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Standards for Netflix Subtitling and Closed Captioning

Standards for Netflix Subtitling and Closed Captioning

All the over-the-top (OTT) streaming industries have started incorporating closed captions and subtitles to their shows and movies, not just to enhance the viewer experience but also to increase their subscriber count. Timed text files (captions and subtitles) are extremely useful for deaf and hard-of-hearing individuals, and we give them a chance to enjoy a show just like other ordinary people. Captions improve your concentration and let you thoroughly enjoy the plot. In addition, captions are helpful when watching foreign language shows and in noise-sensitive environments.

When it comes to Netflix captioning, they have raised their bar on subtitling and closed captioning. Netflix no longer considers captions and subtitles as secondary assets. They are the primary source of reliable communication and engagement. Millions of viewers around the world consider these timed text files as primary assets. Watch content on your schedule with a smart device and a reliable internet connection.


Can you read three lines long caption that only appears on the screen for a second? It’s pretty difficult.  Captions need a duration to be displayed at the right time. 
Minimum duration: 5/6 (five-sixths) of a second per subtitle event (e.g., 20 frames for 24fps)
Maximum duration: 7 seconds per subtitle event

File format:

All subtitles and SDH files for all languages should be delivered in TTML1 format (.xml or .ttml). For the Japanese language, it must be provided in IMSC1.1 format (.xml).

Glyph List:

Only text and characters included in the NETFLIX Glyph List can be used. The file given below has the Gylph List for reference.
Are you finding it challenging to incorporate the text and characters in the Glyph List? Upload your files.
CaptioningStar does flawless Captioning following the specifications given by Netflix

Line Treatment:

The maximum is two lines. Remember to keep the text to one line unless it exceeds the character limitations. Netflix has some rules for captioners when the text has to be broken into two lines.

The line should be broken

  • after punctuation marks
  • before conjunctions
  • before prepositions

The line break should not separate

  • a noun from an article
  • a noun from an adjective
  • the first name from the last name
  • a verb from a subject pronoun
  • a prepositional verb from its preposition
  • A verb from an auxiliary, reflexive pronoun, or negation


For numbers from 1 to 10, it should be written out as one, two,… ten. Numbers above 10 must be written numerically as 11, 12, 13…, and when a number begins a sentence, it should always be spelled out.Times of the day:

    • Use numerals for exact times: 8:30 a.m.
    • When mentioned in dialogue, use lowercase letters for ante meridiem (a.m) and post meridiem (p.m). 
    • Spell out words/phrases that do not include actual numbers: half past, midnight, quarter of, noon
    • Always spell out the number when o’clock is mentioned in dialogue. Eight o’clock, for example.


All subtitles should be center justified and placed at either the top or bottom of the screen, except for Japanese, where vertical positioning is allowed.

In addition, please ensure subtitles are positioned in such a way that they avoid overlap with the onscreen text. If an overlap is impossible to prevent (text at the top and bottom of the screen), the subtitle should be placed wherever it is easier to read.


KNPs/formality tables must be created and used for translation to ensure consistency across episodes and seasons. 


Captions and Subtitles should be timed to the audio or, within three frames of the audio, if needed. If more time is required for better reading speed, the out-time can be extended up to 12 frames past the timecode at which the audio ends. Avoid the subtitles that cross the shot as they can disrupt the viewing experience. When the dialogue crosses the shot changes, the time codes should be adjusted to either be at the shot change or at least 12 frames from it. If dialogue starts between 8-11 frames (green zone) before the shot change, the in-time should be moved up to 12 frames before the shot change.

If dialogue starts 7 frames or less (red zone) before the shot change, the in-time should be moved to the shot change.If dialogue ends between 8-11 frames (green zone) after the shot change, the out-time should be moved out to 12 frames after the shot change.If dialogue ends 7 frames or less (red zone) after the shot change, the time code should be moved to the shot change, respecting the two-frame gap.

If there is one subtitle before and one after the shot change, the second one should start on the shot change, and the first should end before two frames.

Netflix credit translations:

All the translations for Netflix originals title cards must be included in full and forced subtitle streams. Refer to the Original Credit Translation document provided by Netflix. Ensure the subtitle is timed to match the exact duration of the on-screen Original if possible.

Title cards/ Dedication:

Mention plot-pertinent and other relevant on-screen information that is not covered in dialogue and/or redundant in the target language. ‘Based on true events, ‘Facts from 2005- 2009’.


Do not convert currency in subtitle files. The money amounts mentioned in the dialogue should remain in the original currency.

Brand names treatment:

  • Avoid facing a lawsuit. Brand name treatment can be handled in the following ways.
  • Use the same English-language brand name if it is widely known and used in that territory. 
  • Use the name by which the brand is known in that region
  • Use a generic term for the product.
  • Never swap one brand for another company’s trademarked item.

Translator credits:

The last event of the subtitle file should include the translator credits, and it should occur after the end of the main program during the copyright disclaimer card.  Use Netflix approved translation references provided in the Original Credits translation documentTranslators who have translated an asset should be credited. Netflix may not include credits. Translation credits are required for episodic content and features and should be entirely in the target language of the timed text file. These credits aren’t necessary for marketing or supplemental assets. The credits should also be timed for reading speed, with a duration of up to 5 seconds. Also, it should not be on-screen at the same time as the Netflix indent. Include translator credits for subtitles for the Deaf and hard of hearing, only if translating from the original language.

Do not include translator credits for transcribing the original or dubbed audio. Also, you are free to omit translator credits if the translations for episode titles and the approved Netflix Original credits translations and if the translator has submitted a formal waiver. More than one translator can be mentioned in the same credit when translating from multiple source languages.Forced narrative files should credit the subtitle translators expect for files other than Netflix provided translations for episode titles and approved Netflix Original credits translations.

Technical Aspects

All TTML files created for Netflix must adhere to the following technical specifications.

  • Use percentage values, not pixel values
  • Use tts:textAlign and tts:displayAlign for positioning along with static values for tts:extent and tts:origin
  • tts:fontSize shall be defined as 100%. Never use pixel values

  Note: Remember to look into the most recent delivery spec documentation for more information.


In 2011, Netflix was sued by the US National Association of the Deaf for not providing closed captioning for the deaf and hard of hearing for all its content, citing that the company has violated the Americans with Disabilities Act. Netflix then captioned its entire library by 2014 and stated that their new content would make captions available within seven days of release. Today, Netflix captioning specs are so high. Adhering to these specs is not just to get them approved by Netflix, it’s to accommodate everyone’s viewing needs and preferences.  Most files are rejected for poor translations rather than any other sort of error.  

Let us save you from these rejections. Any content submitted to Netflix should carry timed text files according to the Netflix general requirements. We know its time consuming to understand all these specs and create timed text files for your shows and movies. At CaptioningStar, we strictly adhere to all the requirements of Netflix to provide valid captions which are over 99% accurate. We assure to work on your projects with certified translators and captioners. Contact us anytime!!!

Other services- Dubbing, Voice over, Audio Description. 

Read more to know the other Accessibility Features on Netflix.