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 使用libjpeg-turbo進行JPG編解碼-YUV422P轉JPG為例 (qq.com)

一.前言

在UVC項目中需要測試MJPEG的傳輸, 通常JPG使用的是YUV420采樣壓縮，恰好有個UVC的顯示設備不支持YUV420采樣壓縮，只支持YUV422采樣壓縮，所以需要生成YUV422采樣壓縮的JPG文件用于測試。于是使用libjpeg代碼庫生成。這里使用libjpeg-turbo，相對官方的libjpeg，其使用了SIMD進行了速度優化，并且進一步封裝了接口，接口更簡潔更方便使用。

關于YUV422和YUV420采樣的JPG，以下文章有更詳細的說明，總的來說YUV420更常見，畢竟都有損壓縮了，使用YUV422帶來的質量提升已經沒什么意義了，使用YUV420空間更小，質量差異不大。https://calendar.perfplanet.com/2015/why-arent-your-images-using-chroma-subsampling/

項目見: https://github.com/libjpeg-turbo/libjpeg-turbo.git

https://libjpeg-turbo.org/

libjpeg見:http://www.ijg.org/files/

以下基于WSL+Ubuntu環境進行。

二.下載代碼

lhj@lhj:~$ git clone https://github.com/libjpeg-turbo/libjpeg-turbo.git

Cloning into 'libjpeg-turbo'...
remote: Enumerating objects: 19401, done.
remote: Counting objects: 100% (432/432), done.
remote: Compressing objects: 100% (199/199), done.
remote: Total 19401 (delta 259), reused 325 (delta 219), pack-reused 18969
Receiving objects: 100% (19401/19401), 17.02 MiB | 10.70 MiB/s, done.
Resolving deltas: 100% (14372/14372), done.

進入目錄查看文件如下

lhj@lhj:~$ cd libjpeg-turbo/

lhj@lhj:~/libjpeg-turbo$ ls

BUILDING.md        fuzz          jconfig.txt      jdhuff.c    jfdctfst.c          jstdhuff.c      tjexampletest.in
CMakeLists.txt     jaricom.c     jconfigint.h.in  jdhuff.h    jfdctint.c          jutils.c        tjunittest.c
ChangeLog.md       java          jcparam.c        jdicc.c     jidctflt.c          jversion.h.in   tjutil.c
LICENSE.md         jcapimin.c    jcphuff.c        jdinput.c   jidctfst.c          libjpeg.map.in  tjutil.h
README.ijg         jcapistd.c    jcprepct.c       jdlhuff.c   jidctint.c          libjpeg.txt     transupp.c
README.md          jcarith.c     jcsample.c       jdlossls.c  jidctred.c          md5             transupp.h
appveyor.yml       jccoefct.c    jcstest.c        jdmainct.c  jinclude.h          rdbmp.c         turbojpeg-jni.c
cderror.h          jccolext.c    jctrans.c        jdmainct.h  jlossls.h           rdcolmap.c      turbojpeg-mapfile
cdjpeg.c           jccolor.c     jdapimin.c       jdmarker.c  jmemmgr.c           rdgif.c         turbojpeg-mapfile.jni
cdjpeg.h           jcdctmgr.c    jdapistd.c       jdmaster.c  jmemnobs.c          rdjpgcom.1      turbojpeg-mp.c
change.log         jcdiffct.c    jdarith.c        jdmaster.h  jmemsys.h           rdjpgcom.c      turbojpeg.c
cjpeg.1            jchuff.c      jdatadst-tj.c    jdmerge.c   jmorecfg.h          rdppm.c         turbojpeg.h
cjpeg.c            jchuff.h      jdatadst.c       jdmerge.h   jpeg_nbits_table.h  rdswitch.c      usage.txt
doxygen-extra.css  jcmaster.h    jdct.h           jerror.c    jsamplecomp.h       tjbench.c       wrtarga.c
doxygen.config     jcomapi.c     jddctmgr.c       jerror.h    jsimd.h             tjbenchtest.in
example.c          jconfig.h.in  jddiffct.c       jfdctflt.c  jsimddct.h          tjexample.c

lhj@lhj:~/libjpeg-turbo$ code .

三.安裝nasm

lhj@lhj:~/libjpeg-turbo$ sudo apt install nasm

[sudo] password for lhj:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  nasm
0 upgraded, 1 newly installed, 0 to remove and 224 not upgraded.
Need to get 362 kB of archives.
After this operation, 3374 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu focal/universe amd64 nasm amd64 2.14.02-1 [362 kB]
Fetched 362 kB in 2s (185 kB/s)
Selecting previously unselected package nasm.
(Reading database ... 131163 files and directories currently installed.)
Preparing to unpack .../nasm_2.14.02-1_amd64.deb ...
Unpacking nasm (2.14.02-1) ...
Setting up nasm (2.14.02-1) ...
Processing triggers for man-db (2.9.1-1) ...

四.編譯

lhj@lhj:~/libjpeg-turbo$ mkdir build

lhj@lhj:~/libjpeg-turbo$ cd build

lhj@lhj:~/libjpeg-turbo/build$ cmake ../

-- The C compiler identification is GNU 9.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- CMAKE_BUILD_TYPE = Release
-- VERSION = 3.0.1, BUILD = 20230810
-- 64-bit build (x86_64)
-- CMAKE_INSTALL_PREFIX = /opt/libjpeg-turbo
-- CMAKE_INSTALL_BINDIR = bin (/opt/libjpeg-turbo/bin)
-- CMAKE_INSTALL_DATAROOTDIR =  (/opt/libjpeg-turbo)
-- CMAKE_INSTALL_DOCDIR = doc (/opt/libjpeg-turbo/doc)
-- CMAKE_INSTALL_INCLUDEDIR = include (/opt/libjpeg-turbo/include)
-- CMAKE_INSTALL_LIBDIR = lib64 (/opt/libjpeg-turbo/lib64)
-- CMAKE_INSTALL_MANDIR = man (/opt/libjpeg-turbo/man)
-- Shared libraries enabled (ENABLE_SHARED = 1)
-- Static libraries enabled (ENABLE_STATIC = 1)
-- Arithmetic decoding support enabled (WITH_ARITH_DEC = 1)
-- Arithmetic encoding support enabled (WITH_ARITH_ENC = 1)
-- TurboJPEG API library enabled (WITH_TURBOJPEG = 1)
-- TurboJPEG Java wrapper disabled (WITH_JAVA = 0)
-- Emulating libjpeg API/ABI v6.2 (WITH_JPEG7 = 0, WITH_JPEG8 = 0)
-- libjpeg API shared library version = 62.4.0
-- Compiler flags =  -O3 -DNDEBUG
-- Linker flags =
-- Looking for sys/types.h
-- Looking for sys/types.h - found
-- Looking for stdint.h
-- Looking for stdint.h - found
-- Looking for stddef.h
-- Looking for stddef.h - found
-- Check size of size_t
-- Check size of size_t - done
-- Check size of unsigned long
-- Check size of unsigned long - done
-- Performing Test HAVE_BUILTIN_CTZL
-- Performing Test HAVE_BUILTIN_CTZL - Success
-- Performing Test RIGHT_SHIFT_IS_UNSIGNED
-- Performing Test RIGHT_SHIFT_IS_UNSIGNED - Failed
-- Performing Test INLINE_WORKS
-- Performing Test INLINE_WORKS - Success
-- INLINE = __inline__ __attribute__((always_inline)) (FORCE_INLINE = 1)
-- Performing Test HAVE_THREAD_LOCAL
-- Performing Test HAVE_THREAD_LOCAL - Success
-- THREAD_LOCAL = __thread
-- Performing Test HAVE_VERSION_SCRIPT
-- Performing Test HAVE_VERSION_SCRIPT - Success
-- Linker supports GNU-style version scripts
-- CMAKE_EXECUTABLE_SUFFIX =
-- Looking for a ASM_NASM compiler
-- Looking for a ASM_NASM compiler - /usr/bin/nasm
-- The ASM_NASM compiler identification is NASM
-- Found assembler: /usr/bin/nasm
-- CMAKE_ASM_NASM_COMPILER = /usr/bin/nasm
-- CMAKE_ASM_NASM_OBJECT_FORMAT = elf64
-- CMAKE_ASM_NASM_FLAGS =  -DELF -D__x86_64__ -DPIC
-- SIMD extensions: x86_64 (WITH_SIMD = 1)
-- FLOATTEST8 = sse
-- FLOATTEST12 = no-fp-contract
-- RPM architecture = x86_64, DEB architecture = amd64
-- Configuring done
-- Generating done
-- Build files have been written to: /home/lhj/libjpeg-turbo/build

lhj@lhj:~/libjpeg-turbo/build$ make

Scanning dependencies of target simd
[  0%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jsimdcpu.asm.o
[  0%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jfdctflt-sse.asm.o
[  0%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jccolor-sse2.asm.o
[  0%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jcgray-sse2.asm.o
[  1%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jchuff-sse2.asm.o
[  1%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jcphuff-sse2.asm.o
[  1%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jcsample-sse2.asm.o
[  1%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jdcolor-sse2.asm.o
[  1%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jdmerge-sse2.asm.o
[  2%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jdsample-sse2.asm.o
[  2%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jfdctfst-sse2.asm.o
[  2%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jfdctint-sse2.asm.o
[  2%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jidctflt-sse2.asm.o
[  3%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jidctfst-sse2.asm.o
[  3%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jidctint-sse2.asm.o
[  3%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jidctred-sse2.asm.o
[  3%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jquantf-sse2.asm.o
[  3%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jquanti-sse2.asm.o
[  4%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jccolor-avx2.asm.o
[  4%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jcgray-avx2.asm.o
[  4%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jcsample-avx2.asm.o
[  4%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jdcolor-avx2.asm.o
[  5%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jdmerge-avx2.asm.o
[  5%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jdsample-avx2.asm.o
[  5%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jfdctint-avx2.asm.o
[  5%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jidctint-avx2.asm.o
[  5%] Building ASM_NASM object simd/CMakeFiles/simd.dir/x86_64/jquanti-avx2.asm.o
[  6%] Building C object simd/CMakeFiles/simd.dir/x86_64/jsimd.c.o
[  6%] Built target simd
Scanning dependencies of target turbojpeg12


.......
Scanning dependencies of target md5cmp
[ 99%] Building C object md5/CMakeFiles/md5cmp.dir/md5cmp.c.o
[100%] Building C object md5/CMakeFiles/md5cmp.dir/md5.c.o
[100%] Building C object md5/CMakeFiles/md5cmp.dir/md5hl.c.o
[100%] Linking C executable md5cmp
[100%] Built target md5cmp

生成文件如下

lhj@lhj:~/libjpeg-turbo/build$ ls

CMakeCache.txt       cmake_uninstall.cmake  jconfigint.h     libjpeg.so             md5         tjbench-static
CMakeFiles           croptest               jcstest          libjpeg.so.62          pkgscripts  tjbenchtest
CTestTestfile.cmake  djpeg                  jpegtran         libjpeg.so.62.4.0      rdjpgcom    tjexample
Makefile             djpeg-static           jpegtran-static  libturbojpeg.a         sharedlib   tjexampletest
cjpeg                example                jversion.h       libturbojpeg.so        simd        tjunittest
cjpeg-static         example-static         libjpeg.a        libturbojpeg.so.0      strtest     tjunittest-static
cmake_install.cmake  jconfig.h              libjpeg.map      libturbojpeg.so.0.3.0  tjbench     wrjpgcom

五.安裝

lhj@lhj:~/libjpeg-turbo/build$ sudo make install

安裝于/opt/libjpeg-turbo/lib64

[sudo] password for lhj: 
[  6%] Built target simd
[  7%] Built target turbojpeg12
[ 10%] Built target jpeg16
[ 16%] Built target jpeg12
[ 17%] Built target turbojpeg16
[ 31%] Built target turbojpeg
[ 31%] Built target turbojpeg12-static
[ 34%] Built target jpeg16-static
[ 40%] Built target jpeg12-static
[ 53%] Built target jpeg-static
[ 54%] Built target djpeg12-static
[ 54%] Built target djpeg16-static
[ 56%] Built target djpeg-static
[ 56%] Built target example-static
[ 57%] Built target tjexample
[ 57%] Built target turbojpeg16-static
[ 71%] Built target turbojpeg-static
[ 72%] Built target jpegtran-static
[ 73%] Built target tjunittest-static
[ 74%] Built target rdjpgcom
[ 75%] Built target tjunittest
[ 75%] Built target tjbench-static
[ 76%] Built target cjpeg16-static
[ 76%] Built target strtest
[ 77%] Built target cjpeg12-static
[ 79%] Built target cjpeg-static
[ 80%] Built target wrjpgcom
[ 81%] Built target tjbench
[ 81%] Built target cjpeg12
[ 81%] Built target cjpeg16
[ 93%] Built target jpeg
[ 94%] Built target cjpeg
[ 94%] Built target djpeg16
[ 94%] Built target djpeg12
[ 96%] Built target djpeg
[ 97%] Built target jpegtran
[ 98%] Built target example
[ 99%] Built target jcstest
[100%] Built target md5cmp
Install the project...
-- Install configuration: "Release"
-- Installing: /opt/libjpeg-turbo/lib64/libturbojpeg.so.0.3.0
-- Installing: /opt/libjpeg-turbo/lib64/libturbojpeg.so.0
-- Set runtime path of "/opt/libjpeg-turbo/lib64/libturbojpeg.so.0.3.0" to "/opt/libjpeg-turbo/lib64"
-- Installing: /opt/libjpeg-turbo/lib64/libturbojpeg.so
-- Installing: /opt/libjpeg-turbo/bin/tjbench
-- Set runtime path of "/opt/libjpeg-turbo/bin/tjbench" to "/opt/libjpeg-turbo/lib64"
-- Installing: /opt/libjpeg-turbo/lib64/libturbojpeg.a
-- Installing: /opt/libjpeg-turbo/include/turbojpeg.h
-- Installing: /opt/libjpeg-turbo/lib64/libjpeg.a
-- Installing: /opt/libjpeg-turbo/bin/rdjpgcom
-- Set runtime path of "/opt/libjpeg-turbo/bin/rdjpgcom" to "/opt/libjpeg-turbo/lib64"
-- Installing: /opt/libjpeg-turbo/bin/wrjpgcom
-- Set runtime path of "/opt/libjpeg-turbo/bin/wrjpgcom" to "/opt/libjpeg-turbo/lib64"
-- Installing: /opt/libjpeg-turbo/doc/README.ijg
-- Installing: /opt/libjpeg-turbo/doc/README.md
-- Installing: /opt/libjpeg-turbo/doc/example.c
-- Installing: /opt/libjpeg-turbo/doc/tjexample.c
-- Installing: /opt/libjpeg-turbo/doc/libjpeg.txt
-- Installing: /opt/libjpeg-turbo/doc/structure.txt
-- Installing: /opt/libjpeg-turbo/doc/usage.txt
-- Installing: /opt/libjpeg-turbo/doc/wizard.txt
-- Installing: /opt/libjpeg-turbo/doc/LICENSE.md
-- Installing: /opt/libjpeg-turbo/man/man1/cjpeg.1
-- Installing: /opt/libjpeg-turbo/man/man1/djpeg.1
-- Installing: /opt/libjpeg-turbo/man/man1/jpegtran.1
-- Installing: /opt/libjpeg-turbo/man/man1/rdjpgcom.1
-- Installing: /opt/libjpeg-turbo/man/man1/wrjpgcom.1
-- Installing: /opt/libjpeg-turbo/lib64/pkgconfig/libjpeg.pc
-- Installing: /opt/libjpeg-turbo/lib64/pkgconfig/libturbojpeg.pc
-- Installing: /opt/libjpeg-turbo/lib64/cmake/libjpeg-turbo/libjpeg-turboConfig.cmake
-- Installing: /opt/libjpeg-turbo/lib64/cmake/libjpeg-turbo/libjpeg-turboConfigVersion.cmake
-- Installing: /opt/libjpeg-turbo/lib64/cmake/libjpeg-turbo/libjpeg-turboTargets.cmake
-- Installing: /opt/libjpeg-turbo/lib64/cmake/libjpeg-turbo/libjpeg-turboTargets-release.cmake
-- Installing: /opt/libjpeg-turbo/include/jconfig.h
-- Installing: /opt/libjpeg-turbo/include/jerror.h
-- Installing: /opt/libjpeg-turbo/include/jmorecfg.h
-- Installing: /opt/libjpeg-turbo/include/jpeglib.h
-- Installing: /opt/libjpeg-turbo/lib64/libjpeg.so.62.4.0
-- Installing: /opt/libjpeg-turbo/lib64/libjpeg.so.62
-- Set runtime path of "/opt/libjpeg-turbo/lib64/libjpeg.so.62.4.0" to "/opt/libjpeg-turbo/lib64"
-- Installing: /opt/libjpeg-turbo/lib64/libjpeg.so
-- Installing: /opt/libjpeg-turbo/bin/cjpeg
-- Set runtime path of "/opt/libjpeg-turbo/bin/cjpeg" to "/opt/libjpeg-turbo/lib64"
-- Installing: /opt/libjpeg-turbo/bin/djpeg
-- Set runtime path of "/opt/libjpeg-turbo/bin/djpeg" to "/opt/libjpeg-turbo/lib64"
-- Installing: /opt/libjpeg-turbo/bin/jpegtran
-- Set runtime path of "/opt/libjpeg-turbo/bin/jpegtran" to "/opt/libjpeg-turbo/lib64"

六.測試

lhj@lhj:~/libjpeg-turbo/build$ sudo make test

Running tests...
Test project /home/lhj/libjpeg-turbo/build
        Start   1: tjunittest-shared
  1/590 Test   #1: tjunittest-shared ...................................   Passed    3.48 sec
        Start   2: tjunittest-shared-alloc
  2/590 Test   #2: tjunittest-shared-alloc .............................   Passed    3.48 sec
......
        Start 590: example-12bit-static-decompress-cmp
590/590 Test #590: example-12bit-static-decompress-cmp .................   Passed    0.00 sec


100% tests passed, 0 tests failed out of 590


Total Test time (real) =  79.40 sec

七.YUV422P轉JPG

代碼

#include < stdio.h >
#include < stdlib.h >
#include < stdint.h >
#include < sys/time.h >
#include < unistd.h >
#include < sys/stat.h >
#include < turbojpeg.h >


/*
 Y = 0.298R + 0.612G + 0.117B;   [13,235]
 U = -0.168R - 0.330G + 0.498B + 128; [16,239]
 V = 0.449R - 0.435G - 0.083B + 128; [16,239]
*/
uint8_t* yuv422p(uint32_t w, uint32_t h, uint32_t color)
{
    uint8_t* p = (uint8_t*)malloc(w*h*2);
    uint8_t* ret = p;
    if(p == NULL)
    {
        return NULL;
    }


    int y = 0;
    int u = 0;
    int v = 0;
    uint8_t r = 0;
    uint8_t g = 0;
    uint8_t b = 0;
    r = (color > > 16) & 0xFF;
    g = (color > > 8) & 0xFF;
    b = (color > > 0) & 0xFF;
    y = (0.298*r + 0.612*g + 0.117*b);
    u = (-0.168*r - 0.330*g + 0.498*b + 128);
    v = (0.449*r - 0.435*g - 0.083*b + 128);
    if(y >235)
    {
        y=235;
    }
    if(y< 16)
    {
        y=16;
    }
    if(u >239)
    {
        u=239;
    }
    if(u< 16)
    {
        u=16;
    }
    if(v >239)
    {
        v=239;
    }
    if(v< 16)
    {
        v=16;
    }
    for(int i=0;i< w*h;i++)
    {
        *p++ = y;
    }
    for(int i=0;i< w*h/2;i++)
    {
        *p++ = u;
    }
    for(int i=0;i< w*h/2;i++)
    {
        *p++ = v;
    }
    return ret;
}


/*寫內存到文件*/
void write_buffer2file(char *filename, uint8_t *buffer, int size)
{
  FILE *fd = fopen(filename,"wb");
  if (NULL == fd) {
    return;
  }
  fwrite(buffer,1,size,fd);
  fclose(fd);
}


int tyuv2jpeg(unsigned char* yuv_buffer, int yuv_size, int width, int height, int subsample, unsigned char** jpeg_buffer, unsigned long* jpeg_size, int quality,char *name)
{
    tjhandle handle = NULL;
    int flags = 0;
    int padding = 16; // 1或4均可，但不能是0
    int need_size = 0;
    int ret = 0;
 
    handle = tjInitCompress();
   
    flags |= 0;
 
    need_size = tjBufSizeYUV2(width, padding, height, subsample);
    if (need_size != yuv_size)
    {
        printf("we detect yuv size: %d, but you give: %d, check again.n", need_size, yuv_size);
        return 0;
    }
 
    ret = tjCompressFromYUV(handle, yuv_buffer, width, padding, height, subsample, jpeg_buffer, jpeg_size, quality, flags);
    if (ret < 0)
    {
        printf("compress to jpeg failed: %sn", tjGetErrorStr());
    }
    write_buffer2file(name,*jpeg_buffer,*jpeg_size);
    tjDestroy(handle);
 
    return ret;
}


int main()
{
    unsigned long jpeg_size;
    unsigned char* yuv_buffer;
    unsigned char* jpeg_buffer;
    yuv_buffer = yuv422p(800, 480, 0xFFFF00);
    tyuv2jpeg(yuv_buffer, 800*480*2, 800, 480, TJSAMP_422, &jpeg_buffer, &jpeg_size, 90, "out.jpg");
    free(yuv_buffer);
}

編譯

gcc test.c -o test -lturbojpeg -I/opt/libjpeg-turbo/include -L/opt/libjpeg-turbo/lib64

運行

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/libjpeg-turbo/lib64 && ./test

生成out.jpg

八. 總結

以上使用libjpeg實現了YUV422P轉JPG，可以導入自己項目用于UVC的MJPEG測試。后面再單獨講將其移植到MCU以實現軟jpg的編解碼。

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【米爾-全志T113-i開發板試用】JPG硬件解碼的實現和對比測試

全志的視頻引擎庫進行硬件編解碼，具體的sdk下載自 https://github.com/MYIR-ALLWINNER/framework/tree/develop-yt113-framework

發表于 02-08 22:14

【米爾-全志T113-i開發板試用】JPG硬件編碼的實現、YUV轉換neon加速和對比測試

，存放YUV420數據 RGB轉YUV420 開始編碼，獲取返回的 bitstream 數據將 bitstream 數據寫入 out.jpg 其中步驟 1,2,4 是基于cedarc

發表于 02-12 14:06

有償求助！！關于TURBO編解碼和QPSK調制解調

本人最近在做的項目遇到需要TURBO編解碼和QPSK調制解調的技術，有達人做過有關這方面的東西的嗎？有實際應用的仿真程序和源代碼最好，價錢好商量！！！不花力氣賺錢的機會！！有意向的請速聯系我：孫成松電話：***

發表于 10-12 20:30

【NanoPi NEO2試用體驗】libjpeg庫的使用之jpeg解碼

使用libjpeg進行jpeg解碼需要libjpeg動態鏈接庫以及libjpeg的頭文件，上一篇文章已經編譯好了

發表于 07-01 10:15

請教有關ColorSpace_YUV420PSEMI與ColorSpace_YUV422PSEMI的bit位寬問題

ColorSpace_RGB565: case ColorSpace_UYVY: bpp = 16; break;case ColorSpace_GRAY: case ColorSpace_YUV422P: case

發表于 07-27 08:15

在UCGUI下做JPG解碼時不能顯示

用了原子哥JPG解碼碼源，顯示部分：定義圖片顯示格式：unsigned shortJPG2BMP[256]={0};GUI_BITMAP JPG={16, /* XSize */16

發表于 04-18 06:35

linux 相機讀取圖像轉換為RGB后再轉換為JPG圖像失真

我在linux下讀取USB攝像頭的數據，最終輸出一張JPG圖出來，但是讀取出來的圖片失真。用的是jpeglib的接口進行的轉換，我想請問到底哪一步出錯了。//rgb轉jpgint save_j

發表于 10-27 17:45

【100ASK_IMX6ULL(帶屏) 開發板試用體驗】基于samba v4l2庫和libjpeg遠程攝像頭圖像讀取

的特點是生成的文件小，需要使用CPU調用libjpeg軟件編解碼庫占用資源，在不使用多線程并發操作的前提下，保存一張圖片會有毫秒級的延遲，我實測，使用v4l2庫抓取攝像頭換成并保存成jpg文件，間隔

發表于 11-07 16:33

【米爾MYS-8MMX開發板免費試用】使用libjpeg庫和giflib庫顯示JPG圖片和GIF圖片

Linux系統編程中對JPG和GIF圖片的顯示都有集成的軟件庫可以用，顯示JPG圖片可用libjpeg庫，可以直接用apt在線安裝apt install libjpeg62-turbo

發表于 08-30 21:13

JPG轉ARGB888數據的工具軟件

有沒有將JPG圖片轉ARGB888數據的工具軟件？

發表于 06-07 07:48

yuv422p格式數據流轉換成RGB888格式數據流

yuv422p格式數據流轉換成RGB888格式數據流，親測可用

發表于 02-25 18:12 ?14次下載

HEIC格式轉jpg格式怎么做

能夠打開進行查看了！? 圖片轉換器http://www.xunjieshipin.com/heic2jpg? HEIC轉換器http://www.downza.cn/soft/265983.html? 以上就是HEIC格式轉

發表于 07-23 18:18 ?540次閱讀

如何在論文查重軟件將JPG圖片轉PDF問題

最近發現很多網友們對于如何在論文查重軟件將JPG圖片轉PDF問題都非常關注，而我們現在的生活基本上也都離不開手機，想要了解最新的信息也都是直接在手機上進行了解

發表于 07-28 10:22 ?2434次閱讀

Linux應用開發-libjpeg庫交叉編譯與使用

在開發板上如果想要顯示jpeg格式的圖片，必須用到libjpeg庫，不可能自己去編寫jpg的解碼代碼。 libjpeg是一個完全用C語言編寫的庫，包含了被廣泛使用的JPEG

發表于 08-14 09:18 ?2337次閱讀

jpg如何轉psd格式？

jpg如何轉psd格式？將JPG格式轉換為PSD格式是一個比較簡單的過程，只需使用合適的圖像編輯軟件即可完成。在本文中，我將提供詳盡、詳實、細致的步驟，幫助你完成這個轉換過程。首先，我們需要

發表于 12-09 16:09 ?2638次閱讀

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搜索歷史

使用libjpeg-turbo進行JPG編解碼-YUV422P轉JPG為例

一.前言

二.下載代碼

三.安裝nasm

四.編譯

五.安裝

六.測試

七.YUV422P轉JPG

八. 總結

評論

【米爾-全志T113-i開發板試用】JPG硬件解碼的實現和對比測試

【米爾-全志T113-i開發板試用】JPG硬件編碼的實現、YUV轉換neon加速和對比測試

有償求助！！關于TURBO編解碼和QPSK調制解調

【NanoPi NEO2試用體驗】libjpeg庫的使用之jpeg解碼

請教有關ColorSpace_YUV420PSEMI與ColorSpace_YUV422PSEMI的bit位寬問題

在UCGUI下做JPG解碼時不能顯示

linux 相機讀取圖像轉換為RGB后再轉換為JPG圖像失真

【100ASK_IMX6ULL(帶屏) 開發板試用體驗】基于samba v4l2庫和libjpeg遠程攝像頭圖像讀取

【米爾MYS-8MMX開發板免費試用】使用libjpeg庫和giflib庫顯示JPG圖片和GIF圖片

JPG轉ARGB888數據的工具軟件

yuv422p格式數據流轉換成RGB888格式數據流

HEIC格式轉jpg格式怎么做

如何在論文查重軟件將JPG圖片轉PDF問題

Linux應用開發-libjpeg庫交叉編譯與使用

jpg如何轉psd格式？