On Thu, 26 Jul 2007 06:52:25 +0100, Eeyore
wrote:



Spurious Response wrote:

So it isn't "breaking up".

Yes it 'breaks up'. Typically with weird pixellation.

That is an analog expression.

No it isn't.


In digital broadcast streams, the term is "dropout".

No, a dropout is a momentary LOSS of signal.


No. In HDTV broadcast, "dropout" is when a tuned station has more than
about 10% bit error rate, and the FEC cannot repair the data stream, and
everything from a few picture artifacts appears, to complete frame losses
(dropouts) occur. The picture artifacts are also dropouts, just not
those that cause the tuning device to display a blank screen for that
given frame, which they do when it gets beyond a certain point.

If they wanted to, they could show you the frames, and you would see
horrendous amounts of image artifacts, and likely audio problems as well.

It IS called dropout. Lost packets ARE lost "signal" as the packet would
not have been lost, were it not for the tuner's inability to reconstruct
any missing packet data from the FEC coding. This has been true from way
back in the early satellite receiver days.

Videocipher

http://en.wikipedia.org/wiki/Videocipher

Digicipher II (most closely related to the new HDTV broadcast schema).

http://en.wikipedia.org/wiki/DigiCipher_2

The current HDTV broadcast schema is also a General Instrument format,
now owned by Motorola.