标签： 重要

Choose camera, microphone and speaker (opens new window)

View source on GitHub (opens new window)

const selectors = [audioInputSelect, audioOutputSelect, videoSelect];

audioOutputSelect.disabled = !('sinkId' in HTMLMediaElement.prototype);

function gotDevices(deviceInfos) {
  // Handles being called several times to update labels. Preserve values.
  const values = selectors.map(select => select.value);
  selectors.forEach(select => {
    while (select.firstChild) {
      select.removeChild(select.firstChild);
    }
  });
  for (let i = 0; i !== deviceInfos.length; ++i) {
    const deviceInfo = deviceInfos[i];
    const option = document.createElement('option');
    option.value = deviceInfo.deviceId;
    if (deviceInfo.kind === 'audioinput') {
      option.text = deviceInfo.label || `microphone ${audioInputSelect.length + 1}`;
      audioInputSelect.appendChild(option);
    } else if (deviceInfo.kind === 'audiooutput') {
      option.text = deviceInfo.label || `speaker ${audioOutputSelect.length + 1}`;
      audioOutputSelect.appendChild(option);
    } else if (deviceInfo.kind === 'videoinput') {
      option.text = deviceInfo.label || `camera ${videoSelect.length + 1}`;
      videoSelect.appendChild(option);
    } else {
      console.log('Some other kind of source/device: ', deviceInfo);
    }
  }
  selectors.forEach((select, selectorIndex) => {
    if (Array.prototype.slice.call(select.childNodes).some(n => n.value === values[selectorIndex])) {
      select.value = values[selectorIndex];
    }
  });
}

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

// Attach audio output device to video element using device/sink ID.
function attachSinkId(element, sinkId) {
  if (typeof element.sinkId !== 'undefined') {
    element.setSinkId(sinkId)
        .then(() => {
          console.log(`Success, audio output device attached: ${sinkId}`);
        })
        .catch(error => {
          let errorMessage = error;
          if (error.name === 'SecurityError') {
            errorMessage = `You need to use HTTPS for selecting audio output device: ${error}`;
          }
          console.error(errorMessage);
          // Jump back to first output device in the list as it's the default.
          audioOutputSelect.selectedIndex = 0;
        });
  } else {
    console.warn('Browser does not support output device selection.');
  }
}

function changeAudioDestination() {
  const audioDestination = audioOutputSelect.value;
  attachSinkId(videoElement, audioDestination);
}

function gotStream(stream) {
  window.stream = stream; // make stream available to console
  videoElement.srcObject = stream;
  // Refresh button list in case labels have become available
  return navigator.mediaDevices.enumerateDevices();
}

function start() {
  if (window.stream) {
    window.stream.getTracks().forEach(track => {
      track.stop();
    });
  }
  const audioSource = audioInputSelect.value;
  const videoSource = videoSelect.value;
  const constraints = {
    audio: {deviceId: audioSource ? {exact: audioSource} : undefined},
    video: {deviceId: videoSource ? {exact: videoSource} : undefined}
  };
  navigator.mediaDevices.getUserMedia(constraints).then(gotStream).then(gotDevices).catch(handleError);
}

audioInputSelect.onchange = start;
audioOutputSelect.onchange = changeAudioDestination;

videoSelect.onchange = start;

start();

Choose media source and audio output (opens new window)

View source on GitHub (opens new window)

function gotDevices(deviceInfos) {
  const masterOutputSelector = document.createElement('select');

  for (let i = 0; i !== deviceInfos.length; ++i) {
    const deviceInfo = deviceInfos[i];
    const option = document.createElement('option');
    option.value = deviceInfo.deviceId;
    if (deviceInfo.kind === 'audiooutput') {
      console.info('Found audio output device: ', deviceInfo.label);
      option.text = deviceInfo.label || `speaker ${masterOutputSelector.length + 1}`;
      masterOutputSelector.appendChild(option);
    } else {
      console.log('Found non audio output device: ', deviceInfo.label);
    }
  }

  // Clone the master outputSelector and replace outputSelector placeholders.
  const allOutputSelectors = document.querySelectorAll('select');
  for (let selector = 0; selector < allOutputSelectors.length; selector++) {
    const newOutputSelector = masterOutputSelector.cloneNode(true);
    newOutputSelector.addEventListener('change', changeAudioDestination);
    allOutputSelectors[selector].parentNode.replaceChild(newOutputSelector,
        allOutputSelectors[selector]);
  }
}

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

// Attach audio output device to the provided media element using the deviceId.
function attachSinkId(element, sinkId, outputSelector) {
  if (typeof element.sinkId !== 'undefined') {
    element.setSinkId(sinkId)
        .then(() => {
          console.log(`Success, audio output device attached: ${sinkId} to element with ${element.title} as source.`);
        })
        .catch(error => {
          let errorMessage = error;
          if (error.name === 'SecurityError') {
            errorMessage = `You need to use HTTPS for selecting audio output device: ${error}`;
          }
          console.error(errorMessage);
          // Jump back to first output device in the list as it's the default.
          outputSelector.selectedIndex = 0;
        });
  } else {
    console.warn('Browser does not support output device selection.');
  }
}

function changeAudioDestination(event) {
  const deviceId = event.target.value;
  const outputSelector = event.target;
  const element = event.path[2].childNodes[1];
  attachSinkId(element, deviceId, outputSelector);
}

function gotStream(stream) {
  window.stream = stream; // make stream available to console
  gumAudio.srcObject = stream;
  gumVideo.srcObject = stream;
}

function start() {
  if (window.stream) {
    window.stream.getTracks().forEach(track => {
      track.stop();
    });
  }
  const constraints = {
    audio: true,
    video: true
  };
  navigator.mediaDevices.getUserMedia(constraints).then(gotStream).catch(handleError);
}

start();