I had to modify the video_cck module so it doesn't insert empty video fields in the database (which messed up display in Views) :

  case 'insert':
  case 'update':
    if ($field['multiple']) {
      foreach ($items as $delta => $item) {
          $items[$delta]['data'] = serialize($items[$delta]['data']);
      }
    }

change to :

  case 'insert':
  case 'update':
    if ($field['multiple']) {
      foreach ($items as $delta => $item) {
        if (trim($items[$delta]['value'])!='')
          $items[$delta]['data'] = serialize($items[$delta]['data']);
      }
    }

I'm I the only one to have this problem ?