通过XMLHttpRequest预加载音频文件

Question

I am currently trying to pre-load an MP3 file via an XMLHttpRequest in the browser and play it in the audio player. The audio file is played when set directly in the player. Therefore, I must have an error when processing the response.

loadAudio : function(playerId, source) {
    var player = document.getElementById(playerId);
    var request = new XMLHttpRequest();
    request.onreadystatechange = function() {
        console.log('readyState: ' + request.readyState + ', status: ' + request.status)
        if (this.readyState == 4 && this.status == 200) {
            console.log(request.getAllResponseHeaders());
            var blob = new Blob( [request.response] );
            var url = URL.createObjectURL( blob );
            player.src = url;
            player.addEventListener('loaded', function(e) {
                URL.revokeObjectURL(player.src);
            });
            player.play();
        // Typical action to be performed when the document is ready:
        }
    };
    request.open("GET", source, true);
    request.send();
}

I receive the following error message:

DEMUXER_ERROR_COULD_NOT_OPEN: FFmpegDemuxer: open context failed (code 4)

Does anyone have any idea where to find the error? Thank you for your answers.

Answer 1

Try this:

var blob = new Blob( [ request.response], { type: "audio/mp3" } );
var url = null;

if ( window.webkitURL ) {
    url = window.webkitURL.createObjectURL(blob);
} else if ( window.URL && window.URL.createObjectURL ) {
    url = window.URL.createObjectURL(blob);
}
player.addEventListener('loaded', function(e) {
    URL.revokeObjectURL(url);
});
player.addEventListener('load', function(e) {
    URL.revokeObjectURL(url);
});
player.src = url;

Answer 2

You can try setting the response type in your ajax request to blob.

loadAudio : function(playerId, source) {
    var player = document.getElementById(playerId);
    var request = new XMLHttpRequest();
    request.onreadystatechange = function() {
        console.log('readyState: ' + request.readyState + ', status: ' + request.status)
        if (this.readyState == 4 && this.status == 200) {
            var url = URL.createObjectURL( request.response);
            player.src = url;
            player.addEventListener('loaded', function(e) {
                URL.revokeObjectURL(player.src);
            });
            player.play();
        // Typical action to be performed when the document is ready:
        }
    };
    request.open("GET", source, true);
    request.responseType = 'blob';
    request.send();
}