Sign inDemoInstall


Package Overview
File Explorer

Install Socket

Detect and block malicious and high-risk dependencies



convert twitch/youtube chat into softsubs




  • convert twitch/youtube chat into softsubs (webm)
  • supports windows, macos, linux, freebsd
  • MIT-Licensed, 2020-10-12, ed @


  • well-tested, well-regarded software
  • check out some of the authentic user feedback below user feedback

readme TOC


windows users:

  • press Win+R and run cmd to get a terminal to run commands in (protip: rightclick to paste stuff)
  • replace python3 with python in all commands
  • see common problems if you run into issues

first-time setup

  • run these commands:

    python3 -m pip install --user softchat chat-downloader fugashi[unidic]
    python3 -m unidic download
  • download into a folder named noto-hinted in the same place you keep your VOD rips

  • if you want graphical emotes, see --emote_font in dependencies

regular usage

  • download/convert a youtube VOD automatically with (save it next to the noto-hinted folder, not inside it), then either doubleclick it or:

  • ...or do the downloads/conversion steps manually like this:

    python3 -m youtube_dl
    python3 -m chat_downloader --message_groups all -o same-filename.json
    python3 -m softchat -m2 same-filename.json

    the json filename should be whatever youtube-dl decides to use, except replace the extension with .json (and remember quotes depending on OS)

checking for updates

update to the latest version by running this:

python3 -m pip install --user -U softchat chat-downloader

this does not cover ytdl-tui; to check for ytdl-tui updates, run it and press uu

common problems

certificate errors on windows

errors like the following:
[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate

missing cookies


  • youtube-dl failing because the video is members-only
  • chat-downloader spamming a bunch of javascript then exiting

note: generally ytdl-tui should handle most of these scenarios, so you could try that first, otherwise read on

let's export your cookies and make them available to chat-downloader and youtube-dl; should dodge captchas, make it possible to donwload members-only stuff, and also fix the recent consent requirement from EU members

repeat these steps if it breaks again

if you run chat-downloader manually instead of ytdl-tui, append these arguments: -c cookies.txt



mpv is the recommended player, however in danmaku mode, you should resample the video to your monitor's FPS.

  • one way to do this: adding the argument --vf=fps=120 every time
  • another way is adding the following line to input.conf, which lets you press shift-U to toggle upscaling to 120 fps:
    U vf toggle fps=120
  • on linux/mac, input.conf should be here: ~/.config/mpv/input.conf
  • on windows, input.conf should be here: %appdata%\mpv\input.conf

additionally, on windows you may need to --vo=direct3d and not fullscreen for resampling to work -- try the different alternatives in --vo=help and find one which:

  1. doesn't ruin the contrast
  2. doesn't make the text blurry
  3. doesn't make the text jitter

The fonts produced by --emote_font need to be somewhere your media player can see them (either embedded, or in some autoload folder, or installed as system fonts). Set --emote_install to install fonts into ~/.config/mpv/fonts/ (Linux/macos) or %appdata%\mpv\fonts (windows) for local playback using mpv. For other media players, or if you intend to share the subtitles, you should use --embed_files as each font is specific to that particular subtitle file and they need to be used together.

Override automatically vectorized emotes by creating a ".manual.svg" file in the cache directory. So for the emote UCS9uQI-jC3DE0L4IpXyvr6w_Do6dXuL6LZCQ_AP4-buoDQ create the file UCS9uQI-jC3DE0L4IpXyvr6w_Do6dXuL6LZCQ_AP4-buoDQ.manual.svg. This can be used for emotes where the automatic version is of low quality.

Similarly, rather than using --emote_fill to fill the background of all emotes, you can create an empty file named to enable bg-fill for just that one emote.


  • --emote_sz 3 and higher makes things collide (wontfix probably)


  • superchats will display for 2x the time and with inverted colors

  • moderator messages are emphasized
    (larger outline, and prefixed with a ball)

  • mode 1, sidebar chat, creates a huge amount of subtitle events
    which many media players (including mpv) will struggle with

    for example, seeking will take like 5sec

    you can fix this by muxing the subtitle into the vid:
    ffmpeg -i the.webm -i the.ass -c copy muxed.mkv

  • mode 2, danmaku, will look blurry and/or jerky in most players
    unless you have the subtitles render at your native screen res

    for example in mpv you could add these arguments:
    --vo=direct3d --sub-delay=-2 --vf=fps=90

    replace 90 with your monitor's fps

  • after an upgrade, you can reconvert old rips like this:
    grep -lE '^Title: .*softchat' -- *.ass | tr '\n' '\0' | xargs -0rtl python3 -m softchat -m2 --

  • youtube VOD chatlogs are incomplete (about 80% of messages are lost)
    so softchat can now take multiple chat JSONs to splice together:
    it is recommended to run twice,
    first when the stream is live and then afterwards for the VOD chat;
    when running softchat, the VOD json should be the first file provided,
    followed by any live recordings to splice messages from

  • on windows, --kana requires python 3.8 or newer

  • on macos, --kana is currently busted in macports on sonoma


note: on windows, cmd must be reopened after installing dependencies


  • build and release: python rls



Did you know?

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.


Related posts

SocketSocket SOC 2 Logo


  • Package Alerts
  • Integrations
  • Docs
  • Pricing
  • FAQ
  • Roadmap

Stay in touch

Get open source security insights delivered straight into your inbox.

  • Terms
  • Privacy
  • Security

Made with ⚡️ by Socket Inc