OpenSubtitles directly on the client side

[wrgallo]

This discussion is regarding this feature request, as listed in the site rules.

I have already implemented the feature, available on this fork, and this commit. I would like to know if there are some modifications required to allow the pull-request.

[thornbill]

Unfortunately, I think this is a feature that we will not want to include in Jellyfin. Jellyfin clients should rely on a Jellyfin server for any metadata lookups and not bypass the server to directly interact with any metadata providers.

[wrgallo]

The feature does not interact with any metadata provider, it uses the ones provided by the server, if the server does not provide anything, then the filename is used. It only reaches to OpenSubtitles for subtitles, as the app reaches YouTube for trailers.

[thornbill]

OpenSubtitles is a metadata provider. subtitles = metadata.

We make no requests to YouTube except for opening trailers when a metadata provider has already provided a YouTube url for the trailer, so that is completely different from what is being proposed here.

[1hitsong]

I agree. Clients' only dependency should be the server API. If the server opens an API endpoint to provide this data, that's cool, but a client to 3rd party direct connect - I don't like.

[wrgallo]

I truly ask you to reconsider. I will try to divide the discussion in some topics below.

Basic functionality

• Even the media player classic from windows 98/xp has an OpenSubtitles functionality as every application that may be considered competition for the Jellyfin today. I have been in several jellyfin community servers and saw a lot of people complaining about this. They were preferring to migrate to other applications even if it would cost them money, so I was trying to help fix that.
• Usually, someone from a certain country starts a server and will only ensure a certain language would be available for its content. Although the community that helps to maintain that server has people from many countries, so fetching subtitles from the web easily becomes a need.
• This feature is disable-able!

If it can be done on the client, why not do on the client?

• Server may be an old computer that struggles to handle unnecessary requests.
• Sometimes the server struggles to serve the subtitle. In jellyfin-web, the 'Loading additional data' can stay on the screen for minutes just so the subtitle fails to load, requiring to deselect the subtitle and try again. With up to 5 attempts, it may work (happens to me on multiple servers/clients/devices/internet service providers). On Android this happens too, but at least it shows the message 'Failed to load Subtitles'. The OpenSubtitles feature has saved me from those problems several times.
• It is pretty common for one to go to settings, select their settings, and press 'Save' just so nothing happens. The settings are not saved on the server, not even 'app language' or 'preferred audio language' or 'preferred subtitle language' persist. Even IF the server do save, if you go to another client, you may notice those settings don't work (e.g. subtitle preferences set on jellyfin-web, then use the same user on jellyfin on Android). Using this feature the way it was implemented, it will work no matter what settings can or not be saved on the server.

Could be an app plugin, if it was possible

• jellyfin-web has plugins, but unfortunately, there is no way for users to add plugins for jellyfin-web, they are all hardcoded. I only made it this way, because for now it looks like this is the only way.

OpenSubtitles login limitations

• OpenSubtitles allows only 20 downloads per day with a free account, (the paid tiers are higher but also limited). It was meant for clients not servers, as one person watching a maximum of 20 episodes/movies a day is ok, but a server to limit only 20 subtitle downloads would definitely not work well.
• If the server would use my login to fetch the subtitles for me, then there would be security issues involved. By being an app feature and settings, those are not problems.

I would ask to preserve this feature as experimental, and if required I compromise to change the way it works in order for this feature to stay. Even if each subtitle requests must cross the globe twice before reaching the OpenSubtitles server.

[thornbill]

Basic functionality

• Even the media player classic from windows 98/xp has an OpenSubtitles functionality as every application that may be considered competition for the Jellyfin today. I have been in several jellyfin community servers and saw a lot of people complaining about this. They were preferring to migrate to other applications even if it would cost them money, so I was trying to help fix that.
  • Jellyfin is a media server and not a media player. As such the server is responsible for file and metadata management.
  • Jellyfin is a personal media server. Shared "community" servers is not a use case we support.
• Usually, someone from a certain country starts a server and will only ensure a certain language would be available for its content. Although the community that helps to maintain that server has people from many countries, so fetching subtitles from the web easily becomes a need.
  • Again Jellyfin is a personal media server.
• This feature is disable-able!
  • Not really relevant to whether the feature is valid.

If it can be done on the client, why not do on the client?

• Server may be an old computer that struggles to handle unnecessary requests.
  • If requesting new subtitles is unnecessary then this feature is unnecessary. 🤷‍♂️
• Sometimes the server struggles to serve the subtitle. In jellyfin-web, the 'Loading additional data' can stay on the screen for minutes just so the subtitle fails to load, requiring to deselect the subtitle and try again. With up to 5 attempts, it may work (happens to me on multiple servers/clients/devices/internet service providers). On Android this happens too, but at least it shows the message 'Failed to load Subtitles'. The OpenSubtitles feature has saved me from those problems several times.
  • Typically delays in loading subtitles is caused by embedded subtitles needing to be extracted. Other solutions for this already exist.
• It is pretty common for one to go to settings, select their settings, and press 'Save' just so nothing happens. The settings are not saved on the server, not even 'app language' or 'preferred audio language' or 'preferred subtitle language' persist. Even IF the server do save, if you go to another client, you may notice those settings don't work (e.g. subtitle preferences set on jellyfin-web, then use the same user on jellyfin on Android). Using this feature the way it was implemented, it will work no matter what settings can or not be saved on the server.
  • Which settings are saved to the server is determined by the client. Subtitle preferences will vary by client (i.e. I want subtitles always enabled on my TV but not my phone) so this is working as intended.

Could be an app plugin, if it was possible

• jellyfin-web has plugins, but unfortunately, there is no way for users to add plugins for jellyfin-web, they are all hardcoded. I only made it this way, because for now it looks like this is the only way.
  • You are right about this. We haven't really investigated loading web plugins from a separate source. There are obvious security concerns with that and there hasn't really been a demand for that functionality.

OpenSubtitles login limitations

• OpenSubtitles allows only 20 downloads per day with a free account, (the paid tiers are higher but also limited). It was meant for clients not servers, as one person watching a maximum of 20 episodes/movies a day is ok, but a server to limit only 20 subtitle downloads would definitely not work well.
  • Trying to bypass OpenSubtitles API limits is not something we want to encourage. If you are relying their service, you should pay for a higher limit if needed.
• If the server would use my login to fetch the subtitles for me, then there would be security issues involved. By being an app feature and settings, those are not problems.
  • How is the server fetching subtitles a security concern???

[wrgallo]

Jellyfin is a personal media server. Shared "community" servers is not a use case we support.

• Understood, my point is the server manager may share this with friends who can not fetch extra subtitles.
• Even if there is only 1 user, it is inconvenient having all subtitles ready before being able to use it (for every episode/show/movie), only to find out when watching on the TV that it may not work. The server manager will need to go back to the computer and work trying subtitles again.

Jellyfin is not a media player

• Currently there is an official client named Jellyfin Media Player, I thought calling a client a media player would not come as a surprise here, that was my point describing basic media player functionalities that are also important for accessibility.

How is the server fetching subtitles a security concern?

• A 3rd party storing my API credentials

[TheMelmacian]

If this is solely handled on client side, each client needs to implement it separately. Like 1hitsong said, a new API endpoint that does trigger the subtitle download makes much more sense. This way its way easier to provide the same feature for each client.
And if the server handles the subtitle download, it can be stored alongside the media file, so the next time the subtitle is already available and doesn't need to be downloaded again.

I can see that a download limitation can be a problem, if the server is used by many different users.
If jellyfin-web already provides support for plugins, maybe it should be opened up, so that external plugins can be installed.
The question is, is it possible to implement them in a way so they can be somehow loaded/installed locally or do they need to be provided by the server?

[wrgallo]

There are a few other things that may make it harder:

• Error 429: Too Many Requests
  • Too many requests to OpenSubtitles from the same IP, the plugin for the server already struggles with this. If only the server makes all the requests, Error 429 will happen quite often.
  • User may download multiple subtitles for the same movie/episode, trying to find one that perfectly matches (increasing the chances of reaching requests/download limits).
• To keep it alongside the media file would require access to write to that folder;
• How to handle the multiple downloaded subtitles that would pile up, and possibly never to be used again, and they may have the same name although not being the same.

There are already different implementations for clients, maybe doing something to simplify subtitle-plugins in the core parts of jellyfin would help. But making the server do everything would be hard, as the whole OpenSubtitles API is meant for clients.

The Jellyfin for Android TV, for instance, has a better and smaller menu than jellyfin-web (although critical features as preferred languages are missing and not working), the opensubtitles options could be something like “Advanced options” inside the subtitles tab, but still, an app client feature. For example, the On-Demand Subtitle Search available on every Plex clients as a basic accessibility feature.