OpenCV VideoCapture non può leggere affatto dalla mia webcam

Question

Sto usando OpenCV 2.4.6 su Ubuntu 13.04 (su un Chromebook Acer C7), e sto usando un semplice programma di test per vedere se la mia webcam funzionerà con OpenCV. Funziona bene con Cheese e Skype, quindi so che la webcam non è il problema.

Ecco il mio codice (che compila senza errori):

#include "opencv2/opencv.hpp" 
#include <stdio.h> 
#include <stdlib.h> 

using namespace std; 
using namespace cv; 

int main(int argc, char *argv[]) 
{ 
    cv::VideoCapture cap; 
    if(argc > 1) 
    { 
     cap.open(string(argv[1])); 
    } 
    else 
    { 
     cap.open(CV_CAP_ANY); 
    } 
    if(!cap.isOpened()) 
    { 
     printf("Error: could not load a camera or video.\n"); 
    } 
    Mat frame; 
    namedWindow("video", 1); 
    for(;;) 
    { 
    waitKey(20); 
    cap >> frame; 
    if(!frame.data) 
    { 
     printf("Error: no frame data.\n"); 
     break; 
    } 
    imshow("video", frame); 
    } 
} 

Se faccio funzionare il programma senza alcun argomento (in quanto lo voglio usare CV_CAP_ANY), ottengo

Error: could not load a camera or video. 
init done 
opengl support available 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
Error: no frame data. 

Se mi specificare/dev/video0 (la mia unica telecamera) come argomento, ho

demux_wavpack: (open_wv_file:127) open_wv_file: non-seekable inputs aren't supported yet. 
(ERROR)icvOpenAVI_XINE(): Unable to open source '/dev/video0' 
init done 
opengl support available 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12 
GStreamer Plugin: Embedded video playback halted; module source reported: Could not read from resource. 
Error: no frame data. 

Se specifico il percorso un file video come argomento, riproduce il video bene.

Apprezzerei qualsiasi aiuto. Grazie in anticipo!

Answer 1

C'è un bug su Opencv 2.4.6 prega di dare un'occhiata here

inoltre provare questo: cv :: tappo VideoCapture = cv :: VideoCapture (0);

Spero che abbia aiutato!

Answer 2

Si può provare a variare il valore waitKey(20)-20 fino 80. lavora Alcuni computer a valore 20,30,40,50 ....