From c09bb9c575b361228306cf864b55a2a8d5aac120 Mon Sep 17 00:00:00 2001
From: Alper Huseyin Dogan <alperdogan@hotmail.com>
Date: Tue, 28 Jan 2025 21:41:31 +0300
Subject: [PATCH] add split_by_gap

---
 whisperx/alignment.py | 97 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 96 insertions(+), 1 deletion(-)

diff --git a/whisperx/alignment.py b/whisperx/alignment.py
index 3b2fdae9..1c19ff6d 100644
--- a/whisperx/alignment.py
+++ b/whisperx/alignment.py
@@ -72,6 +72,86 @@
     "lv": "jimregan/wav2vec2-large-xlsr-latvian-cv",
 }
 
+def split_by_gap(segments: List[dict], gap_threshold: float = 0.7) -> List[dict]:
+    """
+    Post-process aligned segments to split texts where word gaps exceed threshold.
+    Only splits within existing segments, does not modify already separate segments.
+    """
+    result_segments = []
+
+    for segment in segments:
+        if not segment.get("words") or len(segment["words"]) < 2:
+            result_segments.append(segment)
+            continue
+
+        words = segment["words"]
+        gaps_found = False
+
+        # First check if any gaps exist in this segment
+        for i in range(1, len(words)):
+            prev_word = words[i - 1]
+            curr_word = words[i]
+            if (
+                prev_word.get("end")
+                and curr_word.get("start")
+                and (curr_word["start"] - prev_word["end"]) > gap_threshold
+            ):
+                gaps_found = True
+                break
+
+        # If no gaps found, keep segment as is
+        if not gaps_found:
+            result_segments.append(segment)
+            continue
+
+        # If gaps found, split into multiple segments
+        current_segment = {"text": "", "words": [], "start": None, "end": None}
+
+        for i, word in enumerate(words):
+            if not word.get("start") or not word.get("end"):
+                if current_segment["words"]:
+                    current_segment["words"].append(word)
+                continue
+
+            # First word
+            if current_segment["start"] is None:
+                current_segment["start"] = word["start"]
+                current_segment["words"] = [word]
+                continue
+
+            prev_word = words[i - 1]
+            # Check gap with previous word
+            if (
+                prev_word.get("end")
+                and (word["start"] - prev_word["end"]) > gap_threshold
+            ):
+                # Complete current segment
+                current_segment["end"] = prev_word["end"]
+                current_segment["text"] = " ".join(
+                    w["word"] for w in current_segment["words"]
+                )
+                result_segments.append(current_segment)
+
+                # Start new segment
+                current_segment = {
+                    "text": "",
+                    "words": [word],
+                    "start": word["start"],
+                    "end": None,
+                }
+            else:
+                current_segment["words"].append(word)
+
+        # Add final segment
+        if current_segment["words"]:
+            current_segment["end"] = current_segment["words"][-1]["end"]
+            current_segment["text"] = " ".join(
+                w["word"] for w in current_segment["words"]
+            )
+            result_segments.append(current_segment)
+
+    return result_segments
+
 
 def load_align_model(language_code: str, device: str, model_name: Optional[str] = None, model_dir=None):
     if model_name is None:
@@ -119,6 +199,7 @@ def align(
     return_char_alignments: bool = False,
     print_progress: bool = False,
     combined_progress: bool = False,
+    gap_threshold: float = 0.7,
 ) -> AlignedTranscriptionResult:
     """
     Align phoneme recognition predictions to known transcription.
@@ -376,7 +457,21 @@ def align(
     for segment in aligned_segments:
         word_segments += segment["words"]
 
-    return {"segments": aligned_segments, "word_segments": word_segments}
+    aligned_result = {"segments": aligned_segments, "word_segments": word_segments}
+
+    # Post-process to split segments with large gaps
+    aligned_result["segments"] = split_by_gap(aligned_result["segments"], gap_threshold)
+
+    # Update word_segments list to match new segments
+    word_segments = []
+    for segment in aligned_result["segments"]:
+        if segment.get("words"):
+            word_segments.extend(segment["words"])
+    aligned_result["word_segments"] = word_segments
+
+    return aligned_result
+
+    # return {"segments": aligned_segments, "word_segments": word_segments}
 
 """
 source: https://pytorch.org/tutorials/intermediate/forced_alignment_with_torchaudio_tutorial.html