gstreamer创建管道如何使得输出分辨率自适应显示器分辨率？

Question

gstreamer创建管道如何使得输出分辨率自适应显示器分辨率？
在nvidia jetson nano上使用csi相机时，我创建了一条gstreamer管道：

std::string gstreamer_pipeline (int capture_width, int capture_height, int display_width, int display_height, int framerate, int flip_method)
{
return "nvarguscamerasrc sensor-id=0 ! video/x-raw(memory:NVMM), width=(int)" + std::to_string(capture_width) + ", height=(int)" + std::to_string(capture_height) + ", format=(string)NV12, framerate=(fraction)" + std::to_string(framerate) +"/1 ! nvvidconv flip-method=" + std::to_string(flip_method) + " ! video/x-raw, width=(int)" + std::to_string(display_width) + ", height=(int)" +std::to_string(display_height) + ", format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink";
}

这里只能通过提前设置输出分辨率大小，或者在屏幕上的显示和输入的分辨率大小一致，请问有什么创建管道的方式使得无论在什么分辨率的显示器上都能全屏显示么？

Answer 1

操作1：从驱动读取屏幕大小
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <math.h>
#include <sys/ioctl.h>
int w,h ;
int main(int argc , char *argv[]){
int fd;
struct fb_var_screeninfo fb_var;
fd = open("/dev/fb0",O_RDWR);
ioctl (fd,FBIOGET_VSCREENINFO,&fb_var);
w = fb_var.xres;
h = fb_var.yres;
return 0；
}

操作2：通过xcb库读取屏幕大小
#include <stdio.h>
#include <xcb/xcb.h>
int main (){
/* Open the connection to the X server. Use the DISPLAY environment variable */
int i, screenNum;
xcb_connection_t connection = xcb_connect (NULL, &screenNum);
/ Get the screen whose number is screenNum */
const xcb_setup_t *setup = xcb_get_setup (connection);
xcb_screen_iterator_t iter = xcb_setup_roots_iterator (setup);
// we want the screen at index screenNum of the iterator
for (i = 0; i < screenNum; ++i) {
xcb_screen_next (&iter);
}
xcb_screen_t *screen = iter.data;
/* report */
printf ("\n");
printf ("Informations of screen %ld:\n", screen->root);
printf (" width.........: %d\n", screen->width_in_pixels);
printf (" height........: %d\n", screen->height_in_pixels);
printf (" white pixel...: %ld\n", screen->white_pixel);
printf (" black pixel...: %ld\n", screen->black_pixel);
printf ("\n");
return 0;
}

参考链接： Ubuntu Linux下通过c++获取屏幕大小_weixin_33755554的博客-CSDN博客 为什么80%的码农都做不了架构师？>>> ... https://blog.csdn.net/weixin_33755554/article/details/91741622