音频和视频传输

<audio controls preload="auto">
  <source src="audio-file.mp3" type="audio/mpeg" />

  <!-- fallback for browsers that don't support mp3 -->
  <source src="audio-file.ogg" type="audio/ogg" />

  <!-- fallback for browsers that don't support audio element -->
  <a href="audio-file.mp3">download audio</a>
</audio>

<video
  controls
  width="640"
  height="480"
  poster="initial-image.png"
  autoplay
  muted>
  <source src="video-file.mp4" type="video/mp4" />

  <!-- fallback for browsers that don't support mp4 -->
  <source src="video-file.webm" type="video/webm" />

  <!-- specifying subtitle files -->
  <track src="subtitles_en.vtt" kind="subtitles" srclang="en" label="English" />
  <track
    src="subtitles_no.vtt"
    kind="subtitles"
    srclang="no"
    label="Norwegian" />

  <!-- fallback for browsers that don't support video element -->
  <a href="video-file.mp4">download video</a>
</video>

const myAudio = document.createElement("audio");

if (myAudio.canPlayType("audio/mpeg")) {
  myAudio.setAttribute("src", "audio-file.mp3");
} else if (myAudio.canPlayType("audio/ogg")) {
  myAudio.setAttribute("src", "audio-file.ogg");
}

myAudio.currentTime = 5;
myAudio.play();

<audio id="player" src="data:audio/x-wav;base64,UklGRvC…"></audio>

const myVideo = document.createElement("video");

if (myVideo.canPlayType("video/mp4")) {
  myVideo.setAttribute("src", "video-file.mp4");
} else if (myVideo.canPlayType("video/webm")) {
  myVideo.setAttribute("src", "video-file.webm");
}

myVideo.width = 480;
myVideo.height = 320;

let audioCtx;
let buffer;
let source;

async function loadAudio() {
  try {
    // Load an audio file
    const response = await fetch("viper.mp3");
    // Decode it
    buffer = await audioCtx.decodeAudioData(await response.arrayBuffer());
  } catch (err) {
    console.error(`Unable to fetch the audio file. Error: ${err.message}`);
  }
}

const play = document.getElementById("play");
play.addEventListener("click", async () => {
  if (!audioCtx) {
    audioCtx = new AudioContext();
    await loadAudio();
  }
  source = audioCtx.createBufferSource();
  source.buffer = buffer;
  source.connect(audioCtx.destination);
  source.start();
  play.disabled = true;
});

<video id="webcam" width="480" height="360"></video>

if (navigator.mediaDevices) {
  navigator.mediaDevices
    .getUserMedia({ video: true, audio: false })
    .then((stream) => {
      const video = document.getElementById("webcam");
      video.autoplay = true;
      video.srcObject = stream;
    })
    .catch(() => {
      alert(
        "There has been a problem retrieving the streams - are you running on file:/// or did you disallow access?",
      );
    });
} else {
  alert("getUserMedia is not supported in this browser.");
}

navigator.mediaDevices
  .getUserMedia({ audio: true })
  .then((stream) => {
    const recorder = new MediaRecorder(stream);

    const data = [];
    recorder.ondataavailable = (e) => {
      data.push(e.data);
    };
    recorder.start();
    recorder.onerror = (e) => {
      throw e.error || new Error(e.name); // e.name is FF non-spec
    };
    recorder.onstop = (e) => {
      const audio = document.createElement("audio");
      audio.src = window.URL.createObjectURL(new Blob(data));
    };
    setTimeout(() => {
      rec.stop();
    }, 5000);
  })
  .catch((error) => {
    console.log(error.message);
  });

<audio id="my-audio" src="/shared-assets/audio/guitar.mp3"></audio>
<button id="my-control">play</button>

const myAudio = document.getElementById("my-audio");
const myControl = document.getElementById("my-control");

function switchState() {
  if (myAudio.paused) {
    myAudio.play();
    myControl.textContent = "pause";
  } else {
    myAudio.pause();
    myControl.textContent = "play";
  }
}

function checkKey(e) {
  if (e.code === "Space") {
    // space bar
    switchState();
  }
}

myControl.addEventListener("click", () => {
  switchState();
});

window.addEventListener("keypress", checkKey);

const mediaElement = document.querySelector("#myMediaElementID");
mediaElement.removeAttribute("src");
mediaElement.load();

const mediaElement = document.querySelector("#mediaElementID");
mediaElement.seekable.start(0); // Returns the starting time (in seconds)
mediaElement.seekable.end(0); // Returns the ending time (in seconds)
mediaElement.currentTime = 122; // Seek to 122 seconds
mediaElement.played.end(0); // Returns the number of seconds the browser has played

<video>
  <source
    id="mp4_src"
    src="video.mp4"
    type='video/mp4; codecs="avc1.42E01E, mp4a.40.2"' />
  <source
    id="3gp_src"
    src="video.3gp"
    type='video/3gpp; codecs="mp4v.20.8, samr"' />
  <source
    id="ogg_src"
    src="video.ogv"
    type='video/ogv; codecs="theora, vorbis"' />
</video>

<video controls>
  <source src="dynamicsearch.mp4" type="video/mp4" />
  <a href="dynamicsearch.mp4">
    <img src="dynamicsearch.jpg" alt="Dynamic app search in Firefox OS" />
  </a>
  <p>Click image to play a video demo of dynamic app search</p>
</video>

const v = document.querySelector("video");
const sources = v.querySelectorAll("source");
const lastSource = sources[sources.length - 1];
lastSource.addEventListener("error", (ev) => {
  const d = document.createElement("div");
  d.innerHTML = v.innerHTML;
  v.parentNode.replaceChild(d, v);
});