On a sunny day (Fri, 24 Jan 2014 20:33:32 -0800) it happened josephkk wrote in :
Thank you. We used a delayed timebase Tek to look at the vertical interval..., vectorsope, what not. In a way I think it is important to remember how clever the old analog systems actually were and how bandwidth efficient, not even mentioning the better motion rendering on old CRTs than some modern de-interlacing does on LCDs. I hope they get rid of interlaced video soon. Good de-interlacing is theoretically impossible, and LCDs are not suitable for interlaced, it cannot be compressed a lot, and there is no more need for it now everything has gone digital. The Germans do it right, progressive at 50Hz.
On a sunny day (Fri, 24 Jan 2014 20:22:51 -0800 (PST)) it happened snipped-for-privacy@gmail.com wrote in :
All is digital here now, and I think US has also abandoned analog TV altogether?
Data is transmitted in a 'transport stream' (suffix .ts) made up of 188 byte packets. in those packets are sub streams with packets each with a numerical identifier, the PIDs.
So you basically have: ->- PID1 ->- packets with video (that contain MPEG2 or H264 or whatever packets). RF ->- demodulator ->- transport stream ->- sequenctial switch ->- PID2 ->- packets with audio (mp3, AC3 packets). ->- PID3 ->- packets with other audio ..... ->- more PIDs for things like encryption, tables, teletext, program info, anyting. ->- PIDn many of these tables contain PIDs of services so that all you have to do is enter a service number, and then all relevant streams will be filtered out
Here is some code that will process a transport stream, find the pids for a specific program, and only pass those:
formatting link
scroll down to jpinfo.
Can be done by hand if you know the PIDs:
formatting link
scroll down to jpfilter.
Oh, when digital started it took me a while to find out how it worked, then wrote a lot of soft, hacked it too, that of course is now terrorism, but I had help from Ruper Murdoch who hacked the competition and put the code in a Usenet forum... He is a cool guy, I wish they stopped pestering him so much, its a free world, its the 0bamist demonrats who want their own packoflies media.
The standard are really complex, especially DVB-T2 and DVB-C2, just wondering how many years it takes for the manufacturers to get all things correct in their products, considering the compatibility issues a decade ago with the far simpler DVB-T.
On a sunny day (Sat, 25 Jan 2014 13:04:41 +0200) it happened snipped-for-privacy@downunder.com wrote in :
Yes 720p
Really does not matter, 720p, 4kp, as long as it is not interlaced ;-)
I dunno, I remember some people protested in Germany against 720p, maybe they died by now. There was a paper by the EBU (European Broadcasting Union)that says it all on interlace:
I was trying to keep it simple. The ghost canceller came alot later and wasn't related to correcting problems on the microwave transmissions. That was for multipath.
forth. I remember there was also a signal to indicate the beginning of a commercial break. I don't know if it was used by those devices that claimed to remove the commercials. All I know is I saw it. at the shop I always had an underscanned monitor for a coupe of reasons. Later the came in hand for stting the PG shifters in VCRs. you needed a sharp image of course, but it wasn't hard to count the lines up from the bottom.
manufacturers had a mod to lengthen the vertical blanking pulse. They could generally count on enough overscan but in some cases the white bars of data would reflect off the top of the CRT envelope. The closed caption information was at the very end of the blanking interval.
there was SAP, but there was another carrier even higher called IIRC, PRO.
information. I never had a need to look into it, in fact now that I think of it....
waste my time more...
Some of that is in the wikipedia article and more in the references.
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