Cesium 使用MediaStreamRecorder 或者MediaRecorder录屏并下载视频，以及开启摄像头录像。【转】

Cesium录制canvas视频
利用H5 API MediaRecorder 并借用canvas.captureStream录制屏幕。

安装MediaRecorder 

npm install msr

直接上代码（vue下）

recorderCanvas () {
      let that = this
      let viewer = window.earth
      const stream = viewer.canvas.captureStream()
      const recorder = new MediaRecorder(stream, { MimeType: 'video/webm' })
      that.data = []
      recorder.ondataavailable = function (event) {
        if (event.data && event.data.size) {
          that.data.push(event.data)
        }
      }
      recorder.onstop = () => {
        that.url = URL.createObjectURL(new Blob(that.data, { type: 'video/webm' }))
        that.startDownload(that.url) // 这里创建a标签下载就好了
      }
      recorder.start()
      setTimeout(() => {
        recorder.stop()
      }, 10000)
    },

缺点：只能录制canvas, 页面其他dom录制不了。

附加个打开摄像头录像的，同样采用MediaRecorder 或者 MediaStreamRecorder ，MediaStreamRecorder 提供了更多控制手段，需要把相应的js文件引入。

MediaStreamRecorder GitHub地址

MediaRecorder 方式

注意点，建立MediaRecorder实例时，要正确设置mimeType的值，否则，下载下来的视频会是黑屏，另外视频格式chrome好像只支持wemp格式。

调用MediaRecorder.stop()并不会关闭摄像头，需要手动stream.getTracks关闭视频和音频。

makeRecordes () {
      if (navigator.mediaDevices) {
        console.log('getUserMedia supported.')
 
        var constraints = { audio: true, video: {  1280, height: 720 } }
        var chunks = []
        let that = this
        navigator.mediaDevices.getUserMedia(constraints)
          .then(function (stream) {
            var mediaRecorder = new MediaRecorder(stream, { mimeType: 'video/webm;codecs=vp8,opus' })
 
            mediaRecorder.start()
            mediaRecorder.ondataavailable = function (e) {
              chunks.push(e.data)
            }
            setTimeout(() => {
              mediaRecorder.stop()
              // 关闭摄像头
              stream.getTracks().forEach(function (track) {
                track.stop()
              })
              mediaRecorder.onstop = () => {
                const videoBlob = new Blob(chunks, { 'type': 'video/webm' })
                let videoUrl = window.URL.createObjectURL(videoBlob)
                that.startDownload(videoUrl)
              }
            }, 10000)
          })
          .catch(function (err) {
            console.log('The following error occurred: ' + err)
          })
      }
    },

如果你需要更多的控制，比如暂停，又不想自己实现，那就用MediaStreamRecorder

同样要正确设置值mimeType,否则录得视频会黑屏。

makeRecordesByMSR () {
      if (navigator.mediaDevices) {
        console.log('getUserMedia supported.')
 
        var constraints = { audio: true, video: {  1280, height: 720 } }
        navigator.mediaDevices.getUserMedia(constraints)
          .then(function (stream) {
            // eslint-disable-next-line no-undef
            var mediaRecorder = new MediaStreamRecorder(stream)
            mediaRecorder.stream = stream
            mediaRecorder.width = window.screen.width
            mediaRecorder.height = window.screen.height
            mediaRecorder.mimeType = 'video/webm;codecs=vp8,opus'
            mediaRecorder.ondataavailable = function (blob) {
              mediaRecorder.save(blob, 'myName.webm')
            }
            mediaRecorder.start(6000)
 
            setTimeout(() => {
              mediaRecorder.stream.stop()
            }, 12000)
          })
          .catch(function (err) {
            console.log('The following error occurred: ' + err)
          })
      }
    }

　　

原文链接：https://blog.csdn.net/qq_42081843/article/details/119005254