Diagonal Filtering and 1080i60 Deinterlacing

Deinterlacing 1080i60 to 1080p60 is a computationally intensive process – the PlayStation 3 and LG SuperBlu BH100 do not support this feature at all! In fact, the majority of televisions on the market today convert 1920x1080i down to 1920x540p, discarding as much as half of the usable detail before continuing. Fortunately, more and more manufacturers are beginning to implement 1080i to 1080p deinterlacing.

A good overview of deinterlacing can be found in the video clip at: http://www.hqv.com/technology/index1/deinterlacing.cfm

We recommend viewing that link before continuing.

In general, interlaced video only contains half of the data you need to create a full image. The goal of deinterlacing is to preserve all of the detail that is available in the original image and then mathematically estimating the data in the missing areas. The better the video processor is at estimating the missing data, the better. On the other hand, a video processor should be smart enough to avoid estimating data when the real data can be recovered in the original signal. This requires identifying objects that are in motion and those that are not. This means that a video processor should have to discard data from moving pixels.

Motion Detection Torture Test

The HQV Benchmark Blu-ray features a classic video processing test. You have a high resolution SMTPE test pattern and a spinning white bar. A good deinterlacer will deinterlace the moving bar while leaving the background intact. Since the majority of video processors on the consumer market today discard as much as half of the resolution, HQV’s test clip is designed to showcase just how poor some video processors can be.

Standard HQV benchmark Blu-ray/HD-DVD test

In the corners and center of the screen there are areas that contain fine detail (single pixel high stripes) which are nowhere close to areas of motion. On a poor quality de-interlacer, these areas will either flash or be blurred to gray.



Using this test, HQV and PureVideo processors score perfect scores. In order to challenge the video processors more, we use a tougher deinterlacing test. Instead of having the spinning bar on only one area of the screen, we have a larger one in the middle that crosses the central portion of the screen. To date, only HQV processing and Sharp’s CV-IC System III (which due to cost reasons is now only available in the Aquos LC-65D90U and XV-Z20000 1080p projectors) have successfully passed this torture test. Using the default “automatic” mode of the ATI produces flashing boxes (bad), but users who switch to the “Vector Adaptive” mode will find that the correct result is seen.

ATI Avivo HD vector adaptive

NVIDIA PureVideo HD

Silicon Optix HQV

Image comparison. To see full resolution image, please select click for hi-res version.

Diagonal Filtering

Diagonal filtering refers to a video processor’s ability to prevent jaggies

ATI Avivo HD vector adaptive

NVIDIA PureVideo HD

Silicon Optix HQV

Although it is again, difficult to compare the AMD AVIVO results against PureVideo and HQV due to ATI’s mandatory resizing with PowerDVD, all three manufacturers provide virtually identical results. NVIDIA appears to have the advantage over HQV processing by just a hair, however if you use a more challenging test clip:

ATI Avivo HD vector adaptive

NVIDIA PureVideo HD

Silicon Optix HQV

Image comparison. To see full resolution image, please select click for hi-res version.

You can see that NVIDIA has a slightly blurrier image (one method used to reduce the appearance of jaggies). The edge goes to HQV.