> On 2017-09-01, at 10:44, Pasi 'A1bert' Ojala <a1bert@iki.fi> wrote: > > On 01.09.2017 00:19, Mia Magnusson wrote: >> >> For some reason the decoding process in a TV anyway needs a delay. It's >> likely that the s-video standard were set to make a S-VHS player as >> simple as possible, i.e. bypassing any delay that's needed for a VHS to >> do composite -> separate chroma/luma -> FM modulate luma and frequency >> shift chroma -> record to tape, playback from tape -> FM demodulate >> luma and frequency shift chroma -> combine luma and chroma. >> >> So therefore it makes sense that the signals could have different >> timing specs for composite v.s. s-video in general. > Hi Mia, > > The delay is only needed for PAL (Phase-Alternating Line), and some of the first PAL receivers didn't bother with having the delay. Just for completeness - a delay line is not *only* for PAL, where it could theoretically be omitted, leading to Hannover bars effect ;-) it is also required for SECAM, where it acts as temporary storage between two consecutive lines. True there were no SECAM outputting CBM machines :-) > In theory composite is produced by summing the Y and C of S-VIDEO. In practice you may get time shift whenever they are combined or separated. Which is why studio equipment (TBCs and Co.) has adjustments for keeping them in sync. -- SD! - http://e4aws.silverdr.com/ Message was sent through the cbm-hackers mailing listReceived on 2017-09-01 10:03:30
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