X264编解码器开发: Linux下读取摄像头数据，通过X264压缩编码为X264格式裸流视频文件

一、环境介绍

操作系统:  ubuntu18.04  64位。

X264版本:  x264-snapshot-20181217-2245

博客的下载地址: https://download.csdn.net/download/xiaolong1126626497/12339693

二、X264库编译安装

参考这里: https://blog.csdn.net/xiaolong1126626497/article/details/104919095

三、核心代码

#include <stdio.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip.h> 
#include <pthread.h>
#include <stdlib.h>
#include <sys/select.h>
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>
#include <linux/videodev2.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/mman.h>
#include <string.h>
#include "include/x264.h"

/*摄像头相关的全局变量声明区域*/
#define UVC_VIDEO_DEVICE "/dev/video0"  /*UVC摄像头设备节点*/
int uvc_video_fd; /*存放摄像头设备节点的文件描述符*/
unsigned char *video_memaddr_buffer[4]; /*存放的是摄像头映射出来的缓冲区首地址*/
int Image_Width;  /*图像的宽度*/
int Image_Height; /*图像的高度*/


/*X264编码器相关的全局变量声明区域*/
unsigned char *h264_buf=NULL;
typedef struct
{
	x264_param_t *param;
	x264_t *handle;
	x264_picture_t *picture; //说明一个视频序列中每帧特点
	x264_nal_t *nal;
}Encoder;
Encoder en;
FILE *h264_fp; /*存放视频的文件*/


/*函数声明区域*/
void X264_close_encoder(void); //关闭解码器


/*
函数功能: 处理退出的信号
*/
void exit_sighandler(int sig)
{
	/*关闭视频文件*/
	fclose(h264_fp);
	
	//关闭摄像头
	close(uvc_video_fd);
	
	//释放缓冲区
	free(h264_buf);
		
	//退出进程
	exit(1);
}


/*设置视频录制相关参数*/
static int x264_param_apply_preset(x264_param_t *param, const char *preset)
{
    char *end;
    int i = strtol( preset, &end, 10 );
    if( *end == 0 && i >= 0 && i < sizeof(x264_preset_names)/sizeof(*x264_preset_names)-1 )
        preset = x264_preset_names[i];
	/*快4*/
    if( !strcasecmp( preset, "ultrafast" ) )
    {
        param->i_frame_reference = 1;
        param->i_scenecut_threshold = 0;
        param->b_deblocking_filter = 0;
        param->b_cabac = 0;
        param->i_bframe = 0;
        param->analyse.intra = 0;
        param->analyse.inter = 0;
        param->analyse.b_transform_8x8 = 0;
        param->analyse.i_me_method = X264_ME_DIA;
        param->analyse.i_subpel_refine = 0;
        param->rc.i_aq_mode = 0;
        param->analyse.b_mixed_references = 0;
        param->analyse.i_trellis = 0;
        param->i_bframe_adaptive = X264_B_ADAPT_NONE;
        param->rc.b_mb_tree = 0;
        param->analyse.i_weighted_pred = X264_WEIGHTP_NONE;
        param->analyse.b_weighted_bipred = 0;
        param->rc.i_lookahead = 0;
    }
	/*快3*/
    else if( !strcasecmp( preset, "superfast" ) )
    {
        param->analyse.inter = X264_ANALYSE_I8x8|X264_ANALYSE_I4x4;
        param->analyse.i_me_method = X264_ME_DIA;
        param->analyse.i_subpel_refine = 1;
        param->i_frame_reference = 1;
        param->analyse.b_mixed_references = 0;
        param->analyse.i_trellis = 0;
        param->rc.b_mb_tree = 0;
        param->analyse.i_weighted_pred = X264_WEIGHTP_SIMPLE;
        param->rc.i_lookahead = 0;
    }
	/*快2*/
    else if( !strcasecmp( preset, "veryfast" ) )
    {
        param->analyse.i_me_method = X264_ME_HEX;
        param->analyse.i_subpel_refine = 2;
        param->i_frame_reference = 1;
        param->analyse.b_mixed_references = 0;
        param->analyse.i_trellis = 0;
        param->analyse.i_weighted_pred = X264_WEIGHTP_SIMPLE;
        param->rc.i_lookahead = 10;
    }
	/*快1*/
    else if( !strcasecmp( preset, "faster" ) )
    {
        param->analyse.b_mixed_references = 0;
        param->i_frame_reference = 2;
        param->analyse.i_subpel_refine = 4;
        param->analyse.i_weighted_pred = X264_WEIGHTP_SIMPLE;
        param->rc.i_lookahead = 20;
    }
	/*快速*/
    else if( !strcasecmp( preset, "fast" ) )
    {
        param->i_frame_reference = 2;
        param->analyse.i_subpel_refine = 6;
        param->analyse.i_weighted_pred = X264_WEIGHTP_SIMPLE;
        param->rc.i_lookahead = 30;
    }
	/*中等*/
    else if( !strcasecmp( preset, "medium" ) )
    {
        /* Default is medium */
    }
	/*慢速*/
    else if( !strcasecmp( preset, "slow" ) )
    {
        param->analyse.i_me_method = X264_ME_UMH;
        param->analyse.i_subpel_refine = 8;
        param->i_frame_reference = 5;
        param->i_bframe_adaptive = X264_B_ADAPT_TRELLIS;
        param->analyse.i_direct_mv_pred = X264_DIRECT_PRED_AUTO;
        param->rc.i_lookahead = 50;
    }
    else if( !strcasecmp( preset, "slower" ) )
    {
        param->analyse.i_me_method = X264_ME_UMH;
        param->analyse.i_subpel_refine = 9;
        param->i_frame_reference = 8;
        param->i_bframe_adaptive = X264_B_ADAPT_TRELLIS;
        param->analyse.i_direct_mv_pred = X264_DIRECT_PRED_AUTO;
        param->analyse.inter |= X264_ANALYSE_PSUB8x8;
        param->analyse.i_trellis = 2;
        param->rc.i_lookahead = 60;
    }
    else if( !strcasecmp( preset, "veryslow" ) )
    {
        param->analyse.i_me_method = X264_ME_UMH;
        param->analyse.i_subpel_refine = 10;
	}
    else
    {
        return -1;
    }

    return 0;
}


/*开始视频压缩*/
void compress_begin(Encoder *en, int width, int height) 
{
	en->param = (x264_param_t *) malloc(sizeof(x264_param_t));
	en->picture = (x264_picture_t *) malloc(sizeof(x264_picture_t));

	x264_param_default(en->param); //编码器默认设置

	/*订制编码器压缩的性能*/
	x264_param_apply_preset(en->param,"medium");
	en->param->i_width = width; //设置图像宽度
	en->param->i_height = height; //设置图像高度
	if((en->handle = x264_encoder_open(en->param)) == 0)
	{
		return;
	}

	x264_picture_alloc(en->picture, X264_CSP_I420, en->param->i_width,en->param->i_height);
	en->picture->img.i_csp = X264_CSP_I420;
	en->picture->img.i_plane = 3;
}

/*结束压缩*/
void compress_end(Encoder *en)
{
	if (en->picture)
	{
		x264_picture_clean(en->picture);
		free(en->picture);
		en->picture = 0;
	}
	
	if(en->param)
	{
		free(en->param);
		en->param = 0;
	}
	if(en->handle)
	{
		x264_encoder_close(en->handle);
	}
	free(en);
}


/*初始化编码器*/
void X264_init_encoder(int width,int height)
{
	compress_begin(&en,width,height);
	h264_buf=(uint8_t *)malloc(sizeof(uint8_t)*width*height*3);
	if(h264_buf==NULL)printf("X264缓冲区申请失败!\n");
}


/*压缩一帧数据*/
int compress_frame(Encoder *en, int type, uint8_t *in, uint8_t *out) {
	x264_picture_t pic_out;
	int nNal = 0;
	int result = 0;
	int i = 0 , j = 0 ;
	uint8_t *p_out = out;
	en->nal=NULL;
	uint8_t *p422;

	char *y = en->picture->img.plane[0];
	char *u = en->picture->img.plane[1];
	char *v = en->picture->img.plane[2];


//////////////////////////////////////////////////////////////////////////////////////
	int widthStep422 = en->param->i_width * 2;
	for(i = 0; i < en->param->i_height; i += 2)
	{
		p422 = in + i * widthStep422;
		for(j = 0; j < widthStep422; j+=4)
		{
			*(y++) = p422[j];
			*(u++) = p422[j+1];
			*(y++) = p422[j+2];
		}
		p422 += widthStep422;
		for(j = 0; j < widthStep422; j+=4)
		{
			*(y++) = p422[j];
			*(v++) = p422[j+3];
			*(y++) = p422[j+2];
		}
	}

	switch (type) {
	case 0:
		en->picture->i_type = X264_TYPE_P;
		break;
	case 1:
		en->picture->i_type = X264_TYPE_IDR;
		break;
	case 2:
		en->picture->i_type = X264_TYPE_I;
		break;
	default:
		en->picture->i_type = X264_TYPE_AUTO;
		break;
	}

	/*开始264编码*/
	if (x264_encoder_encode(en->handle, &(en->nal), &nNal, en->picture,
			&pic_out) < 0) {
		return -1;
	}
	en->picture->i_pts++;


	for (i = 0; i < nNal; i++) {
		memcpy(p_out, en->nal[i].p_payload, en->nal[i].i_payload);
		p_out += en->nal[i].i_payload;
		result += en->nal[i].i_payload;
	}

	return result;
	//return nNal;
}

//编码并写入一帧数据
void encode_frame(uint8_t *yuv_frame)
{
	int h264_length = 0;
	//压缩一帧数据
	h264_length = compress_frame(&en, -1, yuv_frame, h264_buf);
	if(h264_length > 0)
	{
		printf("h264_length=%d\n",h264_length);
		//写入视频文件
		fwrite(h264_buf, h264_length,1,h264_fp);
	}
}


/*
函数功能: UVC摄像头初始化
返回值: 0表示成功
*/
int UVCvideoInit(void)
{
	/*1. 打开摄像头设备*/
	uvc_video_fd=open(UVC_VIDEO_DEVICE,O_RDWR);
	if(uvc_video_fd<0)
	{
		printf("%s 摄像头设备打开失败!\n",UVC_VIDEO_DEVICE);
		return -1;
	}
	
	/*2. 设置摄像头的属性*/
	struct v4l2_format format;
	memset(&format,0,sizeof(struct v4l2_format));
	format.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; /*表示视频捕获设备*/
	format.fmt.pix.width=320;  /*预设的宽度*/
	format.fmt.pix.height=240; /*预设的高度*/
	format.fmt.pix.pixelformat=V4L2_PIX_FMT_YUYV; /*预设的格式*/
	format.fmt.pix.field=V4L2_FIELD_ANY; /*系统自动设置: 帧属性*/
	if(ioctl(uvc_video_fd,VIDIOC_S_FMT,&format)) /*设置摄像头的属性*/
	{
		printf("摄像头格式设置失败!\n");
		return -2;
	}
	
	Image_Width=format.fmt.pix.width;
	Image_Height=format.fmt.pix.height;
		
	printf("摄像头实际输出的图像尺寸:x=%d,y=%d\n",format.fmt.pix.width,format.fmt.pix.height);
	if(format.fmt.pix.pixelformat==V4L2_PIX_FMT_YUYV)
	{
		printf("当前摄像头支持YUV格式图像输出!\n");
	}
	else
	{
		printf("当前摄像头不支持YUV格式图像输出!\n");
		return -3;
	}

	/*3. 请求缓冲区: 申请摄像头数据采集的缓冲区*/
	struct v4l2_requestbuffers req_buff;
	memset(&req_buff,0,sizeof(struct v4l2_requestbuffers));
	req_buff.count=4; /*预设要申请4个缓冲区*/
	req_buff.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; /*视频捕获设备*/
	req_buff.memory=V4L2_MEMORY_MMAP; /*支持mmap内存映射*/
	if(ioctl(uvc_video_fd,VIDIOC_REQBUFS,&req_buff)) /*申请缓冲区*/
	{
		printf("申请摄像头数据采集的缓冲区失败!\n");
		return -4;
	}
	printf("摄像头缓冲区申请的数量: %d\n",req_buff.count);

	/*4. 获取缓冲区的详细信息: 地址,编号*/
	struct v4l2_buffer buff_info;
	memset(&buff_info,0,sizeof(struct v4l2_buffer));
	int i;
	for(i=0;i<req_buff.count;i++)
	{
		buff_info.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; /*视频捕获设备*/
		buff_info.memory=V4L2_MEMORY_MMAP; /*支持mmap内存映射*/
		if(ioctl(uvc_video_fd,VIDIOC_QUERYBUF,&buff_info)) /*获取缓冲区的详细信息*/
		{
			printf("获取缓冲区的详细信息失败!\n");
			return -5;
		}
		/*根据摄像头申请缓冲区信息: 使用mmap函数将内核的地址映射到进程空间*/
		video_memaddr_buffer[i]=mmap(NULL,buff_info.length,PROT_READ|PROT_WRITE,MAP_SHARED,uvc_video_fd,buff_info.m.offset); 
		if(video_memaddr_buffer[i]==NULL)
		{
			printf("缓冲区映射失败!\n");
			return -6;
		}
	}

	/*5. 将缓冲区放入采集队列*/
	memset(&buff_info,0,sizeof(struct v4l2_buffer));
	for(i=0;i<req_buff.count;i++)
	{
		buff_info.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; /*视频捕获设备*/
		buff_info.index=i; /*缓冲区的节点编号*/
		buff_info.memory=V4L2_MEMORY_MMAP; /*支持mmap内存映射*/
		if(ioctl(uvc_video_fd,VIDIOC_QBUF,&buff_info)) /*根据节点编号将缓冲区放入队列*/
		{
			printf("根据节点编号将缓冲区放入队列失败!\n");
			return -7;
		}
	}

	/*6. 启动摄像头数据采集*/
	int Type=V4L2_BUF_TYPE_VIDEO_CAPTURE;
	if(ioctl(uvc_video_fd,VIDIOC_STREAMON,&Type))
	{
		printf("启动摄像头数据采集失败!\n");
		return -8;
	}
	return 0;
}


/*
函数功能: 采集摄像头的数据,并进行处理
*/
void *pthread_video_Data_Handler(void *dev)
{
	/*循环采集摄像头的数据*/
	struct pollfd fds;
	fds.fd=uvc_video_fd;
	fds.events=POLLIN;

	struct v4l2_buffer buff_info;
	memset(&buff_info,0,sizeof(struct v4l2_buffer));
	int index=0; /*表示当前缓冲区的编号*/
	
	printf("摄像头开始传输数据.......\n");
	while(1)
	{
		/*1. 等待摄像头采集数据*/
		poll(&fds,1,-1); 

		/*2. 取出一帧数据: 从采集队列里面取出一个缓冲区*/
		buff_info.type=V4L2_BUF_TYPE_VIDEO_CAPTURE;   /*视频捕获设备*/
		ioctl(uvc_video_fd,VIDIOC_DQBUF,&buff_info); /*从采集队列取出缓冲区*/
		index=buff_info.index;
		//printf("采集数据的缓冲区的编号:%d\n",index);

		/*3. 处理数据: 进行H264编码*/
		//video_memaddr_buffer[index]; /*当前存放数据的缓冲区地址*/
		
		/*编码一帧数据*/
		encode_frame(video_memaddr_buffer[index]);

		/*4. 将缓冲区再次放入采集队列*/
		buff_info.memory=V4L2_MEMORY_MMAP; 	/*支持mmap内存映射*/
		buff_info.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; /*视频捕获设备*/
		buff_info.index=index; /*缓冲区的节点编号*/
		ioctl(uvc_video_fd,VIDIOC_QBUF,&buff_info); /*根据节点编号将缓冲区放入队列*/
	}
}


int main(int argc,char **argv)
{
	if(argc!=2)
	{
		printf("./app <视频文件名称>\n");
		return 0;
	}
	pthread_t thread;
	
	/*绑定将要捕获的信号*/
	signal(SIGINT,exit_sighandler);
	signal(SIGSEGV,exit_sighandler);
	signal(SIGPIPE,SIG_IGN);
	
	/*1. 初始化摄像头*/
	if(UVCvideoInit()!=0)
	{
		printf("摄像头数据采集客户端:初始化摄像头失败!\n");
		exit(1);
	}
	
	/*2. 初始化编码器*/
	X264_init_encoder(Image_Width,Image_Height);
	
	/*3.创建存放视频的文件*/
	h264_fp=fopen(argv[1],"wa+");
	if(h264_fp==NULL)
	{
		printf("文件创建失败!\n");
		exit(1);
	}
		
	/*4. 创建线程采集摄像头数据并编码*/
	pthread_create(&thread,NULL,pthread_video_Data_Handler,NULL);
	
	//设置线程的分离属性
	pthread_detach(thread);
	
	while(1)
	{
		
	}
}

四、编译方法

CC=gcc
all:
	$(CC) x264_VideoEncode.c -o x264_video_encode -lx264 -L./lib -lpthread -lm -ldl

使用的是静态库链接编译。

五、运行示例

$ ./x264_video_encode 123.x264

在本地生成一个123.x264文件，可以使用mplayer或者vlc播放器播放。