Linux攝像頭驅動V4L2
阿新 • • 發佈：2018-12-25
video.h
#ifndef VIDEO_H #define VIDEO_H /*¹ý³Ì cam_open("/dev/video0"); cam_setformat(H, W); cam_getinfo(); cam_setbuf(); cam_mapbuf(); cam_start(); while(1) { cam_getdata(bmp_yuv420,V4L2_PIX_FMT_YUV420); //YUV420ΪÏñËØ*1.5,ĬÈÏyuv420 YV12ToBGR24_Table(bmp_yuv420,bmp_rgb24,W,H); } cam_stop(); cam_unmap(); cam_close(); */ int cam_open(const char* path); void cam_getinfo(void); void cam_close(void); int cam_setformat(int height, int width, int format); //»ñÈ¡ÉãÏñͷͼƬ²É¼¯µÄ»º´æbuf int cam_setbuf(void); //Ó³Éäbufµ½Óû§¿Õ¼ä void cam_mapbuf(void); //¿ªÊ¼²É¼¯ void cam_start(); //»ñÈ¡²É¼¯µ½µÄÊý¾Ý int cam_getdata(char *buffer); int cam_stop(); int cam_unmap(); //yuv420--rgb24 bool YV12ToBGR24_Table(unsigned char* pYUV, unsigned char* pBGR24, int width, int height); #endif // !VIDEO_H
video.c
#include "video.h" #include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <getopt.h> #include <fcntl.h> #include <unistd.h> #include <errno.h> #include <malloc.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/time.h> #include <sys/mman.h> #include <sys/ioctl.h> #include <asm/types.h> #include <linux/videodev2.h> int cam_width; int cam_height; int cam_fd; struct cam_buffer { void* start; unsigned length; unsigned offset; }; struct cam_buffer *cam_buffers; //開啟攝像頭裝置 int cam_open(const char* path) { cam_fd=open(path,O_RDWR); if (cam_fd < 0) { printf("Open camera failed\n"); return -1; } } //獲取攝像頭資訊 void cam_getinfo(void) { struct v4l2_format fmt; fmt.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; ioctl(cam_fd, VIDIOC_G_FMT, &fmt); printf("Current data format information:\n\twidth:%d\n\theight:%d\n",fmt.fmt.pix.width,fmt.fmt.pix.height); struct v4l2_fmtdesc fmtdesc; fmtdesc.index=0; fmtdesc.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; while(ioctl(cam_fd,VIDIOC_ENUM_FMT,&fmtdesc)!=-1) { if(fmtdesc.pixelformat & fmt.fmt.pix.pixelformat) { printf("\tformat:%s\n",fmtdesc.description); break; } fmtdesc.index++; } } void cam_close(void) { close(cam_fd); } int cam_setformat(int height,int width,int format) { struct v4l2_format fmt; fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; //這裡必須填這個 fmt.fmt.pix.width = width; //使用者希望設定的寬 fmt.fmt.pix.height = height; //使用者希望設定的高 fmt.fmt.pix.pixelformat = format;//選擇格式：V4L2_PIX_FMT_YUYV或V4L2_PIX_FMT_MJPEG,V4L2_PIX_FMT_YUV420 fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; int ret = ioctl(cam_fd, VIDIOC_S_FMT, &fmt); if (ret < 0) { printf("VIDIOC_S_FMT failed (%d)\n", ret); return -1; } cam_width = fmt.fmt.pix.width; cam_height = fmt.fmt.pix.height; printf("------------VIDIOC_S_FMT---------------\n"); printf("Stream Format Informations:\n"); printf(" type: %d\n", fmt.type); printf(" width: %d\n", fmt.fmt.pix.width); printf(" height: %d\n", fmt.fmt.pix.height); return 0; } //獲取攝像頭圖片採集的快取buf int cam_setbuf(void) { struct v4l2_requestbuffers req; memset(&req, 0, sizeof (req)); req.count = 4; //攝像頭圖片快取buf個數，這裡一般設定4個 req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; req.memory = V4L2_MEMORY_MMAP; if (ioctl(cam_fd,VIDIOC_REQBUFS,&req) <0) { perror("VIDIOC_REQBUFS error \n"); return -1; } return 0; } //對映buf到使用者空間 void cam_mapbuf(void) { struct v4l2_buffer tmp_buf ; //攝像頭緩衝buf臨時儲存buf int numBufs = 0; cam_buffers = (struct cam_buffer*)calloc(4, sizeof(*cam_buffers));//記憶體中建立對應空間 for (numBufs = 0; numBufs < 4; numBufs++) { memset( &tmp_buf, 0, sizeof(tmp_buf)); tmp_buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ; tmp_buf.memory = V4L2_MEMORY_MMAP ; tmp_buf.index = numBufs; //獲取內部buf資訊到tmp_buf if (ioctl(cam_fd, VIDIOC_QUERYBUF, &tmp_buf) < 0) { printf("VIDIOC_QUERYBUF (%d) error\n",numBufs); return; } cam_buffers[numBufs].length = tmp_buf.length; cam_buffers[numBufs].offset = (size_t) tmp_buf.m.offset; //開始對映 cam_buffers[numBufs].start = mmap (NULL, tmp_buf.length,PROT_READ | PROT_WRITE, MAP_SHARED, cam_fd, tmp_buf.m.offset); if (cam_buffers[numBufs].start == MAP_FAILED) { perror("pic_buffers error\n"); //return -1; } //把設定好的buf入佇列 if (ioctl (cam_fd, VIDIOC_QBUF, &tmp_buf) < 0) { printf("VIDIOC_QBUF error\n"); //return -1; } } } //開始採集 void cam_start() { enum v4l2_buf_type type; type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (ioctl (cam_fd, VIDIOC_STREAMON, &type) < 0) { printf("VIDIOC_STREAMON error\n"); // return -1; } } //獲取採集到的資料 int cam_getdata(char *buffer) { struct v4l2_buffer buf; int ret ; buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ; buf.memory = V4L2_MEMORY_MMAP ; buf.index = 0; //把採集到圖片的緩衝出隊 ret = ioctl(cam_fd , VIDIOC_DQBUF , &buf); if(ret != 0) { perror("data fail1"); return -1 ; } //把圖片資料放到buffer中 memcpy(buffer , cam_buffers[buf.index].start , cam_buffers[buf.index].length); ret = ioctl(cam_fd , VIDIOC_QBUF , &buf); if(ret != 0) { perror("data fail2"); return -2 ; } return 0 ; } int cam_stop() { int ret ; int off= 1 ; ret = ioctl(cam_fd , VIDIOC_STREAMOFF, &off); if(ret != 0) { perror("stop Cameral fail"); return -1 ; } return 0 ; } int cam_unmap() { int i ; for(i = 0 ; i < 4 ; i++) { munmap(cam_buffers[i].start , cam_buffers[i].length); } return 0 ; } static int Table_fv1[256] = { -180, -179, -177, -176, -174, -173, -172, -170, -169, -167, -166, -165, -163, -162, -160, -159, -158, -156, -155, -153, -152, -151, -149, -148, -146, -145, -144, -142, -141, -139, -138, -137, -135, -134, -132, -131, -130, -128, -127, -125, -124, -123, -121, -120, -118, -117, -115, -114, -113, -111, -110, -108, -107, -106, -104, -103, -101, -100, -99, -97, -96, -94, -93, -92, -90, -89, -87, -86, -85, -83, -82, -80, -79, -78, -76, -75, -73, -72, -71, -69, -68, -66, -65, -64,-62, -61, -59, -58, -57, -55, -54, -52, -51, -50, -48, -47, -45, -44, -43, -41, -40, -38, -37, -36, -34, -33, -31, -30, -29, -27, -26, -24, -23, -22, -20, -19, -17, -16, -15, -13, -12, -10, -9, -8, -6, -5, -3, -2, 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 14, 15, 16, 18, 19, 21, 22, 23, 25, 26, 28, 29, 30, 32, 33, 35, 36, 37, 39, 40, 42, 43, 44, 46, 47, 49, 50, 51, 53, 54, 56, 57, 58, 60, 61, 63, 64, 65, 67, 68, 70, 71, 72, 74, 75, 77, 78, 79, 81, 82, 84, 85, 86, 88, 89, 91, 92, 93, 95, 96, 98, 99, 100, 102, 103, 105, 106, 107, 109, 110, 112, 113, 114, 116, 117, 119, 120, 122, 123, 124, 126, 127, 129, 130, 131, 133, 134, 136, 137, 138, 140, 141, 143, 144, 145, 147, 148, 150, 151, 152, 154, 155, 157, 158, 159, 161, 162, 164, 165, 166, 168, 169, 171, 172, 173, 175, 176, 178 }; static int Table_fv2[256] = { -92, -91, -91, -90, -89, -88, -88, -87, -86, -86, -85, -84, -83, -83, -82, -81, -81, -80, -79, -78, -78, -77, -76, -76, -75, -74, -73, -73, -72, -71, -71, -70, -69, -68, -68, -67, -66, -66, -65, -64, -63, -63, -62, -61, -61, -60, -59, -58, -58, -57, -56, -56, -55, -54, -53, -53, -52, -51, -51, -50, -49, -48, -48, -47, -46, -46, -45, -44, -43, -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35, -34, -33, -33, -32, -31, -31, -30, -29, -28, -28, -27, -26, -26, -25, -24, -23, -23, -22, -21, -21, -20, -19, -18, -18, -17, -16, -16, -15, -14, -13, -13, -12, -11, -11, -10, -9, -8, -8, -7, -6, -6, -5, -4, -3, -3, -2, -1, 0, 0, 1, 2, 2, 3, 4, 5, 5, 6, 7, 7, 8, 9, 10, 10, 11, 12, 12, 13, 14, 15, 15, 16, 17, 17, 18, 19, 20, 20, 21, 22, 22, 23, 24, 25, 25, 26, 27, 27, 28, 29, 30, 30, 31, 32, 32, 33, 34, 35, 35, 36, 37, 37, 38, 39, 40, 40, 41, 42, 42, 43, 44, 45, 45, 46, 47, 47, 48, 49, 50, 50, 51, 52, 52, 53, 54, 55, 55, 56, 57, 57, 58, 59, 60, 60, 61, 62, 62, 63, 64, 65, 65, 66, 67, 67, 68, 69, 70, 70, 71, 72, 72, 73, 74, 75, 75, 76, 77, 77, 78, 79, 80, 80, 81, 82, 82, 83, 84, 85, 85, 86, 87, 87, 88, 89, 90, 90 }; static int Table_fu1[256] = { -44, -44, -44, -43, -43, -43, -42, -42, -42, -41, -41, -41, -40, -40, -40, -39, -39, -39, -38, -38, -38, -37, -37, -37, -36, -36, -36, -35, -35, -35, -34, -34, -33, -33, -33, -32, -32, -32, -31, -31, -31, -30, -30, -30, -29, -29, -29, -28, -28, -28, -27, -27, -27, -26, -26, -26, -25, -25, -25, -24, -24, -24, -23, -23, -22, -22, -22, -21, -21, -21, -20, -20, -20, -19, -19, -19, -18, -18, -18, -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14, -13, -13, -13, -12, -12, -11, -11, -11, -10, -10, -10, -9, -9, -9, -8, -8, -8, -7, -7, -7, -6, -6, -6, -5, -5, -5, -4, -4, -4, -3, -3, -3, -2, -2, -2, -1, -1, 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 25, 26, 26, 26, 27, 27, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32, 32, 33, 33, 33, 34, 34, 34, 35, 35, 35, 36, 36, 36, 37, 37, 37, 38, 38, 38, 39, 39, 39, 40, 40, 40, 41, 41, 41, 42, 42, 42, 43, 43 }; static int Table_fu2[256] = { -227, -226, -224, -222, -220, -219, -217, -215, -213, -212, -210, -208, -206, -204, -203, -201, -199, -197, -196, -194, -192, -190, -188, -187, -185, -183, -181, -180, -178, -176, -174, -173, -171, -169, -167, -165, -164, -162, -160, -158, -157, -155, -153, -151, -149, -148, -146, -144, -142, -141, -139, -137, -135, -134, -132, -130, -128, -126, -125, -123, -121, -119, -118, -116, -114, -112, -110, -109, -107, -105, -103, -102, -100, -98, -96, -94, -93, -91, -89, -87, -86, -84, -82, -80, -79, -77, -75, -73, -71, -70, -68, -66, -64, -63, -61, -59, -57, -55, -54, -52, -50, -48, -47, -45, -43, -41, -40, -38, -36, -34, -32, -31, -29, -27, -25, -24, -22, -20, -18, -16, -15, -13, -11, -9, -8, -6, -4, -2, 0, 1, 3, 5, 7, 8, 10, 12, 14, 15, 17, 19, 21, 23, 24, 26, 28, 30, 31, 33, 35, 37, 39, 40, 42, 44, 46, 47, 49, 51, 53, 54, 56, 58, 60, 62, 63, 65, 67, 69, 70, 72, 74, 76, 78, 79, 81, 83, 85, 86, 88, 90, 92, 93, 95, 97, 99, 101, 102, 104, 106, 108, 109, 111, 113, 115, 117, 118, 120, 122, 124, 125, 127, 129, 131, 133, 134, 136, 138, 140, 141, 143, 145, 147, 148, 150, 152, 154, 156, 157, 159, 161, 163, 164, 166, 168, 170, 172, 173, 175, 177, 179, 180, 182, 184, 186, 187, 189, 191, 193, 195, 196, 198, 200, 202, 203, 205, 207, 209, 211, 212, 214, 216, 218, 219, 221, 223, 225 }; bool YV12ToBGR24_Table(unsigned char* pYUV, unsigned char* pBGR24, int width, int height) { if (width < 1 || height < 1 || pYUV == NULL || pBGR24 == NULL) return false; const long len = width * height; unsigned char* yData = pYUV; unsigned char* vData = &yData[len]; unsigned char* uData = &vData[len >> 2]; int bgr[3]; int yIdx, uIdx, vIdx, idx; int rdif, invgdif, bdif; for (int i = 0; i < height; i++) { for (int j = 0; j < width; j++) { yIdx = i * width + j; vIdx = (i / 2) * (width / 2) + (j / 2); uIdx = vIdx; rdif = Table_fv1[vData[vIdx]]; invgdif = Table_fu1[uData[uIdx]] + Table_fv2[vData[vIdx]]; bdif = Table_fu2[uData[uIdx]]; bgr[0] = yData[yIdx] + bdif; bgr[1] = yData[yIdx] - invgdif; bgr[2] = yData[yIdx] + rdif; for (int k = 0; k < 3; k++) { idx = (i * width + j) * 3 + k; if (bgr[k] >= 0 && bgr[k] <= 255) pBGR24[idx] = bgr[k]; else pBGR24[idx] = (bgr[k] < 0) ? 0 : 255; } } } return true; }