Virgin Media - V6 Recordings Query

The viewing card is just a lump of plastic with a chip in it, like your bank card. The chip is probably what does all the work in a Sky box, as presumably they can be reprogrammed by the set top box software.

Of course ITV Digital knew all about reprogramming viewing cards, considering they used an insecure system for the pay channels, and the method/technique was cracked. And never changed, presumably because it would cost a lot of money that OnDigital (as it was) didn't have - new cards, new boxes, presumably, and new software. Not cheap. Not that it really mattered in the end as the entire operation had other issues and fell over anyway.

It's difficult to discuss viewing cards and how they work without getting into dodgy territory.

However changing out viewing cards for millions of subscribers is a very costly exercise - so they ensure each generation of card has a lot of 'room for the future'.

What the card does and what the CAM in the receiver do are intertwined - and how they communicate, pair etc. can be changed. In the case of receivers with integrated CAMs the CAM itself can often be upgraded via a box firmware update (particularly if the CAM is implemented largely or entirely in hardware, which then means the receiver design has to be secure, including the processor it runs on)



Yes - though there is a difference between reprogramming a card with new entitlement data (which is effectively like editing a file stored on the card), and actually remotely uploading new code to run on the card's processor (which is like installing a new OS on the card),

Virgin don’t use physical cards anymore, the older TiVo boxes had them to start with but they moved over to a virtual system, so the card wasn’t necessary anymore for the box to work properly. I forget but I don’t think the V6 even has a card slot.

The way that recordings work on Virgin Media boxes is different to the way that Sky do it. My understanding is that whilst the Sky boxes record the encrypted signal as broadcast, the Virgin Media boxes decrypt the signal, but then encrypt it again before saving to disk using a different system and an encryption key that's unique to each box (which is why you can't swap drives between boxes, they wouldn't be able to decrypt a recording made on a different box).

As there is no connection between the encryption system used to broadcast the channels and the system used to save recordings then technically there is no requirement to still be subscribed to a channel to play back a recording. For many years this is how it worked and you could continue to watch recordings from channels that you no longer subscribed to.

At some point Sky decided they didn't like this and required Virgin Media to change they system so that it behaved in the same way as the Sky boxes. This is the point where it went wrong as Virgin Media implemented the new system badly.

The way it works now is that there are restrictions placed on the channels from Sky, but not other broadcasters. The Sky channels are flagged so that the boxes know which channels to apply the restrictions to. When you go to play back a recording the box checks to see if the recording came from a channel that Sky own and if it does then it will only let you play the recording if you still subscribe to the channel. Unlike the Sky boxes there is no technical reason for this restriction, it's a contractual requirement imposed by Sky.
If a recording is from a non Sky channel then the check to see if you're still subscribed isn't done, so you should still be able to play back recordings from non Sky channels that you no longer subscribe to.

The problem is that in order for this check to work the channel still needs to be broadcasting on the system. Shortly after introducing this system a channel closed down and lots of people on various forums complained that they couldn't watch recordings from that channel any more. Because it was no longer broadcasting the check to see if it was flagged as a Sky channel couldn't be done, so the box refused to play back the recording.

As a result, when a channel on Virgin Media closes down it isn't completely removed from the system. The broadcast stops, but the channel remains in the channel tables as a hidden channel for awhile so that any recordings can still be watched. After some time (normally a few months, but it can vary) the channel is completely removed and recordings can no longer be played back.

This can cause a lot of problems, not only when people try to watch old recordings from channels that no longer exist, but also when changes are made to which regional version of a channel is broadcast, or where a channel has gone HD only with the SD version closing. Whilst viewers can still receive the channel, if it's not the exact same version (with the same ID) that the recording was made from then the recordings can't be played back.

That makes total sense. Presumably the Virgin Media DVB-C subsystem has a CAM that can decrypt multiple streams simultaneously (many can) so that recordings can be decrypted from the broadcast encrypted streams whilst live TV is also being decrypted from a different broadcast encrypted stream.

To be fair, you can't blame them for the issue with recordings from deleted channels becoming unplayable, the situation with Sky that created it would have been one they never foresaw.

Thanks for the technical explanations for these playback issues.

Taking Mute’s comprehensive information into account (regarding Sky’s agreement with VM), what’s our educated guess on whether recordings from Nat Geo HD and Discovery HD will play back after my complimentary subscription to those channels ends? I am uncertain if these channels are owned/licensed by Sky, and if not, and I’ve understood things correctly, there seems a chance the recordings will play....

Neither of those channels are owned by Sky, so based on what's been said I would expect recordings from both channels to continue to play.



I would argue that this could easily have been foresaw by Virgin. While I completely understand the way Virgin designed their platform and the decisions they took, anyone with knowledge of premium broadcast rights will know the licensors like their content to be protected as much as possible.

I suspect in this case it's not Sky themselves who are the ones being insistant that old recordings don't play, but rather the contracts they have with the film studios and/or the sports organisations.

Given that's Virgin's PVR platform was developed after Sky+, it should have been expected that some channels/licensors would want their recordings to work in the more locked down way as they do on Sky+. Especially in this case Sky given they hold many premium rights, and designed Sky+.

As it's Tivo and Virgin have licenced it from them rather than entirely developed it themselves, maybe it's limited by Tivo's own platform and how it works anyway.

This system has been around for a while, long before TiVo came along. It looks like when the Virgin Media TiVo was launched they decided to copy the behaviour they had already implemented in the V+ boxes rather than do something different.

For info: Virgin have now removed these additional channels from my package, and - as predicted - the recordings I made from National Geographic HD continue to play!