+ extract_flat: Do not resolve URLs, return the immediate result.
+ Pass in 'in_playlist' to only show this behavior for
+ playlist items.
+ postprocessors: A list of dictionaries, each with an entry
+ * key: The name of the postprocessor. See
+ youtube_dl/postprocessor/__init__.py for a list.
+ as well as any further keyword arguments for the
+ postprocessor.
+ progress_hooks: A list of functions that get called on download
+ progress, with a dictionary with the entries
+ * status: One of "downloading", "error", or "finished".
+ Check this first and ignore unknown values.
+
+ If status is one of "downloading", or "finished", the
+ following properties may also be present:
+ * filename: The final filename (always present)
+ * tmpfilename: The filename we're currently writing to
+ * downloaded_bytes: Bytes on disk
+ * total_bytes: Size of the whole file, None if unknown
+ * total_bytes_estimate: Guess of the eventual file size,
+ None if unavailable.
+ * elapsed: The number of seconds since download started.
+ * eta: The estimated time in seconds, None if unknown
+ * speed: The download speed in bytes/second, None if
+ unknown
+ * fragment_index: The counter of the currently
+ downloaded video fragment.
+ * fragment_count: The number of fragments (= individual
+ files that will be merged)
+
+ Progress hooks are guaranteed to be called at least once
+ (with status "finished") if the download is successful.
+ merge_output_format: Extension to use when merging formats.
+ fixup: Automatically correct known faults of the file.
+ One of:
+ - "never": do nothing
+ - "warn": only emit a warning
+ - "detect_or_warn": check whether we can do anything
+ about it, warn otherwise (default)
+ source_address: (Experimental) Client-side IP address to bind to.
+ call_home: Boolean, true iff we are allowed to contact the
+ youtube-dl servers for debugging.
+ sleep_interval: Number of seconds to sleep before each download.
+ listformats: Print an overview of available video formats and exit.
+ list_thumbnails: Print a table of all thumbnails and exit.
+ match_filter: A function that gets called with the info_dict of
+ every video.
+ If it returns a message, the video is ignored.
+ If it returns None, the video is downloaded.
+ match_filter_func in utils.py is one example for this.
+ no_color: Do not emit color codes in output.
+
+ The following options determine which downloader is picked:
+ external_downloader: Executable of the external downloader to call.
+ None or unset for standard (built-in) downloader.
+ hls_prefer_native: Use the native HLS downloader instead of ffmpeg/avconv.