| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 1 | # WebP tools |
| 2 | |
| 3 | ## Encoding tool |
| 4 | |
| 5 | The examples/ directory contains tools for encoding (cwebp) and decoding (dwebp) |
| 6 | images. |
| 7 | |
| 8 | The easiest use should look like: |
| 9 | |
| 10 | ```shell |
| 11 | cwebp input.png -q 80 -o output.webp |
| 12 | ``` |
| 13 | |
| 14 | which will convert the input file to a WebP file using a quality factor of 80 on |
| 15 | a 0->100 scale (0 being the lowest quality, 100 being the best. Default value is |
| 16 | 75). |
| 17 | |
| 18 | You might want to try the `-lossless` flag too, which will compress the source |
| 19 | (in RGBA format) without any loss. The `-q` quality parameter will in this case |
| 20 | control the amount of processing time spent trying to make the output file as |
| 21 | small as possible. |
| 22 | |
| 23 | A longer list of options is available using the `-longhelp` command line flag: |
| 24 | |
| 25 | ```shell |
| 26 | > cwebp -longhelp |
| 27 | Usage: |
| 28 | cwebp [-preset <...>] [options] in_file [-o out_file] |
| 29 | ``` |
| 30 | |
| 31 | If input size (-s) for an image is not specified, it is assumed to be a PNG, |
| 32 | JPEG, TIFF or WebP file. Note: Animated PNG and WebP files are not supported. |
| 33 | |
| 34 | Options: |
| 35 | |
| 36 | ``` |
| 37 | -h / -help ............. short help |
| 38 | -H / -longhelp ......... long help |
| 39 | -q <float> ............. quality factor (0:small..100:big), default=75 |
| 40 | -alpha_q <int> ......... transparency-compression quality (0..100), |
| 41 | default=100 |
| 42 | -preset <string> ....... preset setting, one of: |
| 43 | default, photo, picture, |
| 44 | drawing, icon, text |
| 45 | -preset must come first, as it overwrites other parameters |
| 46 | -z <int> ............... activates lossless preset with given |
| 47 | level in [0:fast, ..., 9:slowest] |
| 48 | |
| 49 | -m <int> ............... compression method (0=fast, 6=slowest), default=4 |
| 50 | -segments <int> ........ number of segments to use (1..4), default=4 |
| 51 | -size <int> ............ target size (in bytes) |
| 52 | -psnr <float> .......... target PSNR (in dB. typically: 42) |
| 53 | |
| 54 | -s <int> <int> ......... input size (width x height) for YUV |
| 55 | -sns <int> ............. spatial noise shaping (0:off, 100:max), default=50 |
| 56 | -f <int> ............... filter strength (0=off..100), default=60 |
| 57 | -sharpness <int> ....... filter sharpness (0:most .. 7:least sharp), default=0 |
| 58 | -strong ................ use strong filter instead of simple (default) |
| 59 | -nostrong .............. use simple filter instead of strong |
| 60 | -sharp_yuv ............. use sharper (and slower) RGB->YUV conversion |
| 61 | -partition_limit <int> . limit quality to fit the 512k limit on |
| 62 | the first partition (0=no degradation ... 100=full) |
| 63 | -pass <int> ............ analysis pass number (1..10) |
| 64 | -qrange <min> <max> .... specifies the permissible quality range |
| 65 | (default: 0 100) |
| 66 | -crop <x> <y> <w> <h> .. crop picture with the given rectangle |
| James Zern | 34bb332 | 2022-03-17 17:29:02 | [diff] [blame] | 67 | -resize <w> <h> ........ resize picture (*after* any cropping) |
| James Zern | eb4f813 | 2025-04-10 20:05:30 | [diff] [blame] | 68 | -resize_mode <string> .. one of: up_only, down_only, always (default) |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 69 | -mt .................... use multi-threading if available |
| 70 | -low_memory ............ reduce memory usage (slower encoding) |
| 71 | -map <int> ............. print map of extra info |
| 72 | -print_psnr ............ prints averaged PSNR distortion |
| 73 | -print_ssim ............ prints averaged SSIM distortion |
| 74 | -print_lsim ............ prints local-similarity distortion |
| 75 | -d <file.pgm> .......... dump the compressed output (PGM file) |
| 76 | -alpha_method <int> .... transparency-compression method (0..1), default=1 |
| 77 | -alpha_filter <string> . predictive filtering for alpha plane, |
| 78 | one of: none, fast (default) or best |
| 79 | -exact ................. preserve RGB values in transparent area, default=off |
| 80 | -blend_alpha <hex> ..... blend colors against background color |
| 81 | expressed as RGB values written in |
| 82 | hexadecimal, e.g. 0xc0e0d0 for red=0xc0 |
| 83 | green=0xe0 and blue=0xd0 |
| 84 | -noalpha ............... discard any transparency information |
| 85 | -lossless .............. encode image losslessly, default=off |
| James Zern | 24bed3d | 2023-03-17 22:17:31 | [diff] [blame] | 86 | -near_lossless <int> ... use near-lossless image preprocessing |
| 87 | (0..100=off), default=100 |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 88 | -hint <string> ......... specify image characteristics hint, |
| 89 | one of: photo, picture or graph |
| 90 | |
| 91 | -metadata <string> ..... comma separated list of metadata to |
| 92 | copy from the input to the output if present. |
| 93 | Valid values: all, none (default), exif, icc, xmp |
| 94 | |
| 95 | -short ................. condense printed message |
| 96 | -quiet ................. don't print anything |
| 97 | -version ............... print version number and exit |
| 98 | -noasm ................. disable all assembly optimizations |
| 99 | -v ..................... verbose, e.g. print encoding/decoding times |
| 100 | -progress .............. report encoding progress |
| 101 | ``` |
| 102 | |
| 103 | Experimental Options: |
| 104 | |
| 105 | ``` |
| 106 | -jpeg_like ............. roughly match expected JPEG size |
| 107 | -af .................... auto-adjust filter strength |
| 108 | -pre <int> ............. pre-processing filter |
| 109 | ``` |
| 110 | |
| 111 | The main options you might want to try in order to further tune the visual |
| 112 | quality are: |
| 113 | |
| 114 | -preset -sns -f -m |
| 115 | |
| 116 | Namely: |
| 117 | |
| 118 | * `preset` will set up a default encoding configuration targeting a particular |
| 119 | type of input. It should appear first in the list of options, so that |
| 120 | subsequent options can take effect on top of this preset. Default value is |
| 121 | 'default'. |
| 122 | * `sns` will progressively turn on (when going from 0 to 100) some additional |
| 123 | visual optimizations (like: segmentation map re-enforcement). This option |
| 124 | will balance the bit allocation differently. It tries to take bits from the |
| 125 | "easy" parts of the picture and use them in the "difficult" ones instead. |
| 126 | Usually, raising the sns value (at fixed -q value) leads to larger files, |
| 127 | but with better quality. Typical value is around '75'. |
| 128 | * `f` option directly links to the filtering strength used by the codec's |
| 129 | in-loop processing. The higher the value, the smoother the highly-compressed |
| 130 | area will look. This is particularly useful when aiming at very small files. |
| 131 | Typical values are around 20-30. Note that using the option |
| 132 | -strong/-nostrong will change the type of filtering. Use "-f 0" to turn |
| 133 | filtering off. |
| 134 | * `m` controls the trade-off between encoding speed and quality. Default is 4. |
| 135 | You can try -m 5 or -m 6 to explore more (time-consuming) encoding |
| 136 | possibilities. A lower value will result in faster encoding at the expense |
| 137 | of quality. |
| 138 | |
| 139 | ## Decoding tool |
| 140 | |
| 141 | There is a decoding sample in examples/dwebp.c which will take a .webp file and |
| 142 | decode it to a PNG image file (amongst other formats). This is simply to |
| 143 | demonstrate the use of the API. You can verify the file test.webp decodes to |
| 144 | exactly the same as test_ref.ppm by using: |
| 145 | |
| 146 | ```shell |
| 147 | cd examples |
| 148 | ./dwebp test.webp -ppm -o test.ppm |
| 149 | diff test.ppm test_ref.ppm |
| 150 | ``` |
| 151 | |
| 152 | The full list of options is available using -h: |
| 153 | |
| 154 | ```shell |
| 155 | > dwebp -h |
| 156 | Usage: dwebp in_file [options] [-o out_file] |
| 157 | ``` |
| 158 | |
| 159 | Decodes the WebP image file to PNG format [Default]. Note: Animated WebP files |
| 160 | are not supported. |
| 161 | |
| 162 | Use following options to convert into alternate image formats: |
| 163 | |
| 164 | ``` |
| 165 | -pam ......... save the raw RGBA samples as a color PAM |
| 166 | -ppm ......... save the raw RGB samples as a color PPM |
| 167 | -bmp ......... save as uncompressed BMP format |
| 168 | -tiff ........ save as uncompressed TIFF format |
| 169 | -pgm ......... save the raw YUV samples as a grayscale PGM |
| 170 | file with IMC4 layout |
| 171 | -yuv ......... save the raw YUV samples in flat layout |
| 172 | ``` |
| 173 | |
| 174 | Other options are: |
| 175 | |
| 176 | ``` |
| 177 | -version ..... print version number and exit |
| 178 | -nofancy ..... don't use the fancy YUV420 upscaler |
| 179 | -nofilter .... disable in-loop filtering |
| 180 | -nodither .... disable dithering |
| 181 | -dither <d> .. dithering strength (in 0..100) |
| 182 | -alpha_dither use alpha-plane dithering if needed |
| 183 | -mt .......... use multi-threading |
| 184 | -crop <x> <y> <w> <h> ... crop output with the given rectangle |
| James Zern | 34bb332 | 2022-03-17 17:29:02 | [diff] [blame] | 185 | -resize <w> <h> ......... resize output (*after* any cropping) |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 186 | -flip ........ flip the output vertically |
| 187 | -alpha ....... only save the alpha plane |
| 188 | -incremental . use incremental decoding (useful for tests) |
| 189 | -h ........... this help message |
| 190 | -v ........... verbose (e.g. print encoding/decoding times) |
| 191 | -quiet ....... quiet mode, don't print anything |
| 192 | -noasm ....... disable all assembly optimizations |
| 193 | ``` |
| 194 | |
| 195 | ## WebP file analysis tool |
| 196 | |
| 197 | `webpinfo` can be used to print out the chunk level structure and bitstream |
| 198 | header information of WebP files. It can also check if the files are of valid |
| 199 | WebP format. |
| 200 | |
| 201 | Usage: |
| 202 | |
| 203 | ```shell |
| 204 | webpinfo [options] in_files |
| 205 | ``` |
| 206 | |
| 207 | Note: there could be multiple input files; options must come before input files. |
| 208 | |
| 209 | Options: |
| 210 | |
| 211 | ``` |
| 212 | -version ........... Print version number and exit. |
| 213 | -quiet ............. Do not show chunk parsing information. |
| 214 | -diag .............. Show parsing error diagnosis. |
| 215 | -summary ........... Show chunk stats summary. |
| 216 | -bitstream_info .... Parse bitstream header. |
| 217 | ``` |
| 218 | |
| 219 | ## Visualization tool |
| 220 | |
| 221 | There's a little self-serve visualization tool called 'vwebp' under the |
| 222 | examples/ directory. It uses OpenGL to open a simple drawing window and show a |
| 223 | decoded WebP file. It's not yet integrated in the automake build system, but you |
| 224 | can try to manually compile it using the recommendations below. |
| 225 | |
| 226 | Usage: |
| 227 | |
| 228 | ```shell |
| 229 | vwebp in_file [options] |
| 230 | ``` |
| 231 | |
| 232 | Decodes the WebP image file and visualize it using OpenGL |
| 233 | |
| 234 | Options are: |
| 235 | |
| 236 | ``` |
| 237 | -version ..... print version number and exit |
| 238 | -noicc ....... don't use the icc profile if present |
| 239 | -nofancy ..... don't use the fancy YUV420 upscaler |
| 240 | -nofilter .... disable in-loop filtering |
| 241 | -dither <int> dithering strength (0..100), default=50 |
| 242 | -noalphadither disable alpha plane dithering |
| 243 | -usebgcolor .. display background color |
| 244 | -mt .......... use multi-threading |
| 245 | -info ........ print info |
| 246 | -h ........... this help message |
| 247 | ``` |
| 248 | |
| 249 | Keyboard shortcuts: |
| 250 | |
| 251 | ``` |
| 252 | 'c' ................ toggle use of color profile |
| 253 | 'b' ................ toggle background color display |
| 254 | 'i' ................ overlay file information |
| 255 | 'd' ................ disable blending & disposal (debug) |
| 256 | 'q' / 'Q' / ESC .... quit |
| 257 | ``` |
| 258 | |
| 259 | ### Building |
| 260 | |
| 261 | Prerequisites: |
| 262 | |
| 263 | 1. OpenGL & OpenGL Utility Toolkit (GLUT) |
| 264 | |
| 265 | Linux: `sudo apt-get install freeglut3-dev mesa-common-dev` |
| 266 | |
| 267 | Mac + Xcode: These libraries should be available in the OpenGL / GLUT |
| 268 | frameworks. |
| 269 | |
| 270 | Windows: http://freeglut.sourceforge.net/index.php#download |
| 271 | |
| 272 | 2. (Optional) qcms (Quick Color Management System) |
| 273 | |
| 274 | 1. Download qcms from Mozilla / Chromium: |
| 275 | https://hg.mozilla.org/mozilla-central/file/0e7639e3bdfb/gfx/qcms |
| 276 | https://source.chromium.org/chromium/chromium/src/+/main:third_party/qcms/;drc=d4a2f8e1ed461d8fc05ed88d1ae2dc94c9773825 |
| 277 | 2. Build and archive the source files as libqcms.a / qcms.lib |
| 278 | 3. Update makefile.unix / Makefile.vc |
| 279 | 1. Define WEBP_HAVE_QCMS |
| 280 | 2. Update include / library paths to reference the qcms directory. |
| 281 | |
| 282 | Build using makefile.unix / Makefile.vc: |
| 283 | |
| 284 | ```shell |
| 285 | $ make -f makefile.unix examples/vwebp |
| 286 | > nmake /f Makefile.vc CFG=release-static \ |
| 287 | ../obj/x64/release-static/bin/vwebp.exe |
| 288 | ``` |
| 289 | |
| 290 | ## Animation creation tool |
| 291 | |
| 292 | The utility `img2webp` can turn a sequence of input images (PNG, JPEG, ...) into |
| 293 | an animated WebP file. It offers fine control over duration, encoding modes, |
| 294 | etc. |
| 295 | |
| 296 | Usage: |
| 297 | |
| 298 | ```shell |
| James Zern | 2fe27bb | 2023-03-17 22:29:08 | [diff] [blame] | 299 | img2webp [file_options] [[frame_options] frame_file]... [-o webp_file] |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 300 | ``` |
| 301 | |
| 302 | File-level options (only used at the start of compression): |
| 303 | |
| 304 | ``` |
| 305 | -min_size ............ minimize size |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 306 | -kmax <int> .......... maximum number of frame between key-frames |
| 307 | (0=only keyframes) |
| 308 | -kmin <int> .......... minimum number of frame between key-frames |
| 309 | (0=disable key-frames altogether) |
| 310 | -mixed ............... use mixed lossy/lossless automatic mode |
| jzern@google.com | 0825faa | 2023-03-16 01:50:37 | [diff] [blame] | 311 | -near_lossless <int> . use near-lossless image preprocessing |
| 312 | (0..100=off), default=100 |
| 313 | -sharp_yuv ........... use sharper (and slower) RGB->YUV conversion |
| 314 | (lossy only) |
| James Zern | 2fe27bb | 2023-03-17 22:29:08 | [diff] [blame] | 315 | -loop <int> .......... loop count (default: 0, = infinite loop) |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 316 | -v ................... verbose mode |
| 317 | -h ................... this help |
| 318 | -version ............. print version number and exit |
| 319 | ``` |
| 320 | |
| 321 | Per-frame options (only used for subsequent images input): |
| 322 | |
| 323 | ``` |
| 324 | -d <int> ............. frame duration in ms (default: 100) |
| James Zern | 1c8eba9 | 2024-09-04 01:27:45 | [diff] [blame] | 325 | -lossless ............ use lossless mode (default) |
| 326 | -lossy ............... use lossy mode |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 327 | -q <float> ........... quality |
| James Zern | fcff86c | 2024-11-26 21:01:44 | [diff] [blame] | 328 | -m <int> ............. compression method (0=fast, 6=slowest), default=4 |
| James Zern | 57883c7 | 2024-09-04 01:58:13 | [diff] [blame] | 329 | -exact, -noexact ..... preserve or alter RGB values in transparent area |
| 330 | (default: -noexact, may cause artifacts |
| 331 | with lossy animations) |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 332 | ``` |
| 333 | |
| 334 | example: `img2webp -loop 2 in0.png -lossy in1.jpg -d 80 in2.tiff -o out.webp` |
| 335 | |
| 336 | Note: if a single file name is passed as the argument, the arguments will be |
| 337 | tokenized from this file. The file name must not start with the character '-'. |
| 338 | |
| 339 | ## Animated GIF conversion |
| 340 | |
| 341 | Animated GIF files can be converted to WebP files with animation using the |
| 342 | gif2webp utility available under examples/. The files can then be viewed using |
| 343 | vwebp. |
| 344 | |
| 345 | Usage: |
| 346 | |
| 347 | ```shell |
| 348 | gif2webp [options] gif_file -o webp_file |
| 349 | ``` |
| 350 | |
| 351 | Options: |
| 352 | |
| 353 | ``` |
| 354 | -h / -help ............. this help |
| 355 | -lossy ................. encode image using lossy compression |
| 356 | -mixed ................. for each frame in the image, pick lossy |
| 357 | or lossless compression heuristically |
| James Zern | f999d94 | 2024-11-04 20:21:40 | [diff] [blame] | 358 | -near_lossless <int> ... use near-lossless image preprocessing |
| 359 | (0..100=off), default=100 |
| 360 | -sharp_yuv ............. use sharper (and slower) RGB->YUV conversion |
| 361 | (lossy only) |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 362 | -q <float> ............. quality factor (0:small..100:big) |
| James Zern | fcff86c | 2024-11-26 21:01:44 | [diff] [blame] | 363 | -m <int> ............... compression method (0=fast, 6=slowest), default=4 |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 364 | -min_size .............. minimize output size (default:off) |
| 365 | lossless compression by default; can be |
| 366 | combined with -q, -m, -lossy or -mixed |
| 367 | options |
| 368 | -kmin <int> ............ min distance between key frames |
| 369 | -kmax <int> ............ max distance between key frames |
| 370 | -f <int> ............... filter strength (0=off..100) |
| 371 | -metadata <string> ..... comma separated list of metadata to |
| 372 | copy from the input to the output if present |
| 373 | Valid values: all, none, icc, xmp (default) |
| 374 | -loop_compatibility .... use compatibility mode for Chrome |
| 375 | version prior to M62 (inclusive) |
| 376 | -mt .................... use multi-threading if available |
| 377 | |
| 378 | -version ............... print version number and exit |
| 379 | -v ..................... verbose |
| 380 | -quiet ................. don't print anything |
| 381 | ``` |
| 382 | |
| 383 | ### Building |
| 384 | |
| 385 | With the libgif development files installed, gif2webp can be built using |
| 386 | makefile.unix: |
| 387 | |
| 388 | ```shell |
| 389 | $ make -f makefile.unix examples/gif2webp |
| 390 | ``` |
| 391 | |
| 392 | or using autoconf: |
| 393 | |
| 394 | ```shell |
| 395 | $ ./configure --enable-everything |
| 396 | $ make |
| 397 | ``` |
| 398 | |
| 399 | ## Comparison of animated images |
| 400 | |
| 401 | Test utility anim_diff under examples/ can be used to compare two animated |
| 402 | images (each can be GIF or WebP). |
| 403 | |
| 404 | Usage: |
| 405 | |
| 406 | ```shell |
| 407 | anim_diff <image1> <image2> [options] |
| 408 | ``` |
| 409 | |
| 410 | Options: |
| 411 | |
| 412 | ``` |
| 413 | -dump_frames <folder> dump decoded frames in PAM format |
| 414 | -min_psnr <float> ... minimum per-frame PSNR |
| 415 | -raw_comparison ..... if this flag is not used, RGB is |
| 416 | premultiplied before comparison |
| 417 | -max_diff <int> ..... maximum allowed difference per channel |
| 418 | between corresponding pixels in subsequent |
| 419 | frames |
| 420 | -h .................. this help |
| 421 | -version ............ print version number and exit |
| 422 | ``` |
| 423 | |
| 424 | ### Building |
| 425 | |
| 426 | With the libgif development files installed, anim_diff can be built using |
| 427 | makefile.unix: |
| 428 | |
| 429 | ```shell |
| 430 | $ make -f makefile.unix examples/anim_diff |
| 431 | ``` |
| 432 | |
| 433 | or using autoconf: |
| 434 | |
| 435 | ```shell |
| 436 | $ ./configure --enable-everything |
| 437 | $ make |
| 438 | ``` |
| 439 | |
| 440 | ## WebP Mux tool |
| 441 | |
| 442 | The examples/ directory contains a tool (webpmux) for manipulating WebP files. |
| 443 | The webpmux tool can be used to create an extended format WebP file and also to |
| 444 | extract or strip relevant data from such a file. |
| 445 | |
| 446 | A list of options is available using the -help command line flag: |
| 447 | |
| 448 | ```shell |
| 449 | > webpmux -help |
| 450 | Usage: webpmux -get GET_OPTIONS INPUT -o OUTPUT |
| 451 | webpmux -set SET_OPTIONS INPUT -o OUTPUT |
| 452 | webpmux -duration DURATION_OPTIONS [-duration ...] |
| 453 | INPUT -o OUTPUT |
| 454 | webpmux -strip STRIP_OPTIONS INPUT -o OUTPUT |
| 455 | webpmux -frame FRAME_OPTIONS [-frame...] [-loop LOOP_COUNT] |
| 456 | [-bgcolor BACKGROUND_COLOR] -o OUTPUT |
| 457 | webpmux -info INPUT |
| 458 | webpmux [-h|-help] |
| 459 | webpmux -version |
| 460 | webpmux argument_file_name |
| 461 | |
| 462 | GET_OPTIONS: |
| 463 | Extract relevant data: |
| 464 | icc get ICC profile |
| 465 | exif get EXIF metadata |
| 466 | xmp get XMP metadata |
| 467 | frame n get nth frame |
| 468 | |
| 469 | SET_OPTIONS: |
| 470 | Set color profile/metadata/parameters: |
| 471 | loop LOOP_COUNT set the loop count |
| 472 | bgcolor BACKGROUND_COLOR set the animation background color |
| 473 | icc file.icc set ICC profile |
| 474 | exif file.exif set EXIF metadata |
| 475 | xmp file.xmp set XMP metadata |
| 476 | where: 'file.icc' contains the ICC profile to be set, |
| 477 | 'file.exif' contains the EXIF metadata to be set |
| 478 | 'file.xmp' contains the XMP metadata to be set |
| 479 | |
| 480 | DURATION_OPTIONS: |
| 481 | Set duration of selected frames: |
| James Zern | a30f219 | 2022-02-18 01:06:47 | [diff] [blame] | 482 | duration set duration for all frames |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 483 | duration,frame set duration of a particular frame |
| 484 | duration,start,end set duration of frames in the |
| 485 | interval [start,end]) |
| 486 | where: 'duration' is the duration in milliseconds |
| 487 | 'start' is the start frame index |
| 488 | 'end' is the inclusive end frame index |
| 489 | The special 'end' value '0' means: last frame. |
| 490 | |
| 491 | STRIP_OPTIONS: |
| 492 | Strip color profile/metadata: |
| 493 | icc strip ICC profile |
| 494 | exif strip EXIF metadata |
| 495 | xmp strip XMP metadata |
| 496 | |
| 497 | FRAME_OPTIONS(i): |
| 498 | Create animation: |
| James Zern | a30f219 | 2022-02-18 01:06:47 | [diff] [blame] | 499 | file_i +di[+xi+yi[+mi[bi]]] |
| Maryla | 54e61a3 | 2022-02-14 11:19:52 | [diff] [blame] | 500 | where: 'file_i' is the i'th animation frame (WebP format), |
| 501 | 'di' is the pause duration before next frame, |
| 502 | 'xi','yi' specify the image offset for this frame, |
| 503 | 'mi' is the dispose method for this frame (0 or 1), |
| 504 | 'bi' is the blending method for this frame (+b or -b) |
| 505 | |
| 506 | LOOP_COUNT: |
| 507 | Number of times to repeat the animation. |
| 508 | Valid range is 0 to 65535 [Default: 0 (infinite)]. |
| 509 | |
| 510 | BACKGROUND_COLOR: |
| 511 | Background color of the canvas. |
| 512 | A,R,G,B |
| 513 | where: 'A', 'R', 'G' and 'B' are integers in the range 0 to 255 specifying |
| 514 | the Alpha, Red, Green and Blue component values respectively |
| 515 | [Default: 255,255,255,255] |
| 516 | |
| 517 | INPUT & OUTPUT are in WebP format. |
| 518 | |
| 519 | Note: The nature of EXIF, XMP and ICC data is not checked and is assumed to be |
| 520 | valid. |
| 521 | |
| 522 | Note: if a single file name is passed as the argument, the arguments will be |
| 523 | tokenized from this file. The file name must not start with the character '-'. |
| 524 | ``` |