v4l2 video设备支持功能查询

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video设备支持功能查询小工具，

方便v4l2开发

#include <stdio.h>#include <string.h>#include <errno.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <time.h>#include <sys/mman.h>#include <assert.h>#include <linux/videodev2.h>#include <linux/fb.h>#define CLEAR(x)    memset(&(x), 0, sizeof(x))typedef unsigned char BYTE;typedef unsigned short WORD;typedef unsigned int DWORD;typedef long LONG;#define CHECKNUM 8struct {unsigned int type;char *name;} enum_fmt[]={{V4L2_CAP_VIDEO_CAPTURE, "V4L2_CAP_VIDEO_CAPTURE"},{V4L2_CAP_VIDEO_OUTPUT, "V4L2_CAP_VIDEO_OUTPUT"},{V4L2_CAP_VIDEO_OVERLAY, "V4L2_CAP_VIDEO_OVERLAY"},{V4L2_CAP_VIDEO_CAPTURE_MPLANE, "V4L2_CAP_VIDEO_CAPTURE_MPLANE"},{V4L2_CAP_VIDEO_OUTPUT_MPLANE, "V4L2_CAP_VIDEO_OUTPUT_MPLANE"},{V4L2_CAP_VIDEO_M2M_MPLANE, "V4L2_CAP_VIDEO_M2M_MPLANE"},{V4L2_CAP_VIDEO_M2M, "V4L2_CAP_VIDEO_M2M"},{V4L2_CAP_STREAMING, "V4L2_CAP_STREAMING"},};int open_camer_device(char *path){int fd;if((fd = open(path,O_RDWR | O_NONBLOCK)) < 0){perror("Fail to open");exit(EXIT_FAILURE);} printf("open cam:%s success %d\n",path, fd);return fd;}void enum_video_ctrls_and_menus(int fd){ /*  \* To query the attributes of a control applications set the id field of a struct   \* v4l2_queryctrl and call the VIDIOC_QUERYCTRL ioctl with a pointer to this  \* structure. The driver fills the rest of the structure or returns an EINVAL   \* error code when the id is invalid.  \*  \* To enumerate controls call VIDIOC_QUERYCTRL with successive  \* id values starting from V4L2_CID_BASE up to and exclusive V4L2_CID_LASTP1,   \* or starting from V4L2_CID_PRIVATE_BASE until the driver returns EINVAL.   */   struct v4l2_queryctrl queryctrl;    /* Query Control structure as defined in <sys/videodev2.h> */  struct v4l2_querymenu querymenu;    /* Query Menu Structure as defined in <sys/videodev2.h> */  fprintf(stdout,"Discovering controls:\n");   memset (&queryctrl, 0, sizeof (queryctrl));    for (queryctrl.id = V4L2_CID_BASE; queryctrl.id < V4L2_CID_LASTP1; queryctrl.id++) {      if ( ioctl (fd, VIDIOC_QUERYCTRL, &queryctrl) == 0 ) {          /* Check to see if this control is permanently disabled and should be ignored by the application */          if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED)              continue;          /* We got a video control back */          fprintf(stdout,"\nVIDIOC_QUERYCTRL(V4L2_CID_BASE+%d)\n", queryctrl.id-V4L2_CID_BASE);          fprintf(stdout,"   id: %d\n", queryctrl.id);          switch (queryctrl.type){              case V4L2_CTRL_TYPE_INTEGER:                  fprintf(stdout, "   type: INTEGER\n");                  break;              case V4L2_CTRL_TYPE_BOOLEAN:                  fprintf(stdout, "   type: BOOLEAN\n");                  break;              case V4L2_CTRL_TYPE_MENU:                  fprintf(stdout, "   type: MENU\n");                  /* Additional information is required for menu controls, the name of menu items.                    \* To query them applications set the id and index fields of struct v4l2_querymenu                    \*   and call the VIDIOC_QUERYMENU ioctl with a pointer to this structure. The driver                   \*   fills the rest of the structure or returns an EINVAL error code when the id or                    \*   index is invalid. Menu items are enumerated by calling VIDIOC_QUERYMENU with                    \*   successive index values from struct v4l2_queryctrl minimum (0) to maximum, inclusive.                   */                  querymenu.id = queryctrl.id;                  for (querymenu.index = queryctrl.minimum; querymenu.index < queryctrl.maximum; querymenu.index++){                      fprintf(stdout, "      menu id:%d\n", querymenu.index);                      fprintf(stdout, "      menu name:%s\n", querymenu.name);                  }                  break;              case V4L2_CTRL_TYPE_BUTTON:                  fprintf(stdout, "   type: BUTTON\n");                  break;          }          fprintf(stdout,"   name: %s\n", queryctrl.name);          fprintf(stdout,"   minimum: %d\n", queryctrl.minimum);          fprintf(stdout,"   maximum: %d\n", queryctrl.maximum);          fprintf(stdout,"   step: %d\n", queryctrl.step);          fprintf(stdout,"   default_value: %d\n", queryctrl.default_value);          fprintf(stdout,"   flags: %d\n", queryctrl.flags);      } else {             if (errno == EINVAL)                 continue;             perror("VIDIOC_QUERYCTRL");             break;      }   }      } /* End of enum_video_ctrls_and_menus() */int main(int argc, char** argv){int fd;struct v4l2_fmtdesc fmt;struct v4l2_capability cap;struct v4l2_format stream_fmt;struct v4l2_input input;struct v4l2_control ctrl;struct v4l2_streamparm stream;int err;int ret;int i;if (argc < 2) {      //  printusage(argv[0]);  printf("please input path\n");return -1;}fd = open_camer_device(argv[1]);for(i = 0; i < CHECKNUM; i++){memset(&fmt,0,sizeof(fmt));fmt.index = 0;fmt.type = enum_fmt[i].type;//printf("enum_fmt:%s\n", enum_fmt[i].name);while((ret = ioctl(fd,VIDIOC_ENUM_FMT,&fmt)) == 0){fmt.index ++ ;printf("%s:{pixelformat = %c%c%c%c},description = '%s'\n",enum_fmt[i].name,fmt.pixelformat & 0xff,(fmt.pixelformat >> 8)&0xff,(fmt.pixelformat >> 16) & 0xff,(fmt.pixelformat >> 24)&0xff,fmt.description);}}printf("\n\n");enum_video_ctrls_and_menus(fd);//查询视频设备支持的功能ret = ioctl(fd,VIDIOC_QUERYCAP,&cap);if(ret < 0){perror("FAIL to ioctl VIDIOC_QUERYCAP");//exit(EXIT_FAILURE);}//printf("capabilities:%08x\n", cap.capabilities);printf("\ncheck the support capabilities\n");for(i = 0; i < CHECKNUM; i++){if(cap.capabilities & enum_fmt[i].type)printf("%s\n",enum_fmt[i].name);}printf("\n");if(!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)){printf("The Current device is not a video capture device\n");//exit(EXIT_FAILURE);}elseprintf("The Current device is a video capture device\n");if(!(cap.capabilities & V4L2_CAP_STREAMING)){printf("The Current device does not support streaming i/o\n");//exit(EXIT_FAILURE);}elseprintf("The Current device support streaming i/o\n");return 0;}

比如MFC设备

[liujia@210]#./cam_scan /dev/video9open cam:/dev/video9 success 3V4L2_CAP_VIDEO_CAPTURE:{pixelformat = H264},description = 'H264 Encoded Stream'V4L2_CAP_VIDEO_CAPTURE:{pixelformat = MPG4},description = 'MPEG4 Encoded Stream'V4L2_CAP_VIDEO_CAPTURE:{pixelformat = H263},description = 'H263 Encoded Stream'Discovering controls:check the support capabilitiesV4L2_CAP_VIDEO_CAPTURE_MPLANEV4L2_CAP_VIDEO_OUTPUT_MPLANEV4L2_CAP_VIDEO_M2M_MPLANEV4L2_CAP_STREAMINGThe Current device is not a video capture deviceThe Current device support streaming i/o

USB camera设备

[liujia@210]#./cam_scan /dev/video13open cam:/dev/video13 success 3V4L2_CAP_VIDEO_CAPTURE:{pixelformat = YUYV},description = 'YUV 4:2:2 (YUYV)'V4L2_CAP_VIDEO_CAPTURE:{pixelformat = MJPG},description = 'MJPEG'Discovering controls:VIDIOC_QUERYCTRL(V4L2_CID_BASE+0)   id: 9963776   type: INTEGER   name: Brightness   minimum: 0   maximum: 255   step: 1   default_value: 128   flags: 0VIDIOC_QUERYCTRL(V4L2_CID_BASE+1)   id: 9963777   type: INTEGER   name: Contrast   minimum: 0   maximum: 255   step: 1   default_value: 32   flags: 0VIDIOC_QUERYCTRL(V4L2_CID_BASE+2)   id: 9963778   type: INTEGER   name: Saturation   minimum: 0   maximum: 255   step: 1   default_value: 32   flags: 0VIDIOC_QUERYCTRL(V4L2_CID_BASE+12)   id: 9963788   type: BOOLEAN   name: White Balance Temperature, Auto   minimum: 0   maximum: 1   step: 1   default_value: 1   flags: 0VIDIOC_QUERYCTRL(V4L2_CID_BASE+19)   id: 9963795   type: INTEGER   name: Gain   minimum: 0   maximum: 255   step: 1   default_value: 0   flags: 0VIDIOC_QUERYCTRL(V4L2_CID_BASE+24)   id: 9963800   type: MENU      menu id:0      menu name:rÿ¶DRï¶Ä      menu id:1      menu name:rÿ¶DRï¶Ä   name: Power Line Frequency   minimum: 0   maximum: 2   step: 1   default_value: 2   flags: 0VIDIOC_QUERYCTRL(V4L2_CID_BASE+26)   id: 9963802   type: INTEGER   name: White Balance Temperature   minimum: 0   maximum: 10000   step: 10   default_value: 4000   flags: 16VIDIOC_QUERYCTRL(V4L2_CID_BASE+27)   id: 9963803   type: INTEGER   name: Sharpness   minimum: 0   maximum: 255   step: 1   default_value: 24   flags: 0VIDIOC_QUERYCTRL(V4L2_CID_BASE+28)   id: 9963804   type: INTEGER   name: Backlight Compensation   minimum: 0   maximum: 1   step: 1   default_value: 1   flags: 0check the support capabilitiesV4L2_CAP_VIDEO_CAPTUREV4L2_CAP_STREAMINGThe Current device is a video capture deviceThe Current device support streaming i/o

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