jpeg2000-decoder

Decodes JPEG 2000 images in a subprocess, for safety.

IN PROGRESS

Overview

This project generates both a library and an executable. The executable decodes JPEG 2000 images. The library, "jpeg2000-decoder", runs the executable in a subprocess.

This is intended primarily for Second Life / Open Simulator content.

Executable

Usage: jpeg2000-decoder -i INFILE -o OUTFILE

Options

-i INFILE Input file, JPEG 2000. May be a URL or a file.
--input INFILE
-o OUTFILE Output file. Only .png is currently supported.
--output OUTFILE
--maxsize PIXELS Maximum dimension of output image. Image will be fetched and reduced accordingly.
--llsd Enables LLSD mode. The subprocess accepts commands and returns images, using Linden Lab Serial Data marshalling.
--user-agent USERAGENT HTTP user agent to use when making requests.
-v Verbose
--verbose

LLSD mode

The executable accepts commands on standard input, and returns results on standard output.

Request format:

let request: HashMap<String, LLSDValue> = [
    ("url".to_string(), LLSDValue::String("http://www.example.com/file.j2k".to_string())),
    ("maxsize".to_string(), LLSDValue::Integer(999)), // maximum size of returned image, largest dimension. Used to compute discard level.
    ("discard".to_string(), LLSDValue::Integer(2)), // requested image discard level. 0 is full size, 1 halves each dimension, etc.
];

Specify either maxsize or discard, but not both. Specifying maxsize allows getting an image of a specified resolution without knowing what is available.

Reply format:

let reply: HashMap<String, LLSDValue> = [
    ("url".to_string(), LLSDValue::String("http://www.example.com/file.j2k".to_string())), // URL of request, for check
    ("err".to_string(), LLSDValue::String("Error message if any"), // if present, request failed.
    ("discard".to_string(), LLSDValue::Integer(2)), // returned image discard level. 0 is full size, 1 halves each dimension, etc.
    ("h".to_string(), LLSDValue::Integer(512)), // returned image height
    ("w".to_string(), LLSDValue::Integer(512)), // returned image width
    ("d".to_string(), LLSDValue::Integer(4),    // returned image depth (3 for RGB, 4 for RGBA)
    ("image".to_string(), LLSDValue::Binary(bytes), // returned image, raw bytes, no headers, size h * w * d
];

Neopallium / jpeg2000-decoder