From 31a50a09a8d9b80f5380a6da6c1fb4f503da7c32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Kucharczyk?= <lukas@kucharczyk.xyz>
Date: Thu, 4 Dec 2025 15:26:28 +0100
Subject: [PATCH] transcode.py: make it possible to skip AV1

---
 transcode.py | 53 +++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 48 insertions(+), 5 deletions(-)

diff --git a/transcode.py b/transcode.py
index da33dc3..5b455a5 100644
--- a/transcode.py
+++ b/transcode.py
@@ -53,6 +53,33 @@ def setup_logging():
 
     logging.info(f"Logging started. Verbose logs at: {log_file}")
 
+def get_video_codec(input_path):
+    """
+    Uses ffprobe to determine the codec of the first video stream.
+    Returns the codec name (e.g., 'av1', 'h264', 'hevc') or None if detection fails.
+    """
+    cmd = [
+        "ffprobe",
+        "-v", "error",
+        "-select_streams", "v:0",
+        "-show_entries", "stream=codec_name",
+        "-of", "default=noprint_wrappers=1:nokey=1",
+        str(input_path)
+    ]
+    try:
+        # We don't log this subprocess call to avoid spamming debug logs, 
+        # unless it fails.
+        result = subprocess.run(cmd, capture_output=True, text=True, check=True)
+        codec = result.stdout.strip()
+        logging.debug(f"Detected codec for {input_path.name}: {codec}")
+        return codec
+    except subprocess.CalledProcessError as e:
+        logging.warning(f"Failed to probe codec for {input_path.name}: {e}")
+        return None
+    except FileNotFoundError:
+        logging.error("ffprobe not found. Please ensure ffmpeg/ffprobe is installed.")
+        return None
+
 def get_ffmpeg_command(input_path, output_path):
     """
     Constructs the FFmpeg command based on the Handbrake preset requirements.
@@ -77,7 +104,7 @@ def get_ffmpeg_command(input_path, output_path):
     ]
     return cmd
 
-def transcode_file(input_file, output_file):
+def transcode_file(input_file, output_file, skip_av1=True):
     input_path = Path(input_file)
     output_path = Path(output_file)
 
@@ -106,6 +133,13 @@ def transcode_file(input_file, output_file):
         logging.warning(f"File vanished during checks: {input_path.name}")
         return
 
+    # 3. Check Codec (Optional Skip)
+    if skip_av1:
+        codec = get_video_codec(input_path)
+        if codec == 'av1':
+            logging.info(f"SKIP: Input file is already AV1: {input_path.name}")
+            return
+
     # Prepare individual FFmpeg log file
     ffmpeg_logs_dir = get_config_dir() / "ffmpeg_logs"
     ffmpeg_logs_dir.mkdir(parents=True, exist_ok=True)
@@ -140,8 +174,9 @@ def transcode_file(input_file, output_file):
         sys.exit(0)
 
 class NewFileHandler(FileSystemEventHandler):
-    def __init__(self, output_dir):
+    def __init__(self, output_dir, skip_av1=True):
         self.output_dir = Path(output_dir)
+        self.skip_av1 = skip_av1
 
     def on_created(self, event):
         if event.is_directory:
@@ -166,7 +201,7 @@ class NewFileHandler(FileSystemEventHandler):
         new_filename = input_path.stem + ".mp4"
         output_path = self.output_dir / new_filename
 
-        transcode_file(input_path, output_path)
+        transcode_file(input_path, output_path, skip_av1=self.skip_av1)
 
 def main():
     setup_logging()
@@ -178,9 +213,13 @@ def main():
     group.add_argument("--watch-dir", type=str, help="Directory to monitor for new files")
 
     parser.add_argument("--output-dir", type=str, help="Output directory (Required for --watch-dir)")
+    parser.add_argument("--no-skip-av1", action="store_true", help="Force transcoding even if input is already AV1")
 
     args = parser.parse_args()
 
+    # Determine skip policy
+    skip_av1 = not args.no_skip_av1
+
     # --- Mode 1: Single File ---
     if args.input:
         input_path = Path(args.input)
@@ -195,7 +234,7 @@ def main():
         else:
             output_path = input_path.parent / (input_path.stem + "_av1.mp4")
 
-        transcode_file(input_path, output_path)
+        transcode_file(input_path, output_path, skip_av1=skip_av1)
 
     # --- Mode 2: Watch Directory ---
     elif args.watch_dir:
@@ -214,9 +253,13 @@ def main():
 
         logging.info(f"Monitoring {watch_dir}...")
         logging.info(f"Outputting to {output_dir}")
+        if skip_av1:
+            logging.info("Policy: Skipping files that are already AV1.")
+        else:
+            logging.info("Policy: Force transcoding all files (including AV1).")
         logging.info("Press Ctrl+C to stop.")
 
-        event_handler = NewFileHandler(output_dir)
+        event_handler = NewFileHandler(output_dir, skip_av1=skip_av1)
         observer = Observer()
         observer.schedule(event_handler, str(watch_dir), recursive=False)
         observer.start()