v4l2摄像头移植mjpg_streamer笔记

v4l2摄像头移植mjpg_streamer笔记

mjpg-stream的移植需要jpeg的库，所以我们先移植jpeg的库
(1)jpeg库的移植

1)jpeg源码包通过下面这个网址下载 http://www.ijg.org/files/jpegsrc.v8b.tar.gz 2)解压源码包
tar xvf jpegsrc.v8b.tar.gz
3)配置源码
cd jpeg-8b
./configure --prefix=/home/6410/video/jpeg --host=arm-linux
4)编译
make
5)安装
make install
6)拷贝libjpeg.s0.8库到开发板文件系统lib下中
mjpg-stream的移植

1)mjpg-stream源码包通过下面这个网址下载 http://sourceforge.net/projects/mjpg-streamer/ 2)解压源码
tar xvf mjpg-streamer-r63.tar.gz
3)修改源码
cd mjpg-streamer-r63
修改顶层makefile及plugins目录中的各级makefile将所有
CC=gcc
修改为
CC=arm-none-linux-gnueabi-gcc

修改plugins/input_uvc/Makfile
修改
CFLAGS += -O2 -DLINUX -D_GNU_SOURCE -Wall -shared -fPIC
为
CFLAGS += -O2 -DLINUX -D_GNU_SOURCE -Wall -shared -fPIC -I/home/6410/video/jpeg/include
修改
$(CC) $(CFLAGS) -ljpeg -o $@ input_uvc.c v4l2uvc.lo jpeg_utils.lo dynctrl.lo
为
$(CC) $(CFLAGS) -ljpeg -L/home/6410/video/jpeg/lib -o $@ input_uvc.c v4l2uvc.lo jpeg_utils.lo dynctrl.lo
4)编译
make
5)测试
在开发板上mkdir /mjpeg
拷贝*.so到开发板的mjpeg目录下，mjpg_streamer到开发板的bin下并改变权限

打开开开发板运行
mjpg_streamer -i "/webcam/input_uvc.so -y -d /dev/video0" -o "/webcam/output_http.so"
用火狐浏览器打开一个网页输入下面地址就能够看到一个视频(开发板的IP为222.22.253.88)： http://222.22.253.88:8080/?action=stream 打开一个网页输入下面地址就能够看到一个静态图片： http://222.22.253.88:8080/?action=snapshot 
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经常出的问题：
问1：由于摄像头驱动为v4l2架构的，所以安装mjpg_streamer视频服务器,但是运行mjpg_streamer出现如下错误？
# mjpg_streamer
Jan 14 01:57:37 MJPG-streamer [638]: starting application
MJPG Streamer Version.: 2.0
Jan 14 01:57:37 MJPG-streamer [638]: MJPG Streamer Version.: 2.0

ERROR: could not find input plugin
Jan 14 01:57:37 MJPG-streamer [638]: ERROR: could not find input plugin

Perhaps you want to adjust the search path with:
Jan 14 01:57:37 MJPG-streamer [638]:        Perhaps you want to adjust the search path with:

# export LD_LIBRARY_PATH=/path/to/plugin/folder
Jan 14 01:57:37 MJPG-streamer [638]:        # export LD_LIBRARY_PATH=/path/to/plugin/folder

dlopen: File not found
Jan 14 01:57:37 MJPG-streamer [638]:        dlopen: File not found

网友说找不到共享库路径，但是已经添加了/mjpeg/，还是出现这个问题，请问怎么回事？
下面是共享库的环境变量
export LD_LIBRARY_PATH='/mjpeg:/lib'

# ls /mjpeg/ -l
total 344
-rwxrwxrwx    1 root     root         61423 Jan 13 23:59 input_gspcav1.so
-rwxrwxrwx    1 root     root        168284 Jan 13 23:59 input_testpicture.so
-rwxrwxrwx    1 root     root         27718 Jan 13 23:59 input_uvc.so
-rwxrwxrwx    1 root     root         14736 Jan 14 00:01 mjpg_streamer
-rwxrwxrwx    1 root     root         29420 Jan 13 23:59 output_autofocus.so
-rwxrwxrwx    1 root     root         11958 Jan 13 23:59 output_file.so
-rwxrwxrwx    1 root     root         23726 Jan 13 23:59 output_http.so
-rwxr-xr-x    1 root     root          3436 Jan 14 01:06 start.sh

答1： 肯定不是共享库路径的问题了，mjpg_streamer -i "input_testpicture.so",可以正常运行，那就排除库的路径问题了
sean@ubuntu:~/work/cx92755/rishun_driver/web_cam/mjpg-streamer-r63$ file input_uvc.so  input_testpicture.so input_gspcav1.so
input_uvc.so:         ELF 32-bit LSB shared object, ARM, version 1 (SYSV), dynamically linked, not stripped
input_testpicture.so: ELF 32-bit LSB shared object, ARM, version 1 (SYSV), dynamically linked, not stripped
input_gspcav1.so:     ELF 32-bit LSB shared object, ARM, version 1 (SYSV), dynamically linked, not stripped

查看动态库也都是一样的，
通过readelf -d input_uvc.so 发现了问题
sean@ubuntu:~/work/cx92755/rishun_driver/web_cam/mjpg-streamer-r63$ readelf -d input_uvc.so

Dynamic section at offset 0x4898 contains 25 entries:
Tag        Type                         Name/Value
0x00000001 (NEEDED)                     Shared library: [libjpeg.so.8]		//需要依赖的库，然而这个库文件跟我编译jpeg库文件名称不同，修改库文件名称就搞定。
0x00000001 (NEEDED)                     Shared library: [libc.so.0]		//需要依赖的库
0x0000000c (INIT)                       0x1144
0x0000000d (FINI)                       0x3bf8
0x00000019 (INIT_ARRAY)                 0xc820
0x0000001b (INIT_ARRAYSZ)               4 (bytes)
0x0000001a (FINI_ARRAY)                 0xc824
0x0000001c (FINI_ARRAYSZ)               4 (bytes)
0x00000004 (HASH)                       0xb4
0x00000005 (STRTAB)                     0x8f8
0x00000006 (SYMTAB)                     0x338
0x0000000a (STRSZ)                      1049 (bytes)
0x0000000b (SYMENT)                     16 (bytes)
0x00000003 (PLTGOT)                     0xc980
0x00000002 (PLTRELSZ)                   520 (bytes)
0x00000014 (PLTREL)                     REL
0x00000017 (JMPREL)                     0xf3c
0x00000011 (REL)                        0xdec
0x00000012 (RELSZ)                      336 (bytes)
0x00000013 (RELENT)                     8 (bytes)
0x6ffffffe (VERNEED)                    0xdcc
0x6fffffff (VERNEEDNUM)                 1
0x6ffffff0 (VERSYM)                     0xd12
0x6ffffffa (RELCOUNT)                   30
0x00000000 (NULL)                       0x0

问2：在服务器上运行 mjpg_streamer -i "/webcam/input_uvc.so -d /dev/video0" -o "/webcam/output_http.so" ，在firefox浏览器上运行出现全黑？
答2：由于mjpg_streamer软件支持两种编码格式jpeg和yuv格式，如果摄像头是yuv格式，添加-y就可以了
服务器端	 			mjpg_streamer -i "/webcam/input_uvc.so -y -d /dev/video0" -o "/webcam/output_http.so"
客户端	 	 地址栏输入 http://192.168.8.15:8080/?action=stream 
服务器端 mjpg_streamer -i "/webcam/input_uvc.so -y -d /dev/video0" -o "/webcam/output_http.so -w `pwd`/www"