Support rendering subtitles with unset position outside the video bounds

[Pentaphon]

When playing 2:35.1 aspect ratio videos on a 16:9 Television set on Android TV-specific media3 apps such as https://github.com/jellyfin/jellyfin-androidtv/, subtitles are drawn to the video surface rather than the display surface, resulting in subtitles that are much smaller than they should be.

As you can see in the screenshot below, the subtitles should be rendered at least partially on top of the black bars, but they are limited to the video area rather than the display area on a 16:9 television. The original issue, which goes into more detail and discussion about this lack of support for 2.35:1 video on 16:9 television displays, can be found at jellyfin/jellyfin-androidtv#4234

Proposed solution

I propose officially supporting Android TV devices and their 16:9 displays by properly displaying subtitles according to the television display rather than how the video is drawn to the display, so that 2.35:1 aspect videos can have reasonably-sized subtitles when played on 16:9 televisions.

Alternatives considered

Certain Android TV player apps like https://github.com/damontecres/Wholphin and https://github.com/moneytoo/Player work around this issue and a workaround for Jellyfin for Android TV in the form of jellyfin/jellyfin-androidtv#4816 has been submitted, but the developer of Jellyfin for Android TV prefers an officially supported solution for Android TV devices and their (only) 16:9 television displays, which is why I am creating this feature request.

[icbaker]

Many subtitle formats expect to be rendered in a particular location relative to the video (e.g. so they can go to the top of the screen sometimes, or near to text on screen that's being translated). Therefore PlayerView behaves like this. This is explained in your linked issue: jellyfin/jellyfin-androidtv#4234 (comment)

It would be possible to change the behaviour specifically for subtitles with 'unset' positions while maintaining the 'correct' positioning for subtitles that define their position more explicitly.

We are unlikely to make this change in PlayerView, partly because we are mainly investing in new Compose UI components rather than making changes to the legacy View-based UI components. The new Compose components don't support subtitles yet, but we can keep this as a low priority enhancement for when they do.

As you can see in the screenshot below, the subtitles should be rendered at least partially under the black bars

Are you sure that would always be very easy to read? Imagine very bright video content, so the top half of a line of text will have a bright/white background and the bottom half of the text will have a black background. That might be quite hard to read.

[Pentaphon]

We are unlikely to make this change in PlayerView, partly because we are mainly investing in new Compose UI components rather than making changes to the legacy View-based UI components. The new Compose components don't support subtitles yet, but we can keep this as a low priority enhancement for when they do.

Then I'm glad I made this feature request before you have implemented the new Compose UI components. Yes, please do this while keeping in mind that besides touchscreen devices, there's a lot of people who want this implemented on the countless Android TV devices hooked up to 16:9 displays out there and such Android TV devices are only growing in popularity as people invest in home media equipment.

Are you sure that would always be very easy to read? Imagine very bright video content, so the top half of a line of text will have a bright/white background and the bottom half of the text will have a black background. That might be quite hard to read.

That would be an issue if we had no text borders or no way to manually move the text to the bottom of the display but every major video player including Jellyfin for TV Android has a text outline option to make text readable regardless of the background and the ability to move the text up and down to the topmost and bottom-most bounds. The only thing getting in the way right now is the text being unable to be set outside the video bounds.

[mschumacher69]

Are you sure that would always be very easy to read? Imagine very bright video content, so the top half of a line of text will have a bright/white background and the bottom half of the text will have a black background. That might be quite hard to read.

Also, even without borders, this can be fixed by moving the text all the way to the bottom to display on the black bar only, that is my ideal way of displaying subtitles because they wouldn't cover any part of the video.