The World Of High Definition Tape Formats


By Dan Tibi
HTV, Inc.
Copyright 2006 - used with permission

In the beginning TV was so simple it was black and white and our electricity set the frame rate. Power in America is 60 hertz so the field rate had to match that and it did. The reason for the field rate being 60 hertz was the state of electronics back in the early days of television. The components used in that day were not very precise or stable and the reference to the 60 hertz power line was necessary to keep the early CRTs synchronized with the received signal.

Then color came along and messed everything up because both the B&W and color TV’s had to work. Something was needed to be added to the signal to tell the color TV’s to add color but not to interfere with the B&W TV’s and that something was color burst. With the addition of burst this changed the duration of a scan line from approximately 63.49 microseconds to approximately 63.56 microseconds. Changing the duration of a scan line changed the frame rate from 30 frames per second to 29.97 frames per second.

Other countries have power that is 50 hertz so their frame rate is 25 frames per second. So a tape recorded here has to be converted to their standard and vice versa.

High definition was finally going to put an end to all of this with one world standard. But of course that one standard could not be agreed upon. So now there are more high definition formats then all of the standard definition formats.

The six high definition ATSC broadcast formats are not the only formats to be professionally recorded . Here is a list of professional HD record formats:

High Definition Formats for Recording:

Active Lines

Vertical Blanking

Total Lines

Scan Type

Frequency

Active Pixels

Blanking Pixels

Total Pixels

Bit Depth

Sample Rate

 

Bit Rate



720

30

750

p

59.94

1280

370

1650

10

22:11:11

1.4835 Gb/s

720

30

750

p

60

1280

370

1650

10

22:11:11

1.4850 Gb/s

1080

45

1125

i

50

1920

720

2640

10

22:11:11

1.4850 Gb/s

1080

45

1125

i

50

1920

720

2640

10

22:22:22

2.9700 Gb/s

1080

45

1125

i

59.94

1920

280

2200

10

22:11:11

1.4835 Gb/s

1080

45

1125

i

59.94

1920

280

2200

10

22:22:22

2.9670 Gb/s

1080

45

1125

i

60

1920

280

2200

10

22:11:11

1.4850 Gb/s

1080

45

1125

i

60

1920

280

2200

10

22:22:22

2.9700 Gb/s

1080

45

1125

i

23.976

1920

830

2750

10

22:11:11

1.4835 Gb/s

1080

45

1125

i

24

1920

830

2750

10

22:11:11

1.4850 Gb/s

1080

45

1125

p

25

1920

720

2640

10

22:11:11

1.4850 Gb/s

1080

45

1125

PsF

23.976

1920

830

2750

10

22:11:11

1.4835 Gb/s

1080

45

1125

PsF

23.976

1920

830

2750

10

22:22:22

2.9670 Gb/s

1080

45

1125

PsF

24

1920

830

2750

10

22:11:11

1.4850 Gb/s

1080

45

1125

PsF

24

1920

830

2750

10

22:22:22

2.9700 Gb/s

1080

45

1125

PsF

25

1920

720

2640

10

22:11:11

1.4850 Gb/s

1080

45

1125

PsF

25

1920

720

2640

10

22:22:22

2.9700 Gb/s

1080

45

1125

PsF

29.97

1920

280

2200

10

22:11:11

1.4835 Gb/s

1080

45

1125

PsF

29.97

1920

280

2200

10

22:22:22

2.9670 Gb/s

1080

45

1125

PsF

30

1920

280

2200

10

22:11:11

1.4850 Gb/s

Scan lines -
Active Lines - this is the number of lines it takes to make up one frame of visible video.

Vertical Blanking - this is the number of scan lines it takes to make up the vertical blanking. The vertical blanking consists of vertical sync and vanc information, which can include time code, closed captioning, test signals, and even film information like feet and frames.

Total Scan Lines - this number is the total of the active lines and the vertical blanking.

Scan Type -
Interlaced - this is where the picture is scanned from the top of the picture starting with line 1 and scanning every odd line until reaching the bottom and then returning to the top of the frame and scanning all of the even lines. When the odd lines are scanned this makes field 1 and when the even lines are scanned this makes field 2. Two fields make a frame.

Progressive - this is where the picture is scanned from the top of the picture to the bottom in progression to make one frame.

PsF - this is progressive segmented frame, which means that it is recorded to tape in a progressive form but displayed segmented (they didn’t want to call it interlaced). This is video that each field is derived from a common frame capture, either video or film.

Frequency -
For the 1080 line formats this is the number of frames or fields that are in one second. If the number is 23.98, 24, 25, 29.97 or 30 they are frames, but if the number is 50, 59.94, or 60 then they are fields.

For the 720 line formats they are all frames.

Pixels -
Active Pixels - this is the number of pixels it takes to make one visible scan line. A pixel equals a dot of the picture.

Blanking Pixels - this is the number of pixels it takes to make up the horizontal blanking. Horizontal blanking consists of front porch, horizontal sync, breezeway, color burst, and back porch. The audio is even recorded in the horizontal blanking.

Total Pixels - this number is the total of the active pixels and the horizontal blanking.

Bit Depth - this is the depth of a pixel. If the bit rate is 8 then there would 256 samples in a pixel but if the bit rate were 10 then that pixel would have 1024 samples. The video signal is one volt so if it is divided 256 each division would thicker then if it were divided by 1024.

Sample Rate - this is a ratio between how many luminance samples there are to how many chrominance samples. One sample is equal to 3.375 MHz. In SD the ratio is 4:2:2 and in HD it’s 22:11:11 but most people refer to the HD sample rate as 4:2:2 including Sony even on their equipment. In a 22:11:11 signal only half the color information is recorded there are 22 luminance samples to 11 red minus luminance samples to 11 blue minus luminance samples, e.g. in a 1920 picture there would be 1920 Y samples (74.25MHz) and 960 R-Y samples (37.125MHz) and 960 B-Y samples (37.125MHz). In a 22:22:22 signal all of the color is recorded, e.g. in a 1920 picture there would be 1920 R samples (74.25MHz) and 1920 G samples (74.25MHz) and 1920 B samples (74.25MHz).
Y equals luminance.

Note in a 22:22:22 system all the information is not going down one cable it takes two cables and it’s called dual stream. Stream A is a 22:11:11 signal and stream B is a 0:11:11 signal. Also in a 22:22:22 signal it is RGB not color difference.

So after this all said and done if you want to know how information a true high definition signal is pushing around you just use simple math.

It would be total scan lines times the frame rate times the total horizontal pixels times the bit rate. Then after that if the sample rate is 22:11:11 take the total and times it by two if it is 22:22:22 then times the total by four.

These are some examples:

22:11:11 750 * 59.94 * 1650 = 74,175,750 * 10 = 741,757,500 * 2
= 1,483,515,000 or 1.4835 Gb/sec

22:11:11 750 * 60 * 1650 = 74,250,000 * 10 = 742,500,000 * 2
= 1,485,000,000 or 1.4850 Gb/sec

22:11:11 1125 * 29.97 * 2200 = 74,175,750 * 10 = 741,757,500 * 2
= 1,483,515,000 or 1.4835 Gb/sec

22:11:11 1125 * 23.976 * 2750 = 74,175,750 * 10 = 741,757,500 * 2
= 1,483,515,000 or 1.4835 Gb/sec

22:22:22 1125 * 23.976 * 2750 = 74,175,750 * 10 = 741,757,500 * 4
= 2,967,030,000 or 2.9670 Gb/sec

So, welcome to the simple world of recorded high definition.
Line Separator

About HTV, Inc.
High Technology Video is a leader in the business of high definition telecine mastering and artifact free standards conversion.

The company’s predominant focus is mastering feature films and television shows for domestic and international distribution. HTV also performs electronic restoration of images, as well as various types of duplication and audio work.

HTV is the only place in the world that can transfer 70mm and 65/70mm in real time, in both high definition and standard definition. It is a rapidly growing company with major studios and many independent companies as clients.

(From www.htvinc.net)

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