use utf8;
+{
codec => {
	jpeg => {
		name => '<abbr title="Joint Photographic Experts Group">JPEG</abbr>',
		available => 1992,
	},
	gif => {
		name => '<abbr title="Graphics Interchange Format">GIF</abbr>',
		available => 1987,
	},
	png => {
		name => '<abbr title="Portable Network Graphics">PNG</abbr>',
		available => 1996,
	},
	jp2k => {
		name => 'JPEG 2000',
		available => 2000,
	},
	webp => {
		name => 'WebP',
		available => 2010,
	},
	heic => {
		name => '<abbr title="High Efficiency Image Container (HEVC in HEIF)">HEIC</abbr>',
		available => 2015,
	},
	avif => {
		name => '<abbr title="AV1 Image File Format">AVIF</abbr>',
		available => 2019,
	},
	jxl => {
		name => 'JPEG XL',
		available => 2021,
	},
	pnm => {
		name => '<abbr title="Portable aNyMap">PNM</abbr>',
		available => 1988,
	},
},
feature => {
	default => {
		children => [qw( quality_photo quality_art speed limits features royalties overhead support )],
	},
	quality_photo => {
		name => 'compression (photo)',
		score => {
			jpeg => 3,
			pnm  => 'n',
			gif  => 1,
			png  => 1,
			jp2k => 4,
			webp => 3,
			heic => 5,
			avif => 5,
			jxl  => 5,
		},
		children => [qw( quality_photo_1 quality_photo_2 quality_photo_3 quality_photo_ll )],
	},
	quality_photo_1 => {
		parent => 'quality_photo',
		name => 'thumbnails',
		score => {
			jpeg => 2,
			pnm  => 1,
			gif  => 1,
			png  => 1,
			jp2k => 3,
			webp => 4,
			heic => 5,
			avif => 5,
			jxl  => 3,
		},
	},
	quality_photo_2 => {
		parent => 'quality_photo',
		name => 'medium fidelity',
		score => {
			jpeg => 3,
			pnm  => 1,
			gif  => 1,
			png  => 1,
			jp2k => 4,
			webp => 3,
			heic => 4,
			avif => 5,
			jxl  => 5,
		},
	},
	quality_photo_3 => {
		parent => 'quality_photo',
		name => 'high fidelity',
		score => {
			jpeg => 3,
			pnm  => 1,
			gif  => 1,
			png  => 2,
			jp2k => 4,
			webp => 2,
			heic => 3,
			avif => 4,
			jxl  => 5,
		},
	},
	quality_photo_ll => {
		parent => 'quality_photo',
		name => 'lossless',
		score => {
			jpeg => 1,
			pnm  => 1,
			gif  => 1,
			png  => 2,
			jp2k => 4,
			webp => 3,
			heic => 3,
			avif => 3,
			jxl  => 5,
		},
	},
	quality_art => {
		name => 'compression (other images)',
		score => {
			jpeg => 2,
			pnm  => 'n',
			gif  => 1,
			png  => 3,
			jp2k => 2,
			webp => 4,
			heic => 3,
			avif => 4.5,
			jxl  => 5,
		},
		children => [qw( quality_art_2 quality_art_ll quality_art_mixed )],
	},
	quality_art_2 => {
		name => 'lossy non-photographic',
		score => {
			jpeg => 2,
			pnm  => 1,
			gif  => 2,
			png  => 3,
			jp2k => 2,
			webp => 4,
			heic => 3,
			avif => 5,
			jxl  => 5,
		},
	},
	quality_art_ll => {
		name => 'lossless non-photographic',
		score => {
			jpeg => 1,
			pnm  => 1,
			gif  => 1,
			png  => 4,
			jp2k => 2,
			webp => 5,
			heic => 2,
			avif => 3,
			jxl  => 5,
		},
	},
	quality_art_mixed => {
		name => 'mixed photo/nonphoto',
		score => {
			jpeg => 2,
			pnm  => 1,
			gif  => 1,
			png  => 2,
			jp2k => 2,
			webp => 3,
			heic => 3,
			avif => 5,
			jxl  => 5,
		},
	},
	speed => {
		score => {
			jpeg => 5,
			pnm  => 5,
			gif  => 4,
			png  => 4,
			jp2k => 3,
			webp => 4,
			heic => 3,
			avif => 3,
			jxl  => 5,
		},
		children => [qw( speed_encode speed_decode speed_parallel )],
	},
	speed_encode => {
		parent => 'speed',
		name => 'single-core encode',
		score => {
			jpeg => 5,
			pnm  => 0,
			gif  => 3, # palette conversion
			png  => 3,
			jp2k => 4,
			webp => 4,
			heic => 3,
			avif => 2,
			jxl  => 5,
		},
	},
	speed_decode => {
		parent => 'speed',
		name => 'single-core decode',
		score => {
			jpeg => 5,
			pnm  => 0,
			gif  => 5,
			png  => 5,
			jp2k => 4,
			webp => 5,
			heic => 3,
			avif => 3,
			jxl  => 5,
		},
	},
	speed_parallel => {
		parent => 'speed',
		name => 'pararellizable',
		score => {
			jpeg => 2,
			pnm  => 0,
			gif  => 2,
			png  => 2,
			jp2k => 4,
			webp => 2,
			heic => 4,
			avif => 4,
			jxl  => 5,
		},
	},
	limits => {
		score => {
			jpeg => 3,
			pnm  => 3,
			gif  => 2,
			png  => 4,
			jp2k => 5,
			webp => 2,
			heic => 4,
			avif => 4.5,
			jxl  => 5,
		},
		children => [qw( max_dimensions max_bitdepth color_444 hdr max_channels  )],
	},
	max_dimensions => {
		parent => 'limits',
		name => 'maximum image dimensions',
		score => {
			jpeg => [3, '65k²'],   # 2**16
			pnm  => [5,    '∞'],
			gif  => [3, '65k²'],   # 2**16
			png  => [4,  '2G²'],   # 2**31
			jp2k => [4,  '4G²'],   # 2**32
			webp => [1, '16k²'],   # 2**14
			heic => [2,'8k×4k+', 'tilable, only 512×512 on Apple'], # 8193x4320
			avif => [3, '65k²+', 'tilable, 7680×4320 with Advanced profile'], # 2**16
			jxl  => [4,  '1G²'],   # 2**30
		},
	},
	max_bitdepth => {
		parent => 'limits',
		name => 'precision (max. bit depth)',
		score => {
			jpeg => [2,  8],
			pnm  => [2,  8, 'unofficial PFM extension for 32-bit'],
			gif  => [1,  8, '256 colour palette per frame'],
			png  => [4, 16],
			jp2k => [5, 38],
			webp => [2,  8],
			heic => [3, 10], #TODO 16?
			avif => [3, 12, '8, 10, 12 bit'],
			jxl  => [5, 32, '24-bit integer or 32-bit float'],
		},
	},
	color_444 => {
		parent => 'limits',
		name => 'chroma subsampling',
		score => {
			jpeg => ['y', undef, '4:2:0, 4:2:2, 4:4:4'],
			pnm  => [4, '✘'],
			gif  => [4, '✘'],
			png  => [4, '✘'],
			jp2k => 'y',
			webp => [1, '4:2:0'],
			heic => [1, '4:2:0'],
			avif => ['y', undef, '4:2:0, 4:2:2, 4:4:4'],
			jxl  => ['y', undef, 'for JPEG compatibility'],
		},
	},
	hdr => {
		parent => 'limits',
		name => 'wide gamut/HDR',
		score => {
			jpeg => 'n',
			pnm  => 'n',
			gif  => 'n',
			png  => 'y',
			jp2k => 'y',
			webp => 'n',
			heic => 'y',
			avif => 'y',
			jxl  => 'y',
		},
	},
	max_channels => {
		parent => 'limits',
		name => 'maximum number of channels',
		score => {
			jpeg => [3, 4, 'RGB or CMYK'],
			pnm  => [3, 3, 'RGB'],
			gif  => [3, 3, 'RGB palette'],
			png  => [3, 4, 'RGBA'],
			jp2k => [5, 2**15],
			webp => [3, 4, 'RGBA'],
			heic => [3, 3, 'RGB, separate alpha and depth'],
			avif => [3, 3, 'RGB, separate alpha and depth'],
			jxl  => [4, 4099, 'native XYB'],
		},
	},
	features => {
		score => {
			jpeg => 2,
			pnm  => [2, undef, 'great for simplicity and ASCII storage'],
			gif  => 2,
			png  => 3,
			jp2k => 4,
			webp => 2,
			heic => 4,
			avif => 4,
			jxl  => 5,
		},
		children => [qw( animation progressive alpha depthmap overlays authoring reencode compat_jpeg )],
	},
	animation => {
		parent => 'features',
		name => 'supports animation',
		score => {
			jpeg => [2, 'MJPEG'],
			pnm  => 'n',
			gif  => 'y',
			png  => [4, 'APNG', 'later backwards-compatible extension'],
			jp2k => [2, 'MJP2'],
			webp => 'y',
			heic => 'y',
			avif => 'y',
			jxl  => 'y',
		},
	},
	progressive => {
		parent => 'features',
		name => 'progressive decoding',
		score => {
			jpeg => 4,
			pnm  => 'n',
			gif  => 2,
			png  => 2,
			jp2k => 5,
			webp => 'n',
			heic => 'n',
			avif => 'n',
			jxl  => 5,
		},
	},
	alpha => {
		parent => 'features',
		name => 'alpha transparency',
		score => {
			jpeg => 'n',
			pnm  => ['n', undef, 'PAM extension'],
			gif  => [3, '1 bit'],
			png  => 'y',
			jp2k => 'y',
			webp => 'y',
			heic => 'y',
			avif => 'y',
			jxl  => 'y',
		},
	},
	depthmap => {
		parent => 'features',
		name => 'depth map',
		score => {
			jpeg => 'n',
			pnm  => 'n',
			gif  => 'n',
			png  => 'n',
			jp2k => 'n',
			webp => 'n',
			heic => 'y',
			avif => 'y',
			jxl  => 'y',
		},
	},
	overlays => {
		parent => 'features',
		name => 'overlays (layers)',
		score => {
			jpeg => 'n',
			pnm  => 'n',
			gif  => 'y',
			png  => 'n',
			jp2k => 'n',
			webp => 'n',
			heic => 'y',
			avif => 'y',
			jxl  => 'y',
		},
	},
	authoring => {
		parent => 'features',
		name => 'authoring workflow suitability',
		score => {
			jpeg => 2,
			pnm  => 2,
			gif  => 2,
			png  => 3,
			jp2k => 3,
			webp => 2,
			heic => 2,
			avif => 2,
			jxl  => 5,
		},
	},
	reencode => {
		parent => 'features',
		name => 'generation loss resilience',
		score => {
			jpeg => 4,
			pnm  => 0,
			png  => 0,
			gif  => 0,
			jp2k => 3,
			webp => 2,
			heic => 3,
			avif => 3,
			jxl  => 4,
		},
	},
	compat_jpeg => {
		parent => 'features',
		name => 'lossless JPEG recompression',
		score => {
			jpeg => 0,
			pnm  => 'n',
			gif  => 'n',
			png  => 'n',
			jp2k => 'n',
			webp => 'n',
			heic => 'n',
			avif => 'n',
			jxl  => 'y',
		},
	},
	royalties => {
		name => 'royalty-free',
		score => {
			jpeg => 5,
			pnm  => 5,
			gif  => [5, undef, 'patented before 2003'],
			png  => 5,
			jp2k => [3, undef, 'ISO specification not freely available'],
			webp => [4, undef, 'free format, low remaining risk of patent trolls'],
			heic => ['n', undef, 'heavily patented'],
			avif => [4, undef, 'free format, risk of patent trolls'],
			jxl  => [4, undef, 'free format, risk of patent trolls'],
		},
		children => [],
	},
	support => {
		score => {
			jpeg => 5,
			pnm  => [2, undef],
			gif  => 5,
			png  => 5,
			jp2k => [2, undef, 'Apple only'],
			webp => [4, undef, 'modern browsers'],
			heic => [1, undef, 'stored by latest cameras, no browser support'],
			avif => [3, undef, 'all modern browsers except Safari and Edge'],
			jxl  => [2, undef, 'upcoming in most browsers'],
		},
	},
	overhead => {
		name => 'container overhead (file size)',
		score => {
			png  => [3,  67, 'upto 70 bytes for specific RGBA'],
			jpeg => [2, 160, '159 bytes minimum for gray, 288 for specific colours'],
			gif  => [4,  35, '43 bytes for transparent'],
			webp => [4,  34, 'black or transparent lossless; 44-92 bytes lossy'],
			bpg  => [4,  31, 'lossy 29-62 bytes, lossless 37-160'],
			flif => [5,  14, 'black or transparent; 20 bytes for specific RGBA'],
			pnm  => [5,   8, 'monochrome text PBM; 12 bytes PPM; 69 bytes PAM'],
			jxl  => [5,  12, '512×256 black pixels'],
			avif => [1, 282, 'container overhead; 457 bytes with alpha'],
			jp2k => [2, 123, 'experimental results, likely not optimal'],
			heic => [1, 386],
		},
	},
},
}
