python/elearning.py: retry on failure

python/elearning.py

@@ -7,6 +7,7 @@
 import requests
 import subprocess
 import argparse
+import tempfile
 import pathlib
 import getpass
 import json
@@ -29,7 +30,7 @@ parser = argparse.ArgumentParser(
     Download all video lessons from an elearning course.
 
     The videos are taken at the original quality and encoded
-    using h.265 slow profile, 96kb/s opus for audio, via ffmpeg.
+    using x265 slow profile, 96kb/s opus for audio, via ffmpeg.
 
     You can run the program multiple times to keep the archive
     in sync with elearning: existing files won't be replaced or
@@ -282,23 +283,30 @@ def save_video(infos, files, args):
         printr('# skipping', end='\n\n')
         return
 
-    ffmpeg = [
+    # where to save the stream
+    tmp = pathlib.Path(tempfile.gettempdir())
+    original = (tmp / filename).with_suffix('.mkv')
+
+    base = [
         'ffmpeg', '-hide_banner',
         '-loglevel', 'error',
         '-stats'
-    ] + inputs + maps + args.ffmpeg + [
+    ]
+    download = base + inputs + maps + ['-y', original]
+
+    convert = base + args.ffmpeg + [
+        # source
+        '-i', original,
+        '-map', '0',
         # video
         '-c:v', 'libx265', '-preset', 'slow', '-crf', '23',
-                '-x265-params', 'log-level=error',
         # audio
         '-c:a', 'libopus', '-b:a', '96k',
-
         # metadata
         '-metadata', 'title='  + info['description'],
         '-metadata', 'AUTHOR=' + info['userId'],
         '-metadata', 'DATE='   + info['createdAt'],
         '-metadata', 'IDS='    + ids,
-
         # output
         (dir / filename).with_suffix('.mkv')
     ]
@@ -307,8 +315,22 @@ def save_video(infos, files, args):
     printr('# downloading "{description}" '
            '- {duration:.1f}min'.format_map(info))
     printr('# by {userId}, {views} views'.format_map(info))
-    subprocess.run(ffmpeg)
-    printr()
+
+    # retry on failure
+    for _ in range(3):
+        try:
+            print('# copying')
+            subprocess.run(download, check=True)
+            print('# converting')
+            subprocess.run(convert, check=True)
+            print()
+            break
+        except subprocess.CalledProcessError:
+            if input('Conversion failed, retry? [Y/n]') == 'n':
+                break
+
+    # remove original file
+    original.unlink(missing_ok=True)
 
 
 def get_filenames(dir):
@@ -322,8 +344,11 @@ def get_filenames(dir):
     for file in dir.glob('*.mkv'):
         ffprobe = ['ffprobe', file, '-show_format', '-of', 'json']
         output = subprocess.run(ffprobe, capture_output=True).stdout
-        metadata = json.loads(output)['format']
-        files[metadata['tags']['IDS']] = file
+        try:
+            metadata = json.loads(output)['format']
+            files[metadata['tags']['IDS']] = file
+        except KeyError:
+            pass
 
     return files