友善之臂视频监控方案源码学习(5) - 输入控制(共12页)

1、 HYPERLINK /tandesir/article/details/8437272 友善之臂视频监控(jin kn)方案源码学习(5) - 输入控制【问题(wnt)描述】在 HYPERLINK /tandesir/article/details/8435162 友善之臂视频(shpn)监控方案源码学习(4) - 数据流向一文中，对视频数据流向进行了简要阐述。本文对输入控制进行解析。【解析】1 涉及到的文件和目录mjpg-streamer-mini2440-read-only/start_uvc.shmjpg-streamer-mini2440-read-only/mjpg_streame

2、r.cmjpg-streamer-mini2440-read-only/mjpg_streamer.hmjpg-streamer-mini2440-read-only/plugins/input.hmjpg-streamer-mini2440-read-only/plugins/input_uvc2 输入结构mjpg-streamer-mini2440-read-only/plugins目录下input.h中对input结构描述如下：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLIN

3、K /tandesir/article/details/8437272 o copy copy/*structuretostorevariables/functionsforinputplugin*/typedefstruct_inputinput;struct_inputchar*plugin;void*handle;input_parameterparam;int(*init)(input_parameter*);int(*stop)(void);int(*run)(void);int(*cmd)(in_cmd_type,int); HYPERLINK /tandesir/article/

4、details/8373013 友善(yushn)之臂视频监控方案源码学习(1) - 架构分析一文，指出了该方案(fng n)实质上就是实现了输入、输出的接口。从输入看，就是实现了init、stop、run、cmd函数指针。主程序中实际上，只调用了init、run接口。stop接口是在信号的回调函数void signal_handler(int sig);中调用的。3input_init分析(fnx)(1)定义在mjpg-streamer-mini2440-read-only/plugins/input_uvc/Input_uvc.c文件中(2) 在mjpg-streamer-mini2440

5、-read-only/mjpg_streamer.c 的main函数中，默认的输入为：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copychar*input=input_uvc.so-resolution640 x480-fps5-device/dev/video0;若-i参数不为空，则采用下述方法更新输入：html HYPERLINK /tandesir/article/details/8

6、437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copy/*i,input*/case2:case3:input=strdup(optarg);break;传送给Input_uvc.c中input_init的参数为：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyglobal

7、.in.param.parameter_string=strchr(input,);下面分析mjpg-streamer-mini2440-read-only/plugins/input_uvc/input_uvc.c中的input_init接口。接口定义如下：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyintinput_init(input_parameter*param);首先，定义

8、了一系列默认的参数：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copychar*argvMAX_ARGUMENTS=NULL,*dev=/dev/video0,*s;intargc=1,width=640,height=480,fps=5,format=V4L2_PIX_FMT_MJPEG,i;in_cmd_typeled=IN_CMD_LED_AUTO;charfourcc5=0,0,0,

9、0,0;第二(d r)，初始化互斥锁：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copy/*initializethemutesvariable*/if(pthread_mutex_init(&controls_mutex,NULL)!=0)IPRINT(couldnotinitializemutexvariablen);exit(EXIT_FAILURE);第三，参数解析。参数解析又分为(

10、fn wi)下面几个步骤：(a) 读取参数(cnsh)html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyargv0=INPUT_PLUGIN_NAME;if(param-parameter_string!=NULL&strlen(param-parameter_string)!=0)char*arg=NULL,*saveptr=NULL,*token=NULL;arg=(char*)strd

11、up(param-parameter_string);(b) 将字符串形式的参数分解为字符串数组html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyif(strchr(arg,)!=NULL)token=strtok_r(arg,&saveptr);if(token!=NULL)argvargc=strdup(token);argc+;while(token=strtok_r(NULL,&sa

12、veptr)!=NULL)argvargc=strdup(token);argc+;if(argc=MAX_ARGUMENTS)IPRINT(ERROR:toomanyargumentstoinputpluginn);return1;(c) 利用getopt函数解析(ji x)参数html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyreset_getopt();while(1)intoptio

13、n_index=0,c=0;staticstructoptionlong_options=h,no_argument,0,0,help,no_argument,0,0,d,required_argument,0,0,device,required_argument,0,0,r,required_argument,0,0,resolution,required_argument,0,0,f,required_argument,0,0,fps,required_argument,0,0,y,no_argument,0,0,yuv,no_argument,0,0,q,required_argumen

14、t,0,0,quality,required_argument,0,0,m,required_argument,0,0,minimum_size,required_argument,0,0,n,no_argument,0,0,no_dynctrl,no_argument,0,0,l,required_argument,0,0,led,required_argument,0,0,0,0,0,0;/*parsingallparametersaccordingtothelistaboveissufficent*/c=getopt_long_only(argc,argv,long_options,&o

15、ption_index);该过程(guchng)详细请参考 HYPERLINK /tandesir/article/details/8373205 友善之臂视频监控方案源码学习(xux)(2) - 主程序实现细节一文描述。(d) 根据输入的参数执行相应的操作：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copy/*nomoreoptionstoparse*/if(c=-1)break;/*un

16、recognizedoption*/if(c=?)help();return1;/*dispatchthegivenoptions*/switch(option_index)/*h,help*/case0:case1:DBG(case0,1n);help();return1;break;/*d,device*/case2:case3:DBG(case2,3n);dev=strdup(optarg);break;/*r,resolution*/case4:case5:DBG(case4,5n);width=-1;height=-1;/*trytofindtheresolutioninlookup

17、tableresolutions*/for(i=0;iparam-globalhtml HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copy/*keepapointertotheglobalvariables*/pglobal=param-global;这一步非常重要(zhngyo)，视频数据信息就存储在global结构的buf变量中。第五，构建videoIn结构html HYPERLINK /tand

18、esir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyvideoIn=malloc(sizeof(structvdIn);if(videoIn=NULL)IPRINT(notenoughmemoryforvideoInn);exit(EXIT_FAILURE);memset(videoIn,0,sizeof(structvdIn);该结构描述如下：html HYPERLINK /tandesir/article/details/843

19、7272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copystructvdInintfd;char*videodevice;unsignedchar*pFramebuffer;unsignedchar*ptframeOUTFRMNUMB;unsignedchar*memNB_BUFFER;intframelockOUTFRMNUMB;pthread_mutex_tgrabmutex;intframesizeIn;volatileintframe_cour;intbppIn;inthdr

20、width;inthdrheight;intformatIn;intsignalquit;structv4l2_capabilitycap;structv4l2_formatfmt;structv4l2_bufferbuf;structv4l2_requestbuffersrb;intgrayscale;uint32_tquality;主要定义了视频(shpn)输入控制变量。第六，打开(d ki)视频设备html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/art

21、icle/details/8437272 o copy copy/*openvideodeviceandpreparedatastructure*/if(init_videoIn(videoIn,dev,width,height,fps,format,1)0)IPRINT(init_VideoInfailedn);closelog();exit(EXIT_FAILURE);init_videoIn具体(jt)实现如下：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tande

22、sir/article/details/8437272 o copy copyintinit_videoIn(structvdIn*vd,char*device,intwidth,intheight,intfps,intformat,intgrabmethod)if(vd=NULL|device=NULL)return-1;if(width=0|height=0)return-1;if(grabmethod1)grabmethod=1;/mmapbydefault;vd-videodevice=NULL;vd-status=NULL;vd-pictName=NULL;vd-videodevic

23、e=(char*)calloc(1,16*sizeof(char);vd-status=(char*)calloc(1,100*sizeof(char);vd-pictName=(char*)calloc(1,80*sizeof(char);snprintf(vd-videodevice,12,%s,device);vd-toggleAvi=0;vd-getPict=0;vd-signalquit=1;vd-width=width;vd-height=height;vd-fps=fps;vd-formatIn=format;vd-grabmethod=grabmethod;if(init_v4

24、l2(vd)framesizeIn=(vd-width*vd-heightformatIn)caseV4L2_PIX_FMT_MJPEG:vd-tmpbuffer=(unsignedchar*)calloc(1,(size_t)vd-framesizeIn);if(!vd-tmpbuffer)gotoerror;vd-framebuffer=(unsignedchar*)calloc(1,(size_t)vd-width*(vd-height+8)*2);break;caseV4L2_PIX_FMT_YUYV:default:vd-framebuffer=(unsignedchar*)call

25、oc(1,(size_t)vd-framesizeIn);break;/fprintf(stderr,shouldneverarriveexitfatal!n);/gotoerror;/break;if(!vd-framebuffer)gotoerror;return0;error:free(vd-videodevice);free(vd-status);free(vd-pictName);close(vd-fd);return-1;主要是完成了vdIn结构(jigu)的初始化操作。第七，动态控制初始化html HYPERLINK /tandesir/article/details/84372

26、72 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyif(dynctrls)initDynCtrls(videoIn-fd);第八(d b)，LED初始化html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/details/8437272 o copy copyin_cmd_typeled=IN_CMD_LED_AUTO;./*switchtheLEDaccordingtothecommandlineparameters(ifany)*/input_cmd(led,0);其执行(zhxng)的命令定义在input_cmd函数中：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/det