Profile: michaelR-26

Problem: I have a custom URL field that my visitors populate using a front-end Form. The URL is a YouTube video URL, and I would like to display the video in an embedded player with the URL parameter rel=0 attached so no related videos are displayed. However, I do not expect my Users to add the rel=0 parameter when they enter the YouTube URL on the front-end. How can I append the URL parameter programmatically in the template when the video is displayed?

Solution: You need a custom shortcode to do this. The following can be used as a guide:

add_shortcode( 'no-rel-youtube', 'no_rel_youtube_func' );
function no_rel_youtube_func($atts) {
  global $post, $wp_embed;
  $atts = shortcode_atts( array(
    'field-slug' => 'your-field-slug',
    'post-id' => $post->ID
  ), $atts );
  $field_value = get_post_meta( $atts['post-id'], 'wpcf-' . $atts['field-slug'], true );
  return $wp_embed->run_shortcode("[embed width='500' height='300']" . $field_value . "&rel=0[/embed]");
}

Replace your-field-slug with the slug of the field containing the URL, and adjust the height and width of the embed shortcode as needed. Render the player with the custom shortcode, like this:

[no-rel-youtube][/no-rel-youtube]

Relevant Documentation:
https://codex.wordpress.org/Embed_Shortcode