mpv-youtube-chat

Display chat replays overlayed on top of the video for past Youtube livestreams and premiers using yt-dlp

Notes

Untested on platforms other than Linux. If you are not using Linux you may need to manually set the script options live-chat-directory and/or yt-dlp-path.
Does not currenly work for streams are premiers that are currently airing as the live chat won't finish downloading until the stream/premier finishes. If you try to load the chat in one that is active it will still start downloading the live chat, so keep that in mind.
Downloading live chats can take awhile, especially for videos that have a very active chat and/or videos that are very long.

Requirements

yt-dlp is required to download the live_chat.json

Usage

Binding load-chat to a keybinding and press it in a video. If the video is being played locally it will look for video_filename_without_extension.live_chat.json and load that if it exists. Otherwise, if you're watching from a URL, it will check if the video has a subtitle with the language live_chat and if so, it will download it to the path stored in live-chat-directory (see Options) with the filename video_id.live_chat.json if it does not already exist in that path, otherwise it will just load it from disk.

Bindable actions

load-chat -> attempts to load the live chat replay as specified in Usage
unload-chat -> unloads the currently loaded live chat
chat-hidden -> toggles the visibility of the live chat, optionally takes yes or no as a parameter to set it to that value instead of toggling it
chat-anchor -> cycle the chat-anchor (see Options) option from 1 through 9, optionally takes a value to set it directly

To bind an action, use script-message (e.g. CTRL+j script-message load-chat)

Options

auto-load (default no) -> attempt to automatically load live chat when a video loads
live-chat-directory (default C:/ on Windows and XDG_DATA_HOME/youtube-live-chats on all other platforms) -> the directory to download live_chat.json files to
yt-dlp-path (default yt-dlp) -> the path to your yt-dlp executable
show-author (default yes) -> show the author's name with their message
color (default random) -> color of the author's name in the message, or the whole message if show-author is set to no, available values are random, none, or a specific hex value (without a #)
font-size (default 16) -> font size for chat messages
message-duration (default 10000) -> duration that each message is shown for in miliseconds
max-message-line-length (default 40) -> the amount of characters before a message breaks into a new line, with messages only breaking at word boundaries
message-gap (default 10) -> additional spacing between chat messages, given as a percentage of the font height
anchor (default 1) -> where chat displays on the screen in numpad notation (1 is bottom-left, 7 is top-left, 9 is top-right, etc.)

Plans

Parse live chats as they download, circumventing the need to wait for the whole thing to download before loading the chat and also allowing currently active streams and premiers to be supported
Support more chat message types. Currently regular messages and superchats (possible that some might be missed as of right now, there seems to be multiple formats for different kinds of messages and I'm not entirely sure what the difference is between these message formats are, if any) both work, I still need to add support memberships and paid stickers and possibly other kinds of messages I'm unaware of.
Better message rendering. If chat is anchored to the right, every line of every message will also be anchored to the right which looks rather unpleasant. See if I can have the chat be anchored to the right while allowing individual lines to be anchored to the left