Will Head
The first thing you’ll need to start with is a transcript of the final video, so you’ve got a text copy of all the spoken words in a particular film. If your production was scripted – and your performers stuck to the script and didn’t ad lib – then you’ve already got a very good starting point.
If your video is an interview or a live event and you don’t have a copy of its script, then you’ll need to transcribe the audio first, which is a time-intensive process. Unless you’re a particularly fast typist, then it’s unlikely you’ll be able to type at anything approaching the speed of normal speech, which means you’ll constantly have to stop and rewind. If it’s only a short video, then you’ll probably be okay, but if it’s over an hour, then you may want to look into alternatives.
Mac speech recognition software such as Dragon Dictate for Mac (see MacUser, 5 November 2010, p32) is an option, but it only tends to work accurately in a controlled environment and with a voice with which it’s been trained to work. Ask it to attempt to transcribe an interview with an unknown speaker, with lots of background noise, and it’s unlikely to come back with particularly accurate results. You’ll still have to manually correct a fair amount of text, but it may serve as a good starting point if it recognises the key points.
The other alternative is to export the audio file and send it to an online transcription service. Costs start at around 75p per minute of audio that you need converting to text, and most provide an overnight service for urgent results if you’re prepared to pay more. It’s probably worth trying out a few services with a short clip first, as they can vary widely in quality, although the more expensive services tend to be more accurate.
Once you’ve got the audio in plain text format, you can begin creating your subtitles. The simplest solution is to just make titles in your editing application and then place them over the video at the appropriate point, so that they coincide with the audio on the timeline. It’s a fairly labour-intensive process, though, and you’ll end up with a lot of titles, so you may want to number them sequentially to keep track of which goes where.
The downside of this approach is that the subtitles are permanently overlaid on the video file – even for people who don’t want them. They become part of the final video output, so there’s no way to turn them off.
A much more flexible approach is to save the subtitles to a separate file and then let the video player display them at the right time. This way, if the subtitles aren’t needed, they don’t have to be displayed at all.
The most basic subtitle format is called SubRip, which is a text file that contains the subtitle text and the time at which it should be displayed.
An example of a SubRip file is:
1 00:00:10,000 --> 00:00:14,400
This is the first subtitle to be displayed
2 00:00:14,800 --> 00:00:18,800
and this is the second one.
Each subtitle starts with a sequential number followed by a return. The next line specifies when the subtitle should be displayed – the first number is the time in the hours:minutes:seconds,milliseconds format. The number after the –> is when the subtitle should stop being displayed. The next line is the subtitle text itself, and then a blank line signifies the end of that subtitle.
Subtitles in this format are supported by most video clients, and you can even upload titles to YouTube and they’ll be overlaid on the final video when it’s played back on the site. To add subtitles to a YouTube video, click the Edit button after you’ve uploaded it and then on the Captions and Subtitles tab. Click the Add New Captions or Transcript button and then upload your SubRip file.
In terms of creating the subtitles file, you could make it by hand using just a text editor, but unless you’re only subtitling a very short video, there are programs that can help out.
If YouTube is the intended destination for your video, you could use CaptionTube to create the subtitles for you. Visit captiontube.appspot.com, click the Sign In button and follow the instructions to give CaptionTube permission to access your YouTube account. Once authorised, you can then pick the video you want to subtitle from your uploads.
You can then scrub through the video until there’s a part you need to subtitle and click the Add Caption button to add a new title. Enter the text and the duration, then click the Save Caption button when you’re finished. You obviously have to add in each subtitle manually, but at least it takes care of creating all the time codes for you. When you’re finished, you can publish your captions straight to YouTube or download them, email them or just copy them to the Clipboard.
For more control over the subtitling process, you’ll need a standalone program on your Mac. Miyu from Fluffalope Factory (fluffalopefactory.com/miyu) is a useful utility to help with subtitling videos.
To create subtitles, open Miyu and click the Change button in the Movie File section to choose the video you want to subtitle. Adjust the size and frame rate to match your actual video, then use the playback controls to scrub through your video until you find a place that needs a subtitle. Hit the Create button to make a new subtitle and then change the placeholder text to what you want it to say. Scrub to the place where you want the subtitle to stop and press the Out button. The advantage of using a standalone tool like Miyu is that you can preview where the subtitles start and finish in real time, and adjust them if they’re not right.
When you’ve finished adding subtitles to your footage, then it’s simply a case of selecting Export from the File menu and choosing SubRip to get a text file containing the subtitles and timecodes.
Whichever method you use to create subtitles, it will always be a time-consuming process due to the need to create a transcript and then match it up to the actual video footage. However, with support for subtitles included in most video playback applications and even the ability to easily include them on YouTube, you could increase the size of your potential audience by creating them.