/*=========================================================================    capture.cc  -------------------------------------------------------------------------    Example code for video capture under Video4Linux II  -------------------------------------------------------------------------    Copyright 1999, 2000    Anna Helena Reali Costa, James R. Bruce    School of Computer Science    Carnegie Mellon University  -------------------------------------------------------------------------    This source code is distributed "as is" with absolutely no warranty.    See LICENSE, which should be included with this distribution.  -------------------------------------------------------------------------    Revision History:      2000-02-05:  Ported to work with V4L2 API      1999-11-23:  Quick C++ port to simplify & wrap in an object (jbruce)       1999-05-01:  Initial version (annar)  =========================================================================*/#include "capture.h"//==== Capture Class Implementation =======================================//void grabSetFps(int fd, int fps){  struct v4l2_streamparm params;  //printf("called v4l2_set_fps with fps=%d\n",fps);  params.type = V4L2_BUF_TYPE_CAPTURE;  ioctl(fd, VIDIOC_G_PARM, &params);  //printf("time per frame is: %ld\n", params.parm.capture.timeperframe);  params.parm.capture.capturemode |= V4L2_CAP_TIMEPERFRAME;  params.parm.capture.timeperframe = 10000000 / fps;  if (fps == 30)    params.parm.capture.timeperframe = 333667;  // printf("time per frame is: %ld\n", params.parm.capture.timeperframe);  ioctl(fd, VIDIOC_S_PARM, &params);    params.parm.capture.timeperframe = 0;  ioctl(fd, VIDIOC_G_PARM, &params);  // printf("time per frame is: %ld\n", params.parm.capture.timeperframe);  }bool capture::initialize(char *device,int nwidth,int nheight,int nfmt){  struct v4l2_requestbuffers req;  int err;  int i;  // Set defaults if not given  if(!device) device = DEFAULT_VIDEO_DEVICE;  if(!nfmt) nfmt = DEFAULT_VIDEO_FORMAT;  if(!nwidth || !nheight){    nwidth  = DEFAULT_IMAGE_WIDTH;    nheight = DEFAULT_IMAGE_HEIGHT;  }  // Open the video device  vid_fd = open(device, O_RDONLY);  if(vid_fd == -1){    printf("Could not open video device [%s]\n",device);    return(false);  }  fmt.type = V4L2_BUF_TYPE_CAPTURE;  err = ioctl(vid_fd, VIDIOC_G_FMT, &fmt);  if(err){    printf("G_FMT returned error %d\n",errno);    return(false);  }  // Set video format  fmt.fmt.pix.width = nwidth;  fmt.fmt.pix.height = nheight;  fmt.fmt.pix.pixelformat = nfmt;  if(true){    // attempt double framerate    fmt.fmt.pix.flags = V4L2_FMT_FLAG_TOPFIELD; // |V4L2_FMT_FLAG_BOTFIELD;    /*    fmt.fmt.pix.flags = (fmt.fmt.pix.flags |			 V4L2_FMT_FLAG_TOPFIELD | V4L2_FMT_FLAG_BOTFIELD) &                         ~V4L2_FMT_FLAG_INTERLACED;    */  }else{    fmt.fmt.pix.flags = fmt.fmt.pix.flags | V4L2_FMT_FLAG_INTERLACED;  }  err = ioctl(vid_fd, VIDIOC_S_FMT, &fmt);  if(err){    printf("S_FMT returned error %d\n",errno);    perror("S_FMT:");    return(false);  }  // grabSetFps(vid_fd, 30);  // Request mmap-able capture buffers  req.count = STREAMBUFS;  req.type  = V4L2_BUF_TYPE_CAPTURE;  err = ioctl(vid_fd, VIDIOC_REQBUFS, &req);  if(err < 0 || req.count < 1){    printf("REQBUFS returned error %d, count %d\n",	   errno,req.count);    return(false);  }  for(i=0; i<req.count; i++){    vimage[i].vidbuf.index = i;    vimage[i].vidbuf.type = V4L2_BUF_TYPE_CAPTURE;    err = ioctl(vid_fd, VIDIOC_QUERYBUF, &vimage[i].vidbuf);    if(err < 0){      printf("QUERYBUF returned error %d\n",errno);      return(false);    }    vimage[i].data = (char*)mmap(0, vimage[i].vidbuf.length, PROT_READ,			  MAP_SHARED, vid_fd, 			  vimage[i].vidbuf.offset);    if((int)vimage[i].data == -1){      printf("mmap() returned error %d\n", errno);      return(false);    }  }  for(i=0; i<req.count; i++){    if((err = ioctl(vid_fd, VIDIOC_QBUF, &vimage[i].vidbuf))){      printf("1QBUF returned error %d\n",errno);      perror("QBUF error");      return(false);    }  }  // Turn on streaming capture  err = ioctl(vid_fd, VIDIOC_STREAMON, &vimage[0].vidbuf.type);  if(err){    printf("STREAMON returned error %d\n",errno);    return(false);  }  width   = nwidth;  height  = nheight;  current = NULL;  return(true);}void capture::close(){  int i,t;  if(vid_fd >= 0){    t = V4L2_BUF_TYPE_CAPTURE;    ioctl(vid_fd, VIDIOC_STREAMOFF, &t);    for(i=0; i<STREAMBUFS; i++){      if(vimage[i].data){        munmap(vimage[i].data,vimage[i].vidbuf.length);      }    }  }}unsigned char *capture::captureFrame(int &index,int &field){  //if(captured_frame){  //  printf("there may be a problem capturing frame w/o releasing previous frame");  //}  // struct v4l2_buffer tempbuf;  int err;  fd_set          rdset;  struct timeval  timeout;  int		  n;  struct v4l2_buffer tempbuf;  FD_ZERO(&rdset);  FD_SET(vid_fd, &rdset);  timeout.tv_sec = 1;  timeout.tv_usec = 0;  n = select(vid_fd + 1, &rdset, NULL, NULL, &timeout);  err = -1;  if (n == -1) {    fprintf(stderr, "select error.\n");    perror("select msg:");  }  else if (n == 0)    fprintf(stderr, "select timeout\n");  else if (FD_ISSET(vid_fd, &rdset))    err = 0;  if(err) return(NULL);  // Grab last frame  do {    //printf("D");    tempbuf.type = vimage[0].vidbuf.type;    err = ioctl(vid_fd, VIDIOC_DQBUF, &tempbuf);    if(err) {      printf("4DQBUF returned error %d\n",errno);      perror("DQBUF error:");    }    //printf("S");    FD_ZERO(&rdset);    FD_SET(vid_fd, &rdset);    timeout.tv_sec = 0;    timeout.tv_usec = 0;    n = select(vid_fd + 1, &rdset, NULL, NULL, &timeout);    // Uncomment this next line to see how many frames are being skipped.    // 1=frame skipped, 0=frame used    //printf("n%d",n);    if(n==-1) {      fprintf(stderr, "select error.\n");      perror("2select msg:");    }    else if(n==0)      break;    if (!FD_ISSET(vid_fd, &rdset))      printf("huh\n");    //printf("Q");    err = ioctl(vid_fd, VIDIOC_QBUF, &tempbuf);    if(err) {      printf("3QBUF returned error %d\n",errno);      perror("QBUF error:");    }  } while(true);  field = 0;  if(tempbuf.flags & V4L2_BUF_FLAG_TOPFIELD) field = 1;  if(tempbuf.flags & V4L2_BUF_FLAG_BOTFIELD) field = 0;  // Set current to point to captured frame data  current = (unsigned char *)vimage[tempbuf.index].data;  timestamp = tempbuf.timestamp;  index = tempbuf.index;  // gettimeofday(&timeout,NULL);  // timestamp = (stamp_t)((timeout.tv_sec + timeout.tv_usec/1.0E6) * 1.0E9);  // printf("field: %d\n",field);  // Initiate the next capture  //tempbuf.index = (++index - 1) % STREAMBUFS;  //err = ioctl(vid_fd, VIDIOC_QBUF, &tempbuf);  //if(err) printf("QBUF returned error %d\n",errno);    captured_frame = true;  return(current);}void capture::releaseFrame(unsigned char* frame, int index){  int err;  struct v4l2_buffer tempbuf;  //if(frame != current){  //  printf("frame != current, possibly releasing the wrong frame.");  //}  captured_frame = false;  // Initiate the next capture  tempbuf.type = vimage[0].vidbuf.type;  tempbuf.index=index;  //printf("%lx %d\n",tempbuf.type,tempbuf.index);  err = ioctl(vid_fd, VIDIOC_QBUF, &tempbuf);  if(err) {    printf("2QBUF returned error %d\n",errno);    perror("QBUF error:");  }}struct v4l2_buffer tempbuf;unsigned char *capture::captureFrame(){  // struct v4l2_buffer tempbuf;  int err;  fd_set          rdset;  struct timeval  timeout;  int		  n;  FD_ZERO(&rdset);  FD_SET(vid_fd, &rdset);  timeout.tv_sec = 1;  timeout.tv_usec = 0;  n = select(vid_fd + 1, &rdset, NULL, NULL, &timeout);  err = -1;  if (n == -1)    fprintf(stderr, "select error.\n");  else if (n == 0)    fprintf(stderr, "select timeout\n");  else if (FD_ISSET(vid_fd, &rdset))    err = 0;  if(err) return(NULL);  // Grab last frame  tempbuf.type = vimage[0].vidbuf.type;  err = ioctl(vid_fd, VIDIOC_DQBUF, &tempbuf);  if(err) printf("DQBUF returned error %d\n",errno);  // Set current to point to captured frame data  current = (unsigned char *)vimage[tempbuf.index].data;  timestamp = tempbuf.timestamp;  // Initiate the next capture  err = ioctl(vid_fd, VIDIOC_QBUF, &tempbuf);  if(err) printf("QBUF returned error %d\n",errno);  return(current);}