If using HTML5_Media with File Entity module, and configure to display the file with Media Player, I got error when loading a multiple file field using Media upload.

The problem is solved if we add the entity ID to the player ID:

function html5_media_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
$element = array();
switch ($display['type']) {
case 'html5_player':
// Get the display settings.
$settings = $display['settings'];

// Get the ID for this media player.
+ $entity_ids = (entity_extract_ids($entity_type,$entity));
+ $entity_id = array_shift($entity_ids);
+ $id = 'player-' . drupal_clean_css_identifier($field['field_name']) . '-' . $entity_id;

Sorry, I could not provide a better patch for this.