Caption file

A caption file includes the text of what was said in the video and time codes for when captions should display. Below, you’ll find information on the wide variety of caption file formats that YouTube supports.

Preferred formats

Format name File extension Additional information
Scenarist Closed Caption .scc Exact representation of CEA-608 data. The preferred format whenever captions are based on CEA-608 features.

The basic and advanced formats below are less preferred because they do not convey CEA-608. 

Basic formats

Here are some examples of the most basic formats that YouTube supports:

Format name File extension Additional information
SubRip .srt Only basic versions supported -- no style information (markup) is recognized.
SubViewer .sbv or .sub Only basic versions supported -- no style information (markup) is recognized.
MPsub (MPlayer subtitle) .mpsub “FORMAT=” parameter is supported.
LRC .lrc No styling, but enhanced format supported.
Videotron Lambda .cap Primarily used for Japanese subtitles.

If you’re new to creating caption files, you may want to use SubRip (.srt) or SubViewer (.sbv). They only require basic timing information, and can be edited using any plain text editing software.

The main difference between SubRip and SubViewer files is the format of the caption start and stop times. Here are examples of both formats:

SubRip (.srt) example
1
00:00:00,599 --> 00:00:04,160
>> ALICE: Hi, my name is Alice Miller and this is John Brown

2
00:00:04,160 --> 00:00:06,770
>> JOHN: and we're the owners of Miller Bakery.

3
00:00:06,770 --> 00:00:10,880
>> ALICE: Today we'll be teaching you how to make
our famous chocolate chip cookies!

4
00:00:10,880 --> 00:00:16,700
[intro music]

5
00:00:16,700 --> 00:00:21,480
Okay, so we have all the ingredients laid out here
SubViewer (.sbv) example
0:00:00.599,0:00:04.160
>> ALICE: Hi, my name is Alice Miller and this is John Brown

0:00:04.160,0:00:06.770
>> JOHN: and we're the owners of Miller Bakery.

0:00:06.770,0:00:10.880
>> ALICE: Today we'll be teaching you how to make
our famous chocolate chip cookies!

0:00:10.880,0:00:16.700
[intro music]

0:00:16.700,0:00:21.480
Okay, so we have all the ingredients laid out here

Advanced formats

These formats let you have more control over styling (markup) and where you want to place the captions on your video. For each of the formats, we recommend using SCC and discourage TTML and SMPTE-TT.

Format name File extension Additional information
SAMI (Synchronized Accessible Media Interchange) .smi or .sami Only basic features supported -- timecodes and text.
RealText .rt Only basic features supported -- timecodes, text, and simple markup.
WebVTT .vtt Initial implementation.
DFXP (Distribution Format Exchange Profile) .ttml or .dfxp Interpreted as TTML.
TTML (Timed-Text Markup Language) .ttml Partial implementation. SMPTE-TT extensions supported for CEA-608 features. iTunes Timed Text (iTT) file format is supported; iTT is a subset of TTML, Version 1.0.

Broadcast formats

These formats are typically used for closed captions for broadcast content (TV and movies) and support either the CEA-608 or EBU-STL standards. YouTube tries to display the captions from these files just as if they were on a TV, with the same styling, color, and positioning.

Format name File extension Additional information
EBU-STL (binary) .stl European Broadcasting Union standard.
Caption Center (binary) .tds Supports CEA-608 features.
Captions Inc. (binary) .cin Supports CEA-608 features.
Cheetah (ASCII text) .asc Supports CEA-608 features.
Cheetah (binary) .cap Supports CEA-608 features.
NCI (binary) .cap Supports CEA-608 features.

Caption software

If you’re creating a caption file yourself, there are many caption editing software and services that can help you. Alternatively, you can get captions translated for you by sending a request to vendors or friends.