Lines Matching refs:JPEG
4 USAGE instructions for the Independent JPEG Group's JPEG software
7 This file describes usage of the JPEG conversion programs cjpeg and djpeg,
9 the other documentation files if you wish to use the JPEG library within
18 These programs implement JPEG image encoding, decoding, and transcoding.
19 JPEG (pronounced "jay-peg") is a standardized compression method for
25 We provide two programs, cjpeg to compress an image file into JPEG format,
26 and djpeg to decompress a JPEG file back into a conventional image format.
59 JPEG files are in the defacto standard JFIF file format. There are other,
60 less widely used JPEG-based file formats, but we don't support them.
77 -grayscale Create monochrome JPEG file from color input.
81 saying -grayscale, you'll get a smaller JPEG file that
84 -rgb Create RGB JPEG file.
86 colorspace input to the default YCbCr JPEG colorspace.
90 -optimize usually makes the JPEG file a little smaller,
95 -progressive Create progressive JPEG file (see below).
104 the reconstructed image: the higher the quality setting, the larger the JPEG
124 quantization tables, which are considered optional in the JPEG standard.
126 other JPEG programs may be unable to decode the resulting file. Use -baseline
151 JPEG files generated with separate luminance and chrominance quality are
152 fully compliant with standard JPEG decoders.
158 The -progressive switch creates a "progressive JPEG" file. In this type of
159 JPEG file, the data is stored in multiple scans of increasing quality. If the
163 equivalent to a standard JPEG file of the same quality setting, and the total
168 -arithmetic Use arithmetic coding. CAUTION: arithmetic coded JPEG
170 be unable to view an arithmetic coded JPEG file at
203 -restart N Emit a JPEG restart marker every N MCU rows, or every
220 The -restart option inserts extra markers that allow a JPEG decoder to
229 often useful when converting dithered images to JPEG: a moderate smoothing
231 in a smaller JPEG file and a better-looking image. Too large a smoothing
240 actually baseline JPEG. For example, you can use
249 -sample HxV[,...] Set JPEG sampling factors for each color component.
253 The "wizard" switches are intended for experimentation with JPEG. If you
275 -grayscale Force grayscale output even if JPEG file is color.
279 -rgb Force RGB output even if JPEG file is grayscale.
290 is specified, or if the JPEG file is grayscale;
300 is specified, or if the JPEG file is grayscale;
304 default format). PGM is emitted if the JPEG file is
311 emitted if the JPEG file is grayscale or if
324 without SIMD extensions.) If the JPEG image was
338 a more lossy output image than if the JPEG image had
388 Color GIF files are not the ideal input for JPEG; JPEG is really intended for
391 colors. GIF works great on these, JPEG does not. If you want to convert a
392 GIF to JPEG, you should experiment with cjpeg's -quality and -smooth options
395 Avoid running an image through a series of JPEG compression/decompression
398 lossless format while manipulating an image, then convert to JPEG format when
403 quality settings to make very small JPEG files; the percentage improvement
405 mode is always selected when generating progressive JPEG files.)
410 JPEG is usually a bad idea anyway.)
446 jpegtran performs various useful transformations of JPEG files.
447 It can translate the coded representation from one variant of JPEG to another,
448 for example from baseline JPEG to progressive JPEG or vice versa. It can also
450 from landscape to portrait format by rotation. For EXIF files and JPEG files
466 where both the input and output files are JPEG files.
468 To specify the coded JPEG representation used in the output file,
471 -progressive Create progressive JPEG file.
473 -restart N Emit a JPEG restart marker every N MCU rows, or every
477 If you specify none of these switches, you get a plain baseline-JPEG output
525 JPEG format; the upper left corner of the selected region must fall on an iMCU
540 (ie, a standard color JPEG), resulting in a grayscale JPEG file. The
544 encoded as a color JPEG. (In such a case, the space savings from getting rid
546 a grayscale JPEG is substantially less than that for a color JPEG.)
575 The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file.
578 annotations, titles, index terms, etc to your JPEG files, and later retrieve
579 them as text. COM blocks do not interfere with the image stored in the JPEG
581 them as you like in one JPEG file.
584 blocks to a JPEG file.
586 rdjpgcom searches a JPEG file and prints the contents of any COM blocks on
590 characters in JPEG comments. These characters are normally escaped for
592 The switch "-verbose" (or just "-v") causes rdjpgcom to also display the JPEG
594 the JPEG file is read from standard input. (This may not work on some
597 wrjpgcom adds a COM block, containing text you provide, to a JPEG file.
599 can delete the old COM blocks if you wish. wrjpgcom produces a new JPEG
625 supplied, so that the source JPEG file comes from somewhere else.) You can
633 These utility programs do not depend on the IJG JPEG library. In
635 the minimum amount of code required to parse a JPEG file header correctly.