wxml文件

<!--index.wxml-->
<view class='camera'>
  <image src="/images/border.png" mode="widthFix"></image>
  <camera wx:if="{{isAuth}}" device-position="front" flash="off" binderror="error"></camera>
</view>

<button class="takePhoto" type="primary" bindtap="startShootVideo">录像</button>

wxss文件

/**index.wxss**/
.camera {
  width: 430rpx;
  height: 430rpx;
  border-radius: 50%;
  margin: 20px auto 0;
  position: relative;
}

.camera image {
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: 10;
}

.camera camera {
  width: 430rpx;
  height: 430rpx;
}

button.takePhoto:not([size='mini']) {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100vw;
  height: 90rpx;
  border-radius: 0;
}

js文件

// index.js
// 获取应用实例
const app = getApp()
Page({
  data: {
    isAuth: false,
    src: ''
  },
  onLoad() {
    const _this = this
    wx.getSetting({
      success: res => {
        if (res.authSetting['scope.camera']) {
          // 用户已经授权
          _this.setData({
            isAuth: true
          })
        } else {
          // 用户还没有授权，向用户发起授权请求
          wx.authorize({
            scope: 'scope.camera',
            success() { // 用户同意授权
              _this.setData({
                isAuth: true
              })
            },
            fail() { // 用户不同意授权
              _this.openSetting().then(res => {
                _this.setData({
                  isAuth: true
                })
              })
            }
          })
        }
      },
      fail: res => {
        console.log('获取用户授权信息失败')
      }
    })
  },

  // 打开授权设置界面
  openSetting() {
    const _this = this
    let promise = new Promise((resolve, reject) => {
      wx.showModal({
        title: '授权',
        content: '请先授权获取摄像头权限',
        success(res) {
          if (res.confirm) {
            wx.openSetting({
              success(res) {
                if (res.authSetting['scope.camera']) { // 用户打开了授权开关
                  resolve(true)
                } else { // 用户没有打开授权开关， 继续打开设置页面
                  _this.openSetting().then(res => {
                    resolve(true)
                  })
                }
              },
              fail(res) {
                console.log(res)
              }
            })
          } else if (res.cancel) {
            _this.openSetting().then(res => {
              resolve(true)
            })
          }
        }
      })
    })
    return promise;
  },

  takePhoto() {
    const ctx = wx.createCameraContext()
    ctx.takePhoto({
      quality: 'high',
      success: (res) => {
        this.setData({
          src: res.tempImagePath
        })
        console.log(res.tempImagePath)
        wx.previewImage({
          current: res.tempImagePath, // 当前显示图片的http链接
          urls: [res.tempImagePath] // 需要预览的图片http链接列表
        })
      }
    })
  },
  startShootVideo() {
    this.setData({
      videoSrc: ''
    })
    console.log("========= 开始录像 ===========")
    this.ctx = wx.createCameraContext();
    let that = this
    this.ctx.startRecord({
      timeoutCallback: () => {
       
      },
      success: (res) => {
        
        setTimeout(()=>{
          this.ctx.stopRecord({
            compressed: true, //压缩视频
            success: (res) => {
              this.setData({
                videoSrc: res.tempVideoPath
              })
              console.log("========= 结束录像 ===========")
              console.log(res.tempVideoPath)
            }
          });
        },5000)
      },
      fail() {
        wx.showToast({
          title: '录像失败',
          icon: 'none',
          duration:4000
        })
        console.log("========= 调用开始录像失败 ===========")
      }
    })
  },
})

还附带了一个拍照函数，换到网页上就能用。

纳闷怎么没人写微信小程序定时录像的帖子，Debug了好久~