Remove attachment page for audio media type only

You must use this function wp_check_filetype to check what is your media type

$filetype = wp_check_filetype('image.jpg');
echo $filetype['ext']; // will output jpg

then you can have something like this

$file_url = wp_get_attachment_url( $file_id );
$filetype = wp_check_filetype( $file_url );

switch ($filetype) {
    case 'image/jpeg':
    case 'image/png':
    case 'image/gif':
      return   // do whatever you want 
      break;
    case 'video/mpeg':
    case 'video/mp4': 
    case 'video/quicktime':
      return // do whatever you want 
      break;
    case 'text/csv':
    case 'text/plain': 
    case 'text/xml':
      return // do whatever you want 
      break;
    default:
      return // do whatever you want 
  }

so in your function you can first check your attachment file type and when it’s Video you can do your redirect code.

for more information:

1- https://codex.wordpress.org/Function_Reference/get_post_mime_type

2- https://codex.wordpress.org/Function_Reference/wp_check_filetype

Hope it works for you.