Source

File: wp-admin/includes/media.php

function wp_add_id3_tag_data( &$metadata, $data ) {
	foreach ( array( 'id3v2', 'id3v1' ) as $version ) {
		if ( ! empty( $data[ $version ]['comments'] ) ) {
			foreach ( $data[ $version ]['comments'] as $key => $list ) {
				if ( 'length' !== $key && ! empty( $list ) ) {
					$metadata[ $key ] = wp_kses_post( reset( $list ) );
					// Fix bug in byte stream analysis.
					if ( 'terms_of_use' === $key && 0 === strpos( $metadata[ $key ], 'yright notice.' ) ) {
						$metadata[ $key ] = 'Cop' . $metadata[ $key ];
					}
				}
			}
			break;
		}
	}

	if ( ! empty( $data['id3v2']['APIC'] ) ) {
		$image = reset( $data['id3v2']['APIC'] );
		if ( ! empty( $image['data'] ) ) {
			$metadata['image'] = array(
				'data'   => $image['data'],
				'mime'   => $image['image_mime'],
				'width'  => $image['image_width'],
				'height' => $image['image_height'],
			);
		}
	} elseif ( ! empty( $data['comments']['picture'] ) ) {
		$image = reset( $data['comments']['picture'] );
		if ( ! empty( $image['data'] ) ) {
			$metadata['image'] = array(
				'data' => $image['data'],
				'mime' => $image['image_mime'],
			);
		}
	}
}