Video does not play when downloaded from FTP

[wuzhannanan]

I have a form on my website where users can upload a video file. When I test this, I have an issue with the video playback.

I record a video on my camera, and bring it onto my computer. When I bring the video onto my computer, it plays fine. In my Windows Explorer, I can select the video and see some basic information like frame size, etc.

I go to the form on my website and upload the video. Once the video has finished uploading, I log onto my server through FTP and download the video.

I save the video to my desktop and double click it to play. When I do this, I get an error like "Windows Media Player cannot play the file. The Player might not support the file type or might not support the codec that was used to compress the file."

I'm confused because this is the same video file I can play fine before I upload it. What am I missing?

[Coding Start]

Do you have sure your procedure is correct? This is very important to know if you want downloading from FTP.