Linux（Ubutun）V4L2采集YUV422转YUV420，ALSA采集pcm、QT播放音频QOpenGL显示

#include "yuvcapture.h" #define WIDTH 640 #define HEIGHT 480 YuvCapture::YuvCapture(int fd) :fd(fd) {} YuvCapture::~YuvCapture() { StopCapture(); UninitCapture(); free(this->framebuf); close(fd); } //初始化缓存 int YuvCapture::InitMmep() { struct v4l2_requestbuffers req; struct v4l2_buffer buf; memset(&req, 0, sizeof(struct v4l2_requestbuffers)); memset(&buf, 0, sizeof(struct v4l2_buffer)); req.count = 4; req.memory = V4L2_MEMORY_MMAP; req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; //分配内存 if (camera_ioctl(VIDIOC_REQBUFS, &req) == -1) { perror("fail to request buffer"); } if (req.count < 2) { printf("Insufficient buffer memory\n"); return -1; } cout << "frame buffer request done" << endl; //分配用户态内存 framebuf = (video_buf_t *)calloc(req.count, sizeof(video_buf_t)); if (!framebuf) { printf("frambuf err calloc"); return -1; } for (int i = 0; i < req.count; i++) { buf.index = i; //回收缓冲 if (camera_ioctl(VIDIOC_QUERYBUF, &buf) == -1) { perror("VIDIOC_QUERYBUF failed!\n"); return -1; } //mmap buffer framebuf[i].length = buf.length; framebuf[i].start = mmap(NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, buf.m.offset); if (framebuf[i].start == MAP_FAILED) { perror("mmap failed!\n"); return -1; } } } //初始化摄像头采集设备 int YuvCapture::InitCaputer() { if(fd == -1) return -1; //检查摄像头设备，获取信息。 v4l2_capability cap; if (-1 == camera_ioctl(VIDIOC_QUERYCAP, &cap)) { perror("ictol cap!"); return -1; } if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) { fprintf(stderr, "is no video capture device\n"); return -1; } if (!(cap.capabilities & V4L2_CAP_STREAMING)) { fprintf(stderr, "does not support streaming i/o\n"); return -1; } //打印摄像头相关信息 printf("\nVIDOOC_QUERYCAP\n"); printf("the camera driver is %s\n", cap.driver); printf("the camera card is %s\n", cap.card); printf("the camera bus info is %s\n", cap.bus_info); printf("the version is %d\n", cap.version); //摄像头所支持的像素格式 v4l2_fmtdesc fmtdesc; fmtdesc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; fmtdesc.index = 0; printf("Support format:\n"); while (camera_ioctl(VIDIOC_ENUM_FMT, &fmtdesc) != -1) { printf("\t%d.%s\n", fmtdesc.index + 1, fmtdesc.description); fmtdesc.index++; } //设置像素格式 v4l2_format 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; //yuv422 fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; //隔行扫描 //应用设置格式 if (camera_ioctl(VIDIOC_S_FMT, &fmt) < 0) { printf("VIDIOC_S_FMT\n"); return -1; } //读出设置查看是否设置格式成功 if (camera_ioctl(VIDIOC_G_FMT, &fmt) < 0) { printf("VIDIOC_S_FMT\n"); return -1; } printf("fmt.type:\t\t%d\n", fmt.type); printf("pix.pixelformat:\t%c%c%c%c\n", fmt.fmt.pix.pixelformat & 0xFF, (fmt.fmt.pix.pixelformat >> 8) & 0xFF, (fmt.fmt.pix.pixelformat >> 16) & 0xFF, (fmt.fmt.pix.pixelformat >> 24) & 0xFF); printf("pix.height:\t\t%d\n", fmt.fmt.pix.height); printf("pix.width:\t\t%d\n", fmt.fmt.pix.width); printf("pix.field:\t\t%d\n", fmt.fmt.pix.field); //设置fps struct v4l2_streamparm parm; parm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; parm.parm.capture.timeperframe.numerator = 10; parm.parm.capture.timeperframe.denominator = 10; if (ioctl(fd, VIDIOC_S_PARM, &parm) == -1) { perror("VIDIOC_S_PARM failed\n"); return false; } printf("init camera success!\n"); //初始化缓存 InitMmep(); } //开始采集 int YuvCapture::StartCapture() { unsigned int i; v4l2_buffer buf; enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE; memset(&buf, 0, sizeof(struct v4l2_buffer)); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; //放回缓冲区 for (i = 0; i < 4; i++) { buf.index = i; if (camera_ioctl(VIDIOC_QBUF, &buf) < 0) { perror("VIDIOC_DQBUF err\n"); return -1; } } //开始采集 if (camera_ioctl(VIDIOC_STREAMON, &type) < 0) { printf("VIDIOC_STREAMON\n"); return -1; } cout << "satart capture....." << endl; } //暂停采集 int YuvCapture::StopCapture() { enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (camera_ioctl(VIDIOC_STREAMOFF, &type) < 0) { perror("VIDIOC_STREAMOFF"); } printf("Stop caputer...\n"); return -1; } //读取一帧数据 int YuvCapture::ReadOneFrame(unsigned char *outBuf) { v4l2_buffer buf; memset(&buf, 0, sizeof(struct v4l2_buffer)); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; if (camera_ioctl(VIDIOC_DQBUF, &buf) < 0) { switch (errno) { case EAGAIN: return 0; case EIO: /* Could ignore EIO, see spec. */ /* fall through */ default: return -1; } } Yuv422ToYuv420((unsigned char *)framebuf[buf.index].start, outBuf, WIDTH, HEIGHT); //放回缓冲 if (camera_ioctl(VIDIOC_QBUF, &buf) < 0) { printf("VIDIOC_DQBUF ERROR\n"); return -1; } } //解除内存映射 int YuvCapture::UninitCapture() { unsigned int i; for (i = 0; i < 4; i++) { if (munmap(framebuf[i].start, framebuf[i].length) < 0) { printf("munmap\n"); break; } } printf("ummp buf....\n"); free(framebuf); return 1; } //YUV422转YUV420 int YuvCapture::Yuv422ToYuv420(unsigned char *yuv422, unsigned char *yuv420, int width, int height) { int ynum=width*height; int i,j,k=0; //得到Y分量 for(i=0;i<ynum;i++){ yuv420[i]=yuv422[i*2]; } //得到U分量 for(i=0;i<height;i++){ if((i%2)!=0)continue; for(j=0;j<(width/2);j++){ if((4*j+1)>(2*width))break; yuv420[ynum+k*2*width/4+j]=yuv422[i*2*width+4*j+1]; } k++; } k=0; //得到V分量 for(i=0;i<height;i++){ if((i%2)==0)continue; for(j=0;j<(width/2);j++){ if((4*j+3)>(2*width))break; yuv420[ynum+ynum/4+k*2*width/4+j]=yuv422[i*2*width+4*j+3]; } k++; } return 1; } int YuvCapture::camera_ioctl(int request, void *arg) { int r = -1; do { r = ioctl(fd, request, arg); } while (r < 0 && EINTR == errno); return r; }