Sony RDR-GX7 - Manual (Page 22)

Pre processing to achieve DVD recording with
high quality image performance
Achieving “accurate recording for accurate playback” is the
basic aim of any recording and playback device. One of the
biggest features of the RDR-GX7 is that in the stage before
recording, the input video signal is further improved with various
forms of pre-processing. Steps are taken to reduce noise, which
can have a bad effect on the image during MPEG encoding,
while image adjustment through different processing of the input
video signal ensures stable performance during subsequent
MPEG encoding. In short, pre-processing is responsible for a
large improvement in picture quality, while minimizing any
deterioration during the encoding process.
■ Pre Video Equalizer
A desire to save video recordings on DVD is invariably
accompanied by a large collection of previously recorded video
tapes of varying quality and characteristics. To ensure uniform
recording quality, the RDR-GX7 features the Pre Video
Equalizer, a processing system which adjusts for minute
variations in colour in the original video source before recording
onto a DVD disc. Brightness, contrast, hue and colour level, are
adjusted by this system. By adjusting these four parameters to
achieve the desired picture characteristics, there is no need for
troublesome picture adjustments when the discs are played back
on other DVD players.
■ Frame Noise Reduction before encoding
In the RDR-GX7, the video signal undergoes frame noise
reduction processing before MPEG encoding. When comparing
the video images before and after this processing, you can notice
a distinct reduction in random video noise. Reducing this noise
works to minimize wasteful bit allocation on noise during the
MPEG encoding process used for DVD recording. As a result, bit
allocation is more efficient for a higher level of performance.
■ Time Base Corrector
The RDR-GX7 is equipped with a Time Base Corrector (TBC)
circuit. Signals from analogue video decks usually contain time
axis fluctuations called “jitter,” which can cause the generation
of minute horizontal flickering, or vibrations on the screen. Since
this jitter is recorded as movement during MPEG encoding, a
large number of bits are wasted during the process. The TBC
compensates for this jitter, working to eliminate unwanted
flickering and vibrations for a more stable image on the screen.
By encoding a more stable signal, higher quality images can be
recorded.
Chapter 4-4
High quality
image & sound
RDR-GX7 Technical Notes
22
The encoding LSI contains the Pre Frame
Noise Reduction and TBC circuits