DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 1 | ******************************************************************************* |
| 2 | ** Background |
| 3 | ******************************************************************************* |
| 4 | |
| 5 | libjpeg-turbo is a high-speed version of libjpeg for x86 and x86-64 processors |
| 6 | which uses SIMD instructions (MMX, SSE2, etc.) to accelerate baseline JPEG |
DRC | ce1546e | 2010-02-13 23:06:03 +0000 | [diff] [blame] | 7 | compression and decompression. libjpeg-turbo is generally 2-4x as fast |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 8 | as the unmodified version of libjpeg, all else being equal. |
| 9 | |
| 10 | libjpeg-turbo was originally based on libjpeg/SIMD by Miyasaka Masaru, but |
| 11 | the TigerVNC and VirtualGL projects made numerous enhancements to the codec, |
| 12 | including improved support for Mac OS X, 64-bit support, support for 32-bit |
| 13 | and big endian pixel formats, accelerated Huffman encoding/decoding, and |
| 14 | various bug fixes. The goal was to produce a fully open source codec that |
| 15 | could replace the partially closed source TurboJPEG/IPP codec used by VirtualGL |
DRC | ce1546e | 2010-02-13 23:06:03 +0000 | [diff] [blame] | 16 | and TurboVNC. libjpeg-turbo generally performs in the range of 80-120% of |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 17 | TurboJPEG/IPP. It is faster in some areas but slower in others. |
| 18 | |
| 19 | It was decided to split libjpeg-turbo into a separate SDK so that other |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 20 | projects could take advantage of this technology. The libjpeg-turbo shared |
| 21 | libraries can be used as drop-in replacements for libjpeg on most systems. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 22 | |
| 23 | |
| 24 | ******************************************************************************* |
DRC | ce1546e | 2010-02-13 23:06:03 +0000 | [diff] [blame] | 25 | ** License |
| 26 | ******************************************************************************* |
| 27 | |
| 28 | Some of the optimizations to the Huffman encoder/decoder were borrowed from |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 29 | VirtualGL, and thus the libjpeg-turbo distribution, as a whole, falls under the |
| 30 | wxWindows Library Licence, Version 3.1. A copy of this license can be found in |
| 31 | this directory under LICENSE.txt. The rest of the source code, apart from |
| 32 | these modifications, falls under a less restrictive license (see README.) |
DRC | ce1546e | 2010-02-13 23:06:03 +0000 | [diff] [blame] | 33 | |
| 34 | |
| 35 | ******************************************************************************* |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 36 | ** Using libjpeg-turbo |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 37 | ******************************************************************************* |
| 38 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 39 | ============================= |
| 40 | Replacing libjpeg at Run Time |
| 41 | ============================= |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 42 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 43 | If a Unix application is dynamically linked with libjpeg, then you can replace |
| 44 | libjpeg with libjpeg-turbo at run time by manipulating the LD_LIBRARY_PATH. |
| 45 | For instance: |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 46 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 47 | [Using libjpeg] |
| 48 | > time cjpeg <vgl_5674_0098.ppm >vgl_5674_0098.jpg |
| 49 | real 0m0.392s |
| 50 | user 0m0.074s |
| 51 | sys 0m0.020s |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 52 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 53 | [Using libjpeg-turbo] |
| 54 | > export LD_LIBRARY_PATH=/opt/libjpeg-turbo/{lib}:$LD_LIBRARY_PATH |
| 55 | > time cjpeg <vgl_5674_0098.ppm >vgl_5674_0098.jpg |
| 56 | real 0m0.109s |
| 57 | user 0m0.029s |
| 58 | sys 0m0.010s |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 59 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 60 | NOTE: {lib} can be lib, lib32, lib64, or lib/amd64, depending on the O/S and |
| 61 | architecture. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 62 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 63 | System administrators can also replace the libjpeg sym links in /usr/{lib} with |
| 64 | links to the libjpeg dynamic library located in /opt/libjpeg-turbo/{lib}. This |
| 65 | will effectively accelerate every dynamically linked libjpeg application on the |
| 66 | system. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 67 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 68 | The Windows version of libjpeg-turbo installs jpeg62.dll into |
DRC | 7e0b499 | 2010-02-25 05:52:44 +0000 | [diff] [blame^] | 69 | c:\libjpeg-turbo\bin, and the PATH environment variable can be modified such |
| 70 | that this directory is searched before any others that might contain |
| 71 | jpeg62.dll. However, if jpeg62.dll also exists in an application's install |
| 72 | directory, then Windows will load the application's version of it first. Thus, |
| 73 | if an application ships with jpeg62.dll, then back up the application's version |
| 74 | of jpeg62.dll and copy c:\libjpeg-turbo\bin\jpeg62.dll into the application's |
| 75 | install directory to accelerate it. |
| 76 | |
| 77 | libjpeg-turbo's version of jpeg62.dll requires the Visual C++ 2008 C run time |
| 78 | DLL (msvcr90.dll). This library ships with more recent versions of Windows, |
| 79 | but users of older versions can obtain it from the Visual C++ 2008 |
| 80 | Redistributable Package, which is available as a free download from Microsoft's |
| 81 | web site. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 82 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 83 | Mac applications typically embed their own copies of libjpeg.62.dylib inside |
| 84 | the (hidden) application bundle, so it is not possible to globally replace |
| 85 | libjpeg on OS X systems. If an application uses a shared library version of |
| 86 | libjpeg, then it may be possible to replace the application's version of it. |
| 87 | This would generally involve copying libjpeg.62.dylib into the appropriate |
| 88 | place in the application bundle and using install_name_tool to repoint the |
| 89 | dylib to the new directory. This requires an advanced knowledge of OS X and |
| 90 | would not survive an upgrade or a re-install of the application. Thus, it is |
| 91 | not recommended for most users. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 92 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 93 | ======================= |
| 94 | Replacing TurboJPEG/IPP |
| 95 | ======================= |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 96 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 97 | libjpeg-turbo is a drop-in replacement for the TurboJPEG/IPP SDK used by |
| 98 | VirtualGL 2.1.x (and prior) and TurboVNC. libjpeg-turbo contains a wrapper |
| 99 | library (TurboJPEG/OSS) that emulates the TurboJPEG API using libjpeg-turbo |
| 100 | instead of the closed source Intel Performance Primitives. You can replace the |
| 101 | TurboJPEG/IPP package on Linux systems with the libjpeg-turbo package in order |
| 102 | to make existing releases of VirtualGL 2.1.x and TurboVNC use the new codec at |
| 103 | run time. Note that the 64-bit libjpeg-turbo packages contain only 64-bit |
| 104 | binaries, whereas the TurboJPEG/IPP 64-bit packages contain both 64-bit and |
| 105 | 32-bit binaries. Thus, to replace a TurboJPEG/IPP 64-bit package, install |
| 106 | both the 64-bit and 32-bit versions of libjpeg-turbo. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 107 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 108 | You can also build the VirtualGL 2.1.x and TurboVNC source code with |
| 109 | the libjpeg-turbo SDK instead of TurboJPEG/IPP. It should work identically. |
| 110 | libjpeg-turbo also includes static library versions of TurboJPEG/OSS, which |
| 111 | are used to build VirtualGL 2.2 and later. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 112 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 113 | ======================================== |
| 114 | Using libjpeg-turbo in Your Own Programs |
| 115 | ======================================== |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 116 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 117 | For the most part, libjpeg-turbo should work identically to libjpeg, so in |
| 118 | most cases, an application can be built against libjpeg and then run against |
| 119 | libjpeg-turbo. On Unix systems, you can build against libjpeg-turbo instead |
| 120 | of libjpeg by setting |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 121 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 122 | CPATH=/opt/libjpeg-turbo/include |
| 123 | and |
| 124 | LIBRARY_PATH=/opt/libjpeg-turbo/{lib} |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 125 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 126 | ({lib} = lib, lib32, lib64, or lib/amd64, as appropriate.) |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 127 | |
DRC | 0a1f68e | 2010-02-24 07:24:26 +0000 | [diff] [blame] | 128 | If using Cygwin, then set |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 129 | |
DRC | 0a1f68e | 2010-02-24 07:24:26 +0000 | [diff] [blame] | 130 | CPATH=/cygdrive/c/libjpeg-turbo-gcc/include |
| 131 | and |
| 132 | LIBRARY_PATH=/cygdrive/c/libjpeg-turbo-gcc/lib |
| 133 | |
| 134 | If using MinGW, then set |
| 135 | |
| 136 | CPATH=/c/libjpeg-turbo-gcc/include |
| 137 | and |
| 138 | LIBRARY_PATH=/c/libjpeg-turbo-gcc/lib |
| 139 | |
| 140 | Building against libjpeg-turbo is useful, for instance, if you want to build an |
| 141 | application that leverages the libjpeg-turbo colorspace extensions (see below.) |
| 142 | On Linux and Solaris systems, you would still need to manipulate the |
| 143 | LD_LIBRARY_PATH or sym links appropriately to use libjpeg-turbo at run time. |
| 144 | On such systems, you can pass -R /opt/libjpeg-turbo/{lib} to the linker to |
| 145 | force the use of libjpeg-turbo at run time rather than libjpeg (also useful if |
| 146 | you want to leverage the colorspace extensions), or you can link against the |
| 147 | libjpeg-turbo static library. |
| 148 | |
| 149 | To force a Linux, Solaris, or MinGW application to link against the static |
| 150 | version of libjpeg-turbo, you can use the following linker options: |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 151 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 152 | -Wl,-Bstatic -ljpeg -Wl,-Bdynamic |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 153 | |
DRC | 0a1f68e | 2010-02-24 07:24:26 +0000 | [diff] [blame] | 154 | On OS X, simply add /opt/libjpeg-turbo/{lib}/libjpeg.a to the linker command |
| 155 | line (this also works on Linux and Solaris.) |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 156 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 157 | To build Visual C++ applications using libjpeg-turbo, add |
| 158 | c:\libjpeg-turbo\include to your system or user INCLUDE environment variable |
| 159 | and c:\libjpeg-turbo\lib to your system or user LIB environment variable, and |
| 160 | then link against either jpeg.lib (to use jpeg62.dll) or jpeg-static.lib (to |
| 161 | use the static version of libjpeg-turbo.) |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 162 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 163 | ===================== |
| 164 | Colorspace Extensions |
| 165 | ===================== |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 166 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 167 | libjpeg-turbo includes extensions which allow JPEG images to be compressed |
| 168 | directly from (and decompressed directly to) buffers which use BGR, BGRA, |
| 169 | RGBA, ABGR, and ARGB pixel ordering. This is implemented with six new |
| 170 | colorspace constants: |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 171 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 172 | JCS_EXT_RGB /* red/green/blue */ |
| 173 | JCS_EXT_RGBX /* red/green/blue/x */ |
| 174 | JCS_EXT_BGR /* blue/green/red */ |
| 175 | JCS_EXT_BGRX /* blue/green/red/x */ |
| 176 | JCS_EXT_XBGR /* x/blue/green/red */ |
| 177 | JCS_EXT_XRGB /* x/red/green/blue */ |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 178 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 179 | Setting cinfo.in_color_space (compression) or cinfo.out_color_space |
| 180 | (decompression) to one of these values will cause libjpeg-turbo to read the |
| 181 | red, green, and blue values from (or write them to) the appropriate position in |
| 182 | the pixel when YUV conversion is performed. |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 183 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 184 | Your application can check for the existence of these extensions at compile |
| 185 | time with: |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 186 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 187 | #ifdef JCS_EXTENSIONS |
DRC | 101f09a | 2010-02-12 22:52:37 +0000 | [diff] [blame] | 188 | |
DRC | 68fef83 | 2010-02-16 05:29:10 +0000 | [diff] [blame] | 189 | At run time, attempting to use these extensions with a version of libjpeg |
| 190 | that doesn't support them will result in a "Bogus input colorspace" error. |