Introduction
Webcasting
What is webcasting?
Different from Video Conferencing?
What are the drivers?
Key market technologies
Key Elements
Preparation
Capture
Delivery
Reuse
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Summary
References
Articles
Basic audio-visual equipment for webcasting
Audio-Visual Webcasting Tips
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Basic audio-visual equipment for webcasting
For most webcasting events the video and audio source will come
from a single video camera, with possibly a radio microphone
capturing the audio of the speaker. More complex setups are possible
with multiple cameras and microphones for speakers and audiences,
however this will typically require vision and sound mixers and
is beyond the scope of this appendix. It is however worth noting
that some webcast encoders are capable of supporting multiple
video and audio feeds and mixing them within the software for
example Wirecast (Varasoft), Live
Channel Pro (ChannelStorm),
or a hardware based solution such as Sony AWS-G500 Anycast Station
(live streaming in Real Media only).
It is recommended that a DV video camera (Figure 2) is used
in preference to web cams as web cams are typically designed
for capturing video at a short distance and the quality of the
video is likely to be poor in comparison to a DV camera. It is
suggested 3 chip (CCDs) DV camera's are used as they will produce
better images and will be more capable of handling difficult
lighting conditions than single CCD DV cameras. Additional functionality
we would recommend is Firewire (aka IEEE 1394 and iLink) input/output,
good optical zoom, manual exposure controls and external microphone
input.
Figure 2 : Sony DV Camera on Tripod
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Figure 3 : Sennheiser Radio Mic and Receiver
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Audio can be captured via the camera's own built-in microphones,
however this is likely to pick up ambient noise and it is strongly
recommended that a radio microphone and receiver are used, for
example the Sennheiser G2 100 series (Figure 3). Used in combination
with an external microphone input of the camera it is possible
to record to the cameras tape as well feed the audio via the
Firewire output to the encoder. Figure 4 illustrates a radio
microphone receiver mounted on the camera and the Firewire and
external microphone connections.
Figure 4 : Connection Details
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Figure 5 : Desktop tripod
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A tripod with a floating video camera head is highly recommended
(Figure 2), however for more mobile webcasting it is possible
to get small desktop tripods, such as the one illustrated in
Figure 5.
Connection to the encoder is best achieved via a Firewire connection,
however for older video cameras S-Video or Composite video can
be used, together with microphone or line level inputs. Newer
cameras may support USB2 however suitable drivers on the encoder
PC may be required for the encoder software to see the camera.
Although most any video camera can be used, cameras such as
network or IP cameras that capture and broadcast video over a
network connection are not suitable for webcasting in the context
of this paper, and are typically aimed at the security industry.
Suggested audio-visual equipment
Whilst there are many suitable alternative equipment
sets that will work in a fit for purpose webcasting model, we
recommend equipment with a similar specification to the following
for this study.
Video Camera Camcorder |
(3 CCD) Panasonic NV-GS400B MiniDV Digital
(1 CCD) Sony DCRHC96 Mini DV camcorder
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Radio Microphone kit |
Sennheiser G2 100 series Radio Microphone
and Receiver |
Cables |
Firewire cable (4 to 6 pin, or 4 to 4 pin
depending on PC encoder interface) |
Tripod |
Slik U8000
Velbon Video
CX-686 or Video CX-586 |
Table tripod |
Hama |
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