User Manual v.1
QVidium
®
QVDEC4K™ UHD/HEVC Video Decoder
Copyright 2023 QVidium
®
Technologies, Inc.
Page 18 of 34
Figure 3. List of Available Transport Protocols.
2.2.3 Optional UDP Output
The QVDec4K can also output a UDP stream copy of the input stream after processing to correct
for packet loss. This can be a multicast stream and is often helpful for monitoring the video that the
decoder is processing. This second copy of the decoded video stream does not include any error
correction, so it is best suited for sending over a local area network (LAN)
2.2.4 Stream Encryption
Stream encryption is available
SRT
and
RIST
Main Profile
IP transport modes.
SRT
and
RIST
both use a pre-shared key that you must choose beforehand and provide to both the QVDEC4K
decoder and IP stream source device. Please be aware that the encryption is only as good as the
ability to keep this key private. Although
RIST
is capable of DTLS public-private key exchange, the
version of
RIST
that the QVDEC4K does not currently implement DTLS.
2.3 QVidium ARQ Video Transport & Error Correction
The QVidium QVDEC4K Video Decoder
™ features some of the most powerful and advanced error
correction capabilities found in any video over IP product. The QVDEC4K implements QVidium
’s
patented ARQ error correction and clock synchronization (US Patents #7,551,647 and #7,522,528)
for robust video transmission with the lowest delay
. QVidium’s ARQ (Automatic Retransmission
Request) is a dynamically responsive feedback error correction mechanism designed specifically
to enable the highest quality video transport over wireless networks and the Internet. ARQ senses
packet loss at the receiver and requests replacement packets from the server. ARQ can provide
nearly flawless reproduction of a video stream even through extremely lossy or congested
networks.
The QVDEC4K HEVC UHD Video decoder minimizes network bandwidth and loading due to the
high efficiency of HEVC decoding and ARQ video transport. The QVDEC4K
™ implements HEVC
(H.265) Main Profile video decoding, providing advanced coding techniques in hardware.
The QVDEC4K
supports QVidium’s patented ARQ error correction as well as new industry
standard RIST and SRT protocols for interoperability with third-party decoders and decoders. ARQ
is a robust feedback-based error correction that can successfully recover nearly all packet loss,
even in harsh network environments.
In contrast with Forward Error Correction (FEC), ARQ employs a feedback mechanism that detects
packet loss at the receiver and requests the retransmission of only those lost packets from a video
source. A user-configurable buffer at the receiver (decoder) delays the video stream just long
enough to allow the system to replace any missing packets and re-insert them in their proper order
without disturbing play out of the video stream. Because ARQ senses actual packet loss, rather
than attempt to predict packet loss, it can precisely and completely restore all lost packets without
disturbing timing of the video play out. In contrast to FEC, ARQ can successfully recover lost
packets regardless of the magnitude or pattern of the packet losses, provided that the network
connection has enough capacity to send both the original video stream and the replacement
packets.
ARQ shares similarities with robust packet transport protocols, such as TCP/IP in that both use
feedback to create robust network packet transport. However TCP/IP uses a sliding window that