What is the SBV file format?
An .sbv file is a plain-text subtitle and caption file associated with SubViewer and, more widely, with YouTube's caption tooling. Google adopted the format for YouTube Studio, making it the file you receive when you download a video's caption track and one of the accepted formats for uploading captions to a channel.
The structure is deliberately simple. Each caption block consists of three parts: a single timecode line in the form H:MM:SS.mmm,H:MM:SS.mmm (start time and end time separated by a comma, with milliseconds after a dot), one or more lines of caption text, and a blank line that closes the block. There are no sequence numbers, no styling tags, and no positioning metadata - just timing and words.
Because .sbv carries no styling information, it is less capable than WebVTT and has fewer inline formatting options than .srt or .ssa. For distribution to video players and third-party platforms, the file normally needs to be converted to .srt or .vtt first. Tools such as Subtitle Edit handle this conversion on the desktop, while YouTube Studio can export to .sbv directly.
The file is encoded in UTF-8 (an optional BOM may appear at the very start) and contains no binary data, so it can be opened and edited in any plain-text editor.
Security & safety
RISK: LOWAn .sbv is plain text and cannot execute code, so the file itself is safe to open. The only practical cautions are: keep your media player/editor updated (historic subtitle-parsing bugs existed in some players), and watch the text encoding - save as UTF-8 so accented and non-Latin characters display correctly. Captions downloaded from unknown sources may contain misleading text or links; read, don't blindly trust.
Format details
in a nutshell- Superbase form definition file - The original database name for this extension; Superbase is a long-discontinued database, and this meaning is now negligible compared with YouTube/SubViewer captions.
Programs that open SBV files
Windows3 apps
Windows Notepad
Built-in Double-click to read/edit the text; fine for quick fixes, no timing preview. 
Subtitle Edit
Open-source Open the .sbv to edit text and timing with a waveform/video preview, then Save As SRT/VTT for wider use. 
macOS2 apps
MovCaptioner
Paid Caption-authoring app that imports/exports caption formats including YouTube-style captions. 
Linux2 apps
YouTube Studio
Free Upload an .sbv as a caption track (Subtitles > Add), or download a video's captions as .sbv. Technical details
deep spec| Encoding | UTF-8; an optional byte-order mark (BOM) may precede the first timecode line |
| MIME type | text/plain |
| Timecode syntax | H:MM:SS.mmm,H:MM:SS.mmm - start and end time on one line, comma-separated, milliseconds after a dot |
| Cue sequence numbers | Absent; blocks carry no numbering (unlike .srt) |
| Styling and positioning | Not supported; format carries caption text only, no font, color, or placement tags |
| Block structure | Timecode line → one or more text lines → blank line separator (three-part repeating block) |
| Binary signature | None; pure plain text identified by the opening timecode line pattern |
| Millisecond resolution | Three decimal digits (1 ms precision per cue boundary) |
| Multi-line captions | Supported; two or more consecutive text lines before the blank separator form a single cue |
| Typical file size | A few KB to tens of KB for a complete video caption track |
| Primary platform | YouTube Studio - default download format and accepted upload format for video captions |
| Developer | Google (YouTube variant); derived from the SubViewer subtitle format |
| Line endings | LF or CRLF; YouTube's caption processor accepts both |
| Conversion requirement | Must be converted to .srt or .vtt for playback in most offline players and third-party platforms |
| Released | Used by YouTube's caption tooling since the late 2000s (SubViewer-derived format) |
| Latest version | No formal versioning; a stable, simple text format |
| Specification | support.google.com |
SBV conversions
Community Q&A
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