cvvideo.cpp

guide and some example with visualC++

#endif
        // I don't need to rdlock lastframe, since I'm the one who writes it
        //pthread_mutex_lock(&(camera->lastframemutex));
        camera->vid_mmap.frame  = (camera->lastframe + 1)%camera->mbuf.frames;
        //pthread_mutex_unlock(&(camera->lastframemutex));

        pthread_rwlock_wrlock(&(camera->framelock[camera->vid_mmap.frame]));
        pthread_mutex_lock(&(camera->ioctlmutex));
        if(ioctl(camera->device, VIDIOCMCAPTURE, &(camera->vid_mmap)) < 0)
        {
            fprintf(stderr, "icvVideoCaptureProc: ioctl VIDIOCMCAPTURE failed \n");
            pthread_mutex_lock(&(camera->capturestatemutex));
            camera->capturestate = FINISHED;
            pthread_cond_signal(&(camera->capturestatecond));
            pthread_mutex_unlock(&(camera->capturestatemutex));
        }
        if(ioctl(camera->device, VIDIOCSYNC, &(camera->vid_mmap.frame) ) < 0)
        {
            fprintf(stderr, "icvVideoCaptureProc: ioctl VIDIOCSYNC failed \n");
            pthread_mutex_lock(&(camera->capturestatemutex));
            camera->capturestate = FINISHED;
            pthread_cond_signal(&(camera->capturestatecond));
            pthread_mutex_unlock(&(camera->capturestatemutex));
        }//if ioctl(..., VIDIOCSYNK, ...)
        pthread_mutex_unlock(&(camera->ioctlmutex));
        pthread_rwlock_unlock(&(camera->framelock[camera->vid_mmap.frame]));
        pthread_mutex_lock(&(camera->lastframemutex));
        camera->lastframe = camera->vid_mmap.frame;
        pthread_mutex_unlock(&(camera->lastframemutex));
        // if the camera is not rendered, call the callback myself
        if (!camera->rendered && (camera->callback != NULL))
        {
            IplImage *image = icvVideoGetImage(cameraid);
            if(image != NULL) {
                camera->callback(image);
                cvReleaseImage(&image);
            } else {
                fprintf(stderr, "icvVideoCaptureProc: icvVideoGetImage() returned NULL\n");
            }
        }
        // signal that the rendering should be updated, since the image changed
        if (camera->rendered)
        {
            pthread_mutex_lock(&(camera->updatedmutex));
            if(camera->updated == 0)
            {
                pthread_cond_signal(&(camera->updatedcond));
                camera->updated = 1;
            }
            pthread_mutex_unlock(&(camera->updatedmutex));
        }
        // stop here if we're paused
        pthread_mutex_lock(&(camera->pausemutex));
        pthread_mutex_unlock(&(camera->pausemutex));
        pthread_mutex_lock(&(camera->capturestatemutex));
    }
    pthread_mutex_unlock(&(camera->capturestatemutex));
    pthread_mutex_lock(&(camera->capturestatemutex));
    camera->capturestate = FINISHED;
    pthread_cond_signal(&(camera->capturestatecond));
    pthread_mutex_unlock(&(camera->capturestatemutex));
    pthread_exit(NULL);
}
////////////////////////////////////////////////////////////////////////////////

/* Frees all resources */
int cvcamExit()
{
    int cameraid, frame;

#ifdef DEBUG_CVCAM
    printf("cvcamExit(), ncameras = %d\n",ncameras);
#endif
    cvcamStop();
    for(cameraid=0; cameraid<ncameras; cameraid++) {
        CvVideoCamera *const camera = &(cameras[cameraid]);
        close(camera->device);
        pthread_mutex_destroy(&(camera->ioctlmutex));
        pthread_mutex_destroy(&(camera->pausemutex));
        pthread_mutex_destroy(&(camera->capturestatemutex));
        pthread_cond_destroy(&(camera->capturestatecond));
        for(frame=0; frame< camera->mbuf.frames; frame++)
        {
            pthread_rwlock_destroy(&(camera->framelock[frame]));
        }
        free(camera->framelock);
        pthread_mutex_destroy(&(camera->lastframemutex));
        pthread_cond_destroy(&(camera->updatedcond));
        pthread_mutex_destroy(&(camera->updatedmutex));
        camera->initialised = 0;
    }
    free(cameras);
    cameras = NULL;
    ncameras = 0;
    return 1;
}

////////////////////////////////////////////////////////////////////////////////

int icvVideoPauseCamera(int cameraid)
{
    CvVideoCamera *const camera = &(cameras[cameraid]);

    pthread_mutex_lock(&(camera->capturestatemutex));
    if(!(camera->capturestate==CAPTURING))
    {
        pthread_mutex_unlock(&(camera->capturestatemutex));
        return 1;
    }
    pthread_mutex_unlock(&(camera->capturestatemutex));
    // taking this lock will stop grabbing
    if(!camera->paused) {
        pthread_mutex_lock(&(camera->pausemutex));
        camera->paused = 1;
    }
    return 0;
}
////////////////////////////////////////////////////////////////////////////////

int icvVideoResumeCamera(int cameraid)
{
    CvVideoCamera *const camera = &(cameras[cameraid]);

    pthread_mutex_lock(&(camera->capturestatemutex));
    if(!(camera->capturestate==CAPTURING))
    {
        pthread_mutex_unlock(&(camera->capturestatemutex));
        return 1;
    }
    pthread_mutex_unlock(&(camera->capturestatemutex));
    if(camera->paused) {
        camera->paused = 0;
        pthread_mutex_unlock(&(camera->pausemutex));
    }
    return 0;
}
////////////////////////////////////////////////////////////////////////////////

/* Pause the video; should be used for preventing data changes during frame reading 
	using "frame" and other properties */
int cvcamPause()
{
    int i;
    
#ifdef DEBUG_CVCAM
    printf("cvcamPause()\n");
#endif
    for(i=0; i<ncameras; i++)
    {
        icvVideoPauseCamera(i);
    }
    
    
    return 0;

}
////////////////////////////////////////////////////////////////////////////////

/* Resume the video */
int cvcamResume()
{
    int i;
    
#ifdef DEBUG_CVCAM
    printf("cvcamResume()\n");
#endif
    for(i=0; i<ncameras; i++)
    {
        icvVideoResumeCamera(i);
    }
    
    return 0;
    
}
////////////////////////////////////////////////////////////////////////////////

int icvVideoInit(int cameraid)
{
    struct video_channel Channel;
    struct video_capability VidCap;
    CvVideoCamera *const camera = &(cameras[cameraid]);

#ifdef DEBUG_CVCAM
    printf("icvVideoInit(%d)\n",cameraid);
#endif
    char *rgbframe;

    if(camera->initialised)
    {
    /*
    fprintf(stderr, "icvVideoInit:camera %d is already "
                        "initialized\n",camera);*/
        return 0;
    }
    
    if(camera->enabled)
    {
        pthread_mutex_lock(&(camera->ioctlmutex));
        if(ioctl(camera->device,VIDIOCSPICT,
            &(camera->videopp.picture) )==-1)
        {
            pthread_mutex_unlock(&(camera->ioctlmutex));
            fprintf(stdout, "icvVideoInit: ioctl VIDIOCSPICT failed\n");
            fprintf(stdout,"camera=%d,brightness=%d,hue=%d,colour=%d,contrast=%d,whiteness=%d,depth=%d,palette=%d\n",
                    camera,
                    camera->videopp.picture.brightness,
                    camera->videopp.picture.hue,
                    camera->videopp.picture.colour,
                    camera->videopp.picture.contrast,camera->videopp.picture.whiteness,camera->videopp.picture.depth,camera->videopp.picture.palette);
            return 0;
        }
        pthread_mutex_unlock(&(camera->ioctlmutex));
        
        Channel.norm = 1;
        Channel.channel = camera->channel;
        pthread_mutex_lock(&(camera->ioctlmutex));
        if((ioctl(camera->device,VIDIOCSCHAN, &Channel) == -1)||
            (ioctl(camera->device, VIDIOCGCAP, &VidCap)==-1))
        {
            fprintf(stderr,
                "icvVideoInit: ioctl VIDIOCSCHAN or VIDIOCGCAP failed\n");
            pthread_mutex_unlock(&(camera->ioctlmutex));
            return 0;
        }
        pthread_mutex_unlock(&(camera->ioctlmutex));
        
        pthread_mutex_lock(&(camera->ioctlmutex));
        if(ioctl(camera->device, VIDIOCGMBUF,
            &(camera->mbuf)) == -1)
        {
            pthread_mutex_unlock(&(camera->ioctlmutex));
            fprintf(stdout, "icvVideoInit: ioctl VIDIOCGMBUF failed\n");
            return 0;
        }
        pthread_mutex_unlock(&(camera->ioctlmutex));
        
        pthread_mutex_lock(&(camera->ioctlmutex));
        if(ioctl(camera->device,
            VIDIOCSCHAN, &Channel)==-1)
        {
            fprintf(stderr, "icvVideoInit: couldn't set channel %d",
                Channel.channel);
            pthread_mutex_unlock(&(camera->ioctlmutex));
            return 0;
        }
        pthread_mutex_unlock(&(camera->ioctlmutex));
        
        camera->initialised = 1;
        pthread_mutex_lock(&(camera->capturestatemutex));
        camera->capturestate = READY;
        pthread_cond_signal(&(camera->capturestatecond));
        pthread_mutex_unlock(&(camera->capturestatemutex));
        
   }//if(camera->IsEnabled)
   return 1;
}
////////////////////////////////////////////////////////////

int icvVideoStop(int cameraid)
{
    int i, frame;
    CvVideoCamera *const camera = &(cameras[cameraid]);

#ifdef DEBUG_CVCAM
    printf("icvVideoStop(%d)\n",cameraid);
#endif
    pthread_mutex_lock(&(camera->capturestatemutex));
    if(camera->capturestate != CAPTURING)
    {
#ifdef DEBUG_CVCAM
        printf("icvVideoStop: not capturing (state=%d), returning 0\n",camera->capturestate);
#endif
        pthread_mutex_unlock(&(camera->capturestatemutex));
        return 0;
    }
    camera->capturestate = STOPPING;
    pthread_cond_signal(&(camera->capturestatecond));
    pthread_mutex_unlock(&(camera->capturestatemutex));
    if(camera->paused)
        icvVideoResumeCamera(cameraid);

    pthread_mutex_lock(&(camera->capturestatemutex));
    // wait for the end of capture proc
    while (camera->capturestate != FINISHED )
    {
        pthread_cond_wait(&(camera->capturestatecond),&(camera->capturestatemutex));
    }
    // wait for the end of rendering
    while (camera->renderstate)
    {
        // the rendering loop may be waiting for an update
        pthread_mutex_lock(&(camera->updatedmutex));
        camera->updated = 1;
        pthread_cond_signal(&(camera->updatedcond));
        pthread_mutex_unlock(&(camera->updatedmutex));
        pthread_cond_wait(&(camera->capturestatecond),&(camera->capturestatemutex));
    }
    pthread_mutex_unlock(&(camera->capturestatemutex));

    munmap(camera->memorymap,
        camera->mbuf.size);
    
    pthread_mutex_lock(&(camera->capturestatemutex));
    camera->capturestate = READY;
    pthread_cond_signal(&(camera->capturestatecond));
    pthread_mutex_unlock(&(camera->capturestatemutex));
#ifdef DEBUG_CVCAM
        printf("icvVideoStop: returning 1\n",camera->capturestate);
#endif
    return 1;
}
//////////////////////////////////////////////////////////////////

/* Stop the video */
int cvcamStop()
{
    int camera;
#ifdef DEBUG_CVCAM
    printf("cvcamStop()\n");
#endif
    for(camera=0; camera<ncameras; camera++)
    {
        icvVideoStop(camera);
    }//for(camera=0; camera<ncameras; camera++)
    return 1;
}
////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////
int icvVideoFormat2Depth(int format)
{
    switch (format)
    {
    case VIDEO_PALETTE_RGB24:
        return 24;
        
    case VIDEO_PALETTE_RGB32:
        return 32;
        
    case VIDEO_PALETTE_RGB565:
        return 16;
        
    case VIDEO_PALETTE_RGB555:
        return 16;
        
    default:
        return 0;
    }
}
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
int icvVideoSetDefaultValues(int cameraid, int device, int channel, 
     struct video_capability VidCap)
{
    CvVideoCamera *const camera = &(cameras[cameraid]);

    camera->device                = device;
    camera->channel               = channel;
    camera->description.channel   = channel;
    pthread_mutex_init(&(camera->ioctlmutex), NULL);
    camera->enabled               = 0;
    camera->rendered              = 0;
    camera->initialised           = 0;
    camera->paused                = 0;