Not all channels have a HD channel. That and contracts need renewed to offer that channel if there isn’t one
directv satelite change?
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I was just on a conference call today and they discussed a unit to take MPEG 4Hd for a digital QAM SYSTEM for a hotel and down convert it to Mpeg2 SD.
very interesting as this would indicate ALL SD feeds are going away
very interesting as this would indicate ALL SD feeds are going away
Yes this is what the document from KVH said - there will be NO SD duplicates, channels that are currently in HD today will ONLY be in HD by the end of this year. Not sure why a hotel would want a unit to convert MPEG4 to MPEG2 unless their TVs only have MPEG2 capability and they don't want to replace them all.
I think the only thing "non standard" is the physical layer scrambling code used by DTV, otherwise all their uplink hardware is plain vanilla DVB-S2. I haven't seen the SD equipment in some time but it used to be all DVB with a proprietary translator to shuffle the DVB packets to DSS because nobody was making DSS compression equipment.
That's probably correct, you'd know and I don't know the exact details. All I know is people say you can't use e.g. a DVB-S2 tuner on a PC to pick up anything off Directv's transponders, it won't even lock. I mean obviously the channels are encrypted, as they are also encrypted on the DSS transponders but a DSS tuner is still able to pick up TONS of useful info from the unencrypted metadata like the guide etc. as the team who produces the spreadsheets of useful information on the Cutting Edge forum demonstrates.
The physical layer scrambling is separate from encryption and its applied in the modulator. It keeps a receiver from locking on to a transponder unless the receiver is capable of physical layer descrambling and it has the right code selected. This is why satellite meters can't lock onto the HD transponders except for the DTV designed AIM installers meter which can decode the scrambling and it contains all the correct codes if the firmware is up to date.
The reason physical layer scrambling is used is to prevent a receiver from trying to lock onto any remnants of a nearby spot beam, which otherwise has all the same parameters.
The reason physical layer scrambling is used is to prevent a receiver from trying to lock onto any remnants of a nearby spot beam, which otherwise has all the same parameters.
Thanks for that explanation, I've heard of "scrambling codes" before but assumed it was just another layer of obfuscation added by Directv as leftover paranoia from the access card hacking of almost 20 years ago. Now I better understand what it is really all about.
Still confused a bit though, as AFAIK people don't have any problem locking onto Dish's DVB-S2 signals. Wouldn't they have the same issue of wanting to avoid receivers locking onto the 'wrong' spot beam? If they aren't using physical layer scrambling, any idea how are they avoiding this?
A bit of googling shows that the scrambling sequence can be a value between 0 (default) and 262143, so if Directv is changing them more than once a week you probably can't guess them (it would take about six days to test them all on a single transponder if it requires two seconds to determine signal lock failed)
Guess it is a good thing they will have to keep a few DSS transponders around, otherwise all that nifty data at the Cutting Edge site would disappear!
Guess it is a good thing they will have to keep a few DSS transponders around, otherwise all that nifty data at the Cutting Edge site would disappear!
I don't know how Dish operates and I don't believe the scrambling codes have anything to do with pirating. Its just a two or three digit number you enter into the modulator for a transponder and off you go. Of course the receiver needs to be programmed for the same number or nothing works. There is a six digit "gold number" that is derived from the two or three digit scrambling code entered in the modulator that is factored into the scrambling process, but that gold number is only displayed on the modulator and not entered in normal equipment setup. Scrambling codes are rarely changed for a particular transponder and if they were changed every receiver would need an update via download.
OK, so if they are rarely changed it would seem that a sufficiently motivated person would be able to exhaustively iterate through the codes to find the right ones for each Directv DVB-S2 transponder, making it possible for the team doing data collection to look at the various data PIDs in those transponders to see what they contain.
Always good to get information "from the horse's mouth", thanks!!
If you had an appropriate analyzer I would assume so. I have codes for most transponders from a few years ago but cannot not share them outside DTV. If you have an AIM meter or can get a download if its firmware you might be able to figure something out.
OK, so if they are rarely changed it would seem that a sufficiently motivated person would be able to exhaustively iterate through the codes to find the right ones for each Directv DVB-S2 transponder, making it possible for the team doing data collection to look at the various data PIDs in those transponders to see what they contain.
Always good to get information "from the horse's mouth", thanks!!
Well I was thinking more in terms of a DVB-S2 tuner that works with Linux and exposes a way to set the scrambling sequence. Just write a simple script to try sequence=1, sequence=2, and so on, after each time you set the code you see if the transponder will lock or not. Once you've found the code for one transponder, it would go on to the next and so on. It wouldn't be quick (unless all the codes are low numbers or codes are reused for multiple CONUS transponders) but it would get them all eventually.
Heck I even have a cheap DVB-S2 USB tuner laying around that would work with my Linux PC, but I don't have any way to set up a Directv dish at home because I have huge oaks throughout my yard. I suppose I could probably find a gap now that it is the winter, but there's like a foot of snow and frozen ground.
But maybe I should dig out that tuner and see if it lets me set the scrambling sequence...if it does I might be motivated to see if I can find a friend who has an disused Slimline I can steal, grab the spare legacy LNB from the bar and see if I can make this work
If your DVB-S2 tuner has provisions for scrambling codes then I think you could find them without too much difficulty provided you have all other transponder info like symbol rate, FEC, etc. What would you hope to gain from locking on to an HD transponder?
Well I was thinking more in terms of a DVB-S2 tuner that works with Linux and exposes a way to set the scrambling sequence. Just write a simple script to try sequence=1, sequence=2, and so on, after each time you set the code you see if the transponder will lock or not. Once you've found the code for one transponder, it would go on to the next and so on. It wouldn't be quick (unless all the codes are low numbers or codes are reused for multiple CONUS transponders) but it would get them all eventually.
Heck I even have a cheap DVB-S2 USB tuner laying around that would work with my Linux PC, but I don't have any way to set up a Directv dish at home because I have huge oaks throughout my yard. I suppose I could probably find a gap now that it is the winter, but there's like a foot of snow and frozen ground.
But maybe I should dig out that tuner and see if it lets me set the scrambling sequence...if it does I might be motivated to see if I can find a friend who has an disused Slimline I can steal, grab the spare legacy LNB from the bar and see if I can make this work
I dug my DVB-S2 tuner and it gets recognized by the drivers included with Linux, and I found the firmware file I need - just have to set it up to load that and learn how to control the API that's exposed - it will allow setting the scrambling sequence index from 0 to 262142 so I'm good to go there.
Not sure what I hope to gain by it, just that AFAIK no one has ever reported successful locking and being able to read data off Directv's DVB-S2 transponders as is possible with their DSS transponders, so maybe more the challenge than anything. I'm assuming the metadata in the data PIDs is all the same stuff that's already there on the DSS transponders, but you never know unless you look.
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