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Old 12th January 2018, 20:39   #9  |  Link
poisondeathray
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Join Date: Sep 2007
Posts: 5,345
Quote:
Originally Posted by johnmeyer View Post
No one uses "25i" to describe PAL interlaced.

AFIK, "25i" is never used to describe anything and, to be consistent with how other cadences are described, if it were used, it would only be used to describe 12.5 fps interlaced video, something that doesn't exist in nature.
Not this again.

Both are valid . Both mean the same thing. Like my brain is half empty. My brain is half full

BBC uses "25i" terminology. They are not "no one". You might even argue they created the standard

Here is an excerpt from their submission guidelines

Code:
1.1.2.High Definition
Material delivered to this specification must be acquired, post-produced and delivered as follows:
• 1920 x 1080 pixels in an aspect ratio of 16:9 as defined in EBU TECH 3299 System 2;
• 25 frames per second (50 fields) interlaced5 – known as 1080i/25, top field first;
• colour sub-sampled at a ratio of 4:2:2;
• colour space – ITU-R BT.709.
The HD format is fully specified in ITU-R BT.709.

1.1.3.Standard Definition
Where agreed by the broadcaster, legacy material delivered for UK SD TV transmission must be:
• 702 x 576 pixels in an aspect ratio of 16:9;
• 25 frames per second (50 fields) interlaced - known as 576i/25, top field first;
• colour sub-sampled at a ratio of 4:2:2;
• colour space – ITU-R BT.601.
The SD format is fully specified in ITU-R BT.601.
Note: SD video has a picture area with a minimum of 702 x 576 pixels, where the 702-pixel
wide picture must be centred in the active 720-pixel wide line. The picture information may extend
the full width of the 720-pixel wide line, providing the image shape is not distorted.

Last edited by poisondeathray; 12th January 2018 at 20:44.
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