如何通过http标题下载mp4文件

Question

I've got a mp4 file saved on external FTP server. When I save it over "Save video as" when I play this video in classic HTML5 player, everything is ok. But when I download this file over this headers:

header('Content-Description: File Download');
header('Content-Transfer-Encoding: binary');
header('Content-Length: FILE_SIZE');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: no-cache');
header('Expires: Mon, 1 Apr 1974 05:00:00 GMT');
header("Content-type: video/mp4");
header("Content-disposition: attachment; filename=FILE_NAME");
readfile(FILE_URL); // do the double-download-dance (dirty but worky)

(FILE_SIZE, FILE_URL and FILE_NAME are filled correctly of course), than mp4 file is downloaded, but every player say something like "this format is not supported". When i download any other filetype (pdf/ppt,...), everything is ok.

Any ideas, pls??

Answer 1

File 1 (Wrong File, Not able to play):

http://www.vaseakademie.cz/ajax/s:lekceTools/c:lekceTools/m:getFile/loID:177

Through 'Stáhnout lekci'

Filesize: 50156182 MD5:ef0bf2fdfe1774c0a75d26202cdebdcd

File 2 (Correct File, able to play):

http://data.vaseakademie.cz/lekce/kurz_68/b55bf87383652751aeefd02f844f9fd9.mp4

From the source if the playing video. Same with right click, save video as

Filesize: 50156182 MD5:ef72631add8524d72ac1b61bacf0cc1a

Conclusion:

Nothing wrong with the header, the file content is different. You should check your script for file processing, not the header