rlWebcam Class Reference

#include <rlwebcam.h>

Collaboration diagram for rlWebcam:

Public Member Functions
	rlWebcam ()
virtual	~rlWebcam ()
int	setUrl (const char *url)
int	disconnect ()
const char *	getSnapshot (int timeout=3000)
const char *	getFrame (int timeout=3000)
const char *	getUrl ()
const char *	getHost ()
int	getPort ()
const char *	getPath ()
Public Attributes
int	debug
rlString	filename
Private Attributes
rlSocket *	sock
rlString	url
rlString	temp1
rlString	temp2
rlString	temp3

Detailed Description

class for handling networked webcams over http:// that use motion jpeg

If you do not know under which URL your webcam provides the M-JPEG video stream
you may use tcpdump to figure it out.

Example:

tcpdump -X -i eth0 -t -q -s 0 "host 192.168.1.200 && port 80" | grep -A 10 GET

IP myhost.46727 > 192.168.1.200.http: tcp 97
 0x0000:  4500 0089 edb6 4000 4006 c891 c0a8 010e  E.....@.@.......
 0x0010:  c0a8 01c8 b687 0050 d99f 8b7d 0003 d5b2  .......P...}....
 0x0020:  5018 16d0 2460 0000 4745 5420 2f63 6769  P...$`..GET./cgi
 0x0030:  2d62 696e 2f53 7472 6561 6d3f 5669 6465  -bin/Stream?Vide
 0x0040:  6f20 4175 7468 6f72 697a 6174 696f 6e3a  o.Authorization:
 0x0050:  2042 6173 6963 2059 5752 7461 5734 3663  .Basic.YWRtaW46c
 0x0060:  4746 7a63 3364 7663 6d51 3d3f 7765 6263  GFzc3dvcmQ=?webc
 0x0070:  616d 5057 443d 526f 6f74 436f 6f6b 6965  amPWD=RootCookie
 0x0080:  3030 3030 300d 0a0d 0a                   00000....

Usage example for pvbrowser slot functions:

include "rlwebcam.h"

typedef struct // (todo: define your data structure here)
{
  rlWebcam webcamBig;
}
DATA;

static int slotInit(PARAM *p, DATA *d)
{
  if(p == NULL || d == NULL) return -1;
  p->sleep = 20;
  p->force_null_event = 0;
  d->webcamBig.debug = 0;
  d->webcamBig.filename.printf("%swebcam.jpg", p->file_prefix);
  d->webcamBig.setUrl("http://192.168.1.200/cgi-bin/Stream?Video Authorization: Basic YWRtaW46cGFzc3dvcmQ=?webcamPWD=RootCookie00000");
  return 0;
}

static int slotNullEvent(PARAM *p, DATA *d)
{
  if(p == NULL || d == NULL) return -1;
  if(const char *fname = d->webcamBig.getFrame()) // OR if(const char *fname = d->webcamBig.getSnapshot()) 
  {
    pvDownloadFileAs(p,fname,"webcam.jpg");
    pvSetImage(p,WebcamBig,"webcam.jpg"); // WebcamBig is a pvQImage object that accepts jpeg images
  }
  return 0;
}

Definition at line 77 of file rlwebcam.h.

Constructor & Destructor Documentation

rlWebcam::rlWebcam ( )

Definition at line 18 of file rlwebcam.cpp.

00019 {
00020   debug = 0;
00021   sock = NULL;
00022 }

rlWebcam::~rlWebcam ( ) [virtual]

Definition at line 24 of file rlwebcam.cpp.

00025 {
00026   if(sock != NULL) delete sock;
00027 }

Member Function Documentation

int rlWebcam::disconnect ( )

Definition at line 40 of file rlwebcam.cpp.

00041 {
00042   if(sock == NULL) return -1;
00043   if(sock->isConnected()) sock->disconnect();
00044   return 0;
00045 }

const char * rlWebcam::getFrame ( int timeout = 3000 )

Definition at line 60 of file rlwebcam.cpp.

00061 {
00062   unsigned char c1,c2;
00063 
00064   if(sock == NULL)
00065   {
00066     printf("rlWebcam::ERROR sock==NULL\n");
00067     return NULL;
00068   }
00069   if(sock->isConnected() == 0) 
00070   {
00071     sock->connect();
00072     sock->printf("GET /%s%c%c%c%c",getPath(),0x0d,0x0a,0x0d,0x0a);
00073   }  
00074   if(sock->isConnected() == 0)
00075   {
00076     printf("rlWebcam::ERROR sock->isConnected() == 0\n");
00077     return NULL;
00078   }
00079 
00080   // search for startOfImage
00081   while(1)
00082   {
00083     if(sock->read(&c1,1,timeout) < 1) return NULL;
00084     if(debug) printf("%02x ", c1);
00085     if(c1 == 0x0ff)
00086     {
00087       if(sock->read(&c2,1,timeout) < 1) return NULL;
00088       if(debug) printf("%02x ", c2);
00089       if(c2 == 0x0d8)
00090       {
00091         if(debug) printf("\nrlWebcam::Found startOfImage\n");
00092         break;
00093       }
00094     }
00095   }
00096 
00097   // open output file
00098   if(filename.text() == NULL)
00099   {
00100     printf("rlWebcam::ERROR you forgot to set filename\n");
00101     return NULL;
00102   }
00103   FILE *fout = fopen(filename.text(),"w");
00104   if(fout == NULL)
00105   {
00106     printf("rlWebcam::ERROR could not write file %s\n", filename.text());
00107     return NULL;
00108   }
00109   fputc(c1, fout);
00110   fputc(c2, fout);
00111 
00112   // read until endOfImage
00113   while(1)
00114   {
00115     if(sock->read(&c1,1,timeout) < 1) return NULL;
00116     fputc(c1, fout);
00117     if(debug) printf("%02x ", c1);
00118     if(c1 == 0x0ff)
00119     {
00120       if(sock->read(&c2,1,timeout) < 1) return NULL;
00121       fputc(c2, fout);
00122       if(debug) printf("%02x ", c2);
00123       if(c2 == 0x0d9)
00124       {
00125         if(debug) printf("\nrlWebcam::Found endOfImage\n");
00126         break;
00127       }
00128     }
00129   }
00130 
00131   // close output file
00132   fclose(fout);
00133   return filename.text();
00134 }

const char * rlWebcam::getHost ( )

Definition at line 141 of file rlwebcam.cpp.

00142 {
00143   if(url.startsWith("http://") == 0)
00144   {
00145     printf("rlWebcam::wrong url syntax in %s\n", url.text());
00146     printf("url syntax: http://host:port/path_to_webcam_cgi_script\n");
00147     return NULL;
00148   }
00149   char *cptr = url.text();
00150   cptr += 7;
00151   temp1.setText(cptr);
00152   cptr = temp1.strchr('/');
00153   if(cptr != NULL) *cptr = '\0';
00154   cptr = temp1.strchr(':');
00155   if(cptr != NULL) *cptr = '\0';
00156   if(debug) printf("rlWebcam:host=%s\n", temp1.text());
00157   return temp1.text();
00158 }

const char * rlWebcam::getPath ( )

Definition at line 180 of file rlwebcam.cpp.

00181 {
00182   if(url.startsWith("http://") == 0)
00183   {
00184     printf("rlWebcam::wrong url syntax in %s\n", url.text());
00185     printf("url syntax: http://host:port/path_to_webcam_cgi_script\n");
00186     return NULL;
00187   }
00188   char *cptr = url.text();
00189   cptr += 7;
00190   temp3.setText(cptr);
00191   cptr = temp3.strchr('/');
00192   if(cptr == NULL) return "";
00193   cptr++;
00194   if(debug) printf("rlWebcam:path=%s\n", cptr);
00195   return cptr;
00196 }

int rlWebcam::getPort ( )

Definition at line 160 of file rlwebcam.cpp.

00161 {
00162   int port = 80;
00163   if(url.startsWith("http://") == 0)
00164   {
00165     printf("rlWebcam::wrong url syntax in %s\n", url.text());
00166     printf("url syntax: http://host:port/path_to_webcam_cgi_script\n");
00167     return -1;
00168   }
00169   char *cptr = url.text();
00170   cptr += 7;
00171   temp2.setText(cptr);
00172   cptr = temp2.strchr('/');
00173   if(cptr != NULL) *cptr = '\0';
00174   cptr = temp2.strchr(':');
00175   if(cptr != NULL) sscanf(cptr,":%d", &port);
00176   if(debug) printf("rlWebcam:port=%d\n", port);
00177   return port;
00178 }

const char * rlWebcam::getSnapshot ( int timeout = 3000 )

Definition at line 47 of file rlwebcam.cpp.

00048 {
00049   if(sock == NULL)
00050   {
00051     printf("rlWebcam::ERROR sock==NULL\n");
00052     return NULL;
00053   }
00054   if(sock->isConnected()) sock->disconnect();
00055   const char *cptr = getFrame(timeout);
00056   sock->disconnect();
00057   return cptr;
00058 }

const char * rlWebcam::getUrl ( )

Definition at line 136 of file rlwebcam.cpp.

00137 {
00138   return url.text();
00139 }

int rlWebcam::setUrl ( const char * url )

Definition at line 29 of file rlwebcam.cpp.

00030 {
00031   if(urlstr == NULL) return -1;
00032   url.setText(urlstr);
00033   if(sock != NULL) delete sock;
00034   sock = NULL;
00035   if(getHost() == NULL || getPort() < 0) return -1;
00036   sock = new rlSocket(getHost(),getPort(),1);
00037   return 0;
00038 }