transcode.py: handle Ctrl+C better

transcode.py

@@ -12,6 +12,7 @@ import json
 import logging
 import os
 import re
+import signal
 import subprocess
 import sys
 import time
@@ -200,7 +201,6 @@ def get_ffmpeg_command(input_path, output_path):
 
 
 def transcode_file(input_file, output_file=None, skip_av1=True, replace_mode=False):
-    exit_after_next = False
     input_path = Path(input_file)
 
     logging.debug(f"Processing request for: {input_path}")
@@ -285,6 +285,8 @@ def transcode_file(input_file, output_file=None, skip_av1=True, replace_mode=Fal
     cmd = get_ffmpeg_command(input_path, transcode_output_path)
     logging.debug(f"Executing FFmpeg command: {' '.join(cmd)}")
 
+    graceful_exit = False
+
     try:
         with open(ffmpeg_log_file, "w", encoding="utf-8", errors="replace") as f_log:
             # Write the command itself to the top of the log
@@ -292,12 +294,15 @@ def transcode_file(input_file, output_file=None, skip_av1=True, replace_mode=Fal
             f_log.flush()
 
             # Run FFmpeg and process output in real-time with timestamps
+            # NOTE: start_new_session=True ensures Ctrl+C doesn't kill ffmpeg immediately
+            # allowing us to handle the first press gracefully in Python.
             process = subprocess.Popen(
                 cmd,
                 stdout=subprocess.PIPE,
                 stderr=subprocess.STDOUT,
                 text=True,
                 bufsize=1,
+                start_new_session=True,
             )
 
             regex_elapsed = re.compile(r"elapsed=([0-9:.]+)")
@@ -305,6 +310,7 @@ def transcode_file(input_file, output_file=None, skip_av1=True, replace_mode=Fal
             # Write FFmpeg output with timestamps as it's generated
             try:
                 while True:
+                    try:
                         output = process.stdout.readline()  # pyright: ignore[reportOptionalMemberAccess]
                         if output == "" and process.poll() is not None:
                             break
@@ -318,11 +324,30 @@ def transcode_file(input_file, output_file=None, skip_av1=True, replace_mode=Fal
                             )
                             f_log.write(f"[{timestamp}] {output.rstrip()}\n")
                             f_log.flush()
+                    except KeyboardInterrupt:
+                        if not graceful_exit:
+                            logging.info(
+                                " > [GRACEFUL EXIT] Signal received. Finishing current file, then exiting script. Press Ctrl+C again to FORCE QUIT."
+                            )
+                            graceful_exit = True
+                            # Continue loop, process is still running because of start_new_session=True
+                            continue
+                        else:
+                            logging.warning(
+                                " >> [FORCE QUIT] Signal received again. Terminating process..."
+                            )
+                            # Explicitly terminate the process group or process
+                            process.terminate()
+                            try:
+                                process.wait(timeout=5)
+                            except subprocess.TimeoutExpired:
+                                process.kill()
+                            raise  # Re-raise to trigger outer cleanup
 
                 # Wait for process to complete and get return code
                 result = process.wait()
             except Exception as e:
-                # Ensure we clean up temporary files on error
+                # Ensure we clean up temporary files on error (e.g. if we forced kill inside loop)
                 if replace_mode and use_temp_file and transcode_output_path.exists():
                     try:
                         transcode_output_path.unlink()
@@ -410,19 +435,23 @@ def transcode_file(input_file, output_file=None, skip_av1=True, replace_mode=Fal
                 except Exception:
                     pass
 
-        if exit_after_next:
-            logging.info("Quitting early due to user interrupt.")
+        # If a graceful exit was requested, we exit now that the file is fully processed
+        if graceful_exit:
+            logging.info("Exiting script gracefully as requested.")
             sys.exit(0)
 
     except Exception as e:
         logging.exception(f"Unexpected error during transcoding of {input_path}: {e}")
     except KeyboardInterrupt:
-        logging.info(
-            "Will quit after the current file is transcoded. Press Ctrl+C again to force quit."
-        )
-        if exit_after_next:
-            sys.exit(0)
-        exit_after_next = True
+        # This catches the re-raised exception from the inner loop (2nd Ctrl+C / Force Quit)
+        logging.info("Transcoding aborted by user.")
+        # Ensure cleanup happened (redundant check but safe)
+        if replace_mode and use_temp_file and transcode_output_path.exists():
+            try:
+                transcode_output_path.unlink()
+            except Exception:
+                pass
+        sys.exit(1)
 
 
 class NewFileHandler(FileSystemEventHandler):