我正在尝试创建一个应用程序,将视频文件存储到IndexedDB并从中检索。然而,在Firefox中检索和在Chrome中存储时遇到了问题。以下是代码:
(function () {
// IndexedDB
var indexedDB = window.indexedDB || window.webkitIndexedDB || window.mozIndexedDB || window.OIndexedDB || window.msIndexedDB,
IDBTransaction = window.IDBTransaction || window.webkitIDBTransaction || window.OIDBTransaction || window.msIDBTransaction,
dbVersion = 1.0;
// Create/open database
var request = indexedDB.open("videoFiles", dbVersion);
var db;
var createObjectStore = function (dataBase) {
// Create an objectStore
console.log("Creating objectStore")
dataBase.createObjectStore("earth");
},
getVideoFile = function () {
// Create XHR
var xhr = new XMLHttpRequest(),
blob;
xhr.open("GET", "day_the_earth_stood_still.ogv", true);
// Set the responseType to blob
xhr.responseType = "blob";
xhr.addEventListener("load", function () {
if (xhr.status === 200) {
console.log("Video retrieved");
// Blob as response
blob = xhr.response;
console.log("Blob:" + blob);
// Put the received blob into IndexedDB
putEarthInDb(blob);
}
}, false);
// Send XHR
xhr.send();
},
putEarthInDb = function (blob) {
console.log("Putting earth in IndexedDB");
// Open a transaction to the database
var transaction = db.transaction(["earth"], "readwrite");
// Put the blob into the dabase
var put = transaction.objectStore("earth").put(blob, "video");
// Retrieve the file that was just stored
transaction.objectStore("earth").get("video").onsuccess = function (event) {
var vidFile = event.target.result;
console.log("Got earth!" + vidFile);
console.log('File Type: ' + vidFile.type); /// THIS SHOWS : application/xml
// Get window.URL object
var URL = window.URL || window.webkitURL;
// Create and revoke ObjectURL
var vidURL = URL.createObjectURL(vidFile);
// Set vid src to ObjectURL
var vidEarth = document.getElementById("earth");
vidEarth.setAttribute("src", vidURL);
// Revoking ObjectURL
URL.revokeObjectURL(vidURL);
};
};
request.onerror = function (event) {
console.log("Error creating/accessing IndexedDB database");
};
request.onsuccess = function (event) {
console.log("Success creating/accessing IndexedDB database");
db = request.result;
db.onerror = function (event) {
console.log("Error creating/accessing IndexedDB database");
};
// Interim solution for Google Chrome to create an objectStore. Will be deprecated
if (db.setVersion) {
if (db.version != dbVersion) {
var setVersion = db.setVersion(dbVersion);
setVersion.onsuccess = function () {
createObjectStore(db);
getVideoFile();
};
}
else {
getVideoFile();
}
}
else {
getVideoFile();
}
}
// For future use. Currently only in latest Firefox versions
request.onupgradeneeded = function (event) {
createObjectStore(event.target.result);
};
})();
问题1(火狐浏览器):在火狐浏览器中,上面的代码console.log('文件类型:'+vidFile.type);在获取视频文件(mp4、ogv、webm)时会显示“application/xml”,因此Video标签会显示“不支持视频格式或MIME类型”。但是,如果获取的是像png这样的图片文件,则会显示“image/png”,并且如果将img标签的src设置了则可以正常工作。
问题2(谷歌浏览器):在谷歌浏览器中,无论是图像还是视频都没有被存储到IndexedDB中。在以下代码行:
var put = transaction.objectStore("earth").put(blob, "video");
引发了未捕获的错误: 抛出了DataCloneError: DOM IDBDatabase Exception 25。
我对IndexedDB一无所知,不知道如何解决这个问题。我只需要将视频文件存储到IndexedDB中,检索并在Video标签中显示。
以下是HTML代码(mp4):
<div class="myVidDiv">
<video id="earth" type="video/mp4" codecs="avc1.42e01e, mp4a.40.2" controls> </video>
</div>
(ogv):
<div class="myVidDiv">
<video id="earth" type="video/ogg" codecs="theora, vorbis" controls></video>
</div>
我也尝试了不加“codecs”属性的方法,但没有作用。我被这问题困扰了好几天……在谷歌上也找不到任何可行的例子。请有人帮帮我。