Video_Capture.cpp

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// Copyright (c) 2013 by Wayne C. Gramlich.  All rights reserved.

#include <assert.h>
#include <ctype.h>

#include <opencv2/highgui/highgui_c.h>

#include "CV.hpp"
#include "File.hpp"
#include "String.hpp"


int main(int arguments_size, char * arguments[]) {
    CvCapture * capture = NULL;
    String_Const capture_base_name = "video_capture";

    if (arguments_size <= 1) {
        // No arguments; let the user know the usage:
        File__format(stderr,
          "Usage: Video_Capture camera_number [capture_base_name]\n");
        return 1;
    } else {
        // Grab the arguments:
        String argument1 = arguments[1];
        if (arguments_size > 2) {
            capture_base_name = arguments[2];
        }

        // Figure whether to open a video file or a camera;
        if (isdigit(argument1[0])) {
            // Open the camera:
            unsigned int camera_number = String__to_unsigned(argument1);
            int camera_flags = CV_CAP_ANY + (int)camera_number;
            capture = cvCreateCameraCapture(camera_flags);
            if (capture == NULL) {
                File__format(stderr,
                  "Could not open camara %d\n", camera_number);
                return 1;
            }

            // Set the frame size:
            cvSetCaptureProperty(capture,
              CV_CAP_PROP_FRAME_WIDTH, (double)640);
            cvSetCaptureProperty(capture,
              CV_CAP_PROP_FRAME_HEIGHT, (double)480);
        } else {
            // Open a video file format:
            capture = cvCreateFileCapture(argument1);
            if (capture == NULL) {
                File__format(stderr,
                  "Could not open video file '%s'\n", argument1);
                return 1;
            }
        }
    }
    // We should not be able to here without a open *capture*:
    assert(capture != NULL);

    // Create the window to display the video into:
    String_Const window_name = "Video_Capture";
    cvNamedWindow(window_name, CV__window_auto_size);

    // Do a video loop:
    unsigned int capture_number = 0;
    while (1) {
        // Grab a frame from the video source:
        CV_Image frame = cvQueryFrame(capture);
        if (frame == (CV_Image)0) {
            // When *frame* is null, the video source is at end-of-file
            // or disconnected:
            break;
        }
        
        // Show the image:
        cvShowImage(window_name, frame);

        // Deal with key character:
        char character = cvWaitKey(33);
        if (character == '\033') {
            // [Esc] key causes program to escape:
            break;
        } else if (character == ' ') {
            // Write out image out to file system as a .tga file:
            String file_name =
              String__format("%s-%02d.pnm", capture_base_name, capture_number);
            CV_Image__pnm_write(frame, file_name);
            File__format(stderr, "Wrote frame out to file '%s'\n", file_name);
            capture_number += 1;
            String__free(file_name);
        }
    }

    // Clean up and leave:
    cvReleaseCapture(&capture);
    cvDestroyWindow(window_name);

    return 0;
}