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2009-07-16 Information processes (audio, video) + integration

posted Jul 15, 2009, 6:34 PM by Unknown user   [ updated Jul 17, 2009, 12:24 AM by Eddie Woo ]
Over the last few days, I have spent a considerable amount of time writing support documentation.

Today, I worked on finalising my multimedia products, and integrating them into the existing Maths faculty site. To start off, I deleted the "Multimedia" page that I had created for experimentation a long time ago (and evidently forgot about). I also deleted the "Temporary Files" page, as it no longer served any practical purpose (and contained no files whatsoever).

Audio product - interview with Mr. Woodhouse - completed

Conversion to MP3

Using the audio file that I had collected on 2009-07-01, I produced the audio product of my multimedia project. The audio file has been stored in two places - my USB storage device (portable storage) and my hard drive (local storage) - so that if one device failed, I still had a copy of the audio file for retrieval.

I started installing iTunes in order to re-organise the file from WMA (Windows Media Audio) format to MP3 (MPEG Audio Layer 3) format.

The purpose of this re-organising was so that the file could be manipulated in the audio editing software Audacity, which is not capable of opening WMA files. The purpose of this was not for further compression, and therefore, I used the lowest level of compression (i.e. 320 kbps stereo) possible.

Editing the file

I opened the file in Audacity, which analysed the file to produce a graphical representation that approximates the shape of the sound waves described by the file.

The displaying of this graphical representation helped me identify parts of the sound that needed fixing up. For example, the vertical line highlighted in this screenshot identified the location of a sudden noise (perhaps someone dropping something onto the floor), which I subsequently removed - an example of processing the audio data.

However, I did not restrict my usage of Audacity to simply fixing small errors. I also collected audio data (myself introducing the audience, with "To find out more about maths at James Ruse, I talked to Mr. Woodhouse, head teacher of the subject at our school") using a microphone, and appended this new recording to the beginning of the original file:

I also applied some fading effects, as simple transitions to make the audio more enjoyable to listen to:

Adding metadata

After making my corrections to the file, I saved it as a new file, and opened the new file in iTunes to add metadata, an example of analysing:

The file was, at this stage, ready for publication via the Intranet, made possible by the capability of transmitting and receiving between my computer and Google servers.

Video product - students speaking about Maths at JRAHS - completed

I once again needed to retrieve data that I had previously stored, as I found myself dissatisfied with the product that I had created on 2009-07-06. I re-opened the Windows Movie Maker project file, added a few more of the original AVI clips, removed a few AVI clips that I did not believe were suitable, and increased the brightness for several clips.

I did not take many screenshots of the video editing, as it had many still images of people's faces which I did not have permission to upload to Woo Random Files for documentation (as Woo Random Files is public). This is an example of the social and ethical issue of privacy.

Finally, I had to prepare the files for displaying, so I had to organise them into various formats. I made the decision to use MP4 (specifically, H.264/MPEG-4 AVC) and WMV: MP4 because users of non-Windows systems may have difficulty opening WMV files, and WMV because users of Windows systems may have difficulty opening MP4 files.

I saved the final video file with the lowest WMV compression level possible, resulting in a file that was 24.2 MB in size. However, this was far too big for transmitting and receiving to the audience via Google Sites. Hence, I also saved the file with a higher compression level, resulting in a WMV file that was only 7.47 MB in size (the estimation was fairly accurate):

However, I still did not have an MP4 file, as Windows Movie Maker cannot export to MP4. I tried to use VLC media player to convert the larger (24.2 MB) WMV file into MP4 format, but the quality of the resulting MP4 file was unsatisfactory, and could not be improved. I therefore used freeware program Any Video Converter to convert the file into MP4, using the following settings:

For both the MP4 and WMV files, the compression used was an example of processing. The main differences between the two files are shown in the table below:

 Video bitrate
Frame rate
Audio bitrate
File size
10.7 MB
7.47 MB

The level of compression used on WMV was notably higher. This was due to software restrictions - the Windows Movie Maker "compress to" adjustment changed the size of the file by reducing video resolution, and I did not want to reduce the video resolution. I therefore had to use the "portable device" conversion profile, which reduced other factors e.g. audio bitrate. The quality of both files is very good, so this is not a problem.

Numbers - student performance statistics - completed

I had originally planned to get numerical statistics from the Annual School report, but then I realised that they were exactly the same as the statistics in the news archives that I had spent so much time transferring to the Intranet. I therefore used the statistics from the news archives, including:
  • 2008 Junior enrichment results
  • 2008 Olympiad results
  • 2008 AMC/"Westpac" results

Integrating into the site - an 'about' page

In order to elegantly integrate today's products (numbers, audio, video) into the site, I created an "about this subject" page, which describes the purpose and function of mathematics at James Ruse, and subtly encourages students to have positive attitudes towards the subject.

The audio and video files (MP3, MP4, WMV) are attached, and linked to within the body of the page. End users are encouraged to download the files to their computers; however, the disclaimer "To protect the privacy of students, do not publish this video recording to any location other than the James Ruse AHS intranet." was added as a footnote for the video file, because some of the people in the video did not want the recording to be published beyond the James Ruse community.