QVidium QVMP2C-1011 User Manual

Page 35

User’s Manual v.28

QVidium™ MPEG2+4 Codec

encapsulates the video as per COP3.2 (without the FEC) and RFC 2733. However
it relies upon an upstream channel on UDP port 7020.

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RTP disables all error correction mechanisms, but still encapsulates the MPEG-2
multiplexed data according to RFC2733.

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UDP is similar to the RTP transport above, but does not add the RTP header to the
UDP packets. Instead it simply encapsulates the MPEG-2 transport stream data
directly into the UDP/IP packet payload.

Destination IP Address or Hostname: This specifies the IP address or Hostname for the
Video/IP stream.

UDP Port: This specifies the UDP port number (P), base 10, for the Video/IP stream.
ProMPEG Column Parity uses the port at P+2 and Row Parity at P+4.

TS packets per IP packet: This field allows specification of the number of 188-byte
MPEG-2 Transport Stream packets per IP packet. The standard MTU for Ethernet packets
permits a maximum of 7 TS packets per IP packets, which is the default.

Unicast TTL (Time-To-Live): This sets the IP packet’s Time-To-Live field for unicast data
streams and thereby limits the number of intermediate IP router hops that each unicast IP
packet can travel before being dropped by a router. (A unicast packet is a packet destined
to travel to a single IP address.)

Multicast TTL (Time-To-Live): This sets the IP packet’s Time-To-Live field for multicast
data streams and thereby limits the number of intermediate IP router hops that each
multicast IP packet can travel before being dropped by a router.

TOS (Type-of-Service): The TOS (Type-of-Service) field in an IP packet specifies the
packet priority and type of differentiated services requested by the packet to each router at
each hop to a destination. Although setting this field will directly set the TOS byte field in
the IP packets for the output video stream, routers along the way may not necessarily
recognize or comply with this request.

Pacing (Full, Medium, or Off): MPEG video compression produces blocks of data with
each incoming frame or field. The size of these data blocks can vary by more than an
order of magnitude depending upon whether the data corresponds to an I-, P- or B-Frame.
Converting these data blocks into IP packets create intense bursts of packets of varying
magnitude for each video frame. Packet bursts can overwhelm the buffering at switches
and routers along the transmission path. The MPEG2+4 IP Codec includes a unique
packet-pacing mechanism that smoothes out irregularities in the inter-packet transmission
times. Enabling QVidium Packet Pacing will create a smoother, more evenly spaced
packetized video stream. However, Packet Pacing will also add latency to the video
transmission, due to the extra buffering required to store the packet bursts. Full Pacing,
while minimizing packet transmission jitter, can also cause compatibility problems with
some IP MPEG decoders. We therefore suggest leaving this setting at Medium for best
performance and widest compatibility with other video decoders.

This manual is related to the following products:

QVSDI-11-IP