20-05-2024, 10:59 AM
Sync Pulses are what are in the video signal to say that a line starts or finishes
or likewise ( but in analogue world more complexly ) that the field or frame has Started .
As TV is a sequence of frame /field made up of lines it is essentail
that if you are going to change from one source to another that these are aligned.
.... the picture jumps if they are not and the TV may take a frame to recover
(And I can think of some VT Machines which would take many seconds)
Sound is very different -it has no framing structure - execpt when carried digitally
where there is a need to align and /or process the audio over time periods.
Synchronistion is a complex topic - and all the more so when signal are carried (plesi)isochronously
in a Telco Multiplex....... but is the audio embeded on video or carried seperate but needs time synching
IP which has litle inherent timing is a lot easier- except that you need to be able to reconstrct the source clock at the far end over a link with variable transit time.... so some sync signal in content are useful....
and of course (source) clocks have a toleranace and they vary .....
and it may be that Sound and video clocks are linked (hard or softly) or not!!!
or likewise ( but in analogue world more complexly ) that the field or frame has Started .
As TV is a sequence of frame /field made up of lines it is essentail
that if you are going to change from one source to another that these are aligned.
.... the picture jumps if they are not and the TV may take a frame to recover
(And I can think of some VT Machines which would take many seconds)
Sound is very different -it has no framing structure - execpt when carried digitally
where there is a need to align and /or process the audio over time periods.
Synchronistion is a complex topic - and all the more so when signal are carried (plesi)isochronously
in a Telco Multiplex....... but is the audio embeded on video or carried seperate but needs time synching
IP which has litle inherent timing is a lot easier- except that you need to be able to reconstrct the source clock at the far end over a link with variable transit time.... so some sync signal in content are useful....
and of course (source) clocks have a toleranace and they vary .....
and it may be that Sound and video clocks are linked (hard or softly) or not!!!