El-Fish Extractor is a tool for extracting frames from .fsh, .mvy, .aqu and .isb files used by the 1994 El-Fish software. It reads the input file, extracts the frames, and saves them as images in the specified output directory.
This is based on the work of Vidar Holen: https://www.vidarholen.net/contents/elfish/
I ported the java tool to python in the hopes that after doing so, I'd understand enough of the file format to write something that can pack the frames back in to the file. This would be the holy grail for El-Fish: the ability to create new animated objects. The first new feature for El-Fish in over 30 years! However, I wasn't able to crack it. This repo is provided in the hope that somebody else can solve this.
For posterity, I included Vidar's information on the file-format at the bottom of this file.
- Python 3.x
- Pillow library
- Clone the repository:
git clone https://github.com/jifish/elfish-extractor.git
- Install the required dependencies:
pip install -r requirements.txt
To use the Elfish Extractor, run the following command:
python extract.py <input_file> <output_dir><input_file>: Path to the.fsh,.mvy,.aquor.isbfile.<output_dir>: Directory where the extracted frames will be saved.
python extract.py example.fsh output/This command will extract frames from example.fsh and save them in the output/ directory.
Each file is encoded in streams, each stream has a number of frames. All integers are little-endian.
8 bytes Unknown (magic?)
2 bytes Unknown (zero)
--(offset now 0A)--
8 bytes Fish name, zero-padded at end.
4 bytes Unknown (zero)
2 bytes Unknown (rendering progress?)
2 bytes Unknown (rendering total?)
2 bytes Unknown (Total number of animation frames + 7 ?)
4 bytes Unknown
--(offset now 20)--
4 bytes Total file length
103 bytes Unknown
--(offset now 8B)--
4 bytes Stream offset - Detailed frame
4 bytes Stream offset - Icon frame
4 bytes Stream offset - Animation frames
Each stream is a linked list of frames. Each frame has a 30 byte header:
4 bytes Frame length (from start of header)
4 bytes Frame number
4 bytes Previous entry (absolute seek), or 0 if first frame in the series
4 bytes Next entry (absolute seek), or 0 if last frame in the series
4 bytes Unknown (same as frame length)
2 bytes Unknown (movement increment?)
2 bytes X offset (?)
2 bytes Y offset (?)
2 bytes Frame width
2 bytes Frame height
Then follows frame data. Each frame is encoded in lines, each line is built up from plot sections. Each plot section has a length, position, and pixels:
2 bytes 2 bytes 'Length' bytes
[ Data length | Position | Pixel data (1 byte per) ]
If the position is positive (two's complement), this is the start of a line. If it's negative, take its absolute value and plot on the current line (the first line only have negative sections). Simply put the pixel data in the line buffer linearly at the specified position. Any part of a line that is not explicitly colored is transparent. Each pixel is encoded in a fixed palette, which can be found in extract.py