6 ms·

I think you're missing his point. The success of bittorrent as a swarming protocol is that each client tries to download the least available snippet of the fil

by mburns 13y ago

I think you're missing his point. The success of bittorrent as a swarming protocol is that each client tries to download the least available snippet of the file it wants. This increases the chances that other clients will be able to find 100% of the pieces of a file as they go through the download process. With popcorn and other streaming-torrent hybrids, the clients requests are biased towards the snippets of file that the user is about to watch. This makes the beginning of the movie widely available (as all clients start there to begin a stream) but increases the chance that bits of the middle or end of the movie aren't available when a given client needs them.

gonzagonza 13y ago
This is a _very_ interesting comment. There _must_ be a switch on the logic of the streaming. If you want to "stream" the torrent, you will need to start with the first chunks But i think we can do something nice about it. We need to add some transfer stats to the downloading and use it. You have the file xyz.mp4 with 20 chunks. First, you leech the first 4 chunks (first 20 minutes of the xyz.mp4 file) Then you analyze aprox. transfer speed. Let's say you are downloading 2 minutes of movie per second. If you already downloaded the first 20 minutes, you have at least 15 minutes until you need to start downloading the chunk number 5. We should use those 15 minutes to download the last chunks (20, 19, 18...) After 15 minutes you start downloading chunk number 5, 6, 7... and repeat the process. I think this could work fine, YTS should do something about this.
- mrtree 13y ago
  I agree that we should try to make all chunks of a file available for the other peers, but also all files that participate in the p2p network. I am not sure which kind of structured p2p system popcorn time sues, but if it was a DHT it should make sure that there is replication of the rarest files works too. So that people who want to watch weird east European movies also have the opportunity, just as those who want to watch the latest blockbuster. I hope popcorn time does not immediately delete cached chunks...what a waste.
- deizel 13y ago
  XBMCtorrent approaches this by seeding the movie until you finish watching it. In my experience, movies start playing within the first minute and are finished downloading within the first hour (well, 10-20 minutes for popular content), meaning a large portion of the movie's running time is devoted to seeding 100% of the file. https://github.com/steeve/xbmctorrent#doesnt-sequential-download-on-bittorrent-is-bad https://github.com/steeve/xbmctorrent#doesnt-sequential-down...
notimetorelax 13y ago
This may be true, but on my network it takes less than 5 minutes to download a 2GB file and 20 minutes to have 200% upload. I usually stop uploading after that. Now if I were to use Popcorn Movie I'd be uploading for much longer period.
- redwall_hp 13y ago
  And some people have networks where constantly seeding an entire thing—be it a movie or a Linux distro—is not feasible. When you have 3mbps down/1mbps up DSL, it's going to saturate your upload if you leave it unchecked, and still have a very negative impact even if you throttle.
- spoiler 13y ago
  In most countries, your average Internet consumer can't achieve the speeds you described, though. Also, the download-to-upload rate is significantly higher. For example, my peak download speed is 5Mbits while the upload speed peaks at 0.6Mbits. That's on one of the more expensive packages, too.
  - gugol 13y ago
    That's ok, as long as you seed for enough time until you have at least 1:1 ratio which is what the developers should worry about: how do you keep seeding even if the movie is over?
- mrtree 13y ago
  Exactly, people seem to forget the usage patterns.
computer 13y ago
Sure. But the app seems to be focused on streaming very popular torrents, which means that generally all pieces will be available enough. Also, all Popcorntime clients want the same blocks first, meaning they will both need and seed the first blocks more. So they do not cause an imbalance, as long as there are always some peers that have the full movie.
- pikachu_is_cool 13y ago
  > But the app seems to be focused on streaming very popular torrents, which means that generally all pieces will be available enough. This lacks a lot of foresight. > Also, all Popcorntime clients want the same blocks first, meaning they will both need and seed the first blocks more. So they do not cause an imbalance, as long as there are always some peers that have the full movie. And this is just plain wrong.
  - hackmiester 13y ago
    Saying someone is wrong isn't useful if there is no explanation.
    - pikachu_is_cool 13y ago
      http://wiki.vuze.com/w/Sequential_downloading_is_bad http://wiki.vuze.com/w/Sequential_downloading_is_bad
      - comex 13y ago
        > The older peers have already completed the first few files and thus aren't interested in younger peers who currently download the first file exclusively, thus no mutually beneficial relationship can be established between different "generations" of prioritizing peers, effectively splitting the swarm into sparsely connected sets. I don't understand this. Why does it need to be mutually beneficial? The peers should "pay it forward" by uploading to younger peers, even if the ones they downloaded from are not benefitting. > On a small swarm this behavior can lead to pieces drop to the 0 availability because some peers concentrate on the first few files while the last peer/seed that has the rare piece in one of the later file quits after doing his fair share, but he only uploaded data for the first few files because the prioritizing peers were interested in those only. This could be mitigated by using excess bandwidth beyond that needed for streaming to download rare chunks, and ensuring that the streaming application keeps seeding for a while after the video has been watched.
TrainedMonkey 13y ago
I think you are missing the point as well. People will not start watching movie at the same time. When one person is almost done another just begins the movie, thus as long as there are few initial seeds and healthy interest in the movie it does not matter which order chunks will be downloaded.
br78 13y ago
Intriguing... is that really so much of a factor? To torrent-stream successfully you have to have eventually loaded all snippets from beginning to end of a file and could potentially be offering them for download at most only a couple of hours later than if you downloaded it first snippet.
mrtree 13y ago
That is not necessarily true, it will depend on the number of peers and the chunk replication rate. You can tweak the ratios so that the first part is available more often. In fact,you are also forgetting about the usage of each peer application. With traditional torrents you download the movie, close the app and watch the movie. Total seeding time is the same as the downloading time. With popcorn time you are seeding WHILE watching the movie, the total seeding time is much, much longer than in the first case.

by mburns 13y ago

gonzagonza 13y ago

This is a _very_ interesting comment. There _must_ be a switch on the logic of the streaming. If you want to "stream" the torrent, you will need to start with the first chunks But i think we can do something nice about it. We need to add some transfer stats to the downloading and use it. You have the file xyz.mp4 with 20 chunks. First, you leech the first 4 chunks (first 20 minutes of the xyz.mp4 file) Then you analyze aprox. transfer speed. Let's say you are downloading 2 minutes of movie per second. If you already downloaded the first 20 minutes, you have at least 15 minutes until you need to start downloading the chunk number 5. We should use those 15 minutes to download the last chunks (20, 19, 18...) After 15 minutes you start downloading chunk number 5, 6, 7... and repeat the process. I think this could work fine, YTS should do something about this.

mrtree 13y ago
I agree that we should try to make all chunks of a file available for the other peers, but also all files that participate in the p2p network. I am not sure which kind of structured p2p system popcorn time sues, but if it was a DHT it should make sure that there is replication of the rarest files works too. So that people who want to watch weird east European movies also have the opportunity, just as those who want to watch the latest blockbuster. I hope popcorn time does not immediately delete cached chunks...what a waste.
deizel 13y ago
XBMCtorrent approaches this by seeding the movie until you finish watching it. In my experience, movies start playing within the first minute and are finished downloading within the first hour (well, 10-20 minutes for popular content), meaning a large portion of the movie's running time is devoted to seeding 100% of the file. https://github.com/steeve/xbmctorrent#doesnt-sequential-download-on-bittorrent-is-bad https://github.com/steeve/xbmctorrent#doesnt-sequential-down...

notimetorelax 13y ago

This may be true, but on my network it takes less than 5 minutes to download a 2GB file and 20 minutes to have 200% upload. I usually stop uploading after that. Now if I were to use Popcorn Movie I'd be uploading for much longer period.

redwall_hp 13y ago
And some people have networks where constantly seeding an entire thing—be it a movie or a Linux distro—is not feasible. When you have 3mbps down/1mbps up DSL, it's going to saturate your upload if you leave it unchecked, and still have a very negative impact even if you throttle.
spoiler 13y ago
In most countries, your average Internet consumer can't achieve the speeds you described, though. Also, the download-to-upload rate is significantly higher. For example, my peak download speed is 5Mbits while the upload speed peaks at 0.6Mbits. That's on one of the more expensive packages, too.
- gugol 13y ago
  That's ok, as long as you seed for enough time until you have at least 1:1 ratio which is what the developers should worry about: how do you keep seeding even if the movie is over?
mrtree 13y ago
Exactly, people seem to forget the usage patterns.

computer 13y ago

Sure. But the app seems to be focused on streaming very popular torrents, which means that generally all pieces will be available enough. Also, all Popcorntime clients want the same blocks first, meaning they will both need and seed the first blocks more. So they do not cause an imbalance, as long as there are always some peers that have the full movie.

pikachu_is_cool 13y ago
> But the app seems to be focused on streaming very popular torrents, which means that generally all pieces will be available enough. This lacks a lot of foresight. > Also, all Popcorntime clients want the same blocks first, meaning they will both need and seed the first blocks more. So they do not cause an imbalance, as long as there are always some peers that have the full movie. And this is just plain wrong.
- hackmiester 13y ago
  Saying someone is wrong isn't useful if there is no explanation.
  - pikachu_is_cool 13y ago
    http://wiki.vuze.com/w/Sequential_downloading_is_bad http://wiki.vuze.com/w/Sequential_downloading_is_bad
    - comex 13y ago
      > The older peers have already completed the first few files and thus aren't interested in younger peers who currently download the first file exclusively, thus no mutually beneficial relationship can be established between different "generations" of prioritizing peers, effectively splitting the swarm into sparsely connected sets. I don't understand this. Why does it need to be mutually beneficial? The peers should "pay it forward" by uploading to younger peers, even if the ones they downloaded from are not benefitting. > On a small swarm this behavior can lead to pieces drop to the 0 availability because some peers concentrate on the first few files while the last peer/seed that has the rare piece in one of the later file quits after doing his fair share, but he only uploaded data for the first few files because the prioritizing peers were interested in those only. This could be mitigated by using excess bandwidth beyond that needed for streaming to download rare chunks, and ensuring that the streaming application keeps seeding for a while after the video has been watched.

TrainedMonkey 13y ago

I think you are missing the point as well. People will not start watching movie at the same time. When one person is almost done another just begins the movie, thus as long as there are few initial seeds and healthy interest in the movie it does not matter which order chunks will be downloaded.

br78 13y ago

Intriguing... is that really so much of a factor? To torrent-stream successfully you have to have eventually loaded all snippets from beginning to end of a file and could potentially be offering them for download at most only a couple of hours later than if you downloaded it first snippet.

mrtree 13y ago

That is not necessarily true, it will depend on the number of peers and the chunk replication rate. You can tweak the ratios so that the first part is available more often. In fact,you are also forgetting about the usage of each peer application. With traditional torrents you download the movie, close the app and watch the movie. Total seeding time is the same as the downloading time. With popcorn time you are seeding WHILE watching the movie, the total seeding time is much, much longer than in the first case.