git clone https://gitlab.cristal.univ-lille.fr/elevecqu/incompatible-jpeg-blocks.git

pip install -r requirements.txt

from antecedent.image import Image
from antecedent.pipeline import create_pipeline

path = r"path/to/my/image"

img = Image('toy_image', path)
pipeline = create_pipeline('islow', 100, img.is_grayscale, target_is_dct=img.is_jpeg)  # Islow pipeline with QF100

# Example for a double compression pipeline:
# pipeline = create_pipeline(['islow', 'naive'], [90,100], img.is_grayscale, target_is_dct=img.is_jpeg) 

img.set_pipeline(pipeline)
img.set_selection_parameter('random', 10)  # 10% of the blocks randomly

img.search_antecedent(1000)

for pos, block in img.block_collection.items():
    if pipeline in block.status:
        # status is:
        # 3 if block has been ignored
        # 1 if an antecedent has been found
        # 0 otherwise (potentially incompatible)
        # -1 for incompatible
        status = block.status[pipeline]
        antecedent = block.antecedents[pipeline]
        iteration = block.iterations[pipeline]

import numpy as np
from antecedent.block import Block
from antecedent.pipeline import create_pipeline

array = np.random.randint(-1016, 1016, size=(8, 8))  # random DCT block
block = Block(array)
pipeline = create_pipeline('float', 90, grayscale=True, target_is_dct=True)  # Float pipeline with QF90 for grayscale blocks

block.search_antecedent(pipeline, 1000)
antecedent = block.antecedents[pipeline]
iteration = block.iterations[pipeline]
if antecedent is None:
    print('No antecedent found, could be incompatible.')
else:
    print(f"Compatible!\nFound an antecedent in {iteration} iterations: \n{antecedent}")

experiment_name: Experiment Name

seed: 123

data:
  input_path: "path/to/my/image/folder"
  output_path: "path/to/my/output/folder"
  starting_index: 0 # start at the first image of the folder
  ending_index: -1 # end at the last image of the folder

  preprocessing:
    avoid_clipped: True
    avoid_uniform: True
    percentage_block_per_image: 100
    sorting_method: variance

antecedent_search:
  max_workers: null # int, null to use all available CPUs
  pipeline: naive
  quant_tbl: 100

  heuristic_solver:
    use: True
    max_iteration_per_block: 1000

  gurobi_solver: # !! only possible if pipeline == naive !!
    use: False
    max_iteration_per_block: 1000
    mip_focus: 1 # 1, 2 or 3
    threads: 3 # !! total number of jobs will be threads * worker !!
    cutoff: 0.500001
    node_file_start: 0.5 # null for no RAM usage limit

python3 -m antecedent.run_on_dataset <your_config.yaml> --verbose

from antecedent.pipeline import JPEGPipeline


class YourCustomPipeline(JPEGPipeline):
    def __init__(self, quality, grayscale, target_is_dct):
        super().__init__('your_custom_name', quality, grayscale, target_is_dct)

    @classmethod
    def is_named(cls, name):
        return name == 'your_custom_name'

    # Necessary to run the code
    def dct(self, blocks):
        pass

    def idct(self, blocks):
        pass

    # Not necessary but available to custom your pipeline
    def round_dct(self, blocks):
        pass

    def round_pixel(self, blocks):
        pass

    def rgb_to_ycc(self, blocks):
        pass

    def ycc_to_rgb(self, blocks):
        pass

    def define_quant_table(self):
        # Must define self.quant_tbl
        pass

A (DCT) ---- pipe 1 ----> B (Pixel) ---- pipe 2 ----> C (DCT)

antecedent_search:
  max_workers: null # int, null to use all available CPUs
  pipeline: [naive, islow]
  quant_tbl:[75, 98]

from antecedent.pipeline import create_pipeline

grayscale = True  # depends on your image/block

pipeline = create_pipeline(['naive', 'islow'], [75, 98], grayscale=grayscale, target_is_dct=True)

@article{levecque2024finding,
  title={Finding Incompatibles Blocks for Reliable JPEG Steganalysis},
  author={Levecque, Etienne and Butora, Jan and Bas, Patrick},
  journal={arXiv preprint arXiv:2402.13660},
  year={2024}
}