Getting the length of an MP3 the quick way
When you create content for a podcast for iTunes, Amazon Music and Spotify, the xml feed requires the length of the MP3 – that can be a problem if you are using an external mp3 file. It’s not easy to use the PHP get_id3 libraries to determine the length. If you can get them to open the external file, they often time out.
There’s a much easier way – do it client side with javascript!
<script>// Create a non-dom allocated Audio element
var au = document.createElement('audio');
// Define the URL of the MP3 audio file
au.src = "https://mydomain.com/file.mp3";
// Once the metadata has been loaded, display the duration in the console
au.addEventListener('loadedmetadata', function(){
// Obtain the duration in seconds of the audio file (with milliseconds as well, a float value)
var duration = parseInt(au.duration);
console.log("The duration of the song is : " + duration + " seconds");
var date = new Date(null);
date.setSeconds(duration);
var hhmmssFormat = date.toISOString().substr(11, 8);
console.log(hhmmssFormat);
},false);
</script>Here is how I used that snippet in one of my WordPress plugins – when the form field is filled in, the length is detected and the value in hh:mm:ss format is put in the hidden form field.
echo'<tr><th scope="row">'.__('External Audio mp3/M4a URL','church-admin').'</th><td><input type="text" name="audio_url" id="audio_url"';
if(!empty( $errors['audio_url'] ) ) echo 'style="border:1px red solid"';
if(!empty( $current_data->external_file) )echo' value="'.esc_url( $current_data->external_file).'" ';
echo'/>';
echo'<input Type="hidden" name="external_duration" id="external_duration" ';
if( !empty( $current_data->length ) )echo' value="'.esc_attr($current_data->length).'"';
echo '/></td></tr>';
//javascript to detect length of external audio
echo'<script>
jQuery(document).ready(function($){
$("#audio_url").change(function(){
var url=$(this).val();
var au = document.createElement("audio");
// Define the URL of the MP3 audio file
au.src = url;
// Once the metadata has been loaded, display the duration in the console
au.addEventListener("loadedmetadata", function(){
var duration = parseInt(au.duration);
//convert to ISO format
var date = new Date(null);
date.setSeconds(duration);
var hhmmssFormat = date.toISOString().substr(11, 8);
console.log("External duration is "+ hhmmssFormat);
$("#external_duration").val(hhmmssFormat);
},false);
})
});
</script>';