Factors that Affect Picture Quality When Recording
QuVIS video servers, including the QuVIS Encore, have several settings that affect picture quality in
different ways. These can be categorized into two broad groups:
those that affect picture quality
directly
(such as the SNR control) and
those that limit the picture quality possible
(controls related
to data rate management, which may in turn limit picture quality).
Following are the items that affect recorded picture quality.
External Factors
Source Material
Image quality cannot be improved beyond that of the source material. The motion content, clarity and
grain of the source material will have some affect on the data rate of the recorded footage.
Signal Chain
Image processing components (noise/grain reducers, video distribution amplifiers, etc.) in the signal
chain itself can degrade picture quality.
Internal Factors
1.
Image Quality (RECORD – Media menu page)
This control has the greatest direct affect on picture quality.
Note:
Using a high SNR with a low MDR can force a situation where the failsafe is turning on too often. It’s
best to match the SNR setting to the source material, or set it only slightly above the SNR of the source
material, to avoid the data rate reaching the MDR setting.
2.
Maximum Data Rate (RECORD – Media menu page)
MDR can have a moderate to more extreme effect on picture quality, based on whether it is set
correctly or incorrectly for the source material and SNR. Set correctly, it will monitor and gently
soften image quality only as needed for extreme peaks in the data rate. If set incorrectly this setting
can cause the system to constantly turn on the data rate failsafe which can artificially lower image
quality.
Note:
The data rate failsafe mechanism lowers image quality when the data rate exceeds the MDR setting.
Using a high SNR and a low MDR can force a situation where the failsafe is turning on too often. It’s best to
match the SNR setting to the source material, or set it only slightly above the SNR of the source material.
3.
QuVIS Media Format (RECORD – Media menu page)
QMF selects between legacy-format clips and new clip formats with data rate cap options: MDR30
and MDR60.
4.
Destination volume capacity (RECORD – Input menu page)
The destination volume may contain one or two hard disk drives. A one-disk volume cannot receive
data as fast as a volume with two or more drives. Recording 60p or dual-link HD-SDI content to a
single-drive volume is not recommended as the system may find it necessary to soften the picture
quality if the peak data rate exceeds the performance capabilities of the single hard drive.
QuVIS Encore
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QSR Version 3.1
