Linux系统USB摄像头测试程序（四）_视频旋转及缩放-编程知识

下面的程序实现了视频的旋转及缩放，窗口中点击鼠标左键视频向左旋转，点击鼠标右键视频向右旋转并且视频缩小了二分之一。程序中首先把yvyv422转换成了RGB24，然后利用opencv进行了旋转和缩放，其后用sdl2进行了渲染。使用了ffmpeg、sdl2、gtk、opencv四个开源组件，编译时请先安装他们，下面是完整的代码及编译命令。
//rotate_camera.c
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <zconf.h>
#include <linux/videodev2.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <gtk-3.0/gtk/gtk.h>
#include <gdk/gdkx.h>#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libavdevice/avdevice.h"
#include "libavutil/imgutils.h"
#include <libavfilter/avfilter.h>
#include <libavfilter/buffersrc.h>
#include <libavfilter/buffersink.h>#include <SDL2/SDL.h>//dhl:gtk窗口组件
GtkWidget *window;
GtkWidget *fixed;
GtkWidget *button1,*button2,*button3;
GtkWidget *text,*text1,*text2,*text3;
GtkTextBuffer *buffer,*buffer1,*buffer2,*buffer3;
GtkWidget *label1,*label2,*label3,*label_line;//dhl:sdl窗口组件
SDL_Window *sdl_window; 
SDL_Renderer *sdl_renderer;
SDL_Texture *sdl_texture;//dhl:消息缓存
char disp[2048]={0};
char temp[128]={0};//dhl:获取窗口控件的值
int getWHR(char *device_name,char *win_size,int *win_width,int *win_height, char *frame_rate_t)
{GtkTextIter start,end;gtk_text_buffer_get_bounds(GTK_TEXT_BUFFER(buffer1),&start,&end);GtkTextIter s=start,e=end;sprintf(device_name,"%s",gtk_text_buffer_get_text(GTK_TEXT_BUFFER(buffer1),&s,&e,FALSE));gtk_text_buffer_get_bounds(GTK_TEXT_BUFFER(buffer2),&start,&end);s=start,e=end;gchar *win_size1 = gtk_text_buffer_get_text(GTK_TEXT_BUFFER(buffer2),&s,&e,FALSE);sprintf(win_size,"%s",gtk_text_buffer_get_text(GTK_TEXT_BUFFER(buffer2),&s,&e,FALSE));gtk_text_buffer_get_bounds(GTK_TEXT_BUFFER(buffer3),&start,&end);s=start,e=end;sprintf(frame_rate_t,"%s",gtk_text_buffer_get_text(GTK_TEXT_BUFFER(buffer3),&s,&e,FALSE));if (!strcmp(device_name,"")|| !strcmp(win_size,"")||!strcmp(frame_rate_t,"")) {GtkWidget * dialog= dialog = gtk_message_dialog_new (NULL,GTK_DIALOG_DESTROY_WITH_PARENT,GTK_MESSAGE_INFO,GTK_BUTTONS_CLOSE,"请输入摄像头设备名称、窗口尺寸、帧速率");gtk_dialog_run (GTK_DIALOG (dialog));gtk_widget_destroy (dialog);return -1;}sscanf(win_size1, "%dx%d", win_width, win_height);return 0;
}//yuv422 转 RGB24(subfunction)
int convert_yuv_to_rgb_pixel(int y, int u, int v)
{unsigned int pixel32 = 0;unsigned char *pixel = (unsigned char *)&pixel32;int r, g, b;r = y + (1.370705 * (v-128));g = y - (0.698001 * (v-128)) - (0.337633 * (u-128));b = y + (1.732446 * (u-128));if(r > 255) r = 255;if(g > 255) g = 255;if(b > 255) b = 255;if(r < 0) r = 0;if(g < 0) g = 0;if(b < 0) b = 0;pixel[0] = r ;pixel[1] = g ;pixel[2] = b ;return pixel32;
}//yuv422 转 RGB24
int convert_yuv_to_rgb_buffer(unsigned char *yuv, unsigned char *rgb, unsigned int width, unsigned int height)
{unsigned int in, out = 0;unsigned int pixel_16;unsigned char pixel_24[3];unsigned int pixel32;int y0, u, y1, v;for(in = 0; in < width * height * 2; in += 4){pixel_16 = yuv[in + 3] << 24 |yuv[in + 2] << 16 |yuv[in + 1] <<  8 |yuv[in + 0];y0 = (pixel_16 & 0x000000ff);u  = (pixel_16 & 0x0000ff00) >>  8;y1 = (pixel_16 & 0x00ff0000) >> 16;v  = (pixel_16 & 0xff000000) >> 24;pixel32 = convert_yuv_to_rgb_pixel(y0, u, v);pixel_24[0] = (pixel32 & 0x000000ff);pixel_24[1] = (pixel32 & 0x0000ff00) >> 8;pixel_24[2] = (pixel32 & 0x00ff0000) >> 16;rgb[out++] = pixel_24[0];rgb[out++] = pixel_24[1];rgb[out++] = pixel_24[2];pixel32 = convert_yuv_to_rgb_pixel(y1, u, v);pixel_24[0] = (pixel32 & 0x000000ff);pixel_24[1] = (pixel32 & 0x0000ff00) >> 8;pixel_24[2] = (pixel32 & 0x00ff0000) >> 16;rgb[out++] = pixel_24[0];rgb[out++] = pixel_24[1];rgb[out++] = pixel_24[2];}return 0;}//dhl:发现摄像头
void button1_clicked(GtkWidget *widget, gpointer data)
{char camera_devices_name[128]={0};for (int loop=0;loop<10;loop++) {sprintf(camera_devices_name,"/dev/video%d",loop);int fd = open(camera_devices_name, O_RDWR);if(fd < 0){printf("打开设备失败(%s)\n",camera_devices_name);close(fd);continue;}close(fd);sprintf(temp,"发现摄像头:%s\n",camera_devices_name);strcat(disp,temp);gtk_text_buffer_set_text(buffer,disp,-1);}sprintf(disp,"%s","");
}//dhl:查询配置信息
void button2_clicked(GtkWidget *widget, gpointer data)
{int line_num=0;gchar *device_name;GtkTextIter start,end;gtk_text_buffer_get_bounds(GTK_TEXT_BUFFER(buffer1),&start,&end);const GtkTextIter s=start,e=end;device_name=gtk_text_buffer_get_text(GTK_TEXT_BUFFER(buffer1),&s,&e,FALSE);if (!strcmp(device_name,"")){sprintf(temp,"请输入摄像头设备文件名\n");strcat(disp,temp);gtk_text_buffer_set_text(buffer,disp,-1);sprintf(disp,"%s","");return;}//dhl:查询摄像头支持的视频格式int fd = open(device_name, O_RDWR);if(fd < 0){printf("打开设备失败\n");return;}struct v4l2_fmtdesc v4fmt;v4fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; //视频捕获设备int i=0;while(1){v4fmt.index = i++;int ret = ioctl(fd, VIDIOC_ENUM_FMT, &v4fmt);if(ret < 0){printf("获取摄像头格式失败");break;}printf("index=%d\n", v4fmt.index);printf("flags=%d\n", v4fmt.flags);printf("description=%s\n", v4fmt.description);unsigned char *p = (unsigned char *)&v4fmt.pixelformat;printf("pixelformat=%c%c%c%c\n", p[0],p[1],p[2],p[3]);printf("reserved=%d\n", v4fmt.reserved[0]);sprintf(temp,"摄像头支持的视频格式(%d)\n",i);strcat(disp,temp);sprintf(temp,"index=%d,", v4fmt.index);strcat(disp,temp);sprintf(temp,"flags=%d,", v4fmt.flags);strcat(disp,temp);sprintf(temp,"description=%s,", v4fmt.description);strcat(disp,temp);sprintf(temp,"pixelformat=%c%c%c%c,", p[0],p[1],p[2],p[3]);strcat(disp,temp);sprintf(temp,"reserved=%d\n", v4fmt.reserved[0]);strcat(disp,temp);}close(fd);//dhl:MJPG支持的所有分辨率如下fd = open(device_name, O_RDWR);if(fd < 0){perror("打开设备失败");return;}struct v4l2_frmsizeenum frmsize;frmsize.index = 0;frmsize.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;printf("MJPEG格式支持所有分辨率如下:\n");//frmsize.pixel_format = V4L2_PIX_FMT_YUYV;frmsize.pixel_format = V4L2_PIX_FMT_MJPEG;sprintf(temp,"MJPG支持的分辨率:\n");strcat(disp,temp);line_num=1;while(ioctl(fd,VIDIOC_ENUM_FRAMESIZES,&frmsize) == 0){printf("frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);frmsize.index++;if ((line_num % 5) != 0) { sprintf(temp,"MJPEG frame_size<%d*%d>, ",frmsize.discrete.width,frmsize.discrete.height);}else {sprintf(temp,"MJPEG frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);}strcat(disp,temp);line_num++;if (line_num == 6) {line_num = 1;}}close(fd);sprintf(temp,"%s","\n");strcat(disp,temp);//dhl:YUV支持所有分辨率如下fd = open(device_name, O_RDWR);if(fd < 0){perror("打开设备失败");return;}//struct v4l2_frmsizeenum frmsize;frmsize.index = 0;frmsize.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;printf("MJPEG格式支持所有分辨率如下:\n");frmsize.pixel_format = V4L2_PIX_FMT_YUYV;//frmsize.pixel_format = V4L2_PIX_FMT_MJPEG;sprintf(temp,"YUV支持的分辨率:\n");strcat(disp,temp);line_num = 1;while(ioctl(fd,VIDIOC_ENUM_FRAMESIZES,&frmsize) == 0){printf("frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);frmsize.index++;if ((line_num % 5) != 0) { sprintf(temp,"YUYV frame_size<%d*%d>, ",frmsize.discrete.width,frmsize.discrete.height);}else {sprintf(temp,"YUYV frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);}strcat(disp,temp);line_num++;if (line_num == 6) {line_num = 1;}}close(fd);gtk_text_buffer_set_text(buffer,disp,-1);sprintf(disp,"%s","");}//dhl:视频预览并实现视频帧任意角度旋转
void button3_clicked(GtkWidget *widget, gpointer data)
{AVFormatContext *pFormatCtx;int             i, videoindex;AVCodecContext  *pCodecCtx;AVCodec         *pCodec;int ret = -1;int win_width=0, win_height=0;gchar device_name[128];gchar win_size[128];gchar frame_rate_t[128];//dhl:获取gtk窗口数据int iRet=getWHR(device_name,win_size,&win_width,&win_height, frame_rate_t);if (iRet!=0) {return;}if (SDL_Init(SDL_INIT_VIDEO)) {printf("Could not initialize SDL - %s\n", SDL_GetError());return;}else{printf("initialize SDL ok\n");}sdl_window = SDL_CreateWindow("视频预览",SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,win_width,win_height,SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);if(sdl_window == NULL){printf("SDL_window创建失败\n");return;}sdl_renderer = SDL_CreateRenderer(sdl_window,-1,SDL_RENDERER_ACCELERATED);/*dhl:旋转后图片的宽,高也变了，应根据新的尺寸创建纹理,否则图片变形sdl_texture = SDL_CreateTexture(sdl_renderer//,SDL_PIXELFORMAT_IYUV//,SDL_PIXELFORMAT_YUY2,SDL_PIXELFORMAT_RGB24,SDL_TEXTUREACCESS_TARGET,win_width,win_height);*/sdl_texture = SDL_CreateTexture(sdl_renderer//,SDL_PIXELFORMAT_IYUV//,SDL_PIXELFORMAT_YUY2,SDL_PIXELFORMAT_RGB24,SDL_TEXTUREACCESS_TARGET,390,400);SDL_Rect sdl_rect;char *buffer_pixels = malloc(win_width*win_height*4);char *buffer_rgb = malloc(win_width*win_height*3);char *buffer_rgb_reversal = malloc(win_width*win_height*3);pFormatCtx = avformat_alloc_context();const AVInputFormat *ifmt = av_find_input_format("v4l2");AVDictionary *option =NULL;av_dict_set(&option,"video_size",win_size,0);av_dict_set(&option,"framerate",frame_rate_t,0);//av_dict_set(&option,"pixel_format","yuv420p12be",0); //指定格式avformat_open_input(&pFormatCtx, device_name, ifmt,&option);if(avformat_find_stream_info(pFormatCtx, NULL) < 0){printf("Couldn't find stream information.\n");return;}videoindex = -1;for(i = 0; i < pFormatCtx->nb_streams; i++){if(pFormatCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO){videoindex = i;break;}}if(videoindex == -1){printf("Didn't find a video stream.\n");return;}else{printf("Find a video stream:%d.\n", videoindex);}pCodec = (AVCodec*)avcodec_find_decoder(pFormatCtx->streams[videoindex]->codecpar->codec_id);if(pCodec == NULL){printf("Codec not found.\n");return;}pCodecCtx = avcodec_alloc_context3(pCodec);avcodec_parameters_to_context(pCodecCtx, pFormatCtx->streams[videoindex]->codecpar);printf("VideoStream:Frame.Width=%d,Height=%d\n",pCodecCtx->width, pCodecCtx->height);if(avcodec_open2(pCodecCtx, pCodec, NULL) < 0){printf("Could not open codec.\n");return;}AVPacket *pkt = av_packet_alloc();if(!pkt){printf("av_packet_alloc错误\n");return;}AVFrame *frame_yuyv422 = av_frame_alloc();if(!frame_yuyv422){printf("av_frame_alloc错误\n");return;}int frame_count = 0;	//dhl:记录获取的帧数SDL_Event event;int degrees=50;    		//dhl:旋转角度while (av_read_frame(pFormatCtx, pkt) >= 0 ) {if(pkt->stream_index == videoindex){//dhl:发送给解码器if(avcodec_send_packet(pCodecCtx,pkt) != 0){printf("avcodec_send_packet error ...\n");break;}//dhl:从解码器中得到摄像头的原始视频帧int loop=0;while(avcodec_receive_frame(pCodecCtx,frame_yuyv422) == 0){frame_count++;for(int i = 0;i < frame_yuyv422->height;i++){memcpy(buffer_pixels+i * frame_yuyv422->linesize[0],frame_yuyv422->data[0] + i * frame_yuyv422->linesize[0],frame_yuyv422->linesize[0]);}//dhl:转换 yuyv422 到 RGB24convert_yuv_to_rgb_buffer(buffer_pixels, buffer_rgb, win_width, win_height);int w_width=win_width;int h_height=win_height;//dhl:按指定度数旋转图片any_rotate_degrees(buffer_rgb, buffer_pixels,&w_width, &h_height,degrees);  //SDL_UpdateTexture(sdl_texture,NULL,buffer_pixels,win_width*2);SDL_UpdateTexture(sdl_texture,NULL,buffer_pixels,h_height*3);//dhl:将纹理数据拷贝给渲染器sdl_rect.x = 0;sdl_rect.y = 0;sdl_rect.w = h_height;sdl_rect.h = w_width;//dhl:先清空帧画面，再重新绘制SDL_RenderClear(sdl_renderer);SDL_RenderCopy(sdl_renderer,sdl_texture,NULL,&sdl_rect);//dhl:显示帧画面SDL_RenderPresent(sdl_renderer);//dhl:延时渲染//SDL_Delay(frame_rate);}}av_packet_unref(pkt);for (int ll=0;ll<10;ll++) {SDL_PollEvent(&event);}	if (event.type == SDL_QUIT) {break;}else if (SDL_MOUSEBUTTONDOWN == event.type) {if(SDL_BUTTON_LEFT == event.button.button){int px = event.button.x;int py = event.button.y;printf("left x, y %d %d ...............\n", px, py);	printf("degrees %d\n",degrees);degrees=degrees+1;  //dhl:按下鼠标左键向左旋转一度}else if(SDL_BUTTON_RIGHT == event.button.button){int px = event.button.x;int py = event.button.y;printf("right x, y %d %d ...............\n", px, py);printf("degrees %d\n",degrees);degrees=degrees-1;	//dhl:按下鼠标右键向右旋转一度}} av_packet_unref(pkt);		}sprintf(disp,"预览总帧数：%d",frame_count);gtk_text_buffer_set_text(buffer,disp,-1);sprintf(disp,"%s","");av_free(frame_yuyv422);av_packet_free(&pkt);avformat_close_input(&pFormatCtx);free(buffer_pixels);free(buffer_rgb);free(buffer_rgb_reversal);SDL_DestroyTexture(sdl_texture);SDL_DestroyRenderer(sdl_renderer);SDL_DestroyWindow(sdl_window );		SDL_Quit();return;
}int main(int argc,char *argv[])
{gtk_init(&argc,&argv);avdevice_register_all();window = gtk_window_new(GTK_WINDOW_TOPLEVEL);gtk_window_set_title(GTK_WINDOW(window),"USB摄像头测试程序(v1.0.20230728)");//gtk_window_set_resizable(GTK_WINDOW(window),FALSE);gtk_window_set_default_size(GTK_WINDOW(window),1280,800);gtk_window_set_position(GTK_WINDOW(window),GTK_WIN_POS_CENTER);fixed = gtk_fixed_new();gtk_container_add(GTK_CONTAINER(window),fixed);text = gtk_text_view_new();buffer=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text));gtk_text_buffer_set_text(buffer,"",-1);gtk_fixed_put(GTK_FIXED(fixed),text,20,480);gtk_widget_set_size_request(text,1240,300);button1 = gtk_button_new_with_label("查询摄像头");gtk_fixed_put(GTK_FIXED(fixed),button1,320,14);gtk_widget_set_size_request(button1,100,20);label1 = gtk_label_new("摄像头：");gtk_fixed_put(GTK_FIXED(fixed),label1,440,14);gtk_widget_set_size_request(label1,50,30);text1 = gtk_text_view_new();buffer1=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text1));gtk_text_buffer_set_text(buffer1,"",-1);gtk_fixed_put(GTK_FIXED(fixed),text1,500,16);gtk_widget_set_size_request(text1,100,28);sprintf(disp,"/dev/video0");gtk_text_buffer_set_text(buffer1,disp,-1);button2 = gtk_button_new_with_label("查询配置");gtk_fixed_put(GTK_FIXED(fixed),button2,610,14);gtk_widget_set_size_request(button2,80,35);label2 = gtk_label_new("分辨率：");gtk_fixed_put(GTK_FIXED(fixed),label2,740,18);gtk_widget_set_size_request(label2,50,30);text2 = gtk_text_view_new();buffer2=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text2));gtk_text_buffer_set_text(buffer2,"",-1);gtk_fixed_put(GTK_FIXED(fixed),text2,800,16);gtk_widget_set_size_request(text2,100,28);sprintf(disp,"640x480");gtk_text_buffer_set_text(buffer2,disp,-1);label3 = gtk_label_new("帧率：");gtk_fixed_put(GTK_FIXED(fixed),label3,930,18);gtk_widget_set_size_request(label3,50,30);text3 = gtk_text_view_new();buffer3=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text3));gtk_text_buffer_set_text(buffer3,"",-1);gtk_fixed_put(GTK_FIXED(fixed),text3,980,16);gtk_widget_set_size_request(text3,100,28);sprintf(disp,"30");gtk_text_buffer_set_text(buffer3,disp,-1);label_line = gtk_label_new("______________________________________________________________________________________________________________________________");gtk_fixed_put(GTK_FIXED(fixed),label_line,320,45);gtk_widget_set_size_request(label_line,800,3);GtkWidget *labelChild;PangoFontDescription *font;int fontSize = 10;font = pango_font_description_from_string("Sans");				//"Sans"字体名pango_font_description_set_size(font, fontSize * PANGO_SCALE);	//设置字体大小labelChild = gtk_bin_get_child(GTK_WIDGET(button1));			//取出GtkButton里的labelgtk_widget_modify_font(GTK_WIDGET(labelChild), font);			//设置label的字体， 这样这个GtkButton上面显示的字体就变了labelChild = gtk_bin_get_child(GTK_WIDGET(button2));			gtk_widget_modify_font(GTK_WIDGET(labelChild), font);			button3 = gtk_button_new_with_label("视频预览");gtk_fixed_put(GTK_FIXED(fixed),button3,320,80);gtk_widget_set_size_request(button3,80,20);g_signal_connect_swapped(G_OBJECT(window),"destroy",G_CALLBACK(gtk_main_quit),NULL);g_signal_connect_swapped(G_OBJECT(window),"destroy",G_CALLBACK(gtk_main_quit),NULL);g_signal_connect(G_OBJECT(button1), "clicked", G_CALLBACK(button1_clicked),NULL);g_signal_connect(G_OBJECT(button2), "clicked", G_CALLBACK(button2_clicked),NULL);g_signal_connect(G_OBJECT(button3), "clicked", G_CALLBACK(button3_clicked),NULL);	gtk_widget_show_all(window);gtk_main();return 0;
}//edit_image.cpp
#include <opencv2/opencv.hpp>
#include<iostream>
#include<math.h>using namespace cv;
using namespace std;/*** dhl:图片编辑模块，利用opencv4实现旋转等功能**///dhl:any Rotate  degrees
int any_rotate(unsigned char* src_data, unsigned char* des_data,int *width, int *height,int degrees)
{int w_wight=*width;int h_height=*height;Mat dst_mat(h_height,w_wight,CV_8UC3);Mat des,m;memcpy(dst_mat.data,  src_data ,w_wight*h_height*3*sizeof(unsigned char));Point2f center = Point(dst_mat.cols / 2, dst_mat.rows / 2);double angle = degrees,scale=0.5;int w = dst_mat.cols, h = dst_mat.rows;int bound_w = (h * fabs(sin(angle * CV_PI / 180)) + w * fabs(cos(angle * CV_PI / 180))) * scale;int bound_h = (h * fabs(cos(angle * CV_PI / 180)) + w * fabs(sin(angle * CV_PI / 180))) * scale;m = getRotationMatrix2D(center, angle, scale);m.at<double>(0, 2) += (bound_w - dst_mat.cols) / 2;m.at<double>(1, 2) += (bound_h - dst_mat.rows) / 2;warpAffine(dst_mat,des,m,Size2i(bound_h,bound_w));memcpy(des_data,  des.data ,bound_h*bound_w*3);*width=bound_w;*height=bound_h;return 0;
}extern "C" {//dhl:图片上下翻转int reversal_image(unsigned char* src_data, unsigned char* des_data,int data_len){for (int i=0;i<data_len;i++) {des_data[i]=src_data[data_len-i-1];}return 0;}//dhl:left Rotate 90 degreesint left_rotate_image(unsigned char* src_data, unsigned char* des_data,int width, int height){return 0;}//dhl:right Rotate 90 degreesint righht_rotate_image(unsigned char* src_data, unsigned char* des_data,int width, int height){return 0;}//dhl:arbitrary degrees rotateint any_rotate_degrees(unsigned char* src_data, unsigned char* des_data,int *width, int *height,int degrees){any_rotate(src_data, des_data,width, height,degrees);return 0;}}
编译命令：gcc rotate_camera.c edit_image.cpp -o camera_rotate `pkg-config --cflags --libs libavdevice libavfilter libavformat libavcodec libavutil libpostproc libswresample libswscale` `pkg-config --cflags --libs sdl2` `pkg-config --cflags --libs gtk+-3.0` `pkg-config --cflags --libs opencv4` -std=c++11 -lstdc++ -lpthread -lm -w
运行效果图：