Animation Tutorial 2: Creating a multimedia animation with sound using an open source video editor (VirtualDub)

Developed by B. H. Giza, copyright B. H. Giza © 2009.

National Educational Technology Standards for Teachers (2008):

2. Design and Develop Digital-Age Learning Experiences and Assessments
Teachers design, develop, and evaluate authentic learning experiences and assessment incorporating contemporary tools and resources to maximize content learning in context and to develop the knowledge, skills, and attitudes identified in the NETS-S. Teachers:

• a: design or adapt relevant learning experiences that incorporate digital tools and resources to promote student learning and creativity.

Texas Pedagogy and Professional Responsibility, EC-12:

TEXAS PEDAGOGY AND PROFESSIONAL RESPONSIBILITIES (EC-12) STANDARD III

The teacher promotes student learning by providing responsive instruction that makes use of effective communication techniques, instructional strategies that actively engage students in the learning process, and timely, high-quality feedback.

Texas TEKS §126.12.

Technology Applications (Computer Literacy), Grades 6-8
(5) Information acquisition. The student acquires electronic information in a variety of formats, with appropriate supervision.
The student is expected to:

• (A) identify, create, and use files in various formats such as text, bitmapped/vector graphics, image, video, and audio files;

Texas Technology Teacher Standards

Standard VIII. The digital graphics/animation teacher has the knowledge and skills needed to teach the Foundations, Information Acquisition, Work in Solving Problems, and Communication strands of the Technology Applications Texas Essential Knowledge and Skills (TEKS) in digital graphics/animation...
Teachers of Students in Grades 8-12 The beginning teacher of digital graphics/animation is able to:
Foundations

• 8.2s use the vocabulary related to digital graphics and animation software;

• 8.8s distinguish between and use the animation techniques of path and cell animation;

The target audience for this activity is grades 6-8 teachers and prospective teachers. It also applies to teachers working toward Texas EC-12 Educational Technology Certification and the Master Technology Teacher Certification.

The purpose of this activity is to help teachers develop student-centered animations¹ using free tools: Audacity², which is cross-platform and open-source ⁷, and VirtualDub⁵, which is free and open-source, but available for Windows only.

Introduction

VirtualDub is open source video editing software for Windows that will import or acquire a sequence of images and transform them into AVI format (video). It is available as a free download from http://VirtualDub.sourceforge.net/

VirtualDub will import the common JPG⁴ and PNG⁸ file formats which might have been generated by a drawing program, allowing it to be used for cel animation. It will assemble a photographic or drawn image sequence into an animation, outputting it into an AVI format file. It will also allow you to integrate an audio format in either WAV or MP3⁶ format to create a sound track for the animation. What is especially useful is the ability of this program to acquire images from a standard webcam, allowing it to be used for stop motion animation.

What can a classroom teacher do with this kind of project? Here are some ideas:

• They can use it to explore phenomena in our natural world which take place over a time span greater than can be observed in a class period - or that occur at times or at scales that are not easily observed without the assistance of technology. The "Skeeter" and "metamorphosis" examples seen below is an example of this.

• They can use it to build a collaborative story-telling exercise - a group of students work together to plan and generate a stop motion animation that illustrates a concept in language arts, science, or other content area. in adding to a drawing, elaborating and extending it in turn. This builds technology skills, cooperative learning process skills, and the ability to plan and execute procedures in technology.

The objectives for this lesson are:

• The teacher will be able to use VirtualDub to integrate a sequence of image files into a video.

• The teacher will be able use the Audacity to create a sound track in MP3 format for the animation.

• The teacher will be able use the VirtualDub to integrate the sound track with the video to generate a video with a narrated sound track.

Prior to attempting this lesson, the teacher should download or obtain (1) VirtualDub, (2) Audacity^*, and (3) the Animation image file sequence, install them into a folder on a Windows computer and make sure that the software work on the machines that will be used for the activity (including testing the sound card to ensure that the computer can record and output MP3 files).

Animation is an effective way of addressing multiple modes of learning in students - as well as a powerful tool for teaching how graphics and video are related. Animation is also one of the most important ways to show how motion in film is actually an illusion generated by the way our eyes acquire information (in discrete images) and how our brain processes it. For more advanced audiences, this activity may be extended to provide analogies to many "continuous" processes which are actually made up of swiftly changing discrete components...from the "frames" of a digital music file, to the packets of information on a network.

1. VirtualDub can be obtained from http://virtualdub.sourceforge.net/. The software is provided as a zip (compressed folder) file. To unzip it use one of the free software tools such as 7-zip, or simply open it as a compressed folder on Windows XP and above. Make sure that you "Extract" it (decompress all the files) into its own folder, rather than trying to run it from within the compressed folder. If you install it to a particular machine, in most cases you may then drag its installed directory to a USB drive and it will work from that USB drive. It has not been designed to be "portable" but it has that functionality in most cases - test it in advance to see if the portable (directory copy) works for you on a particular machine. It should not require administrative rights to run.

2. Another, equally easy-to-use "Portable" version of VirtualDub is also available from PortableApps.com at http://portableapps.com/apps/music_video/virtualdub_portable. This version is distributed in a form that is easily integrated with the PortableApps menu, and is specifically designed for installing to and running from a USB drive.

3. ^* In this tutorial we use and link to "portable" version of Audacity, which allows it to be installed to a USB drive, or a local (user's) directory such as "My Documents". It can be obtained from http://portableapps.com/apps/music_video/audacity_portable It does not require "Administrator rights" for the installation, and once installed to a USB drive, the entire Portable_Audacity directory can be copied from the USB drive to another location easily. Because of international license restrictions, the plug in for creating MP3s must be downloaded and added separately. The instructions for doing so are available at http://portableapps.com/support/audacity_portable#lame.

The materials for this lesson are:

• A relatively modern computer running Microsoft Windows XP or Vista which has a USB drive and/or an Internet connection for obtaining and installing the software and image files. It must have a working sound card. For our video generation we shall be using the MSVideo1 codec, which is found on all Windows computers.

• A microphone for recording the narration. You may skip this tool if you use the sample narration sound file found here. The best tool for a multiple user lab is a headphone-microphone combination, which allows users to record and playback without interfering with their neighbors.

• The image file sequence used in this tutorial is HERE as a zipped file named skeeter2.zip. The compressed folder (skeeeter2.zip) contains 19 small images of a mosquito larva in a jar of pondwater. The images were obtained by the author in 2002 using a low-cost Intel QX3 microscope, which is essentially a webcam with magnifying lenses. Users of this tutorial may work with the images as long as they do not sell or publish them in any other publication.

• An installed version of the VirtualDub and Audacity software packages. (This tutorial was created with VirtualDub for Windows version 1.8.6 and Audacity_Portable version 1.2.6 Rv3).

Steps (activity summary).

For the purposes of this tutorial, we shall use the Windows XP operating system.

• Step 1: First we shall open VirtualDub and import an image sequence. Then we shall adjust the VirtualDub settings to generate a one frame second video.

• Step 2: Using Audacity we shall record and edit a 19 second sound track for our animation, and export it as an MP3 format file.

• Step 3: Using VirtualDub we shall import our audio file and integrate it with our animation.

• Step 4: Using VirtualDub we shall save our multimedia animation as a video file in MSVideo1 format, which can be played by all the common video players. (And which can be played or imported by commmon software on other modern operating systems, such as those running Macintosh OSX or Linux Gnome and KDE)

• Summing Up

Opening an image sequence in VirtualDub

Open VirtualDub. Assuming that you already have a set of images in a directory, and that they are appropriately named (01.jpg, 02.jpg, etc.), use VirtualDub's FILE: Open Video File Command sequence to navigate to your images in their directory.

In the drop-down menu at the bottom of the file navigation window you may choose the type of file that you want to open. Choose Image sequence as the file type, and touch the first image in your list with your mouse, and select the OPEN button. This should load your image files into VirtualDub. Inb our sample set, the first image is named 01.jpg. If they are not named sequentially, or lack an extension (.JPG, etc.) you might get just the first of a sequence, but when importing our sample fileset you should see a Window displaying all 19 of them - although the first one appears as item 0 in the list created by VirtualDub in its editing window.

We shall now set our video and audio parameters so that we get a video of a specific length, file format, and codec (compression decompression - a setting that controls how video and audio files play on different computers). Here are the settings and sequence we shall use for this particular activity:

• Set the video Frame Rate to 1 Frame per second (this is in step 1, below).

• Set the video compression to Microsoft Video 1 format at 100% quality (this is also in step 1, below).

Ultimately we shall create or import an audio file (Audacity is the tool we use for creating and audio file), add it to the image sequence, and generate a video with sound. Our audio file must be the same length as our video file - in this case, using 19 images at 1 frame per second, a video (and audio) length of 19 seconds. So when we do this we shall:

• Create our audio file (this is in step 2, below).

• Add our audio file (this is in step 3, below).

• Export our video and play it (this is in step 3, below).

We shall use the Video: Frame Rate command sequence to bring up a Frame rate submenu in which we shall switch our frame rate from the "No Change" setting to the one-frame-per-second rate by selecting the "Change frame rate to (FPS)" button and putting a 1 in our "change frame rate" field.

We shall use the Video: Compression command sequence to bring up a Compression (CODEC) submenu in which we shall set our codec to the widely supported, but poorer quality Microsoft Video 1 choice (at 100% quality). There may be many other codecs available - MS video 1 videos will play on all modern Windows and Macintosh machines, and the others might not.

Creating our Animation audio file

Once we have generated our VirtualDub image sequence, we shall add our audio narration. Knowing that we were going to make a 19 second long video (19 images displayed at 1 image per second), we need an audio that is 19 seconds long. Open Audacity and record your narration (or other sound track), trimming and editing it as needed to make it 19 seconds long. Export your sound file as a WAV⁶ (FILE: EXPORT: WAV) or as an MP3⁶ file format (FILE: EXPORT: MP3). When exporting an MP3 you will need to have the LAME encoder installed - Audacity "finds" this with a dialogue in its PREFERENCES: FILE FORMATS Menu. In that same location you may adjust the compression for your sound file. A good final compression setting for a narrated voice is 64 KBS. When exporting MP3s you may fill out the fields for the MP3 header, or simply leave them blank and say OK to continue with empty fields. To skip the recording step for this tutorial, you may simply save and use the 19 second MP3 audio file we have developed for you which is HERE. (Right-click on the link to get a "SAVE" choice).

Importing and integrating our audio file

Using VirtualDub's "AUDIO: Audio from other file" command sequence, navigate to where your audio file is stored and select it. Choose "OPEN" to bring your audio into VirtualDub. Don't be concerned if the narration sound track is longer (extends past) the image sequence for now - we haven't set the frame rate for the video. In our tutorial we are using an MP3⁶ format audio file, but VirtualDub supports other common forms of audio, such as WAV⁶ format.

VirtualDub's Audio import function is located in the AUDIO: Audio from other file... Submenu.

Because we adjusted our video to a frame rate of one frame per second, the two sequences (19 seconds of audio and 19 images) should match closely.

The AUDIO: Audio from other file... Submenu gives a us a navigation window not too diffferent from the Video import naviagation window. We need to select our audio file type (in this case MP3) from the drop down menu at the bottom, navigate to where our audio file is stored, and choose the Open button.

Because we chose MP3 format, we are presented with a submenu of MP3 improt setttings. We can safely choose to let VirtualDub "Autodetect" and decide what the best sound settings might be in this case.

Converting your animation to video.

We now have a video with sound. All we need to do next is save it in AVI (Windows Audio-Video-Interleaved) file format. We do this by using the FILE: Save as Avi command.

The Save As AVI navigation window will prompt you to give a name to your file, as well as a choosing place to save it. We suggest a short descriptive name with no spaces in the name - and don't forget to add .avi at the end!

VirtualDub will process the video (the speed of this will vary according to the power of your computer and the size of the file), and generate an AVI format file that we may play in a media player. It will show a window during the process that allows you to follow, and perhaps preview the preparation of your video.

Here is a link to the AVI format video created in this tutorial.

Summing up: Animations in other educational contexts.

Although the tutorial above focuses on a variation of "stop motion" animation in which a series of photographs is integrated into a video, there are a host of other useful ways to use animation in the classroom. For example, in the "GIMP Animation" activity available from this link, the free and open source Gnu Image Manipulation Program and the popular open source TuxPaint graphics program are used to create GIF³ animation which can be displayed in all common web browsers. In this link free NOAA satellite images are converted into animations using the GIMP, empowering young people to learn about their world and the technology available to explore it in new ways.

¹Animation:

CEL Animation (and the related form known as STOP-MOTION ANIMATION) are among the most traditional approaches to creating an illusion of motion in film. Cel animation is the form used in hand-drawn cartoon animation found in film and television up through the 1980s ("Cel" is short for cellulose - the substance originally used for the transparency upon which a character is drawn - because much of the image is transparent, images can be superimposed on a background). In Cel animation drawings are produced in a sequence with one drawing after another displayed in rapid succession as frames in video sequence. Stop-motion animation works in a similar fashion, except that a model is photographed over and over with small changes to position giving an illusion of motion when the frames are combined into a continuous video. In recent years, computer processing has enhanced the ability of an alternative approaches such as PATH ANIMATION and CGI ANIMATION, with extensive use of computer graphics. VirtualDub can import images in JPG or PNG format that have been created by either CEL animation or Stop Motion Animation techniques (and others). For more extensive information on stop motion or other animation techniques, see the Brick Films Resource pages at: http://www.brickfilms.com/resources.php

²Audacity:

Audacity is a cross-platform and open-source audio recording and editing program with a deceptively simple interface and many powerful features. It and its source-code are freely available as a download from http://audacity.sourceforge.net/. It uses the LAME encoder for MP3 file creation, which must be added in separately (and easily) due to restrictions on MP3 file creation software licenses in certain regions of the world.

³GIF:

GIF (Graphic Image File format) is a proprietary and widely supported graphics file format that in its most common form incorporates sequential display of layers, permitting animated display. It is limited to no more that 255 colors, and is most often used for simple cartoon-like animation.

⁴JPG:

The JPG (or JPEG) graphics file format is a common image file format that is used for detailed images on the Word Wide Web. It can be compressed at a range of quality and file sizes, and is supported by all the common browsers. It is used to display high quality images in up to 16 million colors, but does not generally support animation in its common form. For more information see the Wikipedia image file formats page at: http://en.wikipedia.org/wiki/Image_file_formats

⁵VirtualDub

VirtualDub is a free and open-source Windows-based animation program that has a number of useful features such as the ability to control a webcam for image file acquisition, image file import, audio file integration, and video file export. Its' home page is http://www.virtualdub.org and its may be downloaded from http://virtualdub.sourceforge.net. VirtualDub was originally created by programmer Avery Lee, and information about it may be found on its home page and at http://en.wikipedia.org/wiki/virtualdub .

⁶MP3 & WAV:

WAV and MP3 are sound file formats that are common on modern computer systems. WAV files are larger, and MP3 files are usually much smaller, which is why MP3s are used for many digital music transfers across the World Wide Web. For more information on digital sound file formats see the Wikipedia entry at: http://en.wikipedia.org/wiki/Audio_file_format .

⁷Open-Source:

By its very nature, open-source software is ideal for the educational environment. It differs from proprietary licensing by requiring that the software be provided at no-cost, and that it remain freely alterable, so that it can be adapted or improved as needed. The source code that makes up the software is transparently available along with the software, so that any member of the programming community may examine it for bugs, and improve or adapt it without violating intellectual property rights. The key provisions in this case are:
1. Free Redistribution
The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.
2. Source Code
The program must include source code, and must allow distribution in source code as well as compiled form. Where some form of a product is not distributed with source code, there must be a well-publicized means of obtaining the source code for no more than a reasonable reproduction cost -- preferably, downloading via the Internet without charge. The source code must be the preferred form in which a programmer would modify the program. Deliberately obfuscated source code is not allowed. Intermediate forms such as the output of a preprocessor or translator are not allowed. Source: OSI (2008). The Open Source Definition, Version 1.9. The Open Source Initiative, Inc. Retrieved January 12, 2008 from http://www.opensource.org/docs/definition.php.

⁸PNG:

PNG (Portable Networks Graphics) is an open-standard graphics file format that incorporates file compression and millions of colors (as the JPG format does), as well as hidden text comments, and layers (as the GIF format does). The PNG file format was developed for modern web browsers and is slowly becoming more popular as a graphics format for cross-platform image editing.

⁹TuxPaint:

TuxPaint is an open-source drawing program that integrates sound and other child-friendly features. It and its source-code are freely available as a download from http://www.newbreedsoftware.com/tuxpaint