Convert WebVTT (The Web Video Text Tracks Format, aka html5 video subtitles) into (SubRip file).srt file.，vice versa.【WIP】

遵循了(SubRip file).srt标准转换 只是为了好玩~

dart vtt2srt.dart -D "path"

"path"(cuz whitespace problem, preferably double quotes) not provided，srt files are generated in the original directory. path 使用双引号，然后转换该目录及其子文件夹下所有vtt文件。默认转换当前目录下文件。

support FrontendMasters/fm-transcripts .web_vtt files bug fixed，ie：

>> // ==>  >>

• [] ASS

smplayer's convert

https://github.com/asticode/go-astisub

https://github.com/jamiees2/ass-to-vtt