🗃 para

What?

A decoder and utility for the Flipnote Studios .ppm animation format.

Why this implementation over the original?

This implementation is

• SIGNIFICANTLY faster,
• implemented in safe Rust (a language with strict type-checking!),
• and being actively updated.

Speed

In a two-hundred-forty-four frame .ppm benchmark running the command $ para ./benchmark.ppm gif benchmark.gif on a twelve-core, twenty-four-thread Ryzen 9 processor, para took an average of 603.3459 milliseconds, while ppm-parser took an average of 50.4171397 seconds.

Running the command $ para ./benchmark.ppm 0 benchmark.png on a twelve-core, twenty-four-thread Ryzen 9 processor, para took an average of 8.9794 milliseconds, while ppm-parser took an average of 358.2232 milliseconds.

Rust versus Python isn't very fair, however, this benchmark shows the speed improvements that para brings to the table.

Things To Come

• Support for other formats (namely .kwz)
• Optimizations here and there
• Friendlier CLI
• Possible GUI

Getting up and Running

Installation

Prebuilt binaries for x86_64-based Linux systems and Windows are available in the releases. If you are using a different operating system or architecture such as macOS, you'll have to build and install the tool yourself!

$ cargo install --git https://github.com/Usugata/para --branch main

If you are building and installing yourself, you must have Rust installed!

Usage

usage:  para <in> <index option> <out>
index options:
        gif
        thumb
        dump
        integer(u16)

Examples

• $ para ./example.ppm 23 example.png will output the twenty-fourth frame of example.ppm to example.png
• $ para ./example.ppm thumb example.png will output the thumbnail of example.ppm to example.png
• $ para ./example.ppm dump example.json will output the metadata of example.ppm to example.json
• $ para ./example.ppm gif example.gif will output example.ppm to example.gif

Prebuilt Binaries

Prebuilt binaries for the latest release may or may not be found here.

Credits

• jaames for completing PPM reverse-engineering and writing the original implementation.
• bricklife, mirai-iro, harimau_tigris, and other members of the Japanese Flipnote community who started reverse-engineering the PPM format almost as soon as the app was released.
• Midmad and WDLMaster for identifying the adpcm sound codec used.
• steven and yellows8 for the PPM documentation on DSiBrew.
• PBSDS for more PPM reverse-engineering, as well as writing hatenatools

License

MIT License