If not explicitly set, calculated from timestamp.
uploader_id: Nickname or id of the video uploader.
uploader_url: Full URL to a personal webpage of the video uploader.
+ channel: Full name of the channel the video is uploaded on.
+ Note that channel fields may or may noy repeat uploader
+ fields. This depends on a particular extractor.
+ channel_id: Id of the channel.
+ channel_url: Full URL to a channel webpage.
location: Physical location where the video was filmed.
subtitles: The available subtitles as a dictionary in the format
{tag: subformats}. "tag" is usually a language code, and