User Manual v.1
QVidium
®
QVDEC4K™ UHD/HEVC Video Decoder
Copyright 2023 QVidium
®
Technologies, Inc.
Page 20 of 34
At the receiver, the ARQ error correction mechanism first buffers incoming packets in a
synchronized network de-jitter buffer that maintains a constant, configurable delay for incoming
packets. The de-jitter buffer processes RTP sequence numbers and reorders packets as
necessary to restore proper packet sequence and to buffer against erratic network delays. Its goal
is to output a smooth, consistent flow of packets with increasing sequence numbers. This output
feeds the ARQ error correction mechanism.
The ARQ unit at the receiver watches for gaps in RTP sequence number from the de-jitter buffer
output, and immediately sends out retransmission requests when necessary. Incoming
rereceiveted ARQ packets bypass the de-jitter queue and find their correct place in the ARQ
buffer, so that by the time packet are output by the ARQ buffer, the ARQ error correction
mechanism should no longer contain any missing packets.
When the decoder and decoder are both started, the decoder automatically measures the round-
trip delay and packet jitter to the decoder and automatically configures ARQ for optimal operation
according to a few basic user-specified parameters, as described in Section 2.3.2.
Note:
For testing ARQ error correction, select ARQ transport at both the decoder and decoder and
use the default ARQ parameters at the decoder (receiver).
2.4 Additional Protocol-Specific Parameters
Certain protocols, specifically RIST Main Profile, RTMP, and Zixi have additional features with their
associated additional parameters that will appear in the configuration settings when selected.
RIST Main Profile creates a virtual private network tunnel when started. It therefore has additional
parameters to configure related to this feature. RTMP adds a Key and URL. Zixi has
username/password authentication for connecting to their server and a bonding feature that allows
you to use both of the QVDEC4K Ethernet network ports for bonding and failover features. Please
contact QVidium for further details, should you require any assistance in these additional
configurations.