linux下 ubantu 使用笔记本电脑摄像头,v4l2采集摄像头数据

1 虚拟机添加usb控制器,注意选择兼容3.1

2 添加移动设备

3 在ubantu中输入命令行 cheese 检测摄像头是否工作正常

4 gcc编译如下代码,注意根据摄像头支持的格式    V4L2_PIX_FMT_YUYV    或者其他  代码参考

#Makefile
CC=gcc
CFLAGS= -g -Wall -O2
TARGET= test1.bin
SRCS= camer.c
C_OBJS= camer.o

all:$(TARGET)

$(TARGET):$(C_OBJS)
	$(CC) $(CFLAGS) -o $@ $^
%.o:%.c
	$(CC) $(CFLAGS) -c -o $@ $<
.PHONY:clean
clean:
	rm -rf *.o $(TARGET) $(CXX_OBJS) $(C_OBJS) test1 out.*
	

参考   新建标签页 (csdn.net)   https://blog.csdn.net/weixin_43937576/article/details/109901691

/*************************************************************************
    > File Name: camer.c
    > 作者:YJK 
    > Mail: [email protected] 
    > Created Time: 2020年11月18日 星期三 14时17分50秒
 ************************************************************************/

#include<stdio.h>
#include<unistd.h>
#include<fcntl.h>
#include<stdlib.h>
#include<linux/videodev2.h>
#include<sys/ioctl.h>
#include<errno.h>                                                                                     
#include<string.h>
#include<assert.h>
#include<getopt.h>
#include<sys/stat.h>
#include<sys/mman.h>
#include<asm/types.h>
#include<linux/fb.h>

#define CLEAN(x) (memset(&(x), 0, sizeof(x)))

#define WIDTH 640

#define HEIGHT 480

typedef struct Video_Buffer{
    void * start;
    unsigned int length;
}Video_Buffer;



int ioctl_(int fd, int request, void *arg);

void sys_exit(const char *s);

int open_device(const char * device_name);

int open_file(const char * file_name);

void start_stream(void);

void end_stream(void);

int init_device(void);

int init_mmap(void);

static int read_frame(void);

int process_frame(void);

void close_mmap(void);

void close_device(void);


//#include"camer.h"
#include <linux/i2c.h>
#include <linux/videodev2.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

int fd;
int file_fd;
int frame_size;
static Video_Buffer * buffer = NULL;
FILE * file = NULL;
int ioctl_(int fd, int request, void *arg)
{
    int ret = 0;
    do{
        ret = ioctl(fd, request, arg);
    }while(ret == -1 && ret == EINTR);
        
}

int open_device(const char * device_name)
{
    struct stat st;
    if( -1 == stat( device_name, &st ) )
    {
        printf( "Cannot identify '%s'\n" , device_name );
        return -1;
    }

    if ( !S_ISCHR( st.st_mode ) )
    {
        printf( "%s is no device\n" , device_name );
        return -1;
    }

    fd = open(device_name, O_RDWR | O_NONBLOCK , 0);
    if ( -1 == fd )
    {
        printf( "Cannot open '%s'\n" , device_name );
        return -1;
    }
    return 0;    
}



int init_device(void)
{
    //查询设备信息
    struct v4l2_capability cap;
    
    if (ioctl_(fd, VIDIOC_QUERYCAP, &cap) == -1)
    {
        perror("VIDIOC_QUERYCAP");
        return -1;
    }
    printf("---------------------LINE:%d\n", __LINE__);
    printf("DriverName:%s\nCard Name:%s\nBus info:%s\nDriverVersion:%u.%u.%u\n",
        cap.driver,cap.card,cap.bus_info,(cap.version>>16)&0xFF,(cap.version>>8)&0xFF,(cap.version)&0xFF);    
    if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
        perror("Device not a video capture device\n");
        return -1;
    }
    if(cap.capabilities & V4L2_CAP_STREAMING) {
        printf("Device supports streaming i/o\n");
    }
    if (cap.capabilities & V4L2_CAP_READWRITE) {
        printf("Device supports read i/o\n");
    }
    printf("\n");
    
    //查看视频输入
    if(1){
        struct v4l2_input fmtdesc;
        fmtdesc.index = 0;
        printf("input:\n");
        while(ioctl(fd, VIDIOC_ENUMINPUT, &fmtdesc) != -1){  
            printf("%d.%s\n", fmtdesc.index, fmtdesc.name);
            fmtdesc.index++;
        }
        printf("\n");
    }
    
    //查看摄像头支持的格式
    if(1){
        struct v4l2_fmtdesc fmtdesc;
        fmtdesc.index = 0;
        fmtdesc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        printf("fm:\n");
        while(ioctl(fd, VIDIOC_ENUM_FMT, &fmtdesc) != -1){  
            printf("%d.%s   %c%c%c%c\n", fmtdesc.index + 1, fmtdesc.description, 
                fmtdesc.pixelformat &  0xFF,
                (fmtdesc.pixelformat >> 8) & 0xFF,
                (fmtdesc.pixelformat >> 16) & 0xFF,
                (fmtdesc.pixelformat >> 24) & 0xFF);
            fmtdesc.index++;
        }
        printf("\n");
    }
    
    
    //选择视频输入
    struct v4l2_input input;
    CLEAN(input);
    input.index = 0;
    if ( ioctl_(fd, VIDIOC_S_INPUT,&input) == -1){
        printf("VIDIOC_S_INPUT IS ERROR! LINE:%d\n",__LINE__);
        return -1;
    }
    //设置帧格式
    struct v4l2_format fmt;
    CLEAN(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)
    {
        printf("VIDIOC_S_FMT IS ERROR! LINE:%d\n",__LINE__);
        return -1;
    }
    // 要处理这个调用，驱动会查看请求的视频格式，然后断定硬件是否支持这个格式。如果应用请求的格式是硬件不能支持的，就返回-EINVAL  查看当前设备是否支持请求的帧格式
    // v4l2_format 结构体会在调用后复制给用户空间；驱动应该更新这个结构体以反映改变的参数，这样应用才知道他真正得到的是什么。
    fmt.type = V4L2_BUF_TYPE_PRIVATE;
    if (ioctl_(fd, VIDIOC_S_FMT, &fmt) == -1){
        printf("VIDIOC_S_FMT IS ERROR! LINE:%d\n", __LINE__);
        return -1;
    }
    //查看帧格式
    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    if ( ioctl_(fd, VIDIOC_G_FMT, &fmt) == -1){
        printf("VIDIOC_G_FMT IS ERROR! LINE:%d\n", __LINE__);
        return -1;
    }
    printf("width:%d\nheight:%d\npixelformat:%c%c%c%c\n",
            fmt.fmt.pix.width, fmt.fmt.pix.height,
            fmt.fmt.pix.pixelformat &  0xFF,
            (fmt.fmt.pix.pixelformat >> 8) & 0xFF,
            (fmt.fmt.pix.pixelformat >> 16) & 0xFF,
            (fmt.fmt.pix.pixelformat >> 24) & 0xFF
            );

    __u32 min = fmt.fmt.pix.width * 2;
    if ( fmt.fmt.pix.bytesperline < min )
        fmt.fmt.pix.bytesperline = min;
    min = ( unsigned int )WIDTH * HEIGHT * 3 / 2;
    if ( fmt.fmt.pix.sizeimage < min )
        fmt.fmt.pix.sizeimage = min;
    frame_size = fmt.fmt.pix.sizeimage;
    printf("After Buggy driver paranoia\n");
    printf("    >>fmt.fmt.pix.sizeimage = %d\n", fmt.fmt.pix.sizeimage);
    printf("    >>fmt.fmt.pix.bytesperline = %d\n", fmt.fmt.pix.bytesperline);
    printf("-#-#-#-#-#-#-#-#-#-#-#-#-#-\n");
    printf("\n");
    
    return 0;

}

 int init_mmap()
{
    //申请帧缓冲区
    struct v4l2_requestbuffers req;
    CLEAN(req);
    req.count = 4;
    req.memory = V4L2_MEMORY_MMAP;  //使用内存映射缓冲区
    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    //申请4个帧缓冲区，在内核空间中
    if ( ioctl_(fd, VIDIOC_REQBUFS, &req) == -1 ) 
    {
        printf("VIDIOC_REQBUFS IS ERROR! LINE:%d\n",__LINE__);
        return -1;
    }
    //获取每个帧信息，并映射到用户空间
    buffer = (Video_Buffer *)calloc(req.count, sizeof(Video_Buffer));
    if (buffer == NULL){
        printf("calloc is error! LINE:%d\n",__LINE__);
        return -1;
    }
    
    struct v4l2_buffer buf;
    int buf_index = 0;
    for (buf_index = 0; buf_index < req.count; buf_index ++)
    {
        CLEAN(buf);
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.index = buf_index;
        buf.memory = V4L2_MEMORY_MMAP;
        if (ioctl_(fd, VIDIOC_QUERYBUF, &buf) == -1) //获取每个帧缓冲区的信息 如length和offset
        {
            printf("VIDIOC_QUERYBUF IS ERROR! LINE:%d\n",__LINE__);
            return -1;
        }
        //将内核空间中的帧缓冲区映射到用户空间
        buffer[buf_index].length = buf.length;
        buffer[buf_index].start = mmap(NULL, //由内核分配映射的起始地址
                                       buf.length,//长度
                                       PROT_READ | PROT_WRITE, //可读写
                                       MAP_SHARED,//可共享
                                       fd,
                                       buf.m.offset);
        if (buffer[buf_index].start == MAP_FAILED){
            printf("MAP_FAILED LINE:%d\n",__LINE__);
            return -1;
        }
        //将帧缓冲区放入视频输入队列
        if (ioctl_(fd, VIDIOC_QBUF, &buf) == -1)
        {
            printf("VIDIOC_QBUF IS ERROR! LINE:%d\n", __LINE__);
            return -1;
        }        
        printf("Frame buffer :%d   address :0x%x    length:%d\n",buf_index, (__u32)buffer[buf_index].start, buffer[buf_index].length);
    }    
}

void start_stream()
{
    enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    if (ioctl_(fd, VIDIOC_STREAMON, &type) == -1){
        printf("VIDIOC_STREAMON IS ERROR! LINE:%d\n", __LINE__);
        exit(EXIT_FAILURE);
    }
}
void end_stream()
{
    enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    if (ioctl_(fd, VIDIOC_STREAMOFF, &type) == -1){
        printf("VIDIOC_STREAMOFF IS ERROR! LINE:%d\n", __LINE__);
        exit(EXIT_FAILURE);
    }
}

static int read_frame()
{
    struct v4l2_buffer buf;
    int ret = 0;
    CLEAN(buf);
    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
    if (ioctl_(fd, VIDIOC_DQBUF, &buf) == -1){
        printf("VIDIOC_DQBUF! LINEL:%d\n", __LINE__);
        return -1;
    }
    ret = write(file_fd, buffer[buf.index].start ,frame_size);
    if (ret == -1)
    {
        printf("write is error !\n");
        return -1;
    }
    if (ioctl_(fd, VIDIOC_QBUF, &buf) == -1){
        printf("VIDIOC_QBUF! LINE:%d\n", __LINE__);
        return -1;
    }
    return 0;
}


int open_file(const char * file_name)
{
    
    file_fd = open(file_name, O_RDWR | O_CREAT, 0777);
    if (file_fd == -1)
    {
        printf("open file is error! LINE:%d\n", __LINE__);
        return -1;
    }
        
//    file = fopen(file_name, "wr+");
}

void close_mmap()
{
    int i = 0;
    for (i = 0; i < 4 ; i++)
    {
        munmap(buffer[i].start, buffer[i].length);
    }
    free(buffer);
}
void close_device()
{
    close(fd);
    close(file_fd);
}
int process_frame()
{
    struct timeval tvptr;
    int ret;
    tvptr.tv_usec = 0;  //等待50 us
    tvptr.tv_sec = 2;
    fd_set fdread;
    FD_ZERO(&fdread);
    FD_SET(fd, &fdread);
    ret = select(fd + 1, &fdread, NULL, NULL, &tvptr);
    if (ret == -1){
        perror("EXIT_FAILURE");
        exit(EXIT_FAILURE);
    }
    if (ret == 0){
        printf("timeout! \n");
    }
    read_frame();
}



#include<stdio.h>
//#include"camer.h"

#define DEVICE_NAME "/dev/video0"

#define FILE_NAME "./out.yuv"
int main(int argc,char *argv[])
{
    int ret = 0;
    int i;
    ret = open_device(DEVICE_NAME);
    if (ret == -1) 
        exit(EXIT_FAILURE);
    open_file(FILE_NAME);
    init_device();
    init_mmap();
    start_stream();
 
    for (i = 0 ; i < 100; i++)
    {
        process_frame();    
        printf("frame:%d\n",i);
    }

    end_stream();
    close_mmap();
    close_device();
    
    
    return 0;
}

yuv视频播放 借用开源库   GitHub - Yonsm/RawPlayer: Raw (YUV/RGB) video player and subjective assess tool

GitHub - latelee/YUVPlayer: A little simple YUV player.windows VS2010 MFC project (Windows 7 64bit),support manyYUV format file.

 我编译的exe文件    https://files.cnblogs.com/files/RYSBlog/YUVPlayer.zip?t=1667271754

源码文件    https://files.cnblogs.com/files/RYSBlog/YUVPlayer-master.zip?t=1667271743

 关于 v4l2 与ffmpeg结合可参考  (146条消息) Linux下ffmpeg库开发之读取摄像头数据_IT_阿水的博客-CSDN博客_ffmpeg读取摄像头

#include <stdio.h>
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include <libswresample/swresample.h>
#include <libavdevice/avdevice.h>
#include <libavutil/imgutils.h>
#include <SDL.h>
#include <SDL_image.h>
#include <pthread.h>
#include <unistd.h>
#define VIDEO_DEV "/dev/video2"
pthread_mutex_t fastmutex = PTHREAD_MUTEX_INITIALIZER;//互斥锁
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;//条件变量
typedef enum
{
    false=0,
    true,
}bool;
int width;
int height;
int size;
unsigned char *rgb_buff=NULL;
unsigned char video_flag=1;
void *Video_CollectImage(void *arg);
int main()
{
    /*创建摄像头采集线程*/
    pthread_t pthid;
    pthread_create(&pthid,NULL,Video_CollectImage, NULL);
    pthread_detach(pthid);/*设置分离属性*/
    sleep(1);
    while(1)
    {
        if(width!=0 && height!=0 && size!=0)break;
        if(video_flag==0)return 0;
    }
    printf("image:%d * %d,%d\n",width,height,size);
    unsigned char *rgb_data=malloc(size);
     /*创建窗口 */
    SDL_Window *window=SDL_CreateWindow("SDL_VIDEO", SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,800,480,SDL_WINDOW_ALLOW_HIGHDPI|SDL_WINDOW_RESIZABLE);
    /*创建渲染器*/
    SDL_Renderer *render=SDL_CreateRenderer(window,-1,SDL_RENDERER_ACCELERATED);
    /*清空渲染器*/
    SDL_RenderClear(render);
   /*创建纹理*/
    SDL_Texture*sdltext=SDL_CreateTexture(render,SDL_PIXELFORMAT_IYUV,SDL_TEXTUREACCESS_STREAMING,width,height);
    bool quit=true;
    SDL_Event event;
    SDL_Rect rect;
    while(quit)
    {
        while(SDL_PollEvent(&event))/*事件监测*/
        {
            if(event.type==SDL_QUIT)/*退出事件*/
            {
                quit=false;
                video_flag=0;
                pthread_cancel(pthid);/*杀死指定线程*/
                continue;
            }
        }
        if(!video_flag)
        {
            quit=false;
            continue;
        }
        pthread_mutex_lock(&fastmutex);//互斥锁上锁
        pthread_cond_wait(&cond,&fastmutex);
        memcpy(rgb_data,rgb_buff,size);
        pthread_mutex_unlock(&fastmutex);//互斥锁解锁
        SDL_UpdateTexture(sdltext,NULL,rgb_data,width);
        //SDL_RenderCopy(render, sdltext, NULL,NULL); // 拷贝纹理到渲染器
        SDL_RenderCopyEx(render, sdltext,NULL,NULL,0,NULL,SDL_FLIP_NONE);
        SDL_RenderPresent(render); // 渲染
    }
    SDL_DestroyTexture(sdltext);/*销毁纹理*/
    SDL_DestroyRenderer(render);/*销毁渲染器*/
    SDL_DestroyWindow(window);/*销毁窗口 */
    SDL_Quit();/*关闭SDL*/
    pthread_mutex_destroy(&fastmutex);/*销毁互斥锁*/
    pthread_cond_destroy(&cond);/*销毁条件变量*/
    free(rgb_buff);
    free(rgb_data);
    return 0;
}
void *Video_CollectImage(void *arg)
{
    int res=0;
    AVFrame *Input_pFrame=NULL;
    AVFrame *Output_pFrame=NULL;
    printf("pth:%s\n",avcodec_configuration());
    /*注册设备*/
    avdevice_register_all();
    /*查找输入格式*/
    AVInputFormat *ifmt=av_find_input_format("video4linux2");
    if(ifmt==NULL)
    {
        printf("av_find_input_format failed\n");
        video_flag=0;
        return 0;
    }
    /*打开输入流并读取头部信息*/
    AVFormatContext *ps=NULL;
    res=avformat_open_input(&ps,VIDEO_DEV,ifmt,NULL);
    if(res)
    {
        printf("open input failed\n");
        video_flag=0;
        return 0;
    }
    /*查找流信息*/
    res=avformat_find_stream_info(ps,NULL);
    if(res)
    {
        printf("find stream failed\n");
        video_flag=0;
        return 0;
    }
    /*打印有关输入或输出格式信息*/
    av_dump_format(ps, 0, "video4linux2", 0);
    
    
    
    /*寻找视频流*/
    int videostream=-1;
    videostream=av_find_best_stream(ps,AVMEDIA_TYPE_VIDEO,-1,-1,NULL,0);
    printf("videostram=%d\n",videostream);
    /*寻找编解码器*/
    AVCodec *video_avcodec=NULL;/*保存解码器信息*/
    AVStream *stream = ps->streams[videostream];
    AVCodecContext *context=stream->codec;
    video_avcodec=avcodec_find_decoder(context->codec_id);
    if(video_avcodec==NULL)
    {
        printf("find video decodec failed\n");
        video_flag=0;
        return 0;
    }    
    /*初始化音视频解码器*/
    res=avcodec_open2(context,video_avcodec,NULL);
    if(res)
    {
        printf("avcodec_open2 failed\n");
        video_flag=0;
        return 0;
    }


    
    
    
    
    AVPacket *packet=av_malloc(sizeof(AVPacket));/*分配包*/
    AVFrame *frame=av_frame_alloc();/*分配视频帧*/
    AVFrame *frameyuv=av_frame_alloc();/*申请YUV空间*/
    /*分配空间，进行图像转换*/
    width=context->width;
    height=context->height;
    int fmt=context->pix_fmt;/*流格式*/
    size=av_image_get_buffer_size(AV_PIX_FMT_YUV420P,width,height,16);
    unsigned char *buff=NULL;
    printf("w=%d,h=%d,size=%d\n",width,height,size);    
    buff=av_malloc(size);
    rgb_buff=malloc(size);//保存RGB颜色数据
    /*存储一帧图像数据*/
    av_image_fill_arrays(frameyuv->data,frameyuv->linesize,buff,AV_PIX_FMT_YUV420P,width,height, 16);
    /*转换上下文，使用sws_scale（）执行缩放/转换操作。*/
    struct SwsContext *swsctx=sws_getContext(width,height, fmt,width,height, AV_PIX_FMT_YUV420P,SWS_BICUBIC,NULL,NULL,NULL);
    /*读帧*/
    int go=0;
    int Framecount=0;
    printf("read fream buff\n");
    while(av_read_frame(ps,packet)>=0 && video_flag)
    {
        Framecount++;
        if(packet->stream_index == AVMEDIA_TYPE_VIDEO)/*判断是否为视频*/
        {
            /*解码一帧视频数据。输入一个压缩编码的结构体AVPacket，输出一个解码后的结构体AVFrame*/
            res=avcodec_decode_video2(ps->streams[videostream]->codec,frame,&go,packet);
            if(res<0)
            {
                printf("avcodec_decode_video2 failed\n");
                break;
            }
            if(go)
            {
                /*转换像素的函数*/
                sws_scale(swsctx,(const uint8_t * const*)frame->data,frame->linesize,0,height,frameyuv->data,frameyuv->linesize);
                pthread_mutex_lock(&fastmutex);//互斥锁上锁
                memcpy(rgb_buff,buff,size);
                pthread_cond_broadcast(&cond);//广播唤醒所有线程
                pthread_mutex_unlock(&fastmutex);//互斥锁解锁
            }
        }        
    }
    sws_freeContext(swsctx);/*释放上下文*/
    av_frame_free(&frameyuv);/*释放YUV空间*/
    av_packet_unref(packet);/*释放包*/
    av_frame_free(&frame);/*释放视频帧*/
    avformat_close_input(&ps);/*关闭流*/
    video_flag=0;
    pthread_exit(NULL);    
}

//