NCast Presentation Recorder Reference Manual
If PIP mode is enabled, two signals may be selected (exceptions: HDMI-1 and DVI-D share a digital bus
and may not be used in PIP mode, HDMI-2 and SDI share a digital bus and may not be used in PIP
mode).
12.3. C
OMPRESSION
The digitized RGB signals are converted in format from an {R,G,B} representation to {Y,U,V}. Industry-
standard compression algorithms implemented in the DSP are then used to reduce the source data to a
more manageable size, and to generate sequences of I-P-B frames found in MPEG-4 media streams.
12.4. T
RANSMISSION
The MPEG media stream is split into segments, which are then encapsulated into RTP packets
according to the protocol standards set forth in IETF RFC 3016 or RFC 3984 (H.264). These packets are
presented to the Ethernet hardware interface for subsequent transmission on the attached IP network.
12.5. D
ECOMPRESSION
The received packet stream is decompressed and the resulting image is placed into a video frame buffer.
At that instant it will become visible to the receiving viewers.
12.6. D
ISPLAY
F
UNCTION
The display will output imagery from two different sources. If the unit is configured as the sending unit, a
local copy of the captured image (prior to compression, but after capture and conversion to digital format)
will be displayed. If the unit is a receiving unit, the displayed image will be from the remote sender.
12.7. A
UDIO
S
UBSYSTEM
Each Presentation Recorder supports an audio subsystem consisting of a high-quality codec and
associated input/output connectors. The unit has microphone and line-level input signals, and a line-level
output signal. Each line-level connector supports stereo signals. Balanced audio connectors provides for
stereo balanced audio input. Audio input via the HDMI-1, HDMI-2 and SDI connectors is also supported.
12.8. A
RCHIVE
D
ISK
A 1 TB drive in the Presentation Recorder Hydra is available for recording transmitted sessions. The file
format is standard MPEG-4 Part 10 (H.264, .mp4), which can be played on a variety of desktop client
players, or these same files can be installed on a video-streaming server for on-demand playback over
the Internet. All units come with a mechanical drive as standard, and an SSD may be purchased as an
option.
NCast Corporation
Revision 1.0
Page 92
