> To me bilibili sub seems more useful than hidive so that was set to default, both included You don't seem to understand what the default flag actually means and continue to improperly tag all tracks. https://www.matroska.org/technical/notes.html All language options require a default and any tracks intended for normal use should also have default. Basically only tracks that don't get default is signs (which get forced) and commentary, etc. The only reason the releases work as you currently mux them is because of matroska's fallback that assumes if no tracks of a certain language have default, they all have default thus they're considered default and up for automatic preference despite you tagging as default: no.

the Hidive subs should be better but also the styling for both is really bad, for some reason the bili subs are massive size?

Spoony: My only "goal" with default track flag that if you don't have configured language for the player then use eng one bc otherwise none of them will be used.

Only outdated players that don't abide by the matroska standards set work that way (letting muxer dictate over player what tracks to play). The default flag does not mean "play this track by default if no preference is set" and it was never intended to be. In mpv this release without preference set plays Japanese audio and no subs. So your goal has failed here. mpv doesn't attempt to assume what the user wants and doesn't utilize the default flag outside of it's actual intended use. All video players that follow the spec automatically assume all languages have default. So with every single language having default=yes, how does a player know what language you want to play if you don't tell it? There is no track flag that tells a player to play this track on it's own. Preferences are required so that playback solutions know what the user wants. There are some playback solutions that guess you want English by reading what language your OS is, but that isn't the case for most video players. This is why proper tagging is good because otherwise preferencess don't generally work if tracks aren't correctly tagged. You setting English only to default makes all others have assumed default thanks to matroska realizing most releasers incorrectly utilize track flags such as you. It's thanks to this that any other language is actually selectable at all. And quite a few players will simply play the first track if no preference is set. Setting English to the only default does not do what you think it does and it only happens to work in a select few players that don't properly abide by the correct track flags and usually those simply fallback to playing the first track. Like MPC-HC for example doesn't even utilize the forced flag except in advanced lav filter preferences which is pretty bad design.

Neither k-lite codec or mpv use the first sub (whitout more config I guess) if no default set and sub lang not configured. And why does it even good to set language for sub if it's use that even for dub version so you have to manually change it to none every time if no forced. (I don't use mpv on pc so could be some config option, but don't think that everyone configur mpv. Most likly lot of people use vlc)

* if everything is default then seemingly select the first, or the first forced but some times just randomly the last eng insted of the forced.