Oregon State University spent six months evaluating top-of-the-line lecture capture appliances and issued their final report. This is a well documented study with rankings based on criteria which they felt were critical given their years of experience with lecture capture. The full report is available as a download from this blog post (pdf).
Actually, they are two names for the same device. It’s a writing surface illuminated at the edges by LEDs. Instructors like the ability to face their audience.
“The newest addition to Goedl’s teaching toolbox is a light board, which she writes on as she records introduction lectures for each new course topic. The lecture capture tool allows her to face the camera while writing on a transparent surface. Light board technology also reverses whatever is written on the board during recording, so viewers do not see the content backwards.
The result is an innovative video lecture in which instructors appear to be writing in midair. The polished look keeps students interested and allows them to view the board and the instructor’s face during the entire lecture. During the traditional lecture format, instructors turn their backs to students in order to write on the board. In this process they may even block students’ view by standing in front of the board.”
Of all the technical issues facing an instructor making an online lecture video, audio has to be near the top of the list. A video with noisy, distracting audio is hard to listen to for long periods of time, makes comprehension difficult for students whose language is not native to the audio track, and ruins the dialogue the instructor is trying to establish with the student.
Here are some tips towards getting great audio in your recordings:
Use the right microphone — A microphone that’s up-front and close to the instructor, e.g. a lavalier or headset microphone, is probably the best way to capture decent audio. A shotgun microphone aimed at the speaker might be second best. Microphones that are in a laptop, part of a tablet, or that are sitting away from an instructor on a desk or mounted overhead will not pick up voice as cleanly and will be prone to adding laptop noise, room noise and other impairments. Microphones that are built into the video camera you may be using are not the best sources of good audio.
Use a professional pre-amp to boost the microphone-level signal to a line-level signal for transmission to the recording equipment. Something similar to a Mackie 402-VLZ3 Compact Audio Mixer is an example, and well worth the cost. Microphone-level signals are subject noise pickup and are not suitable for transmission over long distances. Use balanced audio cables (XLR connectors) wherever possible. These cables help in canceling electromagnetic noise interference. USB microphones are great in that they convert weak microphone signals to digital signals that are immune to noise. Our lecture-camera recorder only accepts USB audio.
Wireless microphones, if not good quality, will add unwanted hiss into your recordings. Use a wired microphone if possible.
Review and consider the acoustics of the room where the recording will be done. Are the walls bare and prone to echo sounds? Professional recording studios have special foam on the walls to capture all reflected sound. Perhaps you can find, instead, a room with curtains or books lining the walls. What about fans, air-conditioners, HVAC or other unwanted sound sources? These don’t add any value to your recording. And finally, close out other distracting noises like hallway conversations, cellphone ringers, barking dogs and kids screaming in the background.
Use a high sampling rate for your audio – 44 or 48 KHz. minimum.
Record to an uncompressed format for your original (i.e. AIF or WAV format). Formats like MP3 are already compressed and if they need to be decompressed and recompressed as part of your video editing process you will create a second-generation audio recording and will lose quality.
Finally, when creating your published online video, don’t shortchange the bit-rate settings for the audio. Settings like 11 KHz or 22 KHz will make you sound like an overseas telephone operator. Not a good idea.
Some consideration of the points above will not only make your audio good, but really great.
A few years ago nobody knew what an “action cam” or “helmet cam” was, and now they’re so taken for granted that if you don’t have one or two in your car trunk you’re not up-to-date.
The developers behind Lecture Creator feel that our new LC series recorders are so new and feature rich that they, too, might launch a new product category in the industry. Why? These devices:
Serve as a hi-def camera with a wide range of interchangeable fixed, varifocal or zoom lenses.
Recording is done directly to a highly compressed MP4 file that may be uploaded directly to content sites.
The unit can live-stream concurrently while recording.
The files created can be automatically uploaded to content servers.
It’s simple to setup automatic scheduling for recording.
A variety of web and serial command interfaces enable control of the device.
It will even email you when you need some notifications.
These features are ideal for lecture capture, lecture creation, performance capture and event capture (as described in our post on Lecture Capture and Creation ).
So we’re looking for a good name to refer to this class of devices. There’s nothing like it on the market. There are some video-conference cameras that do streaming, but no recording or scheduling or uploads. Some security cameras are IP-Network based, but their feature set is aimed at a different market (face recognition or license plate reading). A term like “Video Recorder” shortchanges all this unit can do. How about “Classcorder” or “Lecture-Cam” or “Class-cam”?
We’re open to suggestions on names and feature lists. And tell us about similar products.