Get file duration uploaded from custom field wordpress - wordpress

Question

I want to get the duration of audio file when uploaded through custom field and save it in the post meta.

Answer 1

WordPress has built in audio functions using the ID3 library that will help you achieve this.
First you will hook into ACF using the acf/save_post hook. Then you will use the WP function wp_read_audio_metadata() to get the meta data of the audio file. Lastly you will use the update_post_meta() function to save the data to the post. Something like this:
function save_audio_duration($post_id) {
// Get the WP Uploads Directory (where ACF saves files)
$uploads = wp_upload_dir();
$uploads_dir = ( $uploads['baseurl'] . $uploads['subdir'] );
// Get the file name from ACF & create the file string
$file_obj = get_field('audio_file', $post_id);
$file = $uploads_dir . '/' . $file_obj['filename'];
// Use the wp_read_audio_metadata() function to get data
$metadata = wp_read_audio_metadata( $file );
// Save the file length to the post meta
update_post_meta($post_id, 'audio_length', $metadata['length']);
}
// Will execute AFTER post has been saved (change "20" to "1" to execute before)
add_action('acf/save_post', 'save_audio_duration', 20);
Note: $metadata['length'] will return the time in seconds while $metadata['length_formatted'] will return the time in a formatted string.
Note x2: If you change the "20" to "1" in the action to execute this BEFORE the fields are saved to the post you will need to change the get_field() function to $_POST['audio_file'] as the function will be executed before ACF saves the fields to the DB.

Answer 2

I change a little your good code for vídeos:
function save_video_duration($post_id) {
// Get the file name from ACF & create the file string
$file_obj = get_field('video_file', $post_id);
// Get the WP Uploads Directory (where ACF saves files)
$file = get_attached_file( attachment_url_to_postid( get_field('video_file', $post_id) ) );
// Use the wp_read_audio_metadata() function to get data
$metadata = wp_read_video_metadata($file);
// Save the file length to the post meta
update_post_meta($post_id, 'video_file_length', $metadata['length']);
}
// Will execute AFTER post has been saved (change "20" to "1" to execute before)
add_action('acf/save_post', 'save_video_duration', 20);
Thanks