In November (2010) I had the pleasure of joining the extraordinary community of eLearning, training and university educators who attended the Media and Learning: Brussels 2010 Conference. I was thrilled to give one of the plenary keynotes, and wowwed by the strong positive feedback overall as well as the wonderful new friends and colleagues I encountered at the event.
Posts tagged "video"
Frame rate is the number of frames (images) that are shown per second when a video is playing. When a video is being played, typically about 20-30 frames are shown per second depending on the need. Within this limit, more the number of frames per second (FPS) less jerky the video is.
Let us consider a video with lot of action, say a soccer game .The video keeps changing at a fast rate. So, the video is typically encoded in 24 fps which is the upper limit of what a human eye can perceive. Any part of such a video will have 24 frames per second.
Now let us consider a video that has mostly e-learning content. The content does not always change at the rate of 24 images per second. For example, lots of slides made in Adobe Captivate are roughly about 3 seconds. If we take out the time for transition effect and a few more animations, a slide might stay without any changes for about a second. If we use only the frames that change we save a lot in file size – in this example we saved about 23 images. More importantly, processing these extra 23 images takes a lot of time for the video encoder (the program that converts these images to an f4v file) – the encoder would do a better job if it had lesser images to process. So when we know that there is nothing that has changed in the slide, we do not add an extra image to encode.
This means we have a video which has a different frame rate within different parts of the same video. For example a slide with just text will have a lesser frame rate, while a slide with a slide video showing a soccer game might have a higher frame rate. We call this variable frame rate. The earlier option of having 24 (or any other number of) frames per second all across the video is what we call fixed frame rate. Variable frame rate files are smaller in size and encoded with better quality than their fixed frame rate counterparts. Almost all video players understand variable frame rate and play them well.
Why did we give a fixed frame rate option if variable frame rate is better in size and quality? – The answer is: some video converters do not understand variable frame rate F4V files. So when you take the F4V file to a video encoder and convert it to a different format, you might find that converted video is not proper. So we gave you an option of fixed frame rate if you want to encode it further or share it on video sharing sites (which convert the videos again internally).
If you don’t want to understand the technical jargon, here you go with this thumb rule – If you are going to convert the F4V output from Adobe Captivate to a different format or if you are going to share it on video sharing services like YouTube, use F4V fixed frame rate. If you are going to directly use the F4V file use the F4V option – it gives you better quality and smaller file size.
There has been some threads in user forum about the connection error which learners get in Slide Video. I got a chance to closely analyze many of these specific issues and in all the cases it turned out to be server configuration problems.
Some background Info: When you insert video into Captivate as Slide Video, it by default is configured to be progressive download. All you need to do is publish the project and upload the entire publish folder to the server – Some cases just a web server (IIS, Apache etc) and other cases to an LMS. In both these cases, slide video is supposed to work well – you should not be seeing a “connection error” message.
You don’t need to do any more specific changes in your captivate project to get Slide Video working. However some users were continually getting this “connection error”. All these has been due to server (web server or LMS) configuration issues. These things help you correct this:
- Make sure your server allows hosting and downloading FLV / F4V files. Here we see some specific setting required for Win 2003 server (though this has nothing to do with Captivate).
- You can verify whether your server setting is OK by using any FLV player like this. The URL will be http://<your_server>/<your_publish_folder>/<yourflv>.flv. This way you can test whether the server can serve FLV files at least outside captivate SWF.
- You can freely check whether your SCORM package is correctly working with video on scorm.com (here). If this works then it is time you talk to your LMS vendor.
- Lastly you need to talk to your LMS / Server vendor regarding video hosting. I have specifically seen situations where the LMS vendor has to change configuration to allow video.
Audio makes your elearning content more engaging and useful to learners. You can add audio to your Adobe Captivate project either by recording yours or somebody else’s voice directly or by inserting a previously recorded audio file (.AVI, .WAV). When you add audio to a slide, it appears as a separate ‘element’ in the timeline. You can synchronize the audio with the slide by adjusting its timeline.
When you publish the project, Adobe Captivate embeds the audio within the output file. The embedded audio can be a single file or multiple files based on the timing and type of audio. Adobe Flash Player that plays the Adobe Captivate movie also plays the audio along with the movie.
Sometimes, you may notice a lag in the audio timing and that it is not synchronized perfectly with the movie. The audio that must ideally end with a slide spills over to the next slide. In this article, let’s examine why such issues occur and how they can be solved.
Why does this issue occur? Before understanding the reason for this issue, let’s first understand how Adobe Captivate publishes audio.
Whenever an audio starts and ends at the same time as that of the slides, Adobe Captivate ‘stitches’ up the audio objects on the contiguous slides into a single file when the project is published.
Suppose the audio on slide 1 runs till the end of the slide as shown below:
The audio on the next slide, slide 2 starts right from the beginning of the slide as shown below:
In such a case, the audio files on both the slides are ‘stitched’ and published as a single audio file. Similarly, if all the slides contain audio that start at the same time as that of the slides and spread till the end of slide, Adobe Captivate creates a single audio file in the published output.
Note: If the audio on the contiguous slides are of different types (mono and stereo), Adobe Captivate generates separate audio files for each of the types even if the audio starts and ends at the same time as that of the slides.
Adobe Captivate is designed to do so to logically stitch up users’ narrations that are done during or post-recording of a screen or application. A single audio file helps to keep the continuity in the narration intact.
Adobe Flash Player plays the Captivate published audio and stops only when the specified duration elapses or when you intervene and stop it. Therefore, with a single audio file in an Adobe Captivate movie, the audio and video run parallelly at their own pace resulting in synchronization issues.
Is there a workaround? Yes, a very easy one. Tweak the audio timing in such a way that Adobe Captivate generates and embeds multiple audio files in the output. To do so, extend the duration of the slide a little more than that of the audio. For example, if the current slide and audio duration is 4 seconds, extend the slide duration by another 0.3 seconds, and retain the audio duration at 4 seconds.
The following illustration shows the difference between the audio and the slide duration:
Now, Adobe Flash player can control the beginning of each audio file at the specified time in the movie.
People often ask me about Captivate file sizes and how to optimize the learner experience accessing online content. The crux of the question of course is how can i make playback start right away and keep size small enough that it downloads smoothly on the learners’ computer. It’s actually a lot easier than you might think.
I’ve posted a short video below (available along with many others on YouTube’s Adobe eLearning Channel as well) that demonstrates how I easily shrunk a 26 minute Captivate 5 file to a 12 MB SWF and how I used one of Captivate’s many preloaders to make the file start after downloading only a fraction of the content. In fact if you set such content to download only 1% the file would start after downloading only about 120 kb. (Even at 10% It only takes a second or two.) I think it helps to understand that by using preloaders (included with Adobe Captivate) you can create projects that only need to download as little as 1% of the Flash file before they begin. I would recommend downloading about 5% for most projects, as most projects are much shorter than 30 minutes.
So remember to try the optimization and preloader tools for your next online project. You’ll find happy learners as they jump into engaging, rich media eLearning experiences. (By the way, if you’re new to YouTube videos – you can click that 360p button to see a higher definition version of the video.)