Subtitle Edit

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SubRip (SRT) Format Reference

SubRip (file extension .srt) is one of the most widely used subtitle formats, known for its simplicity and broad compatibility.

Overview

SubRip was created by French programmer Brain in 2000 for the SubRip program (written in Borland Delphi). Despite being over two decades old, it remains the most popular subtitle format today and is the default format in Subtitle Edit.

Key Features:

Simple, human-readable plain text format
Can be edited in any text editor
Widely supported by video players, editors, and converters
Can be embedded into Matroska (MKV) files
Supports basic formatting (italic, bold, underline, colors)
Supports some ASS-style tags for advanced positioning

Pros:

✅ Very simple format, easy to learn and use
✅ Can be edited in any text editor
✅ Excellent support in players/converters
✅ Small file size
✅ Human-readable

Cons:

❌ No official specification
❌ Limited styling options compared to ASSA
❌ Inconsistent tag support across players
❌ No built-in font/size control in basic format

File Structure

A SubRip file consists of sequential subtitle blocks, each containing:

Sequence number — A unique number for each subtitle (starting from 1)
Timecode — Start and end time separated by ` –> `
Text — One or more lines of subtitle text
Blank line — Separator between subtitle blocks

Timecode Format

hours:minutes:seconds,milliseconds --> hours:minutes:seconds,milliseconds

Important notes:

Hours, minutes, and seconds use 2 digits (zero-padded)
Milliseconds use 3 digits
Comma (,) is used as decimal separator (not period)
Arrow separator is ` –> ` (space-arrow-space)

Examples:

00:01,000 --> 00:00:03,500
01:15,250 --> 00:01:18,750
30:45,100 --> 01:30:50,900

Basic Example

1
00:00:01,000 --> 00:00:03,000
Hello, World!

2
00:00:03,080 --> 00:00:05,080
This is a simple subtitle.

3
00:00:05,160 --> 00:00:07,160
It supports multiple
lines of text.

Text Formatting

SubRip originally supported only plain text, but modern players support HTML-like formatting tags.

Italic

<i>This text is italic</i>

Bold

<b>This text is bold</b>

Underline

<u>This text is underlined</u>

Font Color

<font color="#ff0000">Red text</font>
<font color="#00ff00">Green text</font>
<font color="#0000ff">Blue text</font>

Note: Colors are specified in hexadecimal RGB format (not BGR like ASS).

Font Face and Size

Some players support:

<font face="Arial">Arial font</font>
<font size="24">Large text</font>
<font face="Courier" size="18" color="#ff0000">Combined attributes</font>

Note: Font face and size support varies widely between players. Test with your target player.

Combining Formatting

<b><i>Bold and italic</i></b>
<font color="#ff0000"><b>Bold red text</b></font>

Advanced Formatting

ASSA-Style Override Tags

Many modern players support ASSA-style override tags in SubRip files, enclosed in curly braces {}:

Alignment

1
00:00:01,000 --> 00:00:03,000
{\an8}Top-aligned text

2
00:00:03,000 --> 00:00:05,000
{\an2}Bottom-centered (default)

3
00:00:05,000 --> 00:00:07,000
{\an7}Top-left corner

Alignment values (numpad-style):

(Top-left)      8 (Top-center)      9 (Top-right)
(Middle-left)   5 (Middle-center)   6 (Middle-right)
(Bottom-left)   2 (Bottom-center)   3 (Bottom-right)

Position

{\pos(640,360)}Positioned at center of 1280×720 video

Other ASSA Tags

Some players support additional ASSA tags like \fs (font size), \c (color), \bord (border), etc. See ASSA Override Tags for details.

Compatibility note: ASS-style tags in SRT files have inconsistent support. Always test with your target player.

Complete Example

1
00:00:01,000 --> 00:00:03,000
Normal text.

2
00:00:03,080 --> 00:00:05,080
Two
lines.

3
00:00:05,160 --> 00:00:07,160
<i>Italic</i>

4
00:00:07,240 --> 00:00:09,240
<b>Bold</b>

5
00:00:09,320 --> 00:00:11,320
<u>Underline</u>

6
00:00:11,400 --> 00:00:13,400
<font color="#ff0000">Red</font>

7
00:00:13,480 --> 00:00:15,480
{\an8}Top aligned

8
00:00:15,560 --> 00:00:17,560
<b><i>Bold and italic</i></b>

9
00:00:17,640 --> 00:00:19,640
<font color="#00ff00"><b>Bold green text</b></font>

10
00:00:19,720 --> 00:00:21,720
Line one
Line two
Line three

Character Encoding

SubRip files should be saved as:

UTF-8 without BOM (recommended, best compatibility)
UTF-8 with BOM (acceptable, but BOM may cause issues in some players)
ANSI/Windows-1252 (legacy, avoid for non-ASCII characters)

Best practice: Always use UTF-8 without BOM for international character support.

Line Breaks

Single line break — Separate lines within the same subtitle (press Enter once)
Double line break (blank line) — Separate subtitle blocks

Example:

1
00:00:01,000 --> 00:00:03,000
First line
Second line

2
00:00:03,000 --> 00:00:05,000
Next subtitle

Common Issues and Solutions

Issue: Timecodes not recognized

Problem: Using period (.) instead of comma (,) in timecodes

Wrong: 00:00:01.000 --> 00:00:03.000
Right: 00:00:01,000 --> 00:00:03,000

Issue: Subtitles not appearing

Problem: Missing blank line between subtitle blocks

Wrong:
1
00:00:01,000 --> 00:00:03,000
Text one
2
00:00:03,000 --> 00:00:05,000
Text two

Right:
1
00:00:01,000 --> 00:00:03,000
Text one

2
00:00:03,000 --> 00:00:05,000
Text two

Issue: HTML tags showing as text

Problem: Player doesn’t support HTML formatting Solution: Use a different player or convert to a format with better styling support (e.g., ASS)

Issue: Special characters not displaying

Problem: Wrong character encoding Solution: Save file as UTF-8 without BOM

Issue: Subtitles out of sync

Problem: Incorrect timecodes or frame rate mismatch Solution: Use Subtitle Edit’s sync features or adjust FPS

Best Practices

Number sequentially: Start at 1 and increment by 1
No overlapping times: End time of one subtitle should be before or equal to start time of next
Use UTF-8 encoding: Ensures international character support
Keep text concise: Aim for 2 lines maximum, 42 characters per line
Reading time: Allow at least 1-1.5 seconds per subtitle, longer for more text
Blank lines: Always separate subtitle blocks with a blank line
Consistent formatting: Use the same formatting style throughout
Test compatibility: Always test with your target player/device

Reading Time Guidelines

Recommended display duration based on character count:

Characters	Minimum Duration	Comfortable Duration
1-20	1.0 seconds	1.5 seconds
21-42	1.5 seconds	2.5 seconds
43-64	2.5 seconds	3.5 seconds
65-84	3.5 seconds	4.5 seconds

Note: These are guidelines. Adjust based on language, complexity, and target audience.

Converting to SubRip

Subtitle Edit can convert many formats to SubRip:

Open your subtitle file
Go to File → Save as…
Select SubRip (*.srt) from format dropdown
Click Save

Tools and Resources

Recommended Tools

Subtitle Edit — Full-featured subtitle editor with SRT support
Aegisub — Advanced subtitle editor
Visual SubSync — Subtitle synchronization tool
Subtitle Workshop — Classic subtitle editor

Validation

Use Subtitle Edit’s Tools → Fix common errors to validate SRT files
Check for proper formatting and timing

Online Resources

SubRip on VideoHelp — Original tool
Matroska Subtitle Specification — Technical details

Technical Specifications

Property	Value
File Extension	`.srt`
MIME Type	`application/x-subrip`, `text/srt`
Character Encoding	UTF-8 (recommended), UTF-8 with BOM, ANSI
Line Endings	Windows (CRLF), Unix (LF), or Mac (CR)
Timecode Format	`HH:MM:SS,mmm --> HH:MM:SS,mmm`
Timecode Precision	Milliseconds (3 digits)
Maximum File Size	No limit (typically a few KB to MB)

Version History

SubRip format has evolved over time:

2000 — Original SubRip format (plain text only)
2000s — HTML-like tags added (italic, bold, underline)
2010s — ASS-style override tags support in some players
Present — Widely supported with varying levels of formatting support

Note: There is no official specification for SubRip. The format is defined by common practice and player implementations.