Fallback to re-encoding audio when ffmpeg quits with error

src/you_get/processor/ffmpeg.py

 #!/usr/bin/env python
 
 import logging
-import os.path
+import os
 import subprocess
 import sys
 from ..util.strings import parameterize
@@ -61,7 +61,23 @@ def ffmpeg_concat_av(files, output, ext):
         if os.path.isfile(file): params.extend(['-i', file])
     params.extend(['-c', 'copy'])
     params.append(output)
-    return subprocess.call(params, stdin=STDIN)
+    if subprocess.call(params, stdin=STDIN):
+        print('Merging without re-encode failed.\nTry again re-encoding audio... ', end="", flush=True)
+        try: os.remove(output)
+        except FileNotFoundError: pass
+        params = [FFMPEG] + LOGLEVEL
+        for file in files:
+            if os.path.isfile(file): params.extend(['-i', file])
+        params.extend(['-c:v', 'copy'])
+        if ext == 'mp4':
+            params.extend(['-c:a', 'aac'])
+            params.extend(['-strict', 'experimental'])
+        elif ext == 'webm':
+            params.extend(['-c:a', 'opus'])
+        params.append(output)
+        return subprocess.call(params, stdin=STDIN)
+    else:
+        return 0
 
 def ffmpeg_convert_ts_to_mkv(files, output='output.mkv'):
     for file in files: