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  "markdown": "eac3to is a command-line tool for Windows, originally written by madshi, for working with Blu-ray (and HD DVD) content and its audio. It lists the titles on an unencrypted disc folder, demuxes the video, audio, subtitle and chapter tracks of a chosen title, and converts audio between formats: decoding DTS-HD MA, TrueHD and LPCM to FLAC or WAV, extracting the DTS core from a DTS-HD track, applying delays and gain, and fixing frame-rate (speed-up/slow-down) conversions.\n\nFor most remuxing work, [FFmpeg](/tools/utilities/ffmpeg/) and [MKVToolNix](/tools/utilities/mkvtoolnix/) are simpler and run on every platform; MKVToolNix opens Blu-ray playlists directly. eac3to is still used when you want its title listing for a disc folder or its audio handling in one step.\n\n## Get it\n\nmadshi stopped development at version 3.36. The code was handed over to the DG tools developers (DGDecNV), who publish new builds at [rationalqm.us/eac3to](https://www.rationalqm.us/eac3to/) and support it on their forum. It is a portable archive: extract it to a folder and add that folder to `PATH`. Some conversions (for example AAC or DTS encoding) depend on external encoders that are not bundled; `eac3to -test` reports which are found.\n\n## Usage\n\nThe general form is:\n\n```text\neac3to source [title)] [track: destination ...] [options]\n```\n\nList the titles of a disc folder, then the tracks of one title:\n\n```text\neac3to \"D:\\Movie\\BDMV\"\neac3to \"D:\\Movie\\BDMV\" 1)\n```\n\nA number followed by `)` selects a title (playlist); a number followed by `:` selects a track in it. Extract several tracks of title 1 in one pass:\n\n```text\neac3to \"D:\\Movie\\BDMV\" 1) 1: chapters.txt 2: video.mkv 3: audio.flac 4: subs.sup\n```\n\nThe output extension decides what happens to each track: `.flac` or `.wav` decodes audio losslessly, while a matching extension (`.dts`, `.thd`, `.ac3`) copies the stream. `-demux` extracts the main video track and all audio tracks in their original formats.\n\nOther common jobs:\n\n```text\neac3to input.dts output.dts -core          # keep only the DTS core of a DTS-HD track\neac3to input.ac3 output.ac3 +200ms         # delay audio by 200 ms\neac3to input.dts output.flac -slowdown     # 25 fps PAL audio to 23.976 fps\n```\n\n| Option                       | Effect                                                                         |\n| ---------------------------- | ------------------------------------------------------------------------------ |\n| `-core`                      | Extract the DTS core of a DTS-HD track, or the AC3 core of a TrueHD track.     |\n| `+100ms`, `-100ms`           | Delay or advance audio.                                                        |\n| `+3dB`, `-3dB`               | Change the gain.                                                               |\n| `-slowdown`, `-speedup`      | Undo PAL speed-up (25 to 23.976 fps), or apply it (23.976 to 25 fps).          |\n| `-down16`                    | Reduce decoded audio to 16-bit.                                                |\n| `-downStereo`, `-downDpl`    | Downmix to plain stereo or Dolby Pro Logic II.                                 |\n| `-keepDialnorm`              | Keep dialogue normalisation, which eac3to otherwise removes when decoding.     |\n| `-demux`                     | Extract the main video track and all audio tracks in their original formats.   |\n| `-log=file.txt`              | Write the log to a specific file.                                              |\n\nRead eac3to's output before trusting the result: it reports problems such as gaps or overlaps in the source and what it did about them.\n\n## Related pages\n\n- [Handle audio and subtitles](/guides/audio-and-subtitles/)\n- [MKVToolNix](/tools/utilities/mkvtoolnix/) and [FFmpeg](/tools/utilities/ffmpeg/)\n- [FLAC](/codecs/audio/flac/) and [Dolby audio formats](/codecs/audio/dolby/)\n"
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