transcode.py: initial version

2025-12-04 15:06:29 +01:00
parent d3132b0ca3
commit 2324a79d3f
1 changed files with 170 additions and 0 deletions
@@ -0,0 +1,170 @@
+# /// script
+# requires-python = ">=3.13"
+# dependencies = [
+#     "ffmpeg",
+#     "watchdog",
+# ]
+# ///
+import argparse
+import time
+import sys
+import subprocess
+import os
+from pathlib import Path
+from watchdog.observers import Observer
+from watchdog.events import FileSystemEventHandler
+
+# Supported video extensions to monitor
+VIDEO_EXTENSIONS = {'.mkv', '.mp4', '.avi', '.mov', '.wmv', '.flv', '.webm', '.m4v', '.ts'}
+
+def get_ffmpeg_command(input_path, output_path):
+    """
+    Constructs the FFmpeg command based on the Handbrake preset requirements.
+    """
+    return [
+        "ffmpeg",
+        "-n",                  # Never overwrite output files (extra safety)
+        "-i", str(input_path), # Input file
+        "-c:v", "av1_nvenc",   # Video Encoder
+        "-pix_fmt", "p010le",  # 10-bit color
+        "-preset", "p4",       # Medium preset
+        "-rc", "vbr",          # Variable Bit Rate control
+        "-cq", "35",           # Constant Quality factor
+        # Filter chain: Deinterlace -> Scale down if >1080p -> Cap FPS at 30
+        "-vf", "yadif,scale='min(1920,iw)':-2,fps=30",
+        "-c:a", "aac",         # Audio Encoder
+        "-b:a", "160k",        # Audio Bitrate
+        "-ac", "2",            # Audio Channels (Stereo)
+        "-color_range", "tv",  # Limited color range
+        "-movflags", "+faststart", # Web optimization
+        str(output_path)       # Output file
+    ]
+
+def transcode_file(input_file, output_file):
+    input_path = Path(input_file)
+    output_path = Path(output_file)
+
+    # 1. Check existence logic
+    if output_path.exists():
+        print(f"[SKIP] Output file already exists: {output_path.name}")
+        return
+
+    # 2. Check if file is ready (simple size stability check)
+    # This prevents transcoding files that are still being copied into the folder
+    print(f"[WAIT] Ensuring file is ready: {input_path.name}...")
+    try:
+        historical_size = -1
+        while True:
+            current_size = input_path.stat().st_size
+            if current_size == historical_size and current_size > 0:
+                break
+            historical_size = current_size
+            time.sleep(2) # Wait 2 seconds between checks
+    except FileNotFoundError:
+        return # File was deleted before we could process it
+
+    print(f"[START] Transcoding: {input_path.name} -> {output_path.name}")
+    
+    cmd = get_ffmpeg_command(input_path, output_path)
+    
+    try:
+        # Run FFmpeg
+        subprocess.run(cmd, check=True)
+        print(f"[DONE] Successfully created: {output_path.name}")
+    except subprocess.CalledProcessError as e:
+        print(f"[ERROR] FFmpeg failed for {input_path.name}")
+    except KeyboardInterrupt:
+        print("\n[STOP] Interrupted by user.")
+        sys.exit(0)
+
+class NewFileHandler(FileSystemEventHandler):
+    def __init__(self, output_dir):
+        self.output_dir = Path(output_dir)
+
+    def on_created(self, event):
+        if event.is_directory:
+            return
+        self.process(event.src_path)
+
+    def on_moved(self, event):
+        if event.is_directory:
+            return
+        self.process(event.dest_path)
+
+    def process(self, file_path_str):
+        input_path = Path(file_path_str)
+        
+        # Filter for video extensions
+        if input_path.suffix.lower() not in VIDEO_EXTENSIONS:
+            return
+
+        # Determine output path
+        # We rename the file to avoid conflicts if input/output dirs are same (though not recommended)
+        new_filename = input_path.stem + ".mp4"
+        output_path = self.output_dir / new_filename
+
+        transcode_file(input_path, output_path)
+
+def main():
+    parser = argparse.ArgumentParser(description="Nvidia AV1 Transcoder & Watcher")
+    
+    # Mutually exclusive group for modes
+    group = parser.add_mutually_exclusive_group(required=True)
+    group.add_argument("--input", type=str, help="Single file to transcode")
+    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)")
+
+    args = parser.parse_args()
+
+    # --- Mode 1: Single File ---
+    if args.input:
+        input_path = Path(args.input)
+        if not input_path.exists():
+            print(f"Error: Input file '{args.input}' not found.")
+            sys.exit(1)
+        
+        # If output dir provided, use it. Otherwise use source folder + _av1 suffix
+        if args.output_dir:
+            out_dir = Path(args.output_dir)
+            out_dir.mkdir(parents=True, exist_ok=True)
+            output_path = out_dir / (input_path.stem + ".mp4")
+        else:
+            output_path = input_path.parent / (input_path.stem + "_av1.mp4")
+
+        transcode_file(input_path, output_path)
+
+    # --- Mode 2: Watch Directory ---
+    elif args.watch_dir:
+        if not args.output_dir:
+            print("Error: --output-dir is required when using --watch-dir")
+            sys.exit(1)
+
+        watch_dir = Path(args.watch_dir)
+        output_dir = Path(args.output_dir)
+
+        if not watch_dir.exists():
+            print(f"Error: Watch directory '{watch_dir}' does not exist.")
+            sys.exit(1)
+        
+        # Create output dir if it doesn't exist
+        output_dir.mkdir(parents=True, exist_ok=True)
+
+        print(f"Monitoring {watch_dir}...")
+        print(f"Outputting to {output_dir}")
+        print("Press Ctrl+C to stop.")
+
+        event_handler = NewFileHandler(output_dir)
+        observer = Observer()
+        observer.schedule(event_handler, str(watch_dir), recursive=False)
+        observer.start()
+
+        try:
+            while True:
+                time.sleep(1)
+        except KeyboardInterrupt:
+            observer.stop()
+        observer.join()
+
+if __name__ == "__main__":
+    main()