I am insatiably curious, so please indulge me in a nob question.
How do the broadcasters communicate with the PVR to tell it to start and stop recording?
Thanks.
My Humax Forum » Freeview HD » FVP 4000T, 5000T
Question: "How do they tell the PVR to record"?
(17 posts)-
| Thu 16 Nov 2017 1:07:56 #1 |
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They use a system of codes called Content Reference Identifiers (CRID).
Basically for every episode in a series a Series Crid identifies all episodes considered by the broadcaster to be part of a series.
Each episode has a programme CRID that identifies each episode. In that way once recorded repeats are ignored.
When you set a series recording the epg is scanned for the first showing of that series this episode is stored in your schedule (Note this may be earlier than the one you actually used to set the recording)
About 15 mins before a programme scheduled start time is due, the box wakes up and watches for the broadcaster to signal the new Now start of recording. At the end of the recording the box stops recording when the current programme status changes to the next programme.
There are a few other bells and whistles like the ability to offer a HD recording when you set from the SD epg entry.
The system lacks a end of series flag so the reservation stays in the list for 13 weeks before it auto deletes. 13 weeks is the minimum gap that the broadcaster has to leave before recycling the series crid for a new series.
You can manually delete them before if you wish.
| Thu 16 Nov 2017 9:19:48 #2 | -
Thanks Graham,
What form does the signal take from the broadcaster to the box that the broadcast is about to start? Is it a sound frequency or visual,signal for example?
| Thu 16 Nov 2017 15:01:32 #3 | -
Thanks, so it is an alphanumeric sequence that is read and translated by the box?
| Thu 16 Nov 2017 15:10:24 #5 | -
uk1 - 3 minutes ago »
Thanks Graham,
What form does the signal take from the broadcaster to the box that the broadcast is about to start? Is it a sound frequency or visual,signal for example?It's part of the broadcast data stream for that channel basically what you see if you look at now/next on a satellite box.
If you look at the photo you can see my HDR-1000S is recording Escape To The Country, it will stop recording when Royal Recipes becomes the now entry.
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| Thu 16 Nov 2017 15:12:51 #6 | -
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uk1 - 4 minutes ago »
Thanks, so it is an alphanumeric sequence that is read and translated by the box?It's digital - a stream of zeros and 1`s. Same way your PC records say a word document to it's hard disk.
Your pvr is a specialised computer. Computers only understand numbers, and as they can only recognise something is there or not there they have to talk in binary, a base 2 counting system rather than decimal.
eg Binary first Decimal next
0 0
1 1
10 2
11 3
100 4
101 5To store alphanumerics you need a code the most common of which is AScii
However your TV doesn't understand alphanumerics either. It's a array of pixels (each one consisting of subpixels Red Green And Blue). Each one is controlled by a transistor to form what you are looking at.
| Thu 16 Nov 2017 15:15:36 #7 | -
Thanks Graham .... very much appreciated.
So the EPG is actually quite fluid and is kept constantly up to date. So a pragramme originally planned due to start at say 5pm might be updated to start at say 4.59pm or 5.01pm?
I'm one of the few ex-mainframe salesman that can actually code!
| Thu 16 Nov 2017 16:40:29 #8 |
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