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    Automatically Generating Captions for Videos

    In this topic you will learn how to automatically generate video captions.
     

    Video Cloud Studio provides the ability to automatically generate video captions for newly uploaded or existing videos. After the caption files are generated, they are automatically configured as part of the video's text tracks properties. Brightcove recommends reviewing the generated captions for accuracy. Processing time to generate the captions will vary but it generally takes about 1.5x the length of the video to generate captions for a video.

    In order to generate captions, the following are required:

    • The videos must have been transcoded using a Context Aware or Dynamic Delivery ingest profile
    • The minimum length of a video to generate auto captions is:
      • 5 seconds, if the language is specified
      • 15 seconds, if the language is auto-detected

    Video Cloud uses the follow process to determine the source that will be used to generate the captions.

    • If the video has default audio track, that will be used as the captions source file (supported by default in the Media module)
    • If the video has no default audio track but a master/mezzanine file exists, that will be used as the source file (supported by default in the Media module)
    • If the video has no default audio track or master/mezzanine files, but audio tracks are specified in the Dynamic Ingest call, the specified audio track will be used (not yet supported in the Media module)
    • If the video has no default audio track, no master/mezzanine files, and no audio track is specified, captions cannot be generated

    If you are using a third-party to generate caption files, see Adding Captions to Videos using the Media Module for information on how to associate caption files with videos.

    Generating captions when uploading videos

    The Upload module provides an option to generate caption files when videos are uploaded. To generate a caption file during upload, follow these steps.

    1. Click Upload in the navigation header to open the Upload module.
    2. Enable the Auto captioning option, the Automatic captioning settings dialog will open.
    3. Select the Language to generate the captions in. If a Language is not selected, the video language is auto-detected. Selecting a language will improve the caption file generation time and may improve overall accuracy.
    4. Enter a Label. The label is typically set to the language used in the video. The label will be displayed in the CC dropdown in the video player and will be used by viewers to select the captions to be displayed.
    5. Click Done.

    Generating captions for an existing video

    The Media module provides the option to generate caption files for existing videos in your account. To generate a caption file for an existing video, follow these steps.

    1. Click Media in the navigation header to open the Media module.
    2. Click the link for the video you want to edit to open the video properties.
    3. Locate the Text Tracks section and click Edit.
    4. Select the Auto caption option.
    5. Select the Language to generate the captions in. If a Language is not selected, the video language is auto-detected. Selecting a language will improve the caption file generation time and may improve overall accuracy.
    6. Enter a Label. The label is typically set to the language used in the video. The label will be displayed in the CC dropdown in the video player and will be used by viewers to select the captions to be displayed.
    7. Click Add Text Track.
    8. Click Save.

    The caption generation process will begin. When complete, a message will be displayed.

    After the captions are generated, Brightcove recommends reviewing the captions.

    Generating captions for multiple videos

    The Media module also provides the option to generate caption files for multiple videos at once. A maximum of 100 videos can be captioned at once. To generate a caption files for multiple videos, follow these steps.

    1. Click Media in the navigation header to open the Media module.
    2. Select the check box next to the videos you want to generate captions for.
    3. Click More > Auto caption.

    Reviewing caption files

    After the caption files are generated, they are automatically configured as part of the video's text tracks properties. Captions will have a Status of Published and appear immediately during video playback. If you would like to review the captions before they appear, there are two options:

    • Deactivate the video - Videos that are deactivated will not play. Review the captions and when they are approved, activate the video.
    • Change the text tracks Status property - Edit the text tracks property for the video and set the Status to Draft. Text tracks with a Status of Draft are not displayed to the viewer. Review the captions and when they are approved, set the Status to Published.

    Downloading caption files

    Chances are the caption generation process will not be perfect and you may need to edit names used in the video and/or punctuation. The Media module provides the ability to download caption files. To download a caption file, follow these steps.

    1. Click Media in the navigation header to open the Media module.
    2. Click the link for the video you want to edit.
    3. Locate the Text Tracks section and click Edit.
    4. Click the download icon () in the Actions column to download the caption file.

    The caption file is a formatted WEBVTT file and can be edited using any text editor. Once the changes are made, delete the existing caption file by clicking on the delete icon () in the Actions column. The edited caption file can then be uploaded. For information on how to upload a new text tracks file, see Configuring the text track properties.

    Supported languages

    Currently, auto captions are limited to the following languages.

    • Arabic (Gulf)
    • Arabic (Modern Standard)
    • Chinese (Mandarin)
    • Dutch
    • English (Australian)
    • English (British)
    • English (Indian)
    • English (Irish)
    • English (US)
    • Farsi
    • French
    • French (Canadian)
    • German
    • German (Swiss)
    • Hebrew
    • Hindi (Indian)
    • Indonesian
    • Italian
    • Japanese
    • Korean
    • Malay
    • Portuguese
    • Portuguese (Brazilian)
    • Russian
    • Spanish
    • Spanish (US)
    • Tamil
    • Telugu
    • Turkish

    Page last updated on 20 Jan 2022