前言
本篇介绍ubuntu平台的GStreamer部署安装,然后测试摄像头,进行性能延迟对比。
准备ubuntu虚拟机
略。
注意
由于在虚拟机ubuntu上也会测试usb摄像头,因为不是直接硬件到ubuntu,而是先到windows然后虚拟机桥接到ubuntu,可能会到usb摄像头的延迟产生一定影响,但根据经验,大概率几毫秒到几十毫秒之间。
关于ubuntu离线安装
离线安装比较难,首先就要安装几十个依赖工具和库,离线没有这些的话,就是套娃+套娃+套娃,需要费很大劲逐一安装,且解决各种依赖问题,所以就算离线安装也需要先把ubuntu的辅助工具都打上做成个镜像,再去离线安装gstreamer,这里不建议没依赖库的时候直接离线安装。
GStreamer在ubuntu部署
步骤一:下载解压

步骤二:更新,并安装gstreamer
shell
sudo apt-get update
sudo apt-get install libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev libgstreamer-plugins-bad1.0-dev gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-libav gstreamer1.0-doc gstreamer1.0-tools gstreamer1.0-x gstreamer1.0-alsa gstreamer1.0-gl gstreamer1.0-gtk3 gstreamer1.0-qt5 gstreamer1.0-pulseaudio
步骤三:运行gstreamer测试
命令行打开usb摄像头
shell
gst-launch-1.0.exe -v ksvideosrc do-stats=TRUE ! videoconvert ! autovideosink
命令行打开播放文件
shell
gst-launch-1.0 playbin uri=file:///<你的视频>
gst-launch-1.0 playbin uri=file:////home/yang/Desktop/test.avi

命令行打开usb摄像头
shell
gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw,framerate=30/1 ! videoconvert ! autovideosink

延迟和内存对比
步骤一:gstreamer延迟和内存
使用gstreamer:
shell
gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw,framerate=30/1 ! videoconvert ! autovideosink
内存占用:
步骤二:cheese延迟和内存
cheese相机:
shell
sudo apt-get install cheese
sudo cheese
内存占用:
Ubuntu打开usb摄像头
步骤三:ffmpeg的ffplay延迟和内存
cpp
sudo apt-get install ffmpeg
ffplay -f v4l2 /dev/video0
对比内存
步骤四:fmplayer延迟和内存
shell
sudo apt-get install fmplayer
对比内存:
Demo
cpp
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/videodev2.h>
#include <errno.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_pixels.h>
#define WIDTH 640
#define HEIGHT 480
int main() {
setbuf(stdout, NULL);
int fd;
struct v4l2_format fmt;
struct v4l2_requestbuffers req;
struct v4l2_buffer buf;
void *buffer_start;
unsigned int buffer_length;
// 打开摄像头设备
fd = open("/dev/video0", O_RDWR);
if (fd == -1) {
perror("打开摄像头设备失败");
return EXIT_FAILURE;
}
// 设置视频格式
memset(&fmt, 0, sizeof(fmt));
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
fmt.fmt.pix.width = WIDTH;
fmt.fmt.pix.height = HEIGHT;
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
if (ioctl(fd, VIDIOC_S_FMT, &fmt) == -1) {
perror("设置视频格式失败");
close(fd);
return EXIT_FAILURE;
}
// 请求缓冲区
memset(&req, 0, sizeof(req));
req.count = 1;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
if (ioctl(fd, VIDIOC_REQBUFS, &req) == -1) {
perror("请求缓冲区失败");
close(fd);
return EXIT_FAILURE;
}
// 映射缓冲区
memset(&buf, 0, sizeof(buf));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = 0;
if (ioctl(fd, VIDIOC_QUERYBUF, &buf) == -1) {
perror("查询缓冲区失败");
close(fd);
return EXIT_FAILURE;
}
buffer_length = buf.length;
buffer_start = mmap(NULL, buffer_length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, buf.m.offset);
if (buffer_start == MAP_FAILED) {
perror("映射缓冲区失败");
close(fd);
return EXIT_FAILURE;
}
// 将缓冲区放入队列
if (ioctl(fd, VIDIOC_QBUF, &buf) == -1) {
perror("缓冲区入队失败");
munmap(buffer_start, buffer_length);
close(fd);
return EXIT_FAILURE;
}
// 开始视频捕获
enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (ioctl(fd, VIDIOC_STREAMON, &type) == -1) {
perror("开始视频捕获失败");
munmap(buffer_start, buffer_length);
close(fd);
return EXIT_FAILURE;
}
// 初始化 SDL
if (SDL_Init(SDL_INIT_VIDEO) < 0) {
fprintf(stderr, "SDL 初始化失败: %s\n", SDL_GetError());
munmap(buffer_start, buffer_length);
close(fd);
return EXIT_FAILURE;
}
SDL_Window *window = SDL_CreateWindow("V4L2 Camera", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, WIDTH, HEIGHT, 0);
if (!window) {
fprintf(stderr, "创建 SDL 窗口失败: %s\n", SDL_GetError());
SDL_Quit();
munmap(buffer_start, buffer_length);
close(fd);
return EXIT_FAILURE;
}
SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, 0);
// SDL_PIXELFORMAT_YV12 = /**< Planar mode: Y + V + U (3 planes) */
// SDL_PIXELFORMAT_IYUV = /**< Planar mode: Y + U + V (3 planes) */
// SDL_PIXELFORMAT_YUY2 = /**< Packed mode: Y0+U0+Y1+V0 (1 plane) */
// SDL_PIXELFORMAT_UYVY = /**< Packed mode: U0+Y0+V0+Y1 (1 plane) */
// SDL_PIXELFORMAT_YVYU = /**< Packed mode: Y0+V0+Y1+U0 (1 plane) */
// SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YV12, SDL_TEXTUREACCESS_STREAMING, WIDTH, HEIGHT);
// SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, WIDTH, HEIGHT);
SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YUY2, SDL_TEXTUREACCESS_STREAMING, WIDTH, HEIGHT);
// SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_UYVY, SDL_TEXTUREACCESS_STREAMING, WIDTH, HEIGHT);
// SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YVYU, SDL_TEXTUREACCESS_STREAMING, WIDTH, HEIGHT);
int running = 1;
SDL_Event event;
while (running) {
// 处理事件
while (SDL_PollEvent(&event)) {
if (event.type == SDL_QUIT) {
running = 0;
}
}
// 捕获帧
memset(&buf, 0, sizeof(buf));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
if (ioctl(fd, VIDIOC_DQBUF, &buf) == -1) {
perror("出队缓冲区失败");
break;
}
// 更新 SDL 纹理
SDL_UpdateTexture(texture, NULL, buffer_start, WIDTH);
// 渲染纹理
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, texture, NULL, NULL);
SDL_RenderPresent(renderer);
// 将缓冲区重新入队
if (ioctl(fd, VIDIOC_QBUF, &buf) == -1) {
perror("缓冲区入队失败");
break;
}
}
// 清理资源
SDL_DestroyTexture(texture);
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
munmap(buffer_start, buffer_length);
close(fd);
return EXIT_SUCCESS;
}
总结
到这里,我们得出结论,gstreamer基本是最优秀的框架之一了,初步测试不是特别严谨,但是基本能反应情况(比如ffmpeg得fmplay本轮测试是最差,但是ffmpeg写代码可以进行ffmpeg源码和编程代码的优化,达到150ms左右,诸如这类情况不考虑)。 gstreamer优于ffmplayer优于cheese优于ffmpeg。 下一篇将使用代码v4l2+SDL以及v4l2+QtOpenGL做进一步测试延迟内存。
入坑
入坑一:摄像头使用cheese打开为黑色
问题
打开黑色,有设备,拔了就提示没设备
尝试
更新安装驱动,未解决,排除驱动问题。 测试sudo cheese,还是黑色,排除权限问题。 修改虚拟机usb兼容性,换不是自己当前的就好了:
然后可以了。
解决
虚拟机兼容性从2.0改成USB3.1,然后: