Bunkai

Decompose subtitles and media into personal language study material

Bunkai (分解) literally means "analysis" or "disassembly" in Japanese. The Bunkai application dissects subtitles and corresponding media files into flash cards for sentence mining with an SRS system like Anki. It is inspired by the linked article on sentence mining and existing tools, which you might want to check out as well.

Features

One or two subtitle files: Two subtitle files can be used together to provide foreign and native language expressions on the same card.
Media files are optional: Requires only a single foreign subtitles file to generate text-only flash cards. Associated media content is optional, but highly recommended.
Multiple subtitle formats: Any format which is supported by go-astisub is also supported by this application, although some formats may work slightly better than others. If in doubt, try to use .srt subtitles.

Installation

There is no proper release process at this time, nor a guarantee of stability of any sort, as I'm the only user of the software that I am aware of. For now, you must install the application from source.

Requirements:

go command in PATH (only to build and install the application)
ffmpeg command in PATH (used at runtime)

go get github.com/ustuehler/bunkai

Usage

Bunkai is mainly used to generate flash cards from one or two subtitle files and a corresponding media file.

For example:

bunkai extract cards -m media-content.mp4 foreign.srt native.srt

The above command generates the tab-separated file foreign.tsv and a corresponding directory foreign.media/ containing the associated images and audio files. To do sentence mining, import the file foreign.tsv into a new deck and then, at least in the case of Anki, copy the media files manually into Anki's collection.media directory.

Before you can import the deck with Anki though, you must add a new Note Type which includes some or all of the fields below on the front and/or back of each card. The columns in the generated .tsv file are as follows:

#	Name	Description
1	Sound	Extracted audio as a `[sound]` tag for Anki
2	Time	Subtitle start time code as a string
3	Source	Base name of the subtitle source file
4	Image	Selected image frame as an `<img>` tag
5	ForeignCurr	Current text in foreign subtitles file
6	NativeCurr	Current text in native subtitles file
7	ForeignPrev	Previous text in foreign subtitles file
8	NativePrev	Previous text in native subtitles file
9	ForeignNext	Next text in foreign subtitles file
10	NativeNext	Next text in native subtitles file

When you review the created deck for the first time, you should go quickly through the entire deck at once. During this first pass, your goal should be to identify those cards which you can understand almost perfectly, if not for the odd piece of unknown vocabulary or grammar; all other cards which are either too hard or too easy should be deleted in this pass. Any cards which remain in the imported deck after mining should be refined and moved into your regular deck for studying the language on a daily basis.

For other uses, run bunkai --help to view the built-in documentation.

Subtitle editors

The state of affairs when it comes to open-source subtitle editors is a sad one, but here's a list of editors which may or may not work passably. If you know a good one, please let me know!

Name	Platforms	Description
Aegisub	macOS & others	Seems to have been a popular choice, but is no longer actively maintained.
Jubler	macOS & others	Works reasonably well, but fixing timing issues is still somewhat cumbersome.

Known alternatives

There are at least three alternatives to this application that I know of, by now. Oddly enough, I found substudy just after the prototype and movies2anki when I published this repository. Something is off with my search skills! :)

movies2anki: Fully-integrated add-on for Anki which has some advanced features and supports all platforms
substudy: CLI alternative to subs2srs with the ability to export into other formats as well, not just SRS decks
subs2srs: GUI software for Windows with many features, and inspiration for substudy and Bunkai

Change log

See the file CHANGELOG.md.

License

MIT

ustuehler / bunkai