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Comment by rnhmjoj | Hacker News Reader

I have been using btfs for years so I can answer.

It can handle videos and other streamable formats if there are enough seeds: the connection is not usually a problem. The pieces are not downloaded strictly sequentially but using a sliding window[1], so if a piece is not immediately available btfs will not waste time and bandwidth waiting for it but just keep downloading other pieces nearby.

The problem is until enough pieces have been assembled, applications reading the file may literally hang: I guess not much software was made with slow I/O in mind.

[1]: https://github.com/johang/btfs/issues/7#issuecomment-1916443...

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There are all kinds of reasons a filesystem could be slower to serve certain bytes: striping across multiple heterogeneous physical disks, network filesystems like nfs/cifs/btfs, even IOp starvation.

Video players can gracefully handle streaming media despite spotty connections; is there a reason that they can't pre-read a sliding window of bytes from a file on disk and plow on in case a given range of bytes is taking too long? They could default to wanting all the bytes, but have a setting that instructs it to treat the filesystem as if it were a network source.

> is there a reason that they can't pre-read a sliding window of bytes from a file on disk and plow on in case a given range of bytes is taking too long?

AFAIK vlc has that functionality. It allows you to buffer the video n seconds in advance.

Setting a modest buffer size helps but does not solve this entirely. For example, turning on the subtitles or switching audio track will usually hang the player for a while.

Is there any way to get it to immediately start downloading the files, then prioritize the bits requested by applications reading the file?

Also, very curious, how have you been using btfs? What have you been using it for?

I think this should be the default behavior: as soon as you mount the torrent btfs start fetching it like any other torrent client.

I use it mainly for streaming videos: btfs comes with a small python script "btplay <magnet>" that will mount the torrent and start your player, very handy. Another cool thing you can do is downloading and extracting a file simultaneously, just mount a torrent and call "unzip".

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