GStreamer开发笔记（二）：GStreamer在ubnutn平台部署安装，测试gstreamer/cheese/ffmpeg/fmplayer打摄像头延迟和内存

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

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

gst-launch-1.0.exe -v ksvideosrc do-stats=TRUE ! videoconvert ! autovideosink

  命令行打开播放文件

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

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：

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：

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

sudo apt-get install ffmpeg
ffplay -f v4l2 /dev/video0

  
  对比内存
  

步骤四：fmplayer延迟和内存

sudo apt-get install fmplayer

  
  对比内存：
  

 

Demo

#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：