Subtitles: ESub, Softsub and External SRT Files

"ESub" in a file name means subtitles are included — not that they are switched on. That one detail accounts for most of the "there are no subtitles" messages we receive.

The three kinds

Embedded (softsub) — what ESub usually means: The subtitle track travels inside the video file and can be turned on, turned off or swapped for another language. Nothing is burned into the picture, so you keep the choice.
External (.srt or .vtt): A separate small text file that sits next to the video. Keep the two in the same folder with the same name and most players will load it automatically; otherwise open it from the player's subtitle menu.
Hardcoded (burned-in): The text is part of the picture itself. It cannot be turned off or changed — if you do not want it, you need a different copy.

Turning them on

VLC (phone or desktop): Subtitle menu → Sub Track → pick a track. To add an external file, Subtitle → Add Subtitle File.
MX Player: tap the screen → the subtitle icon → choose a track, or Open to load an .srt from storage.
A TV or set-top box: look for a "CC", speech-bubble or subtitle button on the remote while the video is playing.
In a browser: the player's own settings menu, usually behind a gear or "CC" control.

Bangla subtitles showing as boxes or question marks

That is a font problem, not a broken subtitle file. The player is loading the text but has no Bangla glyphs to draw it with. VLC lets you point the subtitle renderer at a font that includes Bangla; on a phone, a player with full Unicode font support will show the same file correctly. Trying the same file in a second player is the quickest way to confirm the file itself is fine.

Subtitles out of sync

Most players can shift subtitle timing live — in VLC the G and H keys move it in tenths of a second, and phone players have a subtitle-delay slider. A constant offset is usually a subtitle file made for a different cut of the same film; a drift that grows over time means a different frame rate, and a different subtitle file is the simpler fix.

Dual audio and subtitles together

A dual-audio file carries more than one sound track, chosen from the same menu area as the subtitle track. It is worth checking both menus when a file seems to be in the wrong language — the track you want is often already there.

What the labels in a file name mean is covered in the Quality Guide, and if the picture itself will not appear, see HEVC vs AVC.