jpegdna.codecs package¶

jpegdna.codecs.jpeg_dna module¶

Encoding and decoding main functions for JPEG-DNA

class jpegdna.codecs.jpeg_dna.JpegDNA(alpha, sampler='4:2:2', verbosity=False, verbose=0)[source]¶

Bases: object

General codec for JpegDNA

decode(code)[source]¶

Decoding function that will adapt in function of the format info

Parameters: code (list[str]) – Input oligos to deformat and decode
Returns: Decoded image
Return type: np.array

encode(inp, *args)[source]¶

Encoding function that will adapt infuncion of the input shape

Parameters: inp (np.array) – Input image to encode
Returns: Encoded oligos
Return type: list[str]

jpegdna.codecs.jpeg_dna_gray module¶

Encoding and decoding main functions for JPEG-DNA

class jpegdna.codecs.jpeg_dna_gray.JPEGDNAGray(alpha, formatting=False, channel_type='luma', verbose=False, verbosity=0)[source]¶

Bases: jpegdna.coders.AbstractCoder

JPEG-DNA codec for gray-level images

Parameters

aplha – Alpha value (quantization step multiplier)
formatting (bool) – Formatting enabler
channel_type (str) – Channel type choice (‘luma’ or ‘chroma’)
verbose – bool
verbosity – int

Variables

verbose – Verbosity enabler
verbosity – Verbosity level
alpha (float) – alpha value (compression rate?)
lut (list) – hexa codes for the categories
dct (jpegdna.transforms.dctransform.DCT) – dct transform
zigzag (jpegdna.transforms.zigzag.ZigZag) – Zigzag transform
dc_coeff_coder (jpegdna.coders.coefficientcoder.DCCoefficientCoder) – DC coefficient coder
ac_coeff_coder (jpegdna.coders.coefficientcoder.ACCoefficientCoder) – AC coefficient coder

GAMMAS = array([[ 16, 11, 10, 16, 24, 40, 51, 61], [ 12, 12, 14, 19, 26, 58, 60, 55], [ 14, 13, 16, 24, 40, 57, 69, 56], [ 14, 17, 22, 29, 51, 87, 80, 62], [ 18, 22, 37, 56, 68, 109, 103, 77], [ 24, 35, 55, 64, 81, 104, 113, 92], [ 49, 64, 78, 87, 103, 121, 120, 101], [ 72, 92, 95, 98, 112, 100, 103, 99]])[source]¶

GAMMAS_CHROMA = array([[17, 18, 24, 47, 99, 99, 99, 99], [18, 21, 26, 66, 99, 99, 99, 99], [24, 26, 59, 99, 99, 99, 99, 99], [47, 66, 99, 99, 99, 99, 99, 99], [99, 99, 99, 99, 99, 99, 99, 99], [99, 99, 99, 99, 99, 99, 99, 99], [99, 99, 99, 99, 99, 99, 99, 99], [99, 99, 99, 99, 99, 99, 99, 99]])[source]¶

compute_min_dynamic(img, channel_type='luma')[source]¶

Compute the minimum possible alpha value for a given image

Parameters: img (np.array) – input image
Returns: minimum possible alpha value
Return type: float

decode(code)[source]¶

JPEG-DNA decoder: decodes the input DNA-like bitstream into an block image of size self.n x self.m

Parameters: code (str) – DNA-like bitstream
Returns: block image
Return type: np.array

encode(inp)[source]¶

JPEG-DNA encoder: encodes the image into a DNA-like bitstream

Parameters: inp (np.array) – input image
Returns: DNA-like bitstream
Return type: str

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

full_encode(inp, *args)[source]¶

Encoding method

Parameters

inp (list|str) – Input to encode
args (any) – Encoding arguments

Returns

Encoded message, encoding state

Return type

list|str, any

get_alpha()[source]¶

Getter for alpha value

Returns: alpha value
Return type: float

get_state(case=None)[source]¶: Get codec state after encoding

set_alpha(alpha)[source]¶

Setter for alpha value

Parameters: alpha (float) – alpha value

set_channel_type(channel_type)[source]¶

Setter for the channel type

Parameters: channel_type (str) – Choice between ‘luma’ and ‘chroma’

set_frequencies_default()[source]¶: Sets the frequencies to the package’s default frequency tables

set_frequencies_from_array(freq_dc, freq_ac)[source]¶

Sets the frequencies used using a pre-existing frequency tables

Parameters

freq_dc (array) – DC coefficients frequencies table
freq_ac – AC coefficients frequencies table

set_frequencies_from_img(inp)[source]¶

Computes the frenquencies in function of the image DCT quantized coefficients

Parameters: inp (np.array) – input image

set_state(*args, case=None)[source]¶

Sets the state of the codec

Parameters

freq_dc (list(float)) – List of appearance frequences for each element of the alphabet in the dc values
freq_ac (list(float)) – List of appearance frequences for each element of the alphabet in the ac values
m (int) – length of an image block
n (int) – height of an image block

jpegdna.codecs.jpeg_dna_rgb module¶

Encoding and decoding main functions for JPEG-DNA in RGB

class jpegdna.codecs.jpeg_dna_rgb.JPEGDNARGB(alpha, formatting=False, verbose=False, verbosity=0, channel_sampler='4:2:2')[source]¶

Bases: jpegdna.codecs.jpeg_dna_gray.JPEGDNAGray

JPEG-DNA codec for RGB images

Parameters

aplha – Alpha value (quantization step multiplier)
formatting (bool) – Formatting enabler
channel_sampler (str) – Sampler name used to subsample chrominance channels
verbose – bool
verbosity – int

Variables

verbose – Verbosity enabler
verbosity – Verbosity level
alpha (float) – alpha value (compression rate?)
lut (list) – hexa codes for the categories
dct (jpegdna.transforms.dctransform.DCT) – dct transform
zigzag (jpegdna.transforms.zigzag.ZigZag) – Zigzag transform

compute_min_dynamic(img, channel_type=None)[source]¶

Compute the minimum possible alpha value for a given image

Parameters: img (np.array) – input image
Returns: minimum possible alpha value
Return type: float

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

full_encode(inp, *args)[source]¶

Encoding method

Parameters

inp (list|str) – Input to encode
args (any) – Encoding arguments

Returns

Encoded message, encoding state

Return type

list|str, any

get_default_frequencies_rgb(channel)[source]¶: Gets the frequencies to the package’s default frequency tables

set_alpha(alpha)[source]¶

Setter for alpha value

Parameters: alpha (float) – alpha value

set_frequencies_default_rgb(channel)[source]¶: Sets the frequencies to the package’s default frequency tables