HQV (Test 8)

Test 8: 3:2 Detection

From the HQV manual:

Although video programs are transmitted to your TV using one of two picture refresh rates – 30 frames per second, interlaced (30i) and 60 frames per second, progressive scan (60p) — the original program content may have vastly different refresh rates. For example, motion picture film is shot, edited, and screened with a picture refresh rate of 24 frames per second, progressive scan (24p).

To convert such programs for television, a conversion process is used to find a common mathematical relationship between the original program and the broadcast format in use. One common technique is called 3:2 pulldown. During this technique, one additional film frame is repeated in every fifth field of video — hence, the term ‘3:2’. A complete film-to-video sequence actually has a 2:3:2:3 pattern.

A quality video processing circuit will detect the extra frame and remove it to result in a smooth presentation of motion. However, the 3:2 sequences can be corrupted during digital editing, insertion of video effects and titles, digital compositing, and intercutting with animated sequences (which often have very different cadences).

Electronic editing is the most common source of discontinuities in the 3:2 sequence. If all edits started on the first, odd-numbered field of video (often called the ‘A’ frame), then the job of the 3:2 circuitry in your TV would be quite simple. However, when edits do not start on the ‘A’ frame, your 3:2 processor can lose count and must recapture the sequence.

For this test, your TV’s progressive scan image or 3:2 cadence processor must be set in ‘Automatic’ mode, not ‘Film Mode’. As you watch the test image, pay attention to detail in the rows of seats in the racetrack grandstand. In addition to smooth motion and image detail, observe how quickly the TV’s image processor picks up the 3:2 pattern.

No more than 5 frames (about .2 seconds) should pass before this happens, which is about the time it takes the racecar to reach the ‘HOMESTEAD’ billboard on the wall along the track. If you see a strong moiré interference pattern in the grandstand, it is evidence that the processor has not correctly detected the image cadence.

ATI Radeon X1900 All-in-Wonder Video Card Review - Graphics Cards  1

ATI Radeon X1900 All-in-Wonder Video Card Review - Graphics Cards  2

ATI Screenshot; Score: 10

ATI Radeon X1900 All-in-Wonder Video Card Review - Graphics Cards  3

NVIDIA Screenshot; Score: 10

Both GPUs did a good job of finding the moire effect and cleaned it up very quickly.

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