The torrent file has no data for the stream. Your PHP server will need to start receiving torrent data from other peers (this is how torrents work).
MP4 is not a format that every byte needs to play, so QuickTime can start playing before it is fully loaded (therefore, streaming), but the bytes that need to be played must be at the beginning (or at the end, but in any case) - torrents do not load in byte order. As the above user said, torrents load data into chunks. You need at least a headline.
This is just unreal.
James source share