User Manual v.1
QVidium
®
QVDEC4K™ UHD/HEVC Video Decoder
Copyright 2023 QVidium
®
Technologies, Inc.
Page 28 of 34
7
Appendices
7.1 Appendix A: Decoder Configuration Parameters
This section explains the parameters related to the analog input signals and decoding settings and
how they relate to the operation of the decoder and error correction and network transport setup.
Video Decoding Bit Rate:
Total peak stream bit rate for Variable Bit Rate (VBR) video decoding.
The resulting transport stream bit rate is the sum of the bit rates of the video program, audio
program and program stream information. The video bit rate is specified in bits per second and can
range up to 80 Mbps. The input video resolution can range from 1280x720p59.94 to
3840x2160p59. Typical video bitratesrange from 2 Mbps to 19 Mbps. Higher video stream bit rates
generally produce higher quality video, with greatly diminished returns over about 20 Mbp
(depending upon content and resolution).
Audio Bit Rate (compressed):
The audio bit rate determines decoding audio quality and allows
you to trade off audio throughput for quality. The audio bit rate can be set to one of 16,000, 32,000,
56,000, 64,000, 96,000, 112,000, 128,000, 192,000, 224,000, 256,000, 320,000, or 384,000 bits
per second. Increasing the audio bitrate, up to a maximum value of 384 Kbps increases the audio
fidelity. Regardless of the audio signal level on either channel, selecting an audio bitrate of 64
Kbps or higher will always force the decoder to send 2 channels of audio (stereo audio). Each
audio channel uses one-half of the selected audio bitrate. The H.264 HD Video Decoder
™
decodes audio using either MPEG-1 Layer II decoding, MPEG4 AAC-LC audio decoding or Opus
audio decoding.
Audio Sampling Rate (Hz):
The audio sampling rate specifies the clock rate for capturing and
digitizing the incoming analog audio signal. Because of anti-aliasing filtering, the maximum audio
frequency that can be digitized is limited to a frequency of about 1/3 to 1/2 of the audio sampling
rate. Internal anti-aliasing filters severely attenuate audio signals above a frequency of about 1/3 of
the sampling rate. Thus, for a standard SDI rate of 48 KHz, the maximum audio frequency that the
decoder can pass is about 16 KHz.
SDI formatting requires that the audio sampling rate be fixed at 48 KHz, so the user interface does
not have an Audio Sampling Rate setting..
Network Parameters
The fields below relate to Ethernet/IP video transport settings.
IP Transport:
This selects the type of video IP packet encapsulation and error correction used by
the decoder in generating a Video/IP stream. All packetized video transport mechanisms
encapsulate a multiplexed variable bit rate MPEG-2 transport stream.
ARQ uses QVidi
um’s patented error correction mechanism based on a time-constrained
selective packet retransmission algorithm, in place of FEC. It also encapsulates the video
as per COP3.2 (without the FEC) and RFC 2733. However it relies upon an upstream
channel on UDP port 7020.
RTP disables all error correction mechanisms, but still encapsulates the MPEG-2
multiplexed data according to RFC2733.