yt-dlp-danmaku

yt-dlp plugin for converting Bilibili danmaku into ASS format. Powered by biliass.

Installation and upgrading

Requires yt-dlp 2023.01.02 or above.

You can install or upgrade this package with pip:

pip install -U yt-dlp-danmaku

Usage

Download video along with the ASS subtitle

yt-dlp --write-subs --use-postprocessor danmaku https://www.bilibili.com/video/BV1Sm4y1N78J

Download video embedded with danmaku as a subtitle stream

Bilibili videos are originally mp4 format, but this format does not support ASS subtitle. Therefore, you need to use another format that supports it, such as mkv:

yt-dlp --embed-subs --use-postprocessor danmaku --remux-video mkv https://www.bilibili.com/video/BV1Sm4y1N78J

You can then try playing this video with players that support ASS subtitles, such as mpv and VLC.

Download video and "burn" the danmaku onto it

You need to run FFmpeg yourself to do this. Here is an example how you can do that:

yt-dlp --write-subs --use-postprocessor danmaku --output input https://www.bilibili.com/video/BV1Sm4y1N78J
ffmpeg -i input.mp4 -vf subtitles=input.danmaku.ass output.mp4
rm input.mp4 input.danmaku.ass

Get ASS subtitle without downloading the video

yt-dlp --write-subs --use-postprocessor danmaku:when=before_dl --skip-download https://www.bilibili.com/video/BV1Sm4y1N78J

Use with mpv

mpv --script-opts=ytdl_hook-ytdl_path=yt-dlp --ytdl-raw-options=use-postprocessor=danmaku:when=before_dl,write-subs=,no-simulate=,skip-download= https://www.bilibili.com/video/BV1Sm4y1N78J

You can turn on and off danmaku by using j (by default). Add --sid=1 to turn on danmaku on start. You can add these options to your mpv config file.

Notice: this will leave an ASS file in the current directory. Delete it afterwards if you do not want it.

Configuration

You can pass options to this plugin. For example, to set the opacity of danmaku texts to 0.1 and reserve the bottom half, use --use-postprocessor danmaku:text_opacity=0.1;display_region_ratio=0.5. All available options:

Run biliass -h for more information about these options.

Development

See the Plugin Development section of the yt-dlp wiki.

License

MIT.

MIT License

Copyright (c) 2022 Ulysses Zhan

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.