diff --git a/README.md b/README.md
index c87f2e776..9d544769b 100644
--- a/README.md
+++ b/README.md
@@ -114,25 +114,25 @@ ### Differences in default behavior
 
 Some of yt-dlp's default options are different from that of youtube-dl and youtube-dlc.
 
-1. The options `--id`, `--auto-number` (`-A`), `--title` (`-t`) and `--literal` (`-l`), no longer work. See [removed options](#Removed) for details
-1. `avconv` is not supported as as an alternative to `ffmpeg`
-1. The default [output template](#output-template) is `%(title)s [%(id)s].%(ext)s`. There is no real reason for this change. This was changed before yt-dlp was ever made public and now there are no plans to change it back to `%(title)s.%(id)s.%(ext)s`. Instead, you may use `--compat-options filename`
-1. The default [format sorting](sorting-formats) is different from youtube-dl and prefers higher resolution and better codecs rather than higher bitrates. You can use the `--format-sort` option to change this to any order you prefer, or use `--compat-options format-sort` to use youtube-dl's sorting order
-1. The default format selector is `bv*+ba/b`. This means that if a combined video + audio format that is better than the best video-only format is found, the former will be prefered. Use `-f bv+ba/b` or `--compat-options format-spec` to revert this
-1. Unlike youtube-dlc, yt-dlp does not allow merging multiple audio/video streams into one file by default (since this conflicts with the use of `-f bv*+ba`). If needed, this feature must be enabled using `--audio-multistreams` and `--video-multistreams`. You can also use `--compat-options multistreams` to enable both
-1. `--ignore-errors` is enabled by default. Use `--abort-on-error` or `--compat-options abort-on-error` to abort on errors instead
-1. When writing metadata files such as thumbnails, description or infojson, the same information (if available) is also written for playlists. Use `--no-write-playlist-metafiles` or `--compat-options no-playlist-metafiles` to not write these files
-1. `--add-metadata` attaches the `infojson` to `mkv` files in addition to writing the metadata when used with `--write-infojson`. Use `--compat-options no-attach-info-json` to revert this
-1. `playlist_index` behaves differently when used with options like `--playlist-reverse` and `--playlist-items`. See [#302](https://github.com/yt-dlp/yt-dlp/issues/302) for details. You can use `--compat-options playlist-index` if you want to keep the earlier behavior
-1. The output of `-F` is listed in a new format. Use `--compat-options list-formats` to revert this
-1. Youtube live chat (if available) is considered as a subtitle. Use `--sub-langs all,-live_chat` to download all subtitles except live chat. You can also use `--compat-options no-live-chat` to prevent live chat from downloading
-1. Youtube channel URLs are automatically redirected to `/video`. Either append a `/featured` to the URL or use `--compat-options no-youtube-channel-redirect` to download only the videos in the home page
-1. Unavailable videos are also listed for youtube playlists. Use `--compat-options no-youtube-unavailable-videos` to remove this
+* The options `--id`, `--auto-number` (`-A`), `--title` (`-t`) and `--literal` (`-l`), no longer work. See [removed options](#Removed) for details
+* `avconv` is not supported as as an alternative to `ffmpeg`
+* The default [output template](#output-template) is `%(title)s [%(id)s].%(ext)s`. There is no real reason for this change. This was changed before yt-dlp was ever made public and now there are no plans to change it back to `%(title)s.%(id)s.%(ext)s`. Instead, you may use `--compat-options filename`
+* The default [format sorting](sorting-formats) is different from youtube-dl and prefers higher resolution and better codecs rather than higher bitrates. You can use the `--format-sort` option to change this to any order you prefer, or use `--compat-options format-sort` to use youtube-dl's sorting order
+* The default format selector is `bv*+ba/b`. This means that if a combined video + audio format that is better than the best video-only format is found, the former will be prefered. Use `-f bv+ba/b` or `--compat-options format-spec` to revert this
+* Unlike youtube-dlc, yt-dlp does not allow merging multiple audio/video streams into one file by default (since this conflicts with the use of `-f bv*+ba`). If needed, this feature must be enabled using `--audio-multistreams` and `--video-multistreams`. You can also use `--compat-options multistreams` to enable both
+* `--ignore-errors` is enabled by default. Use `--abort-on-error` or `--compat-options abort-on-error` to abort on errors instead
+* When writing metadata files such as thumbnails, description or infojson, the same information (if available) is also written for playlists. Use `--no-write-playlist-metafiles` or `--compat-options no-playlist-metafiles` to not write these files
+* `--add-metadata` attaches the `infojson` to `mkv` files in addition to writing the metadata when used with `--write-infojson`. Use `--compat-options no-attach-info-json` to revert this
+* `playlist_index` behaves differently when used with options like `--playlist-reverse` and `--playlist-items`. See [#302](https://github.com/yt-dlp/yt-dlp/issues/302) for details. You can use `--compat-options playlist-index` if you want to keep the earlier behavior
+* The output of `-F` is listed in a new format. Use `--compat-options list-formats` to revert this
+* Youtube live chat (if available) is considered as a subtitle. Use `--sub-langs all,-live_chat` to download all subtitles except live chat. You can also use `--compat-options no-live-chat` to prevent live chat from downloading
+* Youtube channel URLs are automatically redirected to `/video`. Either append a `/featured` to the URL or use `--compat-options no-youtube-channel-redirect` to download only the videos in the home page
+* Unavailable videos are also listed for youtube playlists. Use `--compat-options no-youtube-unavailable-videos` to remove this
 
 For ease of use, a few more compat options are available:
-1. `--compat-options all` = Use all compat options
-1. `--compat-options youtube-dl` = `--compat-options all,-multistreams`
-1. `--compat-options youtube-dlc` = `--compat-options all,-no-live-chat,-no-youtube-channel-redirect`
+* `--compat-options all`: Use all compat options
+* `--compat-options youtube-dl`: Same as `--compat-options all,-multistreams`
+* `--compat-options youtube-dlc`: Same as `--compat-options all,-no-live-chat,-no-youtube-channel-redirect`
 
 
 # INSTALLATION
@@ -1283,8 +1283,8 @@ # MODIFYING METADATA
 Note that any field created by this can be used in the [output template](#output-template) and will also affect the media file's metadata added when using `--add-metadata`.
 
 This option also has a few special uses:
-1. You can use this to change the metadata that is embedded in the media file. To do this, set the value of the corresponding field with a `meta_` prefix. For example, any value you set to `meta_description` field will be added to the `description` field in the file. You can use this to set a different "description" and "synopsis", for example
-2. You can download an additional URL based on the metadata of the currently downloaded video. To do this, set the field `additional_urls` to the URL that you want to download. Eg: `--parse-metadata "description:(?P<additional_urls>https?://www\.vimeo\.com/\d+)` will download the first vimeo video found in the description
+* You can use this to change the metadata that is embedded in the media file. To do this, set the value of the corresponding field with a `meta_` prefix. For example, any value you set to `meta_description` field will be added to the `description` field in the file. You can use this to set a different "description" and "synopsis", for example
+* You can download an additional URL based on the metadata of the currently downloaded video. To do this, set the field `additional_urls` to the URL that you want to download. Eg: `--parse-metadata "description:(?P<additional_urls>https?://www\.vimeo\.com/\d+)` will download the first vimeo video found in the description
 
 ## Modifying metadata examples
 
diff --git a/yt_dlp/YoutubeDL.py b/yt_dlp/YoutubeDL.py
index 9a2d0abc2..61c45fd8c 100644
--- a/yt_dlp/YoutubeDL.py
+++ b/yt_dlp/YoutubeDL.py
@@ -1188,7 +1188,7 @@ def process_ie_result(self, ie_result, download=True, extra_info={}):
         if result_type == 'video':
             self.add_extra_info(ie_result, extra_info)
             ie_result = self.process_video_result(ie_result, download=download)
-            additional_urls = ie_result.get('additional_urls')
+            additional_urls = (ie_result or {}).get('additional_urls')
             if additional_urls:
                 # TODO: Improve MetadataFromFieldPP to allow setting a list
                 if isinstance(additional_urls, compat_str):
diff --git a/yt_dlp/postprocessor/embedthumbnail.py b/yt_dlp/postprocessor/embedthumbnail.py
index d3fd2cafd..2d4f42a20 100644
--- a/yt_dlp/postprocessor/embedthumbnail.py
+++ b/yt_dlp/postprocessor/embedthumbnail.py
@@ -4,7 +4,6 @@
 import base64
 import imghdr
 import os
-import struct
 import subprocess
 import re