diff -u b/core/modules/media/src/MediaSourceInterface.php b/core/modules/media/src/MediaSourceInterface.php
--- b/core/modules/media/src/MediaSourceInterface.php
+++ b/core/modules/media/src/MediaSourceInterface.php
@@ -143,20 +143,26 @@
    * Gets the options for the source field in the form/view display.
    *
+   * The display options must have the same structure like the options for
+   * \Drupal\Core\Entity\Display\EntityDisplayInterface::setComponent().
+   * Returning an empty array means that the default display options of the
+   * source field will be used. If the $display_context is 'view', then the
+   * returned array must be a set of formatter options (i.e, for an entity view
+   * display), and if the $display_context is 'form', the returned array must be
+   * a set of widget options (i.e., for an entity form display).
+   *
    * @param \Drupal\media\MediaTypeInterface $type
    *   The media type which is using this source.
    * @param string $display_context
    *   The display context which will use these options. Can be 'view' or 'form.
+   * @param string $view_mode
+   *   The view mode of the display.
    *
    * @return array|bool
    *   The display options, or FALSE for removing this component from
    *   the display.
-   *   The display options must have the same structure like the options for
-   *   EntityDisplayInterface::setComponent($name, array $options = []).
-   *   Returning an empty array means that the default display options of the
-   *   source field will be used.
    *
    * @see \Drupal\Core\Entity\Display\EntityDisplayInterface::setComponent()
    */
-  public function getDisplayOptions(MediaTypeInterface $type, $display_context);
+  public function getDisplayOptions(MediaTypeInterface $type, $display_context, $view_mode = 'default');
 
 }