使用PHP从Web下载后，MP4无法播放(MP4 is not playable after downloaded from web using PHP)

 我有一个可播放的.mp4文件，我使用此代码使用PHP下载文件。 
 
 Web浏览器下载文件正常，但下载后mp4文件无法播放。 
 
 代码有问题吗？ 
 
<?php
// place this code inside a php file and call it f.e. "download.php"
$path = $_SERVER['DOCUMENT_ROOT'] . "/video/";
$fullPath = $path."test_video.mp4";

if ($fd = fopen ($fullPath, "r")) {
    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    header("Content-type: application/octet-stream");
    header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
    header("Content-length: $fsize");
    header("Cache-control: private"); //use this to open files directly
    while(!feof($fd)) {
        $buffer = fread($fd, 2048);
        echo $buffer;
    }
}
fclose ($fd);
exit;
?>

I have a playable .mp4 file and I used this code to download the file using PHP.
 
Web browser downloads file ok, but the mp4 file is not playable after downloading.
 
Does the code have any issue?
 
<?php
// place this code inside a php file and call it f.e. "download.php"
$path = $_SERVER['DOCUMENT_ROOT'] . "/video/";
$fullPath = $path."test_video.mp4";

if ($fd = fopen ($fullPath, "r")) {
    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    header("Content-type: application/octet-stream");
    header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
    header("Content-length: $fsize");
    header("Cache-control: private"); //use this to open files directly
    while(!feof($fd)) {
        $buffer = fread($fd, 2048);
        echo $buffer;
    }
}
fclose ($fd);
exit;
?>

原文：https://stackoverflow.com/questions/39361657