Experimental decoder and utilities (image/video conversion, etc) for Flipnote Studio 3D's .kwz animation format. Frames and audio can both be decoded without any problems.

All scripts were written for Python 3.7 and require the numpy module to be installed.

Credits

• Jaames - general reverse-engineering and python implementation
• Kinnay - reverse-engineering tile compression
• Khangaroo - reverse-engineering a large chunk of the audio format
• Shutterbug - early decompression and frame diffing work
• MrNbaYoh - identifying the use of a line table
• Stary, JoshuaDoes and thejsa - debugging/optimisation help
• Sudofox - audio format help and comment sample files

Utilities

kwzImage

Converts specific kwz frames as well folder icons and Flipnote Gallery World comments (.kwc) to standard image formats such as png, gif, jpeg, etc. Requires the Pillow module to be installed.

Usage:

python kwzImage.py <input path> <frame index> <output path>

<frame index>:

• Specific frame index (e.g. 0 for the first frame)
• thumb to get the thumbnail frame
• gif to encode the whole Flipnote to an animated GIF.

<output path>:

• Can include placeholders: {name} for the input filename (without extention), {ext} for input extention, {index} for the item index and {dirname} for the input file directory.

<input path>:

• You can pass glob patterns as the input filepath to batch convert. For example, the following will extract thumbnail images from all the kwzs in a directory:

  python kwzImage.py "/flipnotes/*.kwz" thumb /flipnotes/{name}.png

kwzVideo

Experimental kwz to mp4 encoder using ffmpeg. Tries to ensure optimal compression and image quality while also upscaling the Flipntote to 480p.

Usage:

python kwzVideo.py <input.kwz> <output.mp4>

kwzAudio

Exports a Flipnote audio track and converts it to WAV.

Usage:

python kwzAudio.py <input.kwz> <track id> <output.wav>

Where <track id> is 0 for BGM, or 1 - 4 for SE1 - SE4.

kwzViewer

Crappy viewer made with pygame. It doesn't quite achieve realtime decoding for most Flipnotes, but it can be useful as a quick debug tool.

Usage:

python kwzViewer.py <input.kwz>