MIVF Player for Nintendo 3DS

A homebrew video player for the Nintendo 3DS. MIVF is a custom, page‑based video container with its own software codecs, a native C player that runs on the console, and a standalone encoder that turns ordinary .mp4 or .mkv files into .mivf.

It is built for the real hardware: the codecs are tuned for the ARM11, the player streams pages from the SD card with a background reader, and the whole UI (file browser, transport, settings) is drawn straight into the RGB565 framebuffers.

Status: Works on real hardware and on the Azahar emulator. Tested primarily at 400×240, 30 fps.

Features

• Custom codecs: M2Y1 (raw token YUV420) and M2Y2 (the same picture, entropy‑coded with a division‑free binary range coder, ~24% smaller and still a locked 30 fps on hardware). Also reads RAWV, M2Y0, and PC16/IA4M audio.
• File browser: Includes thumbnails, posters, synopsis, and favorites.
• Auto‑resume bookmarks: Pick up exactly where you left off.
• Playlists / auto‑advance: Automatically play the next file in the folder.
• Aspect‑ratio modes: FIT (letterbox), STRETCH (fill), NATIVE (1:1).
• A/B scene looper: Mark two points and loop the section.
• Playback speed: 0.5× to 2.0×, audio stays in sync.
• Sleep timer + clamshell pause/park: Closes cleanly and resumes on wake.
• Customization: Subtitles (.srt, multiple tracks), chapters, themes, adjustable brightness, font scale, and a persistent settings menu.
• Touch transport: Drag the timeline to scrub.

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Controls

File Browser

Button	Action
D‑Pad ↑/↓	Move selection
A	Play
Y	Toggle favorite
B / START	Exit

Playback

Button	Action
A	Play / pause
← / →	Seek −/+ (~5 s)
Touch + drag	Scrub timeline
X	Cycle playback speed (0.5×–2.0×)
B	A/B loop: set A → set B → clear
Y	Cycle subtitle track
L + D‑Pad	Audio (volume / stereo)
R + ↑/↓	Screen brightness
R + ←/→	Previous / next chapter
SELECT	Open settings
START	Stop and return to the browser

Settings menu (SELECT)

Use D‑Pad ↑/↓ to move, A / ← / → to change, and B or SELECT to close and save.

Items include: Resume bookmarks, Auto dim, Dim timeout/brightness, Force stereo, Debug overlay, Subtitle tracks, Chapters, Favorites, Theme skin, Font scale, Sleep on lid close, Screen brightness, Aspect ratio, Playback speed, Auto‑advance, and Sleep timer.

Note: Settings, bookmarks, favorites, logs, cache, and benchmark data now live under sdmc:/3ds/mivf_player_3ds/appdata/. Legacy root-level settings/bookmark/favorites files are still read for migration.

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Installing

The easiest way to install MIVF Player is to grab the latest release from the Releases Page.

1. For a HOME-menu icon: Download mivf_player_3ds.cia and install it using a title manager like FBI.
2. For the Homebrew Launcher: Download mivf_player_3ds.3dsx, place it in sdmc:/3ds/, and launch it via the Homebrew Launcher.

Put your compiled .mivf video files in sdmc:/mivf/ (the player also scans sdmc:/3ds/mivf_player_3ds/ and the SD root).

Optional sidecar files

Place these next to yourvideo.mivf:

File	Purpose
yourvideo.srt, yourvideo.1.srt	Subtitle tracks (cycle with Y)
yourvideo.chapters	Chapter marks: SECONDS Label, H:MM:SS Label, or just SECONDS
yourvideo.cover	Poster (raw RGB565, browser‑preview sized)
yourvideo.nfo	Synopsis text shown in the browser

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Encoding videos to .mivf

You can download the standalone PC encoder from the Releases Page to easily convert .mp4 files into .mivf formats without needing to install Python.

The encode_mivf tool wraps ffmpeg and the native encoder to process a single file or a whole folder.

Requirement: ffmpeg must be available on your system (either bundled next to the executable or added to your system's PATH).

Windows Example:

:: Smaller, entropy-coded M2Y2 (Recommended):
encode_mivf.exe input.mp4 output.mivf --m2y2

:: Faster, raw token M2Y1:
encode_mivf.exe input.mp4 output.mivf

::Best Balanced
encode_mivf.exe input.mp4 output.mivf --m2y2 --fps 24 --audio-rate 48000 --jobs 6 --seek-preroll 2 --keep 4 --mv-range 1 --qp 38 --lambda 34

Linux Example:

./encode_mivf input.mp4 output.mivf --m2y2

(Developers can also run the Python front-end directly via python encode_mivf.py input.mp4 output.mivf --m2y2).

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Developer Build Instructions

Building the player (.3dsx)

You need devkitPro with the 3ds-dev group (devkitARM + libctru).

# Make sure DEVKITPRO / DEVKITARM are set and the toolchain is on PATH, then:
make

This produces mivf_player_3ds.3dsx with the embedded SMDH icon/metadata. To skip the icon, run make NO_SMDH=1.

Building an installable .cia

The .cia needs two third‑party tools that are not part of devkitPro:

• makerom
• bannertool

Drop both executables into devkitPro/tools/bin (or anywhere on your PATH), then:

make cia

This builds the banner, reuses the SMDH icon, and packages everything per meta/app.rsf into mivf_player_3ds.cia.

Repository layout

• source/ - Native 3DS player (C). main.c is the app; mivf_*.c/.h are modules. mivf_rc.h is the shared M2Y2 range coder.
• tools/ - Native encoder + M2Y2 transcoder/verifier and helpers.
• meta/ - Icon, banner, banner audio, makerom RSF, asset generator.
• Makefile - Builds the .3dsx (and make cia for the installable title).
• encode_mivf.py - Python front-end for ffmpeg -> .mivf encoding.

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Acknowledgements

Built with devkitPro / devkitARM and libctru. CIA packaging uses makerom and bannertool.

License

Released under the MIT License.