Pnmtojpeg(0) (NAME) pnmtojpeg - PNM JPEG/JFIF (SYNOPSIS) pnmtojpeg [-exif=filespec] [-quality=n] [{-grayscale|-greyscale}] [-density=nxn[dpi,dpcm]] [-optimize|-optimise] [-rgb] [-progressive] [-comment=text] [-dct={int|fast|float}] [-arithmetic] [-restart=n] [-smooth=n] [-maxmemory=n] [-verbose] [-baseline] [-qtables=filespec] [-qslots=n[,...]] [-sample=HxV[,...]] [-scans=filespec] [-tracelevel=N] filename . . . (DESCRIPTION) Netpbm(1) . pnmtojpeg PBM PGM PPM ( ) JFIF . pnmtojpeg JPEG JPEG ( IJG) . http://www.ijg.org . <> <> . JPEG . JPEG JFIF . TIFF JPEG . EXIF JFIF ( JFIF EXIF APP1 ). -exif pnmtojpeg EXIF . (OPTIONS) libnetpbm ( -quiet ) pnmtojpeg : (Basic Options) -exif=filespec EXIF ( JFIF) EXIF JFIF APP1 . . - EXIF . EXIF . EXIF ( ) (most significant byte first) . EXIF -exif . jpegtopnm JFIF PNM pnmtojpeg JFIF EXIF . JFIF EXIF jpegtopnm EXIF . EXIF EXIF JFIF JFIF . EXIF APP1 ( ) EXIF . -quality=n . n 0 () 100 () 75 . 25 . . -grayscale -greyscale -rgb JFIF . -grayscale ( -greyscale) JFIF PPM . -rgb JFIF RGB PPM . PPM YCbCr PBM PGM (grayscale) . YCbCr ( / ) RGB ( ) . RGB JFIF PPM RGB PPM . testimg.ppm Netpbm -rgb 2.3 YCbCr pnmtojpeg 16 CPU . RGB YCbCr . . -rgb Netpbm 10.11 2002 . -density=density ( /) JFIF . (raster) JFIF . xxy dpi dpcm . : 1x1 3x2 300x300dpi 100x200dpcm . . 1 65535 . dpi dpcm . JFIF << >> ( <<>> ) . (aspect ratio) . 1x1 3x2 . JFIF PNM pnmtojpeg PNM . PNM -density=3x2 JFIF . PNM . density -PNM . 1x1 . Netpbm 10.15 ( 2003) pnmtojpeg JFIF 1x1 . -optimize . pnmtojpeg . -optimize JFIF pnmtojpeg . (decompression) -optimize . -progressive JPEG (progressive JPEG) ( ). -comment=text (comment marker) text JFIF . . -quality : JFIF . ( ) . 50 95 75 . -quality=75 5 10 ( ). -quality=100 1 ( ). . 95 . 50 . 5 10 . -quality=2 ( ) . (: 25 2 JFIF . pnmtojpeg JFIF . -baseline .) -progressive <>> . JFIF (scan) . . JFIF . : progressive JPEG JPEG . JPEG2000 . pamtojpeg2k(1) . (Advanced options) -dct=int DCT (). -dct=fast DCT ( ). -dct=float DCT (floating-point). int . . . -arithmetic (arithmetic coding). (Huffman encoding) . . . JPEG IBM AT&T Mitsubishi . FAQ ( ) . JPEG JPEG 1998 . pnmtojpeg JPEG JPEG ( pnmtojpeg ). pnmtojpeg <> <> . -restart=n JPEG (restart marker) n MCU B n MCU. -restart 0 ( ) . -smooth=n (smoothing) (dithering). n 1 100 . 0 () . -maxmemory=n . M . -max=4m 4,000,000 . pnmtojpeg . -verbose (Standard Error). . -restart pnmtojpeg JPEG . . . -restart=1 Usenet . -smooth . JFIF : 10 50 JFIF . . (Wizard Options) -baseline (baseline-compatible). 8 . ( JPEG . -baseline -progressive .) -qtables=filespec . -qslots=n[,...] . -sample=HxV[,...] JPEG . -scans=filespec . . -tracelevel=N . 0 . JPEG . <<>> (wizard) JPEG . . wizard.doc JPEG JPEG . (EXAMPLES) PPM foo.ppm 60 foo.jpg : pnmtojpeg -quality=60 foo.ppm > foo.jpg BMP JFIF : cat foo.bmp | bmptoppm | pnmtojpeg > foo.jpg JPEG (JPEG LOSS) JPEG . JPEG . Netpbm JFIF PNM JFIF . . ( ) . JPEG . PNG JPEG2000 Netpbm . JFIF -quality -smooth pnmtojpeg . -smooth 10 . JFIF . . -optimize pnmtojpeg <<>> . JFIF . ( -optimize JPEG ). () jpegtran JPEG Jpeg . jpegtran JPEG . (OTHER PROGRAMS) cjpeg . cjpeg JPEG JPEG pnmtojpeg JPEG . JPEG . pnmtojpeg cjpeg . cjpeg NetPBM pnmtojpeg NetPBM . NetPBM . pnmtojpeg cjpeg Netpbm . (SCAN SCRIPTS) -scan . -progressive . wizard.doc JPEG JPEG . pnmtojpeg cjpeg . . . JPEG pnmtojpeg . . DC AC . DC 0 AC . DC 0 0 . AC 0 . DC . <<0,2,1>> . <<0,0,0>> . AC . <> Al . Ah Al ( ) Al Ah . DC . <