有哪些软件可以在ubuntu下查看USB摄像头的视频

新版本的内核中Linux内核中已经包含了大部分的USB摄像头驱动，因此，在高版本的linux内核系统中使用USB摄像头并不需要做很多工作。

Linux环境为Ubuntu 10.04，Linux 2.6.32内核，已经包含了大部分USB摄像头的驱动程序，插上摄像头时即可识别。直接将我们USB摄像头插上，查看系统中USB设备信息。

   

root@Ubuntu1004:~# lsusb    //查看系统中的usb设备

Bus 002 Device 002: ID 0e0f:0002 VMware, Inc. Virtual USB Hub

Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 001 Device 005: ID 0ac8:3450 Z-Star Microelectronics Corp.  

//显示干插入的USB设备信息，ID为0ac8:3450，芯片厂商信息为Z-Star Microelectronics Corp.

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

ffmpeg编译

首先解压ffmpeg-0.5.1.tar.bz2,，执行configure命令如下：

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./configure --cc=arm-linux-gnueabihf-gcc --host-cc=arm-linux-gnueabihf --prefix=/home/***/iWork/common/gcc-linaro-arm-linux-gnueabihf-4.8-2013.10_linux --enable-cross-compile --arch=arm --disable-yasm

编译：

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make

出现错误如下：

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arm-linux-gnueabihf-gcc -DHAVE_AV_CONFIG_H -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -I. -I"/home/***/iWork/lamobo/motion-3.2.12-arm-project/ffmpeg-0.5.1"

-D_ISOC99_SOURCE -D_POSIX_C_SOURCE=200112 -std=c99 -fomit-frame-pointer -g -Wdeclaration-after-statement -Wall -Wno-switch -Wdisabled-optimization

-Wpointer-arith -Wredundant-decls -Wno-pointer-sign -Wcast-qual -Wwrite-strings -Wtype-limits -Wundef -O3 -fno-math-errno -fno-signed-zeros -c -o

libavcodec/dsputil.o libavcodec/dsputil.c

/tmp/ccOmDdh7.s: Assembler messages:

/tmp/ccOmDdh7.s:51789: Error: thumb conditional instruction should be in IT block -- `movgt fp,r9'

/tmp/ccOmDdh7.s:51790: Error: thumb conditional instruction should be in IT block -- `movgt r9,r8'

/tmp/ccOmDdh7.s:51792: Error: thumb conditional instruction should be in IT block -- `movle r9,r7'

/tmp/ccOmDdh7.s:51794: Error: thumb conditional instruction should be in IT block -- `movgt fp,r9'

/tmp/ccOmDdh7.s:51889: Error: thumb conditional instruction should be in IT block -- `movgt r9,r8'

/tmp/ccOmDdh7.s:51890: Error: thumb conditional instruction should be in IT block -- `movgt r8,ip'

/tmp/ccOmDdh7.s:51892: Error: thumb conditional instruction should be in IT block -- `movle r8,r6'

/tmp/ccOmDdh7.s:51894: Error: thumb conditional instruction should be in IT block -- `movgt r9,r8'

make: *** [libavcodec/dsputil.o] Error 1

这需要修改~/ffmpeg-0.5.1/config.mak，在OPTFLAGS（line：16）选项中添加：

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-Wa,-mimplicit-it=thumb

加入这句的意思是在使用Thumb ISA指令编译时自动产生“IT”指令。 继续编译，又报错：

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strip: Unable to recognise the format of the input file `ffmpeg'

这是strip没有使用交叉编译的版本所致，由于此时我们需要的库文件已经编成，所以这个错误可以忽略不计，修改config.mak中的strip为arm-linux-gnueabihf-strip，继续让编译完成

motion编译

motion中的ffmpeg.c是对ffmpeg api的封装，向其他模块提供功能。如在主程序文件motion.c中

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//......

#ifdef HAVE_FFMPEG

/* FFMpeg initialization is only performed if FFMpeg support was found

* and not disabled during the configure phase.

*/

ffmpeg_init()

#endif /* HAVE_FFMPEG */

//......

这里ffmpeg_init就是ffmpeg.c中封装的方法：

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void ffmpeg_init()

{

motion_log(LOG_INFO, 0, "ffmpeg LIBAVCODEC_BUILD %d LIBAVFORMAT_BUILD %d", LIBAVCODEC_BUILD, LIBAVFORMAT_BUILD)

av_register_all()

#if LIBAVCODEC_BUILD >4680

av_log_set_callback( (void *)ffmpeg_avcodec_log )

#endif

/* Copy the functions to use for the append file protocol from the standard

* file protocol.

*/

mpeg1_file_protocol.url_read = file_protocol.url_read

mpeg1_file_protocol.url_write = file_protocol.url_write

mpeg1_file_protocol.url_seek = file_protocol.url_seek

mpeg1_file_protocol.url_close = file_protocol.url_close

/* Register the append file protocol. */

#if LIBAVFORMAT_BUILD >= (52<<16 | 31<<8)

av_register_protocol(&mpeg1_file_protocol)

#else

register_protocol(&mpeg1_file_protocol)

#endif

}

我们需要在motion的Makefile中加入对ffmpeg模块的编译，并且打开HAVE_FFMPEG等开关。首先执行configure如下：

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./configure CC=arm-linux-gnueabihf-gcc --host=arm-linux-gnueabihf --prefix=/home/stewart/iWork/common/gcc-linaro-arm-linux-gnueabihf-4.8-2013.10_linux

生成Makefile，在OBJ选项中添加ffmpeg.o:

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OBJ = ffmpeg.o motion.o conf.o draw.o jpegutils.o $(VIDEO_OBJ) netcam.o \

netcam_ftp.o netcam_jpeg.o netcam_wget.o track.o \

alg.o event.o picture.o rotate.o webhttpd.o \

webcam.o

在CFLAGS选项中添加-DHAVE_FFMPEG -DFFMPEG_NEW_INCLUDES -DHAVE_FFMPEG_NEW的定义，加入libjpeg头文件搜索目录

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libdir = ${prefix}/lib

incdir = ${prefix}/include

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CFLAGS = -g -O2 -DHAVE_FFMPEG -DFFMPEG_NEW_INCLUDES -DHAVE_FFMPEG_NEW -D_REENTRANT

-DMOTION_V4L2 -DMOTION_V4L2_OLD -DTYPE_32BIT="int" -DHAVE_BSWAP-Wall

-DVERSION=\"3.2.12\" -Dsysconfdir=\"$(sysconfdir)\"

在LIBS中加入对ffmpeg库的支持：

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LIBS = -L${libdir} -static -lavformat -lavcodec -lavutil -ljpeg -lm -lpthread

预备工作完成，make，编译报错：

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motion.h:44:28: fatal error: linux/videodev.h: No such file or directory

compilation terminated.

由于linux-2.4以上的内核已经取消了videodev.h文件，需要安装libv4l-dev，然后将motion.h，video.h中的

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#include <linux/videodev.h>

修改为

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#include <libv4l1-videodev.h>

继续，又报错：

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track.c: In function ‘uvc_center’:

track.c:587:29: error: storage size of ‘control_s’ isn’t known

track.c:589:24: error: ‘V4L2_CID_PRIVATE_BASE’ undeclared (first use in this function)

track.c:589:24: note: each undeclared identifier is reported only once for each function it appears in

track.c:592:24: error: ‘VIDIOC_S_CTRL’ undeclared (first use in this function)

track.c:601:31: error: storage size of ‘queryctrl’ isn’t known

track.c:605:24: error: ‘VIDIOC_QUERYCTRL’ undeclared (first use in this function)

track.c:601:31: warning: unused variable ‘queryctrl’ [-Wunused-variable]

track.c:587:29: warning: unused variable ‘control_s’ [-Wunused-variable]

track.c:636:25: error: storage size of ‘control_s’ isn’t known

track.c:636:25: warning: unused variable ‘control_s’ [-Wunused-variable]

track.c: In function ‘uvc_move’:

track.c:724:29: error: storage size of ‘control_s’ isn’t known

track.c:726:24: error: ‘V4L2_CID_PRIVATE_BASE’ undeclared (first use in this function)

track.c:729:24: error: ‘VIDIOC_S_CTRL’ undeclared (first use in this function)

track.c:724:29: warning: unused variable ‘control_s’ [-Wunused-variable]

track.c:779:25: error: storage size of ‘control_s’ isn’t known

track.c:779:25: warning: unused variable ‘control_s’ [-Wunused-variable]

make: *** [track.o] Error 1

在track.c中添加:

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#include <linux/videodev2.h>

继续，报错（怎么还有啊？）：

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gcc -L/usr/local/lib -o motion motion.o conf.o draw.o jpegutils.o video.o video2.o video_common.o netcam.o netcam_ftp.o netcam_jpeg.o netcam_wget.o track.o alg.o event.o picture.o rotate.o webhttpd.o webcam.o ffmpeg.o -lm -lpthread -ljpeg -L/usr/local/lib -lavformat -lavcodec -lavutil -lm -lz

/usr/local/lib/libavformat.a(file.o):(.data+0x60): multiple definition of `file_protocol'

ffmpeg.o:(.data+0x0): first defined here

collect2: ld returned 1 exit status

原来结构体file_protocol在libavformat.a和ffmpeg.o中重复定义了，分别打开两个定义：

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//libavformat/file.c:85

URLProtocol file_protocol = {

"file",

file_open,

file_read,

file_write,

file_seek,

file_close,

}

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//ffmpeg.c

URLProtocol file_protocol = {

"file",

file_open,

file_read,

file_write,

file_seek,

file_close,

#if LIBAVFORMAT_BUILD >= (52<<16 | 31<<8)

NULL,

NULL,

NULL,

#endif

}

将libavformat/file.c中的file_protocol定义注掉，重新编译一份libavformat.a。然后继续编译motion，又报错：

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/home/xxx/iWork/Thrid_party/ffmpeg-0.5.1/libavformat/matroskadec.c:917: undefined reference to `BZ2_bzDecompressInit'

/home/xxx/iWork/Thrid_party/ffmpeg-0.5.1/libavformat/matroskadec.c:926: undefined reference to `BZ2_bzDecompress'

/home/xxx/iWork/Thrid_party/ffmpeg-0.5.1/libavformat/matroskadec.c:929: undefined reference to `BZ2_bzDecompressEnd'

这个需要libbz2库，下载地址http://www.bzip.org/downloads.html

编译安装libbz2后将-lbz2加入motion的Makefile的LIBS选项：

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LIBS = -lpthread -ljpeg -L/usr/lib -lavformat -lavcodec -lavutil -lm -lz -lbz2

建议条件允许的话还是使用双目摄像头，毕竟双目识别图像更稳定精准。这里推荐小觅双目摄像头，基于双目视觉的三维重建与6轴传感器矫正等，并充分利用摄像头和运动传感器的互补性，保持双目高清同帧。

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