友善之臂視頻監(jiān)控方案源碼學(xué)習(xí)(5) - 輸入控制(共12頁(yè))

1、 HYPERLINK /tandesir/article/details/8437272 友善之臂視頻監(jiān)控(jin kn)方案源碼學(xué)習(xí)(5) - 輸入控制【問題(wnt)描述】在 HYPERLINK /tandesir/article/details/8435162 友善之臂視頻(shpn)監(jiān)控方案源碼學(xué)習(xí)(4) - 數(shù)據(jù)流向一文中，對(duì)視頻數(shù)據(jù)流向進(jìn)行了簡(jiǎn)要闡述。本文對(duì)輸入控制進(jìn)行解析。【解析】1 涉及到的文件和目錄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 輸入結(jié)構(gòu)mjpg-streamer-mini2440-read-only/plugins目錄下input.h中對(duì)input結(jié)構(gòu)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)之臂視頻監(jiān)控方案源碼學(xué)習(xí)(1) - 架構(gòu)分析一文，指出了該方案(fng n)實(shí)質(zhì)上就是實(shí)現(xiàn)了輸入、輸出的接口。從輸入看，就是實(shí)現(xiàn)了init、stop、run、cmd函數(shù)指針。主程序中實(shí)際上，只調(diào)用了init、run接口。stop接口是在信號(hào)的回調(diào)函數(shù)void signal_handler(int sig);中調(diào)用的。3input_init分析(fnx)(1)定義在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函數(shù)中，默認(rèn)的輸入為：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參數(shù)不為空，則采用下述方法更新輸入：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;傳送給Input_uvc.c中input_init的參數(shù)為：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。接口定義如下：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，定義

8、了一系列默認(rèn)的參數(shù)：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)，初始化互斥鎖：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);第三，參數(shù)解析。參數(shù)解析又分為(

10、fn wi)下面幾個(gè)步驟：(a) 讀取參數(shù)(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) 將字符串形式的參數(shù)分解為字符串?dāng)?shù)組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函數(shù)解析(ji x)參數(shù)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);該過程(guchng)詳細(xì)請(qǐng)參考 HYPERLINK /tandesir/article/details/8373205 友善之臂視頻監(jiān)控方案源碼學(xué)習(xí)(xux)(2) - 主程序?qū)崿F(xiàn)細(xì)節(jié)一文描述。(d) 根據(jù)輸入的參數(shù)執(zhí)行相應(yīng)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;這一步非常重要(zhngyo)，視頻數(shù)據(jù)信息就存儲(chǔ)在global結(jié)構(gòu)的buf變量中。第五，構(gòu)建videoIn結(jié)構(gòu)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);該結(jié)構(gòu)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;主要定義了視頻(shpn)輸入控制變量。第六，打開(d ki)視頻設(shè)備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具體(jt)實(shí)現(xiàn)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結(jié)構(gòu)(jigu)的初始化操作。第七，動(dòng)態(tài)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);其執(zhí)行(zhxng)的命令定義在input_cmd函數(shù)中：html HYPERLINK /tandesir/article/details/8437272 o view plain view plain HYPERLINK /tandesir/article/det