Different Aspect Ratio of 4:1:1, 4:2:2, 4:4:4, 4:4:4:4, 4:3, 16:9

Nov 23rd, 2011 by Boren 5,597 views |Comments Off

4:1:1

A ratio used to describe the sampling frequency of a digitized signal. The ratio describes luminance is sampled at 3.37 MHz 4 times, while the color is sampled 1 time at 3.37 MHz in each of the separate parts. DV, DVCAM and DVCPRO25 use 4:1:1 color sampling. Formulated as: Y (luminance) is sampled at 13.5 MHz (or 3.37 x 4), R-Y (color) is at 3.37 MHz (or 3.37 x 1) sampled, B-Y (color) is set to 3.37 MHz (or 3.37 x 1) equals 4:1:1.

4:2:2, 4:4:4, 4:4:4:4

Put simply 4:4:4 and 4:2:2 terms are descriptions of the sample formats used in digital video. In the early 80’s experiments were conducted to determine the sample formats and rates for digital video. The final sample structure used for SDI video ended up being four times the base sample rate chosen.

The first 4 in the 4:2:2 terms is for luminance or the black and white information, and that’s where most of the picture detail is. The early experiments in television human eye detect a greater sensitivity to black and white information, while the color filled in with less detailed areas of the human eye. This means you can reduce the color information and your eye can not really distinguish. This is what the 2:2 part of 4:2:2 is for. It means the red and blue channels of the video signal are half the bandwidth of the luminance information. Green is not sent, as you can calculate green from red, blue, and luminance.

This color bandwidth reduction has been used for years in broadcast color TV, andin fact the color bandwidth of 4:2:2 is much higher than composite video. This all adds up to 4:2:2 compatible with black and white or composite television, as the color and luminance information is sent separately, while only 2 / 3 of the data rate is required for about the same visual quality video.

4:4:4 video is similar, but this time all the color information is sent. RGB computer graphics are really 4:4:4. The 4:4:4:4 format adds a key channel.

4:3

4:3 means 4 units wide by 3 units high. It is the standard television format.

16:9

16:9 get the acceptance as the new standard for widescreen TV, high-definition video and DVD. 16:9 supporters state that the wider picture corresponds much better to the human visual field than the almost square 4:3.

To mention about aspect ratio, there is a player which can adjust the aspect ratio on any screen mode. The Smart stretch in DVD X Player let video fit on all monitor with different aspect ratio, avoid video loss or distortion.

All you need to do is right click the player and you will see “Video Window”, there you can keep aspect ratio, stretch to 16:9 and click video desktop.

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