>> Hello, welcome back to our podcast captioning tutorial series.  This segment is about open captioning.  We're going to show you how to produce open captioned video content for podcasts.  Open captioning is essentially forcing the captions onto the video screen so that they are always visible.  They become part of the video signal itself.  The advantage to open captioning is that it doesn't require any inherent captioning support on the playback device.  Any device that can play video will display open captions.  There are 2 disadvantages however, the user cannot turn the captions off and the production process is slightly more complex.  

There are many ways to do open captioning.  We're going to use QuickTime Pro in this example and here are the steps we're going to follow.  We're going to obtain the caption file for your MOV file, that's the qt.txt caption track.  We're going to embed this text track in your MOV file using QuickTime Pro, we're going to scale the movie to the correct size and position the captions and then we're going to export the movie as an MP4 file.  It may seem counterintuitive, but do not export it as an M4V file for your iPod.  If you do it will drop the captions.  We first need to export it as an MP4 and then the MP4 can be converted to your target media using for example, the iTunes "convert to iPod" function.  

For open captioning we do need to pay attention to the video size and the font characteristics to make sure that the captions are readable.  We found that using 2 lines of 20 point font in a 50 pixel caption window produces a very readable result.  As an aside, note that you do not have to overlay the captions on top of the video content like you might see in television captioning.  You can if you want, but you can also choose to resize your video content to be slightly smaller, say 430 pixels high, and leave the 50 pixel window underneath to place the caption so that the captions do not overwrite the video content.  

Okay, so let's walk through an example of open captioning a video.  Here we have our original MOV file and the qt.txt file and the SCC file that we generated using AST's CaptionSync server; and you saw how to do that in the obtaining the caption files tutorial video.  You will also need QuickTime Pro to complete this tutorial.  If you do not have it, you can find QuickTime Pro at the Apple website.  First let's open our MOV file with QuickTime.  Next, under the Window menu select the Show Movie Properties.  Select the video track and the visual settings tab.  Here we can control the size of the movie.  Video content for iPods needs to be 640 by 480, so let's scale this movie accordingly.  We could make the height of this movie 480 and then place the captions over the bottom of the movie but instead let's make it 430 and leave a 50 pixel window at the bottom so our captions do not overlay the video content.  

Because we have the preserve aspect ratio checked, this automatically scales the width to 481 for this movie; smaller than the 640 we need.  For this movie that gives us a 159 pixels of extra width so let's use the horizontal offset to center the resulting movie.  640 minus 481 is 159 divided by 2 is about 80.  Okay.  That gets our movie to the correct size.  Now let's add the captions in.  Open the qt.txt file in QuickTime as well.  You can actually just play this text track and watch the captions appear.  Instead let's use a command-A to select all the captions and the command-C to copy them.  Let's go back to our main video window and put the play head at the beginning of the file.  Now use the Add-to-Movie function under the edit menu to paste our captions in.  

Now let's open the movie properties window again and you will see that there's now a text track in the movie.  Under the visual settings tab for the text track, let's set the size to 640 by 50.  And we'll set the vertical offset to 430 so that our captions appear underneath the window, underneath the video pane.  So far we have just embedded the QuickTime caption track into our MOV file.  If we save this file out as an MOV, it will store the caption track as text data within the movie which only QuickTime knows how to parse in this way.  However, if we ask QuickTime to render this movie as an MP4 file it will write the captions into the video data, resulting in an open captioned movie.  Under the File menu, select the Export option.  

Now select the movie-to-mpeg4, export type, and then save your movie out as an MP4 file.  Do not choose the movie-to-iPod option as that will generate an M4V file, but it will drop your captions.  You need to export it as an MP4 file so that it writes the captions into the video data.  Okay, let's quit this original movie.  We'll find that MP4 file on our disk.  Now that we have an open captioned MP4 movie, we can play it in QuickTime or iTunes and see that it is captioned.  

>> Hello I'm going to show you how easy it is to choose Automatic Sync Technology's CaptionSync automated caption service to caption a webcast.

>> Good.  If we load this movie in iTunes, we can convert the movie to an iPod format and the resulting movie will play with captions on your iPod.  Because the movie is open captioned, we're not relying on any specific captioning support on the playback device so the captions will appear on any device that we use to play this media file.