feat: implement flexible head file detection supporting i.mp4 and i<number>.mp4 patterns

cut_head.py

@@ -3,6 +3,7 @@ import json
 import os
 import glob
 import sys
+import re
 
 def probe_streams(video_path):
     """Probes the input file and returns info about its streams."""
@@ -177,16 +178,37 @@ def main():
     if target_files is None:
         target_files = glob.glob("*.mp4")
 
-    baseline_file = "i.mp4"
+    # --- Head file detection ---
+    # Priority 1: exact "i.mp4"
+    # Priority 2: files matching "i<number>.mp4" (e.g. i10.mp4, i9.mp4)
+    baseline_file = None
+    head_pattern = re.compile(r'^i(\d+)\.mp4$', re.IGNORECASE)
+    head_files = []  # all files that match head patterns (to exclude from processing)
 
-    # Check if baseline exists in the target directory
-    if not os.path.exists(baseline_file):
-        print(f"Error: '{baseline_file}' not found in the target folder: {target_dir}")
+    if os.path.exists("i.mp4"):
+        baseline_file = "i.mp4"
+        head_files.append("i.mp4")
+        print("Using head file: i.mp4")
+    else:
+        # Find all i<number>.mp4 candidates
+        candidates = []
+        for f in glob.glob("i*.mp4"):
+            m = head_pattern.match(f)
+            if m:
+                candidates.append((int(m.group(1)), f))
+                head_files.append(f)
+        if candidates:
+            # Sort by the numeric suffix and pick the first (smallest number)
+            candidates.sort(key=lambda x: x[0])
+            baseline_file = candidates[0][1]
+            print(f"Using head file (fallback): {baseline_file}")
+
+    if not baseline_file:
+        print(f"Error: No head file found (i.mp4 or i<number>.mp4) in: {target_dir}")
         return
 
-    # Remove the baseline file from the processing list
-    if baseline_file in target_files:
-        target_files.remove(baseline_file)
+    # Remove all head-pattern files from the processing list
+    target_files = [f for f in target_files if f not in head_files]
 
     if not target_files:
         print("No other .mp4 files found to process.")