SRT vs SMI Subtitle Comparison

Understanding the differences and strengths of each format

📄 What is SRT?

SRT (SubRip Text) is the most widely used subtitle format. It's a simple text-based format supported by almost all media players.

File Structure

1
00:00:01,000 --> 00:00:04,000
Hello, this is the first subtitle.

2
00:00:05,500 --> 00:00:08,000
This is the second subtitle.
Multiple lines are supported.
Subtitle Number

Sequential numbering

Time Format

HH:MM:SS,mmm

📝 What is SMI?

SMI (SAMI) is a subtitle format developed by Microsoft with an HTML-like structure. It's particularly popular in Korea and Japan.

File Structure

<SAMI>
<HEAD>
<STYLE TYPE="text/css">
.ENCC { Name:English; lang:en-US; }
</STYLE>
</HEAD>
<BODY>
<SYNC Start=1000><P Class=ENCC>Hello
<SYNC Start=4000><P Class=ENCC>&nbsp;
</BODY>
</SAMI>
HTML-based

Styling with tags possible

Time Format

Milliseconds (1000 = 1 second)

📊 SRT vs SMI Comparison

Feature SRT SMI
Developer Open format Microsoft
File Extension .srt .smi, .sami
Structure Simple text HTML-based
Styling Limited CSS supported
Compatibility ★★★★★ ★★★☆☆
Ease of Editing ★★★★★ ★★★☆☆
Popular In Worldwide Korea, Japan

💡 Which Format Should You Use?

Use SRT

  • Uploading to YouTube, Netflix, etc.
  • Playing on various devices
  • Sharing internationally
  • Simple and quick editing

Use SMI

  • Using Korean players like PotPlayer
  • Custom subtitle styling needed
  • Multiple languages in one file
  • Compatibility with existing SMI files

Convert between SRT and SMI formats for free

← Go to subtitle converter

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