Lines Matching full:jpeg
1 USAGE instructions for the Independent JPEG Group's JPEG software
4 This file describes usage of the JPEG conversion programs cjpeg and djpeg,
6 the other documentation files if you wish to use the JPEG library within
15 These programs implement JPEG image compression and decompression. JPEG
17 and gray-scale images. JPEG is designed to handle "real-world" scenes,
19 non-realistic images are not JPEG's strong suit; on that sort of material
22 JPEG is lossy, meaning that the output image is not necessarily identical to
23 the input image. Hence you should not use JPEG if you have to have identical
32 We provide two programs, cjpeg to compress an image file into JPEG format,
33 and djpeg to decompress a JPEG file back into a conventional image format.
65 JPEG files are in the defacto standard JFIF file format. There are other,
66 less widely used JPEG-based file formats, but we don't support them.
83 -grayscale Create monochrome JPEG file from color input.
87 saying -grayscale, you'll get a smaller JPEG file that
92 -optimize usually makes the JPEG file a little smaller,
97 -progressive Create progressive JPEG file (see below).
106 the reconstructed image: the higher the quality setting, the larger the JPEG
126 quantization tables, which are considered optional in the JPEG standard.
128 other JPEG programs may be unable to decode the resulting file. Use -baseline
131 The -progressive switch creates a "progressive JPEG" file. In this type of
132 JPEG file, the data is stored in multiple scans of increasing quality. If the
136 equivalent to a standard JPEG file of the same quality setting, and the total
138 JPEG is not yet widely implemented, so many decoders will be unable to view a
139 progressive JPEG file at all.
154 -restart N Emit a JPEG restart marker every N MCU rows, or every
171 The -restart option inserts extra markers that allow a JPEG decoder to
180 often useful when converting dithered images to JPEG: a moderate smoothing
182 in a smaller JPEG file and a better-looking image. Too large a smoothing
191 actually baseline JPEG. For example, you can use
200 -sample HxV[,...] Set JPEG sampling factors for each color component.
204 The "wizard" switches are intended for experimentation with JPEG. If you
226 -grayscale Force gray-scale output even if JPEG file is color.
238 is specified, or if the JPEG file is gray-scale;
248 is specified, or if the JPEG file is gray-scale;
252 default format). PGM is emitted if the JPEG file is
259 emitted if the JPEG file is gray-scale or if
316 Color GIF files are not the ideal input for JPEG; JPEG is really intended for
319 colors. GIF works great on these, JPEG does not. If you want to convert a
320 GIF to JPEG, you should experiment with cjpeg's -quality and -smooth options
323 Avoid running an image through a series of JPEG compression/decompression
326 lossless format while manipulating an image, then convert to JPEG format when
331 quality settings to make very small JPEG files; the percentage improvement
333 mode is always selected when generating progressive JPEG files.)
337 of GIF files to JPEG is usually a bad idea anyway.)
403 jpegtran performs various useful transformations of JPEG files.
404 It can translate the coded representation from one variant of JPEG to another,
405 for example from baseline JPEG to progressive JPEG or vice versa. It can also
421 where both the input and output files are JPEG files.
423 To specify the coded JPEG representation used in the output file,
426 -progressive Create progressive JPEG file.
427 -restart N Emit a JPEG restart marker every N MCU rows, or every
431 If you specify none of these switches, you get a plain baseline-JPEG output
472 (ie, a standard color JPEG), resulting in a grayscale JPEG file. The
476 encoded as a color JPEG. (In such a case, the space savings from getting rid
478 a grayscale JPEG is substantially less than that for a color JPEG.)
505 The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file.
508 annotations, titles, index terms, etc to your JPEG files, and later retrieve
509 them as text. COM blocks do not interfere with the image stored in the JPEG
511 them as you like in one JPEG file.
514 blocks to a JPEG file.
516 rdjpgcom searches a JPEG file and prints the contents of any COM blocks on
519 The switch "-verbose" (or just "-v") causes rdjpgcom to also display the JPEG
521 the JPEG file is read from standard input. (This may not work on some
524 wrjpgcom adds a COM block, containing text you provide, to a JPEG file.
526 can delete the old COM blocks if you wish. wrjpgcom produces a new JPEG
552 supplied, so that the source JPEG file comes from somewhere else.) You can
560 These utility programs do not depend on the IJG JPEG library. In
562 the minimum amount of code required to parse a JPEG file header correctly.
