John Lark>
>> >>
>>
>>>On Sep 3, 8:27 pm, isw wrote in
>>>
formatting link
:
>>>
>>>
>>>>Prolonged blacks can damage television transmitters, however (video
>>>>is inverted for transmission, so black requires full power from the
>>>>transmitter).
>>>
>>>Why is video inverted for transmission?
>>
>>
>> So black, which is the sync pulse, which is the retrace blanking, gets
>> lots of transmit power, so things tend to stay in sync. Max-black also
>> make dc restoration work nicely.
>>
>
>Other than brief portions of the evening news the question arises:
>What's the whole point in restoration these days? If OTA-TV really goes
>digital some distant day we might not even bother buying a new set.
Goddamned cross posting happy retards!
In digital transmissions, an all black frame is a very short "data word". It doesn't require much info at all. The retrace info is NEVER transmitted. Only the frame-to-frame differences. The retrace is reconstructed on the receive side. That is what MPEG2 was all about.
Credit General Instrument for allowing us to have up to 12 6MHz wide std NTSC signals fit into ONE 6MHz wide slot.