32 replies to this topic

[mrvica]

oh, something is wrong with /proc, on SAT.1 720x576i25

root@h7:/tmp# cat /proc/stb/video/videomode
1080p50

shows the same

[littlesat]

This proc gives the output video mode where it is converted to and not the input (received) video mode.

So what is coming in is transcoded to 1080p50 on the HDMI of your enigma2 box.

That is also why you see on any station 1080p50

Edited by littlesat, 15 August 2023 - 14:03.

[mrvica]

now i am enlightened

[gh_n]

I hope this helps?

Not a big help I see.
I did not mean to start a discussion.

Being a A/V engineer for half a decade I use i50, like all other professionals.
But using i25 is fine for me, as we mean the same thing.

Hi Old Satterhand
I do agree with you that's why creating this post as it was a little odd and strange to me and as i said in previous posts in this way i could accept the calculation and the result
Anyway i gut the point
Thanks

Edited by Tech, 15 August 2023 - 20:37.
Fixed quote...

[Stan]

[...] In my world i50 is used. Check some EBU or ETSI documents and learn. [...]

 

The EBU uses the denotation 1080i /25

 

 EBU_TV-Standards.jpg   133.28KB   3 downloads

 

[Old Satterhand]

@Stan

 

Wow, that is a real old document you found. Thank you for your efforts.

Yes in the old days we had only 4 standards in Europe.

 

But when the number of Tv standards increased, in daily practice we changed the denotation.

That was to avoid confusion.

The number 25 or 50 stands for the framerate of the original signal (and also for the de-interlaced endresult).

 

You can also look at it as the frequency of the V sync.

 

 

This is a page from the CEA-861 -D document, showing the timing of the 1080i50 format.

That document also shows the timing of all supported standards in HDMI.

 

 1080i50 timing.jpg   65.52KB   2 downloads

[Stan]

[...] Wow, that is a real old document you found. [...]

It's actually from 2010 and is still valid.

 

The CEA (now CTA) deal with digital interfaces in consumer electronics, not TV-standards. They use denotations like 1920x1080i @ 50Hz, but this is another story...

Edited by Stan, 15 August 2023 - 21:55.

[Old Satterhand]

...The CEA (now CTA) deal with digital interfaces in consumer electronics, not TV-standards. They use denotations like 1920x1080i @ 50Hz, but this is another story.....

 

That explanes the difference, 1920x1080i @ 50Hz is always shortened to 1080i50.

The difference between theory and practice.

 

If you want to see examples look at the topic 'Testkaart' in the feedhunter subforum at s4a.

 

A few examples:

 

 ATP500Queens.jpg   43.39KB   2 downloads       Uefa.jpg   31.59KB   2 downloads

[Stan]

The difference between theory and practice.

 

 

I see your point there. I believe, the misunderstanding is caused by the EBU. Their nomenclature is obviously faulty, as it insists on indicating the number of  FULL frames. This collides with the interlaced standard, which does not work with full frames.

 

Their denotation 1080i /25 is indeed misleading as it wrongly suggests only 25 frames/second. In reality the signal consists of 50 different frames per second.

 

One can only speculate why the EBU chose this nomenclature... perhaps it was intentional. Back then, influential members of the EBU (including Germany and Switzerland) opted for the 720p standard, while the private broadcastes went for 1080i.

 

Maybe they just wanted 1080i to look worse on paper than it actually is.

Edited by Stan, 16 August 2023 - 13:50.

[littlesat]

Long time ago I saw a demonstration and there it was clear that 720p gives a better picture than 1080i… when people are not indicated which screen displayed what resolution. And when the numbers 720p and 1080i were shown under the monitor they chose 1080i. Maybe because 1080 is a higher number so it better.
And beleive me 720p really gives a better picture…. Most people choose that one…

Edited by littlesat, 17 August 2023 - 06:45.

[Trial]

Especially with fast content changes like in soccer.

 

Ralf

[gh_n]

Long time ago I saw a demonstration and there it was clear that 720p gives a better picture than 1080i… when people are not indicated which screen displayed what resolution. And when the numbers 720p and 1080i were shown under the monitor they chose 1080i. Maybe because 1080 is a higher number so it better.
And beleive me 720p really gives a better picture…. Most people choose that one…

Hi littlesat

The quality of the deinterlacing algorithm, is dependent on your device If you have a shitty deinterlacer and content with a lot of panning / fast motion, specially with the fast-moving objects you may indeed be better off with a progressive signal, totally it is the result of many factors in addition to resolution, including screen refresh rate/motion processing, color processing, contrast, brightness, background video noise and artifacts, and video scaling and processing.

[Old Satterhand]

@Stan

Thank you for your postings.

You have a good knowledge of this matter.

 

In due time I wil start a discussion about the lack of choosing the correct Colour Gamut for HD, UHD and HDR output.

I am not so happy with the choices made right now. It is fixed and cannot be changed by the user.

I hope to meet you again in that topic.