sampsyo/beets — pull request #713 by yevgenybezman (2014-04-20 05:11:56+00:00)
Title: Add support for ffmpeg backend to replaygain plugin

FFmpeg is able to calculate EBU R128 loudness through its command line interface.
Things that need to be done:
- [ ] Implement single-file support through the command line interface.
- [ ] Implement "album gain" by running the filter on the concatenated album.
- [ ] Do both steps with a single invocation.
- [ ] Document