Google offers an “auto caption” feature for YouTube uploads by which text-to-speech software attempts to automatically generate captions from a video’s soundtrack. If you’d like slightly more control over the content of your captions, Google has also implemented “automatic caption timing.” To use this feature, simply transcribe all of the words found in your video, and upload it as you would your SRT (timed) caption file (see below). The same text-to-speech algorithms used for “auto caption” will synchronize your transcribed text for you, eliminating the need to worry about timecodes. (Check YouTube help for more about these automatic features.)However, the safest (and most accurate) bet would be to upload an SRT file with your video; once completed, this will enable a “CC” button on the video player interface and captioning will be turned on by default. YouTube has provided instructions for users interested in adding captions to their YouTube videos.