Sony S9000ES High-quality Progressive Output from Film, High Performance Mpeg Image Processor

Motion Adaptive Field Noise Reproduction

Data compressed formats such as DVD are susceptible to noise. In the video signal, noise appears as tiny flecks or specks of unwanted color. Typically, the circuits that reduce noise also suppress fine picture detail. Viewers are asked to sacrifice the ultimate in resolution for the ultimate in low noise picture clarity.

Video

DVD Technical Notes

High-quality Progressive Output from Film	devices are not sophisticated enough to detect and maintain this
	integrity. Here again, a well-designed DVD player surpasses
One potential way to cut corners in 525P output is to adopt	most outboard devices.
relatively inexpensive frame memory. However, simple frame
memory systems can expose the signal to motion blur on two out	High Performance MPEG Image Processor
of every five frames. This becomes clear when we review the 3-
2 pulldown process. In simple frame memory reverse conversion,	Sony’s progressive scanning outputs represent a new benchmark
the player combines the present field with the previous one — no		in home video perfor-
matter what cinema frame it came from. If the previous field		mance. But Sony’s design
came from the same cinema frame, all is well and a good 525P		goals for the DVP-
picture results. But if the previous field came from the previous		S9000ES required even
cinema frame — an event that occurs regularly on two out of		more. Sony built a new
every five frames — then images that were captured 1/30 second		MPEG Image Processor to
apart will be artificially combined on the television screen. The		undertake three crucial
	Photo 1: Sony’s MPEG Image Processor LSI
result will be a blur of any moving objects in the video picture.		functions:
	performs three important functions to optimize
Such motion artifacts would be completely unacceptable in the
	image quality.
design program of the DVP-S9000ES. That’s why the player
undergoes the full 3-2 reverse conversion process.	1. Motion Adaptive Field Noise Reduction.
	2. Block Noise Reduction.
Achieving 525P: DVD Player vs. Television	3. Clear Frame Still Image Performance.

Many televisions capable of 525P have internal line doubling or scaling circuitry capable of converting conventional 525i inputs into 525P display. Sony’s own such circuits include the Digital Reality CreationTM (DRCTM) and DRC Multi-Function (DRC- MF) systems. With seemingly similar capabilities in both the DVD player and the television, it’s only natural to ask which is preferable. In most cases the 525P output of the DVD player will provide superior results. There are two reasons.

	Many designs attempt to overcome this limitation by comparing
	the pictures from several video fields at once. Pixels that
	correlate from one field to the next are considered accurate.
		Pixels that vary are
		considered noisy. This
		method performs
		beautifully as long as
		the images are still.
Fig. 4: Allowing the television to transform the signal to 525P (top) exposes the signal to		But because different
		fields can capture the
the losses entailed in additional D/A and A/D conversions. Performing the conversion in
the DVP-S9000ES (bottom) simplifies the signal path for an image with lower noise and		image at different
lower distortion.		times, the noise
		reduction system can
First, only the DVD player can perform the transformation on the		easily misinterpret
DVD’s digital signal in the digital domain. The alternative is to	Fig. 5: Conventional digital noise reduction	movement as noise.
convert the signal to analog, transfer this analog signal to the	assumes that any difference between two fields is	When this happens, the
television, reconvert the signal back to digital and perform 525P	video noise. This effectively reduces the	noise reduction circuit
	background noise, but can create new problems.
conversion. This exposes the signal to the losses and distortions	In this example, the movement of the car is	can create ghost
of an additional analog-to-digital and digital-to-analog	interpreted as noise, resulting in an unwanted ghost	images, unwanted
conversion. So the DVD player has a natural advantage.	image — a motion artifact behind the car.	motion artifacts that
	may be more annoying than the original noise. In the past, Sony
Second, when designed properly, DVD player will observe the	has overcome this by exempting areas of screen movement from
correct 3-2 inverse conversion, respecting the integrity of the	noise reduction. Of course, this allows some video noise to
original film frames. The overwhelming majority of outboard	reach the television — another compromise.

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