YT Audio Encoding

server/youtube_utils.py

@@ -0,0 +1,52 @@
+import yt_dlp
+import os
+import time
+
+def download_audio(url, output_folder, max_length_seconds=600):
+    """
+    Downloads audio from a YouTube URL.
+    Returns the path to the downloaded file or raises an Exception.
+    Enforces max_length_seconds (default 10 mins).
+    """
+    
+    timestamp = int(time.time())
+    output_template = os.path.join(output_folder, f'yt_{timestamp}_%(id)s.%(ext)s')
+
+    ydl_opts = {
+        'format': 'bestaudio/best',
+        'outtmpl': output_template,
+        'postprocessors': [{
+            'key': 'FFmpegExtractAudio',
+            'preferredcodec': 'mp3',
+            'preferredquality': '192',
+        }],
+        'quiet': True,
+        'no_warnings': True,
+        'noplaylist': True,
+        'match_filter': yt_dlp.utils.match_filter_func("duration <= " + str(max_length_seconds))
+    }
+
+    try:
+        with yt_dlp.YoutubeDL(ydl_opts) as ydl:
+            info = ydl.extract_info(url, download=True)
+            # The file path might differ slightly because of the postprocessor (mp3 conversion)
+            # yt-dlp usually returns the final filename in 'requested_downloads' or similar, 
+            # but constructing it from info is safer if we know the template.
+            # However, extract_info returns the info dict. 
+            
+            # Since we force mp3, the file will end in .mp3
+            # We used %(id)s in template, so we can reconstruct or find it.
+            
+            # Let's find the file in the folder that matches the timestamp prefix
+            # This is safer than guessing what yt-dlp named it exactly
+            
+            valid_files = [f for f in os.listdir(output_folder) if f.startswith(f'yt_{timestamp}_') and f.endswith('.mp3')]
+            if not valid_files:
+                 raise Exception("Download failed: Audio file not found after processing.")
+            
+            return os.path.join(output_folder, valid_files[0])
+
+    except yt_dlp.utils.DownloadError as e:
+        if "video is too long" in str(e).lower() or "duration" in str(e).lower():
+             raise Exception(f"Video is too long. Maximum allowed duration is {max_length_seconds} seconds.")
+        raise Exception(f"Failed to download video: {str(e)}")