seg_idx + 1].tokens) { + if (ntok.id < whisper_token_eot(ctx)) { + return ntok.t_dtw; + } + } + } + return fallback; + }; + + // helper: get token text length (excluding leading space) + auto get_text_len = [&](whisper_token id) -> std::pair { + const char * text = whisper_token_to_str(ctx, id); + int len = text ? (int)strlen(text) : 1; + if (len > 0 && text && text[0] == ' ') { text++; len--; } + if (len < 1) len = 1; + return {text, len}; + }; + + // pass 1: onset shift + min duration adjustment for (size_t i = i_segment; i < i_segment + n_segments; ++i) { auto & segment = state->result_all[i]; const int n_tokens = segment.tokens.size(); for (int t = 0; t < n_tokens; ++t) { auto & tok = segment.tokens[t]; - if (tok.id >= whisper_token_eot(ctx)) continue; - int len = 1; - const char * text = whisper_token_to_str(ctx, tok.id); - if (text) { - len = (int)strlen(text); - if (len > 0 && text[0] == ' ') { - text++; - len--; - } - } + auto text_pair = get_text_len(tok.id); + const char * text = text_pair.first; + int len = text_pair.second; - // onset shift - { + // onset shift: move start earlier for vowels/plosives + if (len > 0 && text) { + char c = tolower(text[0]); int shift = 0; - if (len > 0 && text) { - char c = tolower(text[0]); - if (strchr("aeiouywbcdgkpqqt", c)) { - shift = 15; - } else if (c >= 'a' && c <= 'z') { - shift = 8; - } + if (strchr(DTW_ONSET_PHONEMES, c)) { + shift = DTW_ONSET_VOWEL; + } else if (c >= 'a' && c <= 'z') { + shift = DTW_ONSET_CONSONANT; } - if (shift > 0) { - int64_t prev_end = 0; - if (t > 0) { - for (int t2 = t - 1; t2 >= 0; --t2) { - if (segment.tokens[t2].id < whisper_token_eot(ctx)) { - prev_end = segment.tokens[t2].t_dtw; - break; - } - } - } else if (i > 0 && !state->result_all[i-1].tokens.empty()) { - prev_end = state->result_all[i-1].tokens.back().t_dtw; - } - + int64_t prev_end = get_prev_end(i, t); if (tok.t_dtw - shift > prev_end + 1) { tok.t_dtw -= shift; } } } - // min duration - { - int64_t next_t_dtw = -1; - for (int t2 = t + 1; t2 < n_tokens; ++t2) { - if (segment.tokens[t2].id < whisper_token_eot(ctx)) { - next_t_dtw = segment.tokens[t2].t_dtw; - break; - } - } + // min duration: extend backward if too short + int64_t next_start = get_next_start(i, t, segment.t1); + int64_t duration = next_start - tok.t_dtw; + int64_t len_based_min = (int64_t)(len * DTW_DUR_PER_CHAR); + int64_t adaptive_min = (DTW_MIN_TOKEN_DUR > len_based_min) ? DTW_MIN_TOKEN_DUR : len_based_min; - if (next_t_dtw < 0) { - next_t_dtw = segment.t1; - } - - int64_t duration = next_t_dtw - tok.t_dtw; - const int64_t adaptive_min = std::max((int64_t)5, (int64_t)(len * 2)); - - if (duration < adaptive_min && duration >= 0) { - int64_t needed = adaptive_min - duration; - - int64_t prev_end = 0; - if (t > 0) { - for (int t2 = t - 1; t2 >= 0; --t2) { - if (segment.tokens[t2].id < whisper_token_eot(ctx)) { - prev_end = segment.tokens[t2].t_dtw; - break; - } - } - } else if (i > 0 && !state->result_all[i-1].tokens.empty()) { - prev_end = state->result_all[i-1].tokens.back().t_dtw; - } - - int64_t new_start = tok.t_dtw - needed; - if (new_start > prev_end + 2) { - tok.t_dtw = new_start; - } + if (duration >= 0 && duration < adaptive_min) { + int64_t prev_end = get_prev_end(i, t); + int64_t new_start = tok.t_dtw - (adaptive_min - duration); + if (new_start > prev_end + 2) { + tok.t_dtw = new_start; } } } } - // propagate to t0/t1 + // pass 2: propagate t_dtw to t0/t1 with max duration cap for (size_t i = i_segment; i < i_segment + n_segments; ++i) { auto & segment = state->result_all[i]; const int n_tokens = segment.tokens.size(); for (int t = 0; t < n_tokens; ++t) { auto & tok = segment.tokens[t]; - if (tok.id >= whisper_token_eot(ctx)) continue; tok.t0 = tok.t_dtw; - int64_t next_t_dtw = -1; - for (int t2 = t + 1; t2 < n_tokens; ++t2) { - if (segment.tokens[t2].id < whisper_token_eot(ctx)) { - next_t_dtw = segment.tokens[t2].t_dtw; - break; - } - } + auto text_pair2 = get_text_len(tok.id); + int len2 = text_pair2.second; + int64_t next_start = get_next_start(i, t, segment.t1); + int64_t len_based_max = (int64_t)(len2 * DTW_MAX_DUR_PER_CHAR); + int64_t max_dur = (DTW_MAX_DUR_BASE > len_based_max) ? DTW_MAX_DUR_BASE : len_based_max; - if (next_t_dtw < 0 && i + 1 < state->result_all.size()) { - for (const auto & ntok : state->result_all[i + 1].tokens) { - if (ntok.id < whisper_token_eot(ctx)) { - next_t_dtw = ntok.t_dtw; - break; - } - } - } - - int64_t raw_t1 = (next_t_dtw >= 0) ? next_t_dtw : segment.t1; - - // max duration - { - int len = 1; - const char * text = whisper_token_to_str(ctx, tok.id); - if (text) { - len = (int)strlen(text); - if (len > 0 && text[0] == ' ') len--; - if (len < 1) len = 1; - } - - int64_t max_dur = std::max((int64_t)10, (int64_t)(len * 15)); - - if (raw_t1 < tok.t0 + min_dur) { - raw_t1 = tok.t0 + min_dur; - } - - tok.t1 = (raw_t1 - tok.t0 > max_dur) ? tok.t0 + max_dur : raw_t1; - } + int64_t min_t1 = tok.t0 + DTW_MIN_TOKEN_DUR; + int64_t raw_t1 = (next_start > min_t1) ? next_start : min_t1; + tok.t1 = (raw_t1 - tok.t0 > max_dur) ? tok.t0 + max_dur : raw_t1; } - // segment bounds - { - int64_t first_t0 = -1; - int64_t last_t1 = -1; - for (int t = 0; t < n_tokens; ++t) { - const auto & tok = segment.tokens[t]; - if (tok.id >= whisper_token_eot(ctx)) continue; - if (first_t0 < 0) first_t0 = tok.t0; - last_t1 = tok.t1; - } - if (first_t0 >= 0) segment.t0 = first_t0; - if (last_t1 >= 0) segment.t1 = last_t1; + // sync segment boundaries with token bounds + int64_t first_t0 = -1, last_t1 = -1; + for (int t = 0; t < n_tokens; ++t) { + const auto & tok = segment.tokens[t]; + if (tok.id >= whisper_token_eot(ctx)) continue; + if (first_t0 < 0) first_t0 = tok.t0; + last_t1 = tok.t1; } + if (first_t0 >= 0) segment.t0 = first_t0; + if (last_t1 >= 0) segment.t1 = last_t1; } // Print DTW timestamps