To add in Automatic Speech Recognition captions to your video, you may follow this steps:

For the video you wish to add in caption, click on "Edit".
Under "Captions", select "Import automatic captions".
You may notice that the captions might not be accurate. Still in edit mode, playback the video and correct any errors by selecting the text boxes.
To change the caption timing, select the 3 dots.

Click Apply to save changes.
Click on "Publish" to make the video available to viewers, or go to Settings and schedule the publish date.

Go to Setting > Captions and select "Download file".
To edit this downloaded .txt file, open using Notepad and edit the text accordingly based on the timestamp provided. Save your file as the same extension e.g. "sample.ashx".
Re-upload the file again by selecting "Browse..." and click "Upload Captions".
Once the processing is done, you will be able to see the caption on your video.
In case you would like to remove the close captions generated, go to Settings > Captions > "Delete Captions".

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