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README.md

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+# retrotool [![Build Status]][actions]
+
+[Build Status]: https://github.com/encounter/retrotool/actions/workflows/build.yml/badge.svg
+[actions]: https://github.com/encounter/retrotool/actions
+
+> **Warning**
+> Under active development, not guaranteed to be useful or even function.
+
+Tools for working with Retro game formats. Currently only supports *Metroid Prime Remastered*.
+
+## Commands
+
+### pak extract
+
+Extracts files from a given `.pak`.
+
+```shell
+$ retrotool pak extract [in_pak] [out_dir]
+```
+
+### pak package
+
+Re-packages a `.pak`, given an extracted directory.
+
+```shell
+$ retrotool pak package [in_dir] [out_pak]
+```
+
+### fmv0 extract
+
+Extracts the contained video from a given `FMV0` file.
+
+```shell
+$ retrotool fmv0 extract [in_fmv0] [out_mp4]
+```
+
+### fmv0 replace
+
+Replaces the video within the given `FMV0` file.
+
+```shell
+$ retrotool fmv0 replace [inout_fmv0] [in_mp4]
+```