QuotaExceededError using MediaStream API

Question

My application receives some video chunks from a ServerSentEvent (SSE) and, using MediaStream API, it should append them in a buffer and visualize them into an HTML5 video tag. The problem is MediaSource API, that stops working when the program tries to append a chunk to the mediaStream buffer.

The error appears when the program tries to append the first chunk.

This is the client-side code:

window.MediaSource = window.MediaSource || window.WebKitMediaSource;
window.URL = window.URL || window.webkitURL;
if (!!!window.MediaSource) {alert('MediaSource API is not available');}

var video = document.getElementById("video");
var mediaSource = new MediaSource();
video.src = window.URL.createObjectURL(mediaSource);

mediaSource.addEventListener('sourceopen', function(e) {
    var source = new EventSource('http://localhost:5000/video');
    // this is the line that catch the error
    var sourceBuffer = mediaSource.addSourceBuffer('video/webm; codecs="vorbis,vp8"');

    source.addEventListener('chunkStreamed', function(e){
        var chunk = new Blob(JSON.parse(e.data));
        console.log("chunk: ", chunk);
        var reader = new FileReader();
        reader.onload = function(e) {
            // error is caused by this line
            sourceBuffer.appendBuffer(new Uint8Array(e.target.result));
        };
        reader.readAsArrayBuffer(chunk);
    });

    source.addEventListener('endStreaming', function(e){
        console.log(e.data);
        // mediaSource.endOfStream();
        // endOfStream() not here, sourceBuffer.appendBuffer will done after this command and will cause InvalidStateError 
    });

    source.onopen = function(e) {
        console.log("EventSource open");
    };

    source.onerror = function(e) {
        console.log("error", e);
        source.close();
    };

}, false);

and this is the complete error log:

Uncaught QuotaExceededError: An attempt was made to add something to storage that exceeded the quota.

The problem comes out when the app tries to do sourceBuffer.appendBuffer(new Uint8Array(e.target.result));.
I really can't understand way this error appear. Code is really like the code of this example