Preparing High-Quality Content
Goals: In this session, we will discuss the technical criteria for creation of high-quality audio and video. We will discuss hardware and facility resources to help UW-Madison faculty and staff get started on media development.
Campus Facilities and Resources
When preparing for the technical aspects of an audio or video project, make sure to use good quality equipment. If good quality audio and video is captured from the outset, it will be easier to work with it in the capturing, editing and compression stages. If the necessary equipment is not available, there are rental resources on campus available - some of them are free. Some are available to all campus faculty and instructional staff while others are department specific.
Biology New Media Center
The Biology New Media Center (BNMC - 425 Henry Mall, Room 3130 Genetics / Biotech Center - 265-4817) has audio and video equipment available (video cameras, wireless microphones, tripods, a tape deck with microphones, laptops, and lighting kits) for rental to faculty and staff working on UW projects.
College Library Computer and Media Center
The College Library Computer and Media Center (CMC) also has equipment available for checkout - digital still cameras, video cameras, and laptops.
LSS - Learning Support Services
Learning Support Services (LSS - 279 Van Hise Hall - 262-1408) provides a wide variety of audiovisual resources to instructional staff in the College of Letters and Sciences. Ron Cramer from LS offered many excellent suggestions for additions in this module. In addition to computer training and production assistance, they also offer excellent facilities and audiovisual resources:
- Production of AV materials - LSS can assist L&S instructional staff in preparing AV materials. For minor projects, usually there is no charge. For major projects (e.g. an entire course) the cost of materials and staff time may apply.
- Audio recording studio - A professionally equipped soundproof studio (248 Van Hise) is available to L&S instructional staff for recording, editing necessary to prepare audio recordings for use in class or for individual student use.
- Equipment rental - A collection of audiovisual equipment is available without charge in 275 Van Hise. It may be used by anyone teaching in Van Hise Hall.
CIMC - Center for Instructional Materials and Computing
The Center for Instructional Materials and Computing (CIMC - 225 North Mills Street - 263-4750) has equipment available for check-out to School of Education students, staff, and faculty. Non-School of Education patrons may use the equipment within the CIMC. They also have additional media equipment available at the CIMC. Some examples of equipment they have for checkout are: tape decks, omni directional microphones, digital still cameras, tripods, video cameras, and laptops.
LS - Learning Solutions
The Learning Solutions (LS - 1307 University Ave.) team in DoIT is a production level service to help faculty and staff design, program, and implement instructional technology applications. In general terms, LS serves faculty and instructional staff or other groups at UW-Madison who are developing instructional materials that utilize technology and the Web. Within that broad scope they adapt their service offerings to meet a range of needs. For audiovisual projects, contact Les Howles at 265-5045 for project scope, costs and time estimates.
IMDC - Instructional Materials Development Center
The Instructional Materials Development Center's Video Production Unit (IMDC - 142 Educational Sciences - 262-3330) provides media support primarily to faculty, staff and students within the School of Education, and secondarily to the University System and other State Agencies. IMDC staff assist in media design, perform video taping and post production services depending on client needs and requests (text from the IMDC web site). The IMDC does a great deal of audio editing for a variety of projects, including video, audio, web, multimedia production, streamed video/audio, web casting, and telecourse production.
Digital Media Properties
Digital media uses a fair amount of hard drive space. Five minutes of DV format video takes up about 1 gigabyte (GB) of hard drive space. About one hour and 40 minutes of CD quality audio fits in the same amount of space! The issue of hard drive space management is important especially for larger projects. As newer high definition formats come into more common use - HDTV, DVD audio, etc. - it is certain that hard drive space will continue to be an issue. For that reason, its a good idea to understand the basic properties of digital media so appropriate choices can be made when capturing and editing a projects. Digital audio properties are in the Sound Forge session of the series, and digital video properties are in the Vegas session.
Because digital media takes up so much space, CODECs (compression / decompression algorithms) are often used to compress the media into much smaller files. The basic rule to keep in mind is that the cleaner and better looking and sounding media is from the outset, the better the results will look and sound after encode to CD, DVD or the Internet. More details on compression and CODECs are in the compression session. For now, we are going to focus on making sure the recorded audio and video is the best it can be.
Recording Audio
The basic properties of a good recording depend on what kind of recording is being performed. For the most part, a recording with a fair dynamic range- low background noise and clear, audible audio of the subject is desired - be it a speaker or frog calls. The basics to remember are: selecting a good location, using the appropriate equipment and microphone, and getting good levels.
Selecting a Good Location
As they say in business: location, location, and . . . location. If it is possible to control where recordings are made, try to find a location that has low noise levels and has a lockable door so people can't walk in . Computers and air conditioning with the low level hum of electricity and fans are enemies when trying to get a good recording. Access to a sound recording studio is, of course, the best case scenario! However, many of us don't have access to high end recording studios and can't completely control the location. To some extent, this can be alleviated by using an appropriate microphone or in post when editing.
Using the Appropriate Microphone
When buying a stereo, they say the most important component is the speakers because it's the speakers that are actually physically reproducing the sound. For recording audio, the most important component is the microphone because it determines what the audio sounds like when it is recorded.
Omni
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The simplest microphone design will pick up all sound, regardless of its point of origin, and is, thus, known as an omni directional microphone. They are very easy to use and generally have good to outstanding frequency response. |
Cardioid
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This pattern is popular for sound reinforcement or recording lectures where class noise is a possible problem. The concept is great - a microphone that picks up sounds it is pointed at. The reality is different. The first problem is that sounds from the back are not completely rejected, but merely reduced in volume. This can surprise novice users. Another issue is that the microphone will emphasize the low frequency components of any source that is very close to the diaphragm. This is known as the "proximity effect", and many singers and radio announcers rely on it to add depth or "chest" to a basically light voice. |
Shotgun
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It is possible to exaggerate the directionality of cardioid type microphones. The shotgun is extremely sensitive along the main axis, but possesses pronounced extra lobes which vary drastically with frequency. In fact, the frequency response of this microphone is so bad it is usually electronically restricted to the voice range, where it is used to record dialogue for film and video. |
Lavaliere
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The lavaliere (or lav) microphone is commonly used with wireless systems so a speaker can move around freely without being tied to a microphone stand or podium. The pickup range is small and the mic is usually clipped to a shirt or lapel. |
Different Media Formats and Choices
Some of the common choices available to faculty and staff will be tape decks, mini disc recorders, video cameras (audio can still be recorded to a video tape even the video is not going to be used!) and recording directly to a computer.
Audio Tape
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There are both low and high end tape decks available on campus. Everyone knows how to use a tape deck - push record. In addition, the higher end Maratnz decks allow monitoring of the recording both with a set of headphones and level meters. The disadvantage is that audio tape is not especially sturdy, degrades over time as it is played, and has background tape hiss. |
MP3 Player / Recorder
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With digital formats becoming more popular, certain mp3 players have the ability to record audio directly into a digital audio format. These devices are small, reliable, and can store massive amounts of audio without the need to switch tapes. Certain models can store upwards of 5 hours of audio to a wav or mp3 format. This would be ideal if the audio is to be used on a computer because it wouldn't need to be captured on the computer in real time, thus saving time. Even with certain advantages, high end mp3 recorders are expensive and the internal hard drives may stop working after extreme shock. |
Mini Disc
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Mini disc recorders and discs are both compact, easily portable, sturdy and high quality. Using the mini disc recorder for lectures or interviews with an appropriate microphone attachment works well. One disadvantage is that recordable mini discs are somewhat harder to find than audio tapes. The second disadvantage is that the audio recorded to a mini disc is compressed in order to fit on the smaller media. For some audio recording purposes in which the audio has to be analyzed scientifically for certain frequencies, the mini disc recorder is not appropriate because the compression artificially degrades the audio signal. While many people cannot hear the difference, the audio compression would definitely color any scientific analysis of the sound. |
Videotape
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An often overlooked source and somewhat more common resource for doing audio recording are video cameras. While not built specifically for audio recording, they nonetheless can record good audio given an appropriate microphone attachment. The disadvantage is that monitoring of the recording can not be done with some consumer video cameras to tell if the signal is too soft or too loud. The only way to combat this is to do a short test recording and then rewind and play it back with headphones connected to the camera to tell if decent audio levels are being captured. |
Recording to a Computer
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The advantage of recording directly to a computer is that there is no intermediary media to deal with, and this saves time. This would be a choice with a laptop or a controlled location like a sound studio. One disadvantage is often the computer itself. The fan creates background noise and often the microphones that come with computer are extremely low end. At the very least, try to find a good microphone if recording directly to a computer. The other disadvantage is knowing how to use the software to record the files to a computer, whereas, with a tape deck, most people know how to push "record". |
Monitoring the Recording
It is a good idea to always bring headphones to monitor the audio. If the equipment being used has the ability to monitor the recording, as with the Marantz tape decks or higher end video cameras, do so. If this isn't possible, it is important to take test recordings before beginning program recording to make sure a recording with enough level to produce a clear recording without being too loud is being captured. When a track gets too loud, it over-saturates and clips, producing a very poor sound reproduction. The wireless microphone base stations also have a level adjuster so that can be used if no other method is available.
Levels
If the equipment or software being used has level meters, have the meters just brushing near the red without going into them. This is the 0 dB marker. Going over this will cause clipping and distortion of the recording.
Recording Video
Shooting video that looks good when its compressed means following many principles. Almost all output formats must have some form of compression, be it a DVD or for the Web. In fact, even NTSC DV is a compressed format. Certain cameras can shoot in either interlaced (movie) or progressive scan (pscan) mode. A general rule of thumb is to shoot in interlaced mode if there is fast action sequences or if there are many handheld shots. Progressive scan should produce better results if there are more static shots (dialogues, lectures) with a tripod. Additionally, when shooting, the SP mode (short play) is higher quality than LP (long play) but SP can only capture one hour of video while LP can capture one and a half hours. The ESP and ELP can hold more video, but they currently can not be imported into the computer for editing. For the more part, they should not be used.
Storyboarding
Planning what is needed ahead of time will ensure that the video captured will be of a high quality. Storyboarding can range all the way from drawing out each scene with framing information and dialogue to just writing down a vision of the shoot. Storyboards are typically a series of sketches, similar to a comic strip, which outlines the action and dialogue in a scene. While this may not be necessary for taping someone at a podium in a lecture hall, the idea is to think about what about a shoot before looking through the camera.
Paying Attention to Lighting
If an audience can't see the subject (and this refers to over and under exposure), they will lose interest quickly and the video will compress especially badly. When compressed, video that is too dark or light detail will be lost. Here are a few things to consider to help combat bad lighting:
- Consider the location. If shooting video at night or in a room with bad lighting, consider a better lit location or time of day if it is an outdoor shot. Ample lighting is needed to clearly make out all subjects of the video.
- Consider working with the camera's manual controls - both exposure lock and shutter speed.
- When it is not possible to change the location, consider bringing a portable lighting kit so the light on the subject can be controlled.
Exposure Lock
If it is absolutely impossible to change the lighting, there are certain camera settings that might improve the poor lighting conditions. If a subject that is backlit, consider using the exposure lock.
To do so, zoom in the camera to the subject's face and wait for the lighting to adjust. Then, press the exposure lock button. This will lock the settings on the camera at that exposure level so when the camera is zoomed back out, it won't readjust itself to take account of the lighting from the back. Please note though that this will overexpose the background, often making it pure white light.
Shutter Speed
The shutter speed can be slowed down. In doing so, the shutter is open for a longer amount of time and it lets in more light. The disadvantage of a slow shutter speed is that because lens is open for a longer amount of time, it will capture more motion blur if the subject is moving quickly. Note that the shutter speed of a camera can not be changed if it is exposure locked.
Using Lighting Kits
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Lastly, consider using a lighting kit. They add to the equipment needed to be carried but significantly increase the quality and professional look of a video. The three basic lights to remember are: key light, fill light, and back light. Key light is the main light source on the subject and should be the source of the greatest amount of light. Keep this light about two times as bright as the fill light on the subject. The key light lights up the subject's face - which is important for most instructional uses of video. Back Light is a separation light. It separates the subject from the background and adds depth to the video. |
Placement of the light is dependent on personal aesthetic preferences, program, and location demands. However, the diagram below depicts basic placement.
With the development of more and more sensitive electronic cameras we are seeing less use of the fill light as a third element in the setup for a single individual. Cameras see into the shadows so well that the key light is enough to fill the negative side of the subject and the back separation light tends to add readable fill up over the top of the subject . Some of the information on lighting is from a Web page by Bill Fletcher.
Simplifying the Background
For most instructional use of video, make sure that the subject of the video is clearly conveyed and focused. Help the viewer by simplifying the background. A noisy background of say, a busy street will be distracting to the viewer. In addition, any motion in the frame makes the video harder to compress. If the compressor can largely ignore the background (due to a flat or blurred background), it can provide a clearer foreground subject with more detail. Some techniques for simplifying the background are to shoot the subject against the sky or a grassy background. Consumer camcorders also have a portrait mode where depth of field can be used to blur the background if the subject is relatively close to the camera.
Cropping the Subject - Get Close
One thing to keep in mind for computer based video, especially video that is being shot with the intent to stream it, is that the frame size is typically smaller than what most people are used to when watching video. Video that was composed to look good on a TV will not necessarily look good when it is compressed because of the smaller frame size.
To combat this, compose shots so
the subject takes up more of the frame and is closer to
the camera. Creating a tighter frame can also offset some lighting
problems. Skin doesn't wash-out on close-ups unless the lighting
is really hot, and tighter frames can show more detail especially
in low-light situations.
Using a Tripod
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As mentioned before, motion within the video frame makes more work for the compressor. Take that rule of thumb and multiply it by one-hundred. When the camera is moved, every pixel of every frame changes. Because of this, handheld shots are some of the most difficult video to compress and still look acceptable. Beyond that, handheld shots tend to be somewhat unsettling to the viewer because the presence of the camera can't be denied (The frame is moving all the time!) which makes it more difficult for the viewer to focus on the subject. By using a tripod, the subject has a stable background that doesn't distract from the subject of the video. |
Avoiding Excessive Panning Back and Forth and Zooming In and Out
Panning and zooming can be distracting even though the camera operator is usually doing it to follow or focus on a subject. If taping a moving subject as in a lecture hall - the ideal is to have a multi-camera set up. If multi-cameras are not set up, but different shots are desired - instead of panning and zooming, try picking up the camera with the tripod and moving it to a different location to get a second or third shot. The general rule of thumb for panning and zooming is that a shot should pan once or zoom in or out once - not back and forth. It is usually better if possible to cut between a well composed pan and stills of a subject rather than constantly pan back and forth or zooming in and out.
Using Other Manual Controls
Naturally, this only applies if a camera has manual controls. Even the most low-end cameras should allow the following:
Manual focus is better than auto-focus especially in low-light
situations. Even the slightest change of depth by the subject matter
can force an adjustment by the lens when it is in auto focus mode.
This softens the image momentarily and will come out even worse
in compression. Low-light situations are bad for auto because the
lens can have problems distinguishing the foreground from the background
and it will constantly be trying to adjust - coming in and out
of focus. If a tripod is being used and there is only one stationary
subject, always use manual focus. To manually focus
on a subject, just point the camera at the subject until it is
in focus and then hit the "Focus" button.
Manual white balance is better than auto white balance. White
balancing is typically done by placing a white card in front of
the camera where the subject is and pressing a "white balance" button
on the camera or in the LCD menu. With a manual balance, a more
accurate reading of the existing light and color temperature is
being taken because it is been read off the white
card. Auto white balance reads color off of whatever light is coming
into the lens from the existing environment. If time allows,
compare the manual controls to the auto controls before starting
to shoot. To white balance one of the BNMC's cameras, click
the "Menu" button
on the back of the camera. Scroll to and select "CAM SETUP".
Scroll to and select "WHITE BAL.". Place a piece of white
paper in front of the camera. Change the white balance option from "Auto" to
manual (the SET function on our cameras). The menu will momentarily
flash "SET" white it white balances the camera. When
it is done flashing, press the menu button again to exit the menu.
Using an External or Wireless Microphone
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What good is the video shot if one can't understand what the subject is saying? Many home videos have either low fidelity audio that sound tinny or noisy or that are too low in volume to make out what is being said. This isn't the videotape's fault. It is the camera's built in microphone. As noted above, higher quality audio compresses more cleanly. An added side benefit is that the more the audio is compressed, the more space is available for the video -- this resulting in higher quality video! |