5 name => '<abbr title="Joint Photographic Experts Group">JPEG</abbr>',
9 name => '<abbr title="Graphics Interchange Format">GIF</abbr>',
13 name => '<abbr title="Portable Network Graphics">PNG</abbr>',
25 name => '<abbr title="High Efficiency Image Container (HEVC in HEIF)">HEIC</abbr>',
29 name => '<abbr title="AV1 Image File Format">AVIF</abbr>',
37 name => '<abbr title="Portable aNyMap">PNM</abbr>',
43 children => [qw( quality_photo quality_art speed limits features royalties overhead support )],
46 name => 'compression (photo)',
58 children => [qw( quality_photo_1 quality_photo_2 quality_photo_3 quality_photo_ll )],
61 parent => 'quality_photo',
76 parent => 'quality_photo',
77 name => 'medium fidelity',
91 parent => 'quality_photo',
92 name => 'high fidelity',
105 quality_photo_ll => {
106 parent => 'quality_photo',
121 name => 'compression (other images)',
133 children => [qw( quality_art_2 quality_art_ll quality_art_mixed )],
136 name => 'lossy non-photographic',
150 name => 'lossless non-photographic',
163 quality_art_mixed => {
164 name => 'mixed photo/nonphoto',
189 children => [qw( speed_encode speed_decode speed_parallel )],
193 name => 'single-core encode',
197 gif => 3, # palette conversion
208 name => 'single-core decode',
223 name => 'pararellizable',
248 children => [qw( max_dimensions max_bitdepth color_444 hdr max_channels )],
252 name => 'maximum image dimensions',
254 jpeg => [3, '65k²'], # 2**16
256 gif => [3, '65k²'], # 2**16
257 png => [4, '2G²'], # 2**31
258 jp2k => [4, '4G²'], # 2**32
259 webp => [1, '16k²'], # 2**14
260 heic => [2,'8k×4k+', 'tilable, only 512×512 on Apple'], # 8193x4320
261 avif => [3, '65k²+', 'tilable, 7680×4320 with Advanced profile'], # 2**16
262 jxl => [4, '1G²'], # 2**30
267 name => 'precision (max. bit depth)',
270 pnm => [2, 8, 'unofficial PFM extension for 32-bit'],
271 gif => [1, 8, '256 colour palette per frame'],
275 heic => [3, 10], #TODO 16?
276 avif => [3, 12, '8, 10, 12 bit'],
277 jxl => [5, 32, '24-bit integer or 32-bit float'],
282 name => 'chroma subsampling',
284 jpeg => ['y', undef, '4:2:0, 4:2:2, 4:4:4'],
289 webp => [1, '4:2:0'],
290 heic => [1, '4:2:0'],
291 avif => ['y', undef, '4:2:0, 4:2:2, 4:4:4'],
292 jxl => ['y', undef, 'for JPEG compatibility'],
297 name => 'wide gamut/HDR',
312 name => 'maximum number of channels',
314 jpeg => [3, 4, 'RGB or CMYK'],
315 pnm => [3, 3, 'RGB'],
316 gif => [3, 3, 'RGB palette'],
317 png => [3, 4, 'RGBA'],
319 webp => [3, 4, 'RGBA'],
320 heic => [3, 3, 'RGB, separate alpha and depth'],
321 avif => [3, 3, 'RGB, separate alpha and depth'],
322 jxl => [4, 4099, 'native XYB'],
328 pnm => [2, undef, 'great for simplicity and ASCII storage'],
337 children => [qw( animation progressive alpha depthmap overlays authoring reencode compat_jpeg )],
340 parent => 'features',
341 name => 'supports animation',
343 jpeg => [2, 'MJPEG'],
346 png => [4, 'APNG', 'later backwards-compatible extension'],
355 parent => 'features',
356 name => 'progressive decoding',
370 parent => 'features',
371 name => 'alpha transparency',
374 pnm => ['n', undef, 'PAM extension'],
385 parent => 'features',
400 parent => 'features',
401 name => 'overlays (layers)',
415 parent => 'features',
416 name => 'authoring workflow suitability',
430 parent => 'features',
431 name => 'generation loss resilience',
445 parent => 'features',
446 name => 'lossless JPEG recompression',
460 name => 'royalty-free',
464 gif => [5, undef, 'patented before 2003'],
466 jp2k => [3, undef, 'ISO specification not freely available'],
467 webp => [4, undef, 'free format, low remaining risk of patent trolls'],
468 heic => ['n', undef, 'heavily patented'],
469 avif => [4, undef, 'free format, risk of patent trolls'],
470 jxl => [4, undef, 'free format, risk of patent trolls'],
480 jp2k => [2, undef, 'Apple only'],
481 webp => [4, undef, 'modern browsers'],
482 heic => [1, undef, 'stored by latest cameras, no browser support'],
483 avif => [3, undef, 'all modern browsers except Safari and Edge'],
484 jxl => [2, undef, 'upcoming in most browsers'],
488 name => 'container overhead (file size)',
490 png => [3, 67, 'upto 70 bytes for specific RGBA'],
491 jpeg => [2, 160, '159 bytes minimum for gray, 288 for specific colours'],
492 gif => [4, 35, '43 bytes for transparent'],
493 webp => [4, 34, 'black or transparent lossless; 44-92 bytes lossy'],
494 bpg => [4, 31, 'lossy 29-62 bytes, lossless 37-160'],
495 flif => [5, 14, 'black or transparent; 20 bytes for specific RGBA'],
496 pnm => [5, 8, 'monochrome text PBM; 12 bytes PPM; 69 bytes PAM'],
497 jxl => [5, 12, '512×256 black pixels'],
498 avif => [1, 282, 'container overhead; 457 bytes with alpha'],
499 jp2k => [2, 123, 'experimental results, likely not optimal'],