Not sure how many people know this but it is possible to watch torrents of video files while they are not finished downloading. Before I found this out I waited for vids to download like a fool. This post will be a quick explanation on how to do this. I am using two programs to do this:
I'm going to use Big Buck Bunny, a free & open-source short animated film for this demonstration. Here is a magnet link to get the torrent. Once you open the torrent, you'll see the torrent dialog. Check the "download in sequential order" and the "download first and last pieces first" options, and then click OK to begin the torrent download:
Once you have those options checked, you can either right-click on the torrent and click "preview file", or you can go to the folder your torrent is being downloaded to and just open the video file. And everything should work fine:
There are some small caveats to doing this that make it a little different from viewing videos on, say, YouTube or Netflix. First off, the video file has to be downloading quicker than you are watching it, otherwise you'll have to wait for it to buffer. If the estimated download time (ETA) is less than the length of the video, then you should be fine to watch the video. Secondly, you can't just scrub ahead/around to the parts that aren't downloaded yet and have them load instantly, you can only scrub around the earlier parts of the video that are downloaded.
That's how it works basically. Hope this helps you out. Enjoy watching video torrents on demand!
2023-04-20 update: Apparently you don't need the "first and last pieces first" option for MKV files. Also, many people in the torrenting community do not like it when things are downloaded sequentially because apparently it makes torrents more fragile or something. This is why sequential downloads are not available on many clients. Just keep this stuff in mind, and seed your torrents a little pl0x.