Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 1 | CHANGE LOG for Independent JPEG Group's JPEG software |
| 2 | |
| 3 | |
Guido Vollbeding | f18f81b | 2010-02-28 00:00:00 +0000 | [diff] [blame^] | 4 | Version 8a 28-Feb-2010 |
| 5 | ----------------------- |
| 6 | |
| 7 | Writing tables-only datastreams via jpeg_write_tables works again. |
| 8 | |
| 9 | Support 32-bit BMPs (RGB image with Alpha channel) for read in cjpeg. |
| 10 | Thank to Brett Blackham for the suggestion. |
| 11 | |
| 12 | Improve accuracy in floating point IDCT calculation. |
| 13 | Thank to Robert Hooke for the hint. |
| 14 | |
| 15 | |
Guido Vollbeding | 989630f | 2010-01-10 00:00:00 +0000 | [diff] [blame] | 16 | Version 8 10-Jan-2010 |
| 17 | ---------------------- |
| 18 | |
| 19 | jpegtran now supports the same -scale option as djpeg for "lossless" resize. |
| 20 | An implementation of the JPEG SmartScale extension is required for this |
| 21 | feature. A (draft) specification of the JPEG SmartScale extension is |
| 22 | available as a contributed document at ITU and ISO. Revision 2 or later |
| 23 | of the document is required (latest document version is Revision 3). |
| 24 | The SmartScale extension will enable more features beside lossless resize |
| 25 | in future implementations, as described in the document (new compression |
| 26 | options). |
| 27 | |
| 28 | Add sanity check in BMP reader module to avoid cjpeg crash for empty input |
| 29 | image (thank to Isaev Ildar of ISP RAS, Moscow, RU for reporting this error). |
| 30 | |
| 31 | Add data source and destination managers for read from and write to |
| 32 | memory buffers. New API functions jpeg_mem_src and jpeg_mem_dest. |
| 33 | Thank to Roberto Boni from Italy for the suggestion. |
| 34 | |
| 35 | |
Guido Vollbeding | 5996a25 | 2009-06-27 00:00:00 +0000 | [diff] [blame] | 36 | Version 7 27-Jun-2009 |
| 37 | ---------------------- |
| 38 | |
| 39 | New scaled DCTs implemented. |
| 40 | djpeg now supports scalings N/8 with all N from 1 to 16. |
| 41 | cjpeg now supports scalings 8/N with all N from 1 to 16. |
| 42 | Scaled DCTs with size larger than 8 are now also used for resolving the |
| 43 | common 2x2 chroma subsampling case without additional spatial resampling. |
| 44 | Separate spatial resampling for those kind of files is now only necessary |
| 45 | for N>8 scaling cases. |
| 46 | Furthermore, separate scaled DCT functions are provided for direct resolving |
| 47 | of the common asymmetric subsampling cases (2x1 and 1x2) without additional |
| 48 | spatial resampling. |
| 49 | |
| 50 | cjpeg -quality option has been extended for support of separate quality |
| 51 | settings for luminance and chrominance (or in general, for every provided |
| 52 | quantization table slot). |
| 53 | New API function jpeg_default_qtables() and q_scale_factor array in library. |
| 54 | |
| 55 | Added -nosmooth option to cjpeg, complementary to djpeg. |
| 56 | New variable "do_fancy_downsampling" in library, complement to fancy |
| 57 | upsampling. Fancy upsampling now uses direct DCT scaling with sizes |
| 58 | larger than 8. The old method is not reversible and has been removed. |
| 59 | |
| 60 | Support arithmetic entropy encoding and decoding. |
| 61 | Added files jaricom.c, jcarith.c, jdarith.c. |
| 62 | |
| 63 | Straighten the file structure: |
| 64 | Removed files jidctred.c, jcphuff.c, jchuff.h, jdphuff.c, jdhuff.h. |
| 65 | |
| 66 | jpegtran has a new "lossless" cropping feature. |
| 67 | |
| 68 | Implement -perfect option in jpegtran, new API function |
| 69 | jtransform_perfect_transform() in transupp. (DP 204_perfect.dpatch) |
| 70 | |
| 71 | Better error messages for jpegtran fopen failure. |
| 72 | (DP 203_jpegtran_errmsg.dpatch) |
| 73 | |
| 74 | Fix byte order issue with 16bit PPM/PGM files in rdppm.c/wrppm.c: |
| 75 | according to Netpbm, the de facto standard implementation of the PNM formats, |
| 76 | the most significant byte is first. (DP 203_rdppm.dpatch) |
| 77 | |
| 78 | Add -raw option to rdjpgcom not to mangle the output. |
| 79 | (DP 205_rdjpgcom_raw.dpatch) |
| 80 | |
| 81 | Make rdjpgcom locale aware. (DP 201_rdjpgcom_locale.dpatch) |
| 82 | |
| 83 | Add extern "C" to jpeglib.h. |
| 84 | This avoids the need to put extern "C" { ... } around #include "jpeglib.h" |
| 85 | in your C++ application. Defining the symbol DONT_USE_EXTERN_C in the |
| 86 | configuration prevents this. (DP 202_jpeglib.h_c++.dpatch) |
| 87 | |
| 88 | |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 89 | Version 6b 27-Mar-1998 |
| 90 | ----------------------- |
| 91 | |
| 92 | jpegtran has new features for lossless image transformations (rotation |
| 93 | and flipping) as well as "lossless" reduction to grayscale. |
| 94 | |
| 95 | jpegtran now copies comments by default; it has a -copy switch to enable |
| 96 | copying all APPn blocks as well, or to suppress comments. (Formerly it |
| 97 | always suppressed comments and APPn blocks.) jpegtran now also preserves |
| 98 | JFIF version and resolution information. |
| 99 | |
| 100 | New decompressor library feature: COM and APPn markers found in the input |
| 101 | file can be saved in memory for later use by the application. (Before, |
| 102 | you had to code this up yourself with a custom marker processor.) |
| 103 | |
| 104 | There is an unused field "void * client_data" now in compress and decompress |
| 105 | parameter structs; this may be useful in some applications. |
| 106 | |
| 107 | JFIF version number information is now saved by the decoder and accepted by |
| 108 | the encoder. jpegtran uses this to copy the source file's version number, |
| 109 | to ensure "jpegtran -copy all" won't create bogus files that contain JFXX |
| 110 | extensions but claim to be version 1.01. Applications that generate their |
| 111 | own JFXX extension markers also (finally) have a supported way to cause the |
| 112 | encoder to emit JFIF version number 1.02. |
| 113 | |
| 114 | djpeg's trace mode reports JFIF 1.02 thumbnail images as such, rather |
| 115 | than as unknown APP0 markers. |
| 116 | |
| 117 | In -verbose mode, djpeg and rdjpgcom will try to print the contents of |
| 118 | APP12 markers as text. Some digital cameras store useful text information |
| 119 | in APP12 markers. |
| 120 | |
| 121 | Handling of truncated data streams is more robust: blocks beyond the one in |
| 122 | which the error occurs will be output as uniform gray, or left unchanged |
| 123 | if decoding a progressive JPEG. The appearance no longer depends on the |
| 124 | Huffman tables being used. |
| 125 | |
| 126 | Huffman tables are checked for validity much more carefully than before. |
| 127 | |
| 128 | To avoid the Unisys LZW patent, djpeg's GIF output capability has been |
| 129 | changed to produce "uncompressed GIFs", and cjpeg's GIF input capability |
| 130 | has been removed altogether. We're not happy about it either, but there |
| 131 | seems to be no good alternative. |
| 132 | |
| 133 | The configure script now supports building libjpeg as a shared library |
| 134 | on many flavors of Unix (all the ones that GNU libtool knows how to |
| 135 | build shared libraries for). Use "./configure --enable-shared" to |
| 136 | try this out. |
| 137 | |
| 138 | New jconfig file and makefiles for Microsoft Visual C++ and Developer Studio. |
| 139 | Also, a jconfig file and a build script for Metrowerks CodeWarrior |
| 140 | on Apple Macintosh. makefile.dj has been updated for DJGPP v2, and there |
| 141 | are miscellaneous other minor improvements in the makefiles. |
| 142 | |
| 143 | jmemmac.c now knows how to create temporary files following Mac System 7 |
| 144 | conventions. |
| 145 | |
| 146 | djpeg's -map switch is now able to read raw-format PPM files reliably. |
| 147 | |
| 148 | cjpeg -progressive -restart no longer generates any unnecessary DRI markers. |
| 149 | |
| 150 | Multiple calls to jpeg_simple_progression for a single JPEG object |
| 151 | no longer leak memory. |
| 152 | |
| 153 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 154 | Version 6a 7-Feb-96 |
| 155 | -------------------- |
| 156 | |
| 157 | Library initialization sequence modified to detect version mismatches |
| 158 | and struct field packing mismatches between library and calling application. |
| 159 | This change requires applications to be recompiled, but does not require |
| 160 | any application source code change. |
| 161 | |
| 162 | All routine declarations changed to the style "GLOBAL(type) name ...", |
| 163 | that is, GLOBAL, LOCAL, METHODDEF, EXTERN are now macros taking the |
| 164 | routine's return type as an argument. This makes it possible to add |
| 165 | Microsoft-style linkage keywords to all the routines by changing just |
| 166 | these macros. Note that any application code that was using these macros |
| 167 | will have to be changed. |
| 168 | |
| 169 | DCT coefficient quantization tables are now stored in normal array order |
| 170 | rather than zigzag order. Application code that calls jpeg_add_quant_table, |
| 171 | or otherwise manipulates quantization tables directly, will need to be |
| 172 | changed. If you need to make such code work with either older or newer |
| 173 | versions of the library, a test like "#if JPEG_LIB_VERSION >= 61" is |
| 174 | recommended. |
| 175 | |
| 176 | djpeg's trace capability now dumps DQT tables in natural order, not zigzag |
| 177 | order. This allows the trace output to be made into a "-qtables" file |
| 178 | more easily. |
| 179 | |
| 180 | New system-dependent memory manager module for use on Apple Macintosh. |
| 181 | |
| 182 | Fix bug in cjpeg's -smooth option: last one or two scanlines would be |
| 183 | duplicates of the prior line unless the image height mod 16 was 1 or 2. |
| 184 | |
| 185 | Repair minor problems in VMS, BCC, MC6 makefiles. |
| 186 | |
| 187 | New configure script based on latest GNU Autoconf. |
| 188 | |
| 189 | Correct the list of include files needed by MetroWerks C for ccommand(). |
| 190 | |
| 191 | Numerous small documentation updates. |
| 192 | |
| 193 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 194 | Version 6 2-Aug-95 |
| 195 | ------------------- |
| 196 | |
| 197 | Progressive JPEG support: library can read and write full progressive JPEG |
| 198 | files. A "buffered image" mode supports incremental decoding for on-the-fly |
| 199 | display of progressive images. Simply recompiling an existing IJG-v5-based |
| 200 | decoder with v6 should allow it to read progressive files, though of course |
| 201 | without any special progressive display. |
| 202 | |
| 203 | New "jpegtran" application performs lossless transcoding between different |
| 204 | JPEG formats; primarily, it can be used to convert baseline to progressive |
| 205 | JPEG and vice versa. In support of jpegtran, the library now allows lossless |
| 206 | reading and writing of JPEG files as DCT coefficient arrays. This ability |
| 207 | may be of use in other applications. |
| 208 | |
| 209 | Notes for programmers: |
| 210 | * We changed jpeg_start_decompress() to be able to suspend; this makes all |
| 211 | decoding modes available to suspending-input applications. However, |
| 212 | existing applications that use suspending input will need to be changed |
| 213 | to check the return value from jpeg_start_decompress(). You don't need to |
| 214 | do anything if you don't use a suspending data source. |
| 215 | * We changed the interface to the virtual array routines: access_virt_array |
| 216 | routines now take a count of the number of rows to access this time. The |
| 217 | last parameter to request_virt_array routines is now interpreted as the |
| 218 | maximum number of rows that may be accessed at once, but not necessarily |
| 219 | the height of every access. |
| 220 | |
| 221 | |
Thomas G. Lane | a8b67c4 | 1995-03-15 00:00:00 +0000 | [diff] [blame] | 222 | Version 5b 15-Mar-95 |
| 223 | --------------------- |
| 224 | |
| 225 | Correct bugs with grayscale images having v_samp_factor > 1. |
| 226 | |
| 227 | jpeg_write_raw_data() now supports output suspension. |
| 228 | |
| 229 | Correct bugs in "configure" script for case of compiling in |
| 230 | a directory other than the one containing the source files. |
| 231 | |
| 232 | Repair bug in jquant1.c: sometimes didn't use as many colors as it could. |
| 233 | |
| 234 | Borland C makefile and jconfig file work under either MS-DOS or OS/2. |
| 235 | |
| 236 | Miscellaneous improvements to documentation. |
| 237 | |
| 238 | |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 239 | Version 5a 7-Dec-94 |
| 240 | -------------------- |
| 241 | |
| 242 | Changed color conversion roundoff behavior so that grayscale values are |
| 243 | represented exactly. (This causes test image files to change.) |
| 244 | |
| 245 | Make ordered dither use 16x16 instead of 4x4 pattern for a small quality |
| 246 | improvement. |
| 247 | |
| 248 | New configure script based on latest GNU Autoconf. |
| 249 | Fix configure script to handle CFLAGS correctly. |
| 250 | Rename *.auto files to *.cfg, so that configure script still works if |
| 251 | file names have been truncated for DOS. |
| 252 | |
| 253 | Fix bug in rdbmp.c: didn't allow for extra data between header and image. |
| 254 | |
| 255 | Modify rdppm.c/wrppm.c to handle 2-byte raw PPM/PGM formats for 12-bit data. |
| 256 | |
| 257 | Fix several bugs in rdrle.c. |
| 258 | |
| 259 | NEED_SHORT_EXTERNAL_NAMES option was broken. |
| 260 | |
| 261 | Revise jerror.h/jerror.c for more flexibility in message table. |
| 262 | |
| 263 | Repair oversight in jmemname.c NO_MKTEMP case: file could be there |
| 264 | but unreadable. |
| 265 | |
| 266 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 267 | Version 5 24-Sep-94 |
| 268 | -------------------- |
| 269 | |
| 270 | Version 5 represents a nearly complete redesign and rewrite of the IJG |
| 271 | software. Major user-visible changes include: |
| 272 | * Automatic configuration simplifies installation for most Unix systems. |
| 273 | * A range of speed vs. image quality tradeoffs are supported. |
| 274 | This includes resizing of an image during decompression: scaling down |
| 275 | by a factor of 1/2, 1/4, or 1/8 is handled very efficiently. |
| 276 | * New programs rdjpgcom and wrjpgcom allow insertion and extraction |
| 277 | of text comments in a JPEG file. |
| 278 | |
| 279 | The application programmer's interface to the library has changed completely. |
| 280 | Notable improvements include: |
| 281 | * We have eliminated the use of callback routines for handling the |
| 282 | uncompressed image data. The application now sees the library as a |
| 283 | set of routines that it calls to read or write image data on a |
| 284 | scanline-by-scanline basis. |
| 285 | * The application image data is represented in a conventional interleaved- |
| 286 | pixel format, rather than as a separate array for each color channel. |
| 287 | This can save a copying step in many programs. |
| 288 | * The handling of compressed data has been cleaned up: the application can |
| 289 | supply routines to source or sink the compressed data. It is possible to |
| 290 | suspend processing on source/sink buffer overrun, although this is not |
| 291 | supported in all operating modes. |
| 292 | * All static state has been eliminated from the library, so that multiple |
| 293 | instances of compression or decompression can be active concurrently. |
| 294 | * JPEG abbreviated datastream formats are supported, ie, quantization and |
| 295 | Huffman tables can be stored separately from the image data. |
| 296 | * And not only that, but the documentation of the library has improved |
| 297 | considerably! |
| 298 | |
| 299 | |
| 300 | The last widely used release before the version 5 rewrite was version 4A of |
| 301 | 18-Feb-93. Change logs before that point have been discarded, since they |
| 302 | are not of much interest after the rewrite. |