Symfony2 form builder, choices multiple, excepted array also on sample code - php

Question

After hours of searching on this forum and google no answer worked.
I have tried more types of array like array of arrays, and simple key => value array.
Also i have tried code for: expanded true, and multiple true at http://symfony.com/doc/current/reference/forms/types/choice.html
I am getting error " Expected an array. 500 Internal Server Error - TransformationFailedException " When i turn on "multiple" I have tried it with array of arrays and key pair array.
What i want is to do and what its doing.
I select videos from database
make conversion
$video = $this->entityManager->getRepository("CMMSHomeBundle:Video")->findAll();
if (!$video)
{
return '0';
}
$video_arr = array();
for ($i = 0; $i < count($video); $i++)
{
//$video_arr[$i]["id"] = $video[$i]->getId();
//$video_arr[$i]["videoid"] = $video[$i]->getVideoid();
$video_arr[$video[$i]->getId()] = $video[$i]->getVideoid();
}
return $video_arr;
print_f if array is correct: Array ( [1] => X-77txuiVXs [5] => uelHwf8o7_U ) OR Array ( [0] => Array ( [id] => 1 [videoid] => X-77txuiVXs ) [1] => Array ( [id] => 5 [videoid] => uelHwf8o7_U ) )
Do the magick
$form = $this->createFormBuilder($product);
$form->add('name', 'text');
$form->add('short', 'textarea');
$form->add("description", "textarea");
$form->add("price", "text");
$form->add("images", "text");
$form->add('videos', 'choice', array(
'choices' => $videos,
'expanded' => true,
'multiple' => true,
)
);
$form->add("files", "text");
$form->add("size", "text");
$form->add("weight", "text");
$form->add("category", "text");
$form->add("active", "text");
$form->add('save', 'submit');
$form->getForm();
$form is chained, i unchained it to get correct formating by this soverflow editor.
It wont work :-( As soon i turn on multiple
Thank you