[O] shift-srt

scripts/bin/shift-srt.py

@@ -1,6 +1,6 @@
-#!/usr/bin/env python3
 import argparse
 from datetime import datetime, timedelta
+from pathlib import Path
 
 def parse_time(s):
     return datetime.strptime(s, "%H:%M:%S,%f")
@@ -8,27 +8,32 @@ def parse_time(s):
 def format_time(t):
     return t.strftime("%H:%M:%S,%f")[:-3]
 
-def shift_srt(input_path, output_path, offset_seconds):
+def shift_srt_in_memory(input_path: Path, offset_seconds: float, output_path: Path = None):
     offset = timedelta(seconds=offset_seconds)
 
-    with open(input_path, "r", encoding="utf-8") as infile, open(output_path, "w", encoding="utf-8") as outfile:
-        for line in infile:
-            if "-->" in line:
-                start, end = line.strip().split(" --> ")
-                new_start = format_time(parse_time(start) + offset)
-                new_end = format_time(parse_time(end) + offset)
-                outfile.write(f"{new_start} --> {new_end}\n")
-            else:
-                outfile.write(line)
+    lines = input_path.read_text(encoding="utf-8").splitlines(keepends=True)
+
+    shifted_lines = []
+    for line in lines:
+        if "-->" in line:
+            start, end = line.strip().split(" --> ")
+            new_start = format_time(parse_time(start) + offset)
+            new_end = format_time(parse_time(end) + offset)
+            shifted_lines.append(f"{new_start} --> {new_end}\n")
+        else:
+            shifted_lines.append(line)
+
+    target_path = output_path if output_path else input_path
+    target_path.write_text("".join(shifted_lines), encoding="utf-8")
 
 def main():
     parser = argparse.ArgumentParser(description="Shift subtitle timings in an SRT file.")
-    parser.add_argument("input", help="Path to the input .srt file")
-    parser.add_argument("output", help="Path to the output .srt file")
+    parser.add_argument("input", type=Path, help="Path to the input .srt file")
     parser.add_argument("offset", type=float, help="Time offset in seconds (e.g., 2.5 or -1.25)")
+    parser.add_argument("-o", "--output", type=Path, help="Optional output file. If not provided, input file is overwritten.")
 
     args = parser.parse_args()
-    shift_srt(args.input, args.output, args.offset)
+    shift_srt_in_memory(args.input, args.offset, args.output)
 
 if __name__ == "__main__":
     main()