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Old 07 July 2015, 21:41   #56
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Join Date: Jun 2010
Location: PL
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Originally Posted by Mrs Beanbag View Post
Well technically maybe, but not all lines are visible, only 576 of the 625 lines are "active" according to the PAL standard. (some of these Inactive lines occur during the vertical blank, and were used to encode teletext signals)
My point was that Amiga may produce video that have different number of lines short/long fields and as such different vertical frequency which is important for such device as video converter.
288p is functional description for default video mode but in real life even OCS can produce almost 'ANY' amount of lines video - this is even more challenging as based on pixel clock rest of video acquisition need to be done in a smart way.
Only one thing is sure in Amiga - Sys clock and if you do video capture from Amiga you need to be perfectly in sync - best way to do this is provide own system clock.

Originally Posted by Supamax View Post
No, all PAL TVs could accept interlaced-only signals.
Via SCART/composite/RGB socket/RF (modulator), only 576i was possible.

Sinclair Spectrum, QL, C64, Amiga 500, game consoles, VCRs, ... all have video exits @ 15 KHz 50Hz interlaced.
Nope and nope - Amiga is first interlace computer on market - rest is progressive generating 288p50 (and VCR recording frame that consisting two fields) - and so called interlace mode are nothing else than switching content between two fields however without interlace - interlace is strange concept of half line - old computer count always integer, Amiga also btw but two field can be different in length and as such after average half line is produced.
Second TV's can accept various video - trust i made lot of experiments - you are limited in CRT only by V and H deflection circuits - digital TV's are different story as they need to be programmed with tight tolerance and as such they support only official mode (even if they circuitry can accommodate more modes than regular CRT even multisync).

Originally Posted by demolition View Post
Yes, you cannot broadcast an Amiga 288p signal without first converting it to interlaced (with quality loss).
Nope - you can perfectly broadcast 288p from Amiga without converting it to interlace - A520 modulator is clear example - analog circuitry in TV (and most digital) can deal with this kind of signal.

Last edited by pandy71; 07 July 2015 at 22:03.
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