详解HTML5 使用video标签实现选择摄像头功能

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详解HTML5 使用video标签实现选择摄像头功能

1. html

//

<div id="vdoOne" style="display:none">

2. javascript

//// Elements for taking the snapshot
var canvasPreview = document.getElementById('canvasPreview');
var canvasUpload = document.getElementById('canvasUpload');
var contextPreview = canvasPreview.getContext('2d');
var contextUpload = canvasUpload.getContext('2d');

//#################### Video Source #######################3 
var videoElement = document.querySelector('video'); 
var videoSelect = document.querySelector('select#videoSource'); 


navigator.mediaDevices.enumerateDevices() 
  .then(gotDevices).then(getStream).catch(handleError); 


videoSelect.onchange = getStream; 




function gotDevices(deviceInfos) { 
  for (var i = 0; i < deviceInfos.length; ++i) { 
    var deviceInfo = deviceInfos[i]; 
    var option = document.createElement('option'); 
    option.value = deviceInfo.deviceId; 
    if (deviceInfo.kind === 'videoinput') { 
      option.text = deviceInfo.label || 
        'camera ' + 
        (videoSelect.length + 1); 
      videoSelect.appendChild(option); 
    } else { 
      console.log('Found ome other kind of source/device: ',deviceInfo); 
    } 
  } 
} 


var _streamCopy = null; 
function getStream() { 
  if (_streamCopy != null) { 
    try { 
      _streamCopy.stop(); // if this method doesn't exist,the catch will be executed. 
    } catch (e) { 
      _streamCopy.getVideoTracks()[0].stop(); // then stop the first video track of the stream 
    } 
  } 

  var constraints = { 
    au<a href="/tag/dio/" target="_blank" class="keywords">dio</a>:false,video: { 
      optional: [ 
        { 
          sourceId: videoSelect.value 
        } 
      ] 
    } 
  }; 

  navigator.mediaDevices.getUserMedia(constraints).then(gotStream).catch(handleError); 
} 


function gotStream(stream) { 
  _streamCopy = stream; // make stream available to console 
  videoElement.srcObject = stream; 
} 


function handleError(error) { 
  alert(error.name + ": " + error.message); 
} 


//######################## End Video Source ################# 




// Get access to the camera! 
if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) { 
  navigator.mediaDevices.getUserMedia({ video: true }).then(function(stream) { 
    videoElement.src = window.URL.createObjectURL(stream); 
    videoElement.play(); 


  }); 
} else { 
  document.getElementById("pnlVideo1").style.display = "none"; 
} 




//// Trigger photo take 
document.getElementById("snap").addEventListener("click",function() { 
    contextPreview.drawImage(videoElement,300,224); 
    contextUpload.drawImage(videoElement,224); 
    document.getElementById("video").style.display = "none"; 
    document.getElementById("snap").style.display = "none"; 
    document.getElementById("canvasPreview").style.display = "block"; 


    var image = document.getElementById("canvasUpload").toDataURL("image/jpeg"); 
    image = image.replace('data:image/jpeg;base64,',''); 
    $("#imgValue").val(image); 

    alert("image value :" + image); 
  }); 


//// Trigger photo take 




document.getElementById("btnOpen1").addEventListener("click",function() { 
    document.getElementById("vdoOne").style.display = "block"; 
    document.getElementById("video").style.display = "block"; 
    document.getElementById("snap").style.display = "block"; 
    document.getElementById("canvasPreview").style.display = "none"; 
  }); 

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