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Case Study: Good Newts / Bad Newts

A representative scenario, designed to help address common areas of interest regarding the audio and screen capture of PowerPoint presentations in lecture theatres.

Presented to us as a fictional scenario, designed to incorporate typical real-world issues and key areas of interest.

Original enquiry

[quoted with permission - our thanks to Jules Cook - ESU, University of Bristol, and Suzi Wells, Faculty of Science, University of Bristol]

Scenario 1: Amanda records her newt lecture

Amanda would like to record her lecture about newts this Friday. She wants to capture the PowerPoint presentation along with the audio so that the students can use it for revision at exam time (several months from now). The lecture contains technical language and she's particularly aware that some students have English as a 2nd language, so audio must be clear.

She plans to make it available via Blackboard so that the students can access it from home as well as on campus. She thinks that some of the students will want to download it onto their personal video players. The head of department would also like to be able to view it on his iPhone.

She'll lecture for 40 minutes, then have a 10 minute question and answer session, which she is also keen to include in the recording. There is often only about 5 minutes changeover time between lectures.

Her PowerPoint presentation contains text (with animations), some diagrams she scanned from a book and two 1 minute videos of newt mating rituals, which she filmed in the field.

She uses the lecture theatre's PC, next to the podium, and the projector provided. There's a stick microphone on podium which is connected to PA system (its output can be picked-up by PC but isn't by default). The back of the PC isn't accessible. The only inputs accessible are the 2 front USB ports. She could borrow a radio mic. Amanda tends to pace back and forth while lecturing, coming back to the podium to change slides.

She doesn't have permission to save to the lecture theatre machine, but she does have a 1GB memory stick (with some files already on it) and access to network file storage area of 50MB only (and part of this is already taken). The PC has internet access. The PC is managed by the Estates department, and new software can only be installed on it over the summer but it already has the latest version of Camtasia Studio.

Some background noise is expected. There will be about 200 students in the large echoing lecture theatre. There is sporadic building work next door and a squeaky door (so the inevitable late-comers always briefly disturb the flow of the lecture). When the day comes Amanda has a stinking cold. She would very much like to edit out her coughing, and an interruption due to the building work next door, if possible.

She has the grudging agreement of the department's over-stretched computing officer that he will process the recording to make it available online. He doesn't have experience with video-editing software.

Analysis

1. Amanda would like to record her lecture about newts this Friday. She wants to capture the PowerPoint presentation along with the audio so that the students can use it for revision at exam time (several months from now). The lecture contains technical language and she's particularly aware that some students have English as a second language, so audio must be clear.

Camtasia Studio is a PC application used widely in education, which allows the user to record the output of their computer's display in real time, as a video file. Additionally, the software can simultaneously record the computer's audio input. Camtasia will therefore allow Amanda to record her PowerPoint presentation on the lecture theatre PC as it is delivered, along with the audio input from her microphone. This will ensure correct timing of slide transitions to synchronise to the audio soundtrack. Camtasia can also simultaneously record live video from an external camera if required (though this is not a specified need in this scenario).

The ability of Camtasia to offer support for audio and/or video capture, in addition to screen capture, will depend on the capabilities of the PC in question, and the availability of suitable peripherals [see below]. Camtasia is a relatively simple piece of software to use, and a minimal training period should be required for most technically aware users to feel comfortable with its use.

The clarity of the voice recording will depend primarily on the combination of microphone and the computer's audio interface - be it an internal soundcard, as found on most PCs, or an external USB audio device (a separate box with audio connections on it, which connects to a USB port) - and their correct set-up. It is recommended that both the microphone and a separate USB audio interface are supplied by the recordist (Amanda or her assistant), to avoid relying on the unknown audio capabilities of the onsite PC, which may well not have been specified with audio capture in mind. The recommended additional equipment for audio recording is therefore a simple clip-on radio mic (Sennheisser Freeport Presenter Set or similar) and a USB audio interface (soundcard) with microphone input, such as the Tascam US122 or Edirol UA25.

A training/familiarisation period is strongly recommended before using the recording system in a ‘live' situation. Familiarity and technical confidence will ensure smooth and stress-free set-up on the day, and will allow Amanda to be comfortable with the sensation and sound of having her voice amplified and recorded. As much as any technical detail, this will help her to capture a good recording.

2. She plans to make her lecture available via Blackboard, so that students can access it from home as well as on campus. She thinks that some of the students will want to download it onto their personal video players. The head of department would also like to be able to view it on his iPhone.

When it comes to exporting her edited 'master' [see section 4] for delivery to her students, it is possible to specify different framerates, codecs and settings, suitable for different playback devices. Recordings can be exported as Flash, Quicktime or Windows Media movies, suitable for download, email and web streaming, or as AVIs suitable for CD and DVD media. Camtasia includes a 'wizard' which chooses suitable file compression settings based on the answers to a few simple questions, which ascertain nature of the content and the intended delivery method. These settings can be further manually refined by the more advanced user, but offer a very useful starting point.

NB: Care should be taken when planning presentations, and when choosing compression settings, to consider reproduction - especially the clarity of written text - on devices with small screens (iPods etc).

If Amanda's institution also intends to support Camtasia Relay (the new network version of Camtasia) then this offers the facility to compress recordings automatically for a variety of devices, and upload to Blackboard as a learning resource for one of her specified courses. [Note for Blackboard Administrators: These preferences can be managed centrally, and stored as part of a user's network profile, subject to suitable expansion of the LDAP schema].

3. She'll lecture for 40 minutes, then have a 10-minute question and answer session, which she is also keen to include in the recording. There is often only about 5 minutes changeover time between lectures.

A second room microphone would be required to pick up questions from her audience. However, a common technique used by professional broadcast interviewers etc is simply to repeat the question before answering. In this way, Amanda's microphone will serve as the single point of contact, greatly simplifying the setup process.

Amanda's familiarity with the setup procedure of her microphone will be paramount, and it is recommended that she or her regular assistant is trained in setting up for some representative situations. If she uses the same venues on a regular basis, then this procedure can be further simplified by correct installation of any necessary software drivers onto onsite computers.

4. Her PowerPoint presentation contains text (with animations), some diagrams she scanned from a book and two 1-minute videos of newt mating rituals, which she filmed in the field... Some background noise is expected. There will be about 200 students in the large echoing lecture theatre. There is sporadic building work next door and a squeaky door (so the inevitable late-comers always briefly disturb the flow of the lecture). When the day comes Amanda has a stinking cold. She would very much like to edit out her coughing, and an interruption due to the building work next door, if possible.

Camtasia will capture the presentation as it appears on the screen, either in a specified window or by capturing full-screen (chosen when commencing recording). This recording will be captured in a proprietary format (.camrec), for use while working within Camtasia Studio - recording, compositing and editing. Video remains at full resolution until exported from Camtasia using the 'Produce Video' wizard, which assists in choosing video and audio compression settings for the final output file(s). It is recommended that she saves her 'onsite' recording to her memory stick as a Camtasia project (a .camproj file), and copies this to her own PC, to allow her to choose compression settings, and to carry out any necessary editing at her own pace.

Both video and audio tracks can be edited within Camtasia Studio. In simple terms, if Amanda wishes to remove sections of the recording, she can define a region by clicking and dragging across the Timeline in Camtasia, then choosing 'Cut Selection' to remove it. Similarly, unwanted sounds can be removed without disrupting the flow of the video by selecting the offending section and using the 'Replace with Silence' editing command. Audio fades, and more sophisticated editing and compositing techniques are also available to the more advanced user, all of which will contribute towards a more polished final product.

5. She uses the lecture theatre's PC, next to the podium, and the projector provided. There's a stick microphone on podium which is connected to PA system (its output can be picked-up by PC but isn't by default). The back of the PC isn't accessible. The only inputs accessible are the 2 front USB ports. She could borrow a radio mic. Amanda tends to pace back and forth while lecturing, coming back to the podium to change slides.

Connecting the microphone to the computer's built-in soundcard is - in the absence of an alternative - an acceptable solution. If the back of the PC is inaccessible then some PCs offer a mini-jack microphone input to the on-board soundcard on the PC's front panel, though this should not be relied upon (nor is it specified in the given scenario). However, many onboard PC soundcards are low-gain, low A/D conversion quality, and noisy, and a dedicated external USB audio interface is strongly recommended. In practice, this means Amanda providing an external USB audio interface, in addition to the microphone itself [see section 1] .

The audio input device (soundcard) should be adjusted to suit the microphone to be used. Input gain levels should be set to peak at around 75% on louder passages. As a general rule, this should allow headroom for the louder signals, but ensure that quieter ones remain audible.

If Amanda is to be free to move about as she wishes, then a fixed podium microphone is not suitable for recording her voice, and in any case it cannot be relied on to give acceptable clarity or definition. Also the variations in level and the room acoustics will lead to unusable audio. The solution would ideally be a clip-on radio microphone and receiver, which will give clarity and freedom of movement.

Once a suitable pairing of radio microphone and USB audio interface has been decided upon, Amanda should be assisted/trained in finding appropriate levels of input gain (ie mic input level/volume) for their interaction. This will have a significant effect on the recorded volume and quality - insufficient or excessive input gain will result in audio that is either too quiet or distorted (respectively). Once this level is set it should be noted down to enable recall for future events.

If sound reinforcement (ie amplification) is required in the theatre to ensure audibility, then a monitor feed can be taken from the audio interface and fed to the PA system in place of the podium microphone. It should however be borne in mind that there is a trade-off between amplified volume and recording quality, as an amplified signal will tend to be more reverberant, and may also lead to issues with feedback, as the microphone picks up the sound of the P.A, all of which artefacts will be present in the recording. Additional amplification of Amanda's voice should therefore be kept to the minimum acceptable level, and if she can speak more loudly, rather than relying on the PA, then she will get a better recording in 99% of cases.

6. She doesn't have permission to save to the lecture theatre machine, but she does have a 1GB memory stick (with some files already on it) and access to network file storage area of 50MB only (and part of this is already taken). The PC has internet access. The PC is managed by the Estates department, and new software can only be installed on it over the summer but it already has the latest version of Camtasia Studio.

Camtasia is able to save as it records, to a temporary location on the local drive, and then export the final recording to the external USB memory stick. However, even leaving aside the various choices of frame rate and audio codec, Camtasia's output file size can vary enormously for the same length of recording, depending on the degree of motion in the screen capture area. In practice, this can affect file size by a factor of 50 or more. Assuming light use of video elements in Amanda's presentation, mp3 audio, and a resonable framerate (10fps or so) then her 1Gb stick should be sufficient for her recording. This however cannot be guaranteed, and a dry run on a similar machine, to allow experimentation with Camtasia's recording preferences, is highly recommended. Given the relatively low price of USB memory sticks, a larger capacity (4Gb+) would be preferable.

System requirements : There must be sufficient free space on the PC hard drive for temporary buffering of Amanda's recording; USB sticks are not suitable for direct streaming of audio or video files (even as a temporary cache), and though the file will not be permanently stored on the PC drive, it must reside there temporarily (at least for the duration of the lecture). For a media-rich presentation, we would recommend her requesting that at least 4Gb of free drive space be available for this purpose, which we would anticipate giving sufficient room for the vast majority of presentations.

7. She has the grudging agreement of the department's over-stretched computing officer that he will process the recording to make it available online. He doesn't have experience with video-editing software.

As described above, Amanda should be able to edit her recording to her satisfaction within Camtasia and compress it to a number of final file types and sizes, using either the built-in wizard or specifying her own preferred settings. If the computing officer can specify a target filesize and format, Amanda should be able to provide her recording in a suitable format, given some basic training on Camtasia.

At time of writing, a suggested video size for delivery on Blackboard VLE might be 320x240 pixels, which gives reasonable clarity without excessive storage needs. However, please note that Blackboard's current maximum allowed file size is 50Mb per file, which does not allow for a very large or high resolution video file. Amanda may therefore be required to chop up her video file into small ‘bite-sized' chunks, to cirumnavigate this limitation of Blackboard.

An additional caveat regarding Blackboard is that the backup/archive service provided within the control panel on Blackboard does not include video resources within its archive, so independent archiving of these course materials should be addressed (ideally at or before the time of uploading) if an archive is desired.

Known Assets:

  • Lecture theatre PC with Windows XP, built-in soundcard, and accessible USB ports (x2).
  • Projector
  • PowerPoint
  • Camtasia Studio
  • In-house Public Address (PA) and podium microphone [not used]

Requirements:

  • Camtasia audio/video capture of PowerPoint presentation with live audio.
  • Full quality screen capture suitable for editing/export to a variety of final file types/sizes for delivery by Blackboard VLE/mobile devices
  • Good quality audio capture from wireless microphone
  • Simple setup procedure

Additional Equipment - Recommended:

  • Wireless lapel microphone + receiver
  • Low latency USB audio interface with microphone input and direct monitor output
  • 4Gb+ USB memory stick (fast access)