Notice: Undefined index: file uploading video - php

Question

I am trying to upload a video to my uploads folder. I got the code from another question on here and that works fine. But I keep getting this notice error and I don't know how to fix it. I've been trying all day. I tried to check if it was isset() and that still didn't work. Can someone help me please ?
<?php
$allowedExts = array("jpg", "jpeg", "gif", "png", "mp3", "mp4", "wma");
$_FILES = $_FILES['file'];
$extension = pathinfo($_FILES['file']['name'], PATHINFO_EXTENSION);
$unique = date('Y-m-d_H-i-s');
if ((null !==($_FILES["file"]["type"] == "video/mp4")
|| (null !==($_FILES["file"]["type"] == "audio/mp3"))
|| ($_FILES["file"]["type"] == "audio/wma")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg"))
&& ($_FILES["file"]["size"] < 2000000)
&& in_array($extension, $allowedExts)) {
if ($_FILES["file"]["error"] > 0) {
echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
} else {
echo 'File uploaded successfully';
if (file_exists("upload/" . $_FILES["file"]["name"])) {
echo $_FILES["file"]["name"] . " already exists. ";
} else {
$datetime = date('Y-m-d_H-i-s');
move_uploaded_file($_FILES["file"]["tmp_name"],
"uploads/" . $_FILES["file"]["name"] . $datetime . md5($_FILES["file"]["name"]));
}
}
} else {
echo "Invalid file";
}
?>
<form action="profile.php" id="videoupload" method="post" enctype="multipart/form-data">
<label for="file"><span>Filename:</span></label>
<input type="file" name="file" id="file" />
<br />
<input type="submit" name="submit" value="Submit" />
</form>

Answer 1

You're trying to process the file upload before a file is uploaded. You have to check if the form was posted first.
<?php
if (isset($_FILES['file'])) {
$allowedExts = array("jpg", "jpeg", "gif", "png", "mp3", "mp4", "wma");
// $_FILES = $_FILES['file']; // <-- remove this line
$extension = pathinfo($_FILES['file']['name'], PATHINFO_EXTENSION);
$unique = date('Y-m-d_H-i-s');
if ((null !==($_FILES["file"]["type"] == "video/mp4")
|| (null !==($_FILES["file"]["type"] == "audio/mp3"))
|| ($_FILES["file"]["type"] == "audio/wma")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg"))
&& ($_FILES["file"]["size"] < 2000000)
&& in_array($extension, $allowedExts)) {
if ($_FILES["file"]["error"] > 0) {
echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
} else {
echo 'File uploaded successfully';
if (file_exists("upload/" . $_FILES["file"]["name"])) {
echo $_FILES["file"]["name"] . " already exists. ";
} else {
$datetime = date('Y-m-d_H-i-s');
move_uploaded_file($_FILES["file"]["tmp_name"],
"uploads/" . $_FILES["file"]["name"] . $datetime . md5($_FILES["file"]["name"]));
}
}
} else {
echo "Invalid file";
}
}
?>
<form action="profile.php" id="videoupload" method="post" enctype="multipart/form-data">
<label for="file"><span>Filename:</span></label>
<input type="file" name="file" id="file" />
<br />
<input type="submit" name="submit" value="Submit" />
</form>

Answer 2

$_FILES['file']
means you have input type = file named 'file'. if you don't have the input named 'file', you got an undefined index notice.
if you have that,
$_FILES = $_FILES['file'];
this will bring error to other codes. because it try to override $_FILES.