NG
Programme Delivery Control is effectively hidden signals in the Teletext signal.
On a Digital platform there is no Teletext, therefore there is no PDC.
Theoretically it should still be possible (and it probably is under the Sky channels that use PDC and still have a traditional Teletext service) but I think next generation PDC will have to evolve first, and on a DTT service this will very much depend on how good your box is, bearing in mind some of them make a pig's ear out of some of the digital text services.
Not quite right.
The issue that means PDC doesn't work well, if at all, for digital services isn't just that it requires teletext (as DSat can carry teletext with no problem at all, and Sky boxes will re-insert text with no problems), it is that it requires an internal tuner on the recorder rather than an external set top box. (Unless you can dedicate a set top box entirely for recordings)
Why?
Well for PDC to work, the VCR, when in standby waiting to timer record, has to constantly change channels on its internal tuner, to check for the PDC information for its recordings on each channel,
to see if it has changed start time/stop time etc. If you have an external set top box connected to your VCR then a) it has to be able to remotely change channel to do this and b) if you are watching the set top box you would get very bored with it changing channel every 5".
For PDC the VCR, when in timer record standby, is constantly changing channels on its analogue tuner (so flipping between BBC One, BBC Two, ITV1, C4 and Five) - to check for updated schedule changes so that it doesn't miss programmes that are starting early or late. It can't really do this on digital, hence the lack of reliable PDC on most digital channels. This is also why PDC sometimes fails when you have two recordings close to each other on different channels - as once it starts the first recording it can't check for changes to the next one until it has finished recording.
For DSat there is the Sky EPG (and soon the open Freesat one) and on DTT there is the open EPG (which is now updated dynamically) which allow PDC functions to be implemented in equipment with digital tuners without the "constant surf" PDC limitation, so PDC is effectively defunct anyway on digital services. These provide updated schedule info constantly, and you don't need to be tuned to a specific service to receive schedule info for that service - as they are carried on all outlets.
Sky have their VCR/DVD Recorder control on the VCR SCART that allows compatible VCRs to be remotely switched in to record by the EPG, and of course have their own Sky+ recorders.
Freeview Playback PVRs offer similar functionality - though non-Playback PVRs and DVD Recorders may not fully use the dynamic EPG, and just use it as a way of setting start and stop times when you initially request the recording, rather than accepting EPG updates after you've set a show to record.
noggin
Founding member
Neil Jones posted:
Programme Delivery Control is effectively hidden signals in the Teletext signal.
On a Digital platform there is no Teletext, therefore there is no PDC.
Theoretically it should still be possible (and it probably is under the Sky channels that use PDC and still have a traditional Teletext service) but I think next generation PDC will have to evolve first, and on a DTT service this will very much depend on how good your box is, bearing in mind some of them make a pig's ear out of some of the digital text services.
Not quite right.
The issue that means PDC doesn't work well, if at all, for digital services isn't just that it requires teletext (as DSat can carry teletext with no problem at all, and Sky boxes will re-insert text with no problems), it is that it requires an internal tuner on the recorder rather than an external set top box. (Unless you can dedicate a set top box entirely for recordings)
Why?
Well for PDC to work, the VCR, when in standby waiting to timer record, has to constantly change channels on its internal tuner, to check for the PDC information for its recordings on each channel,
to see if it has changed start time/stop time etc. If you have an external set top box connected to your VCR then a) it has to be able to remotely change channel to do this and b) if you are watching the set top box you would get very bored with it changing channel every 5".
For PDC the VCR, when in timer record standby, is constantly changing channels on its analogue tuner (so flipping between BBC One, BBC Two, ITV1, C4 and Five) - to check for updated schedule changes so that it doesn't miss programmes that are starting early or late. It can't really do this on digital, hence the lack of reliable PDC on most digital channels. This is also why PDC sometimes fails when you have two recordings close to each other on different channels - as once it starts the first recording it can't check for changes to the next one until it has finished recording.
For DSat there is the Sky EPG (and soon the open Freesat one) and on DTT there is the open EPG (which is now updated dynamically) which allow PDC functions to be implemented in equipment with digital tuners without the "constant surf" PDC limitation, so PDC is effectively defunct anyway on digital services. These provide updated schedule info constantly, and you don't need to be tuned to a specific service to receive schedule info for that service - as they are carried on all outlets.
Sky have their VCR/DVD Recorder control on the VCR SCART that allows compatible VCRs to be remotely switched in to record by the EPG, and of course have their own Sky+ recorders.
Freeview Playback PVRs offer similar functionality - though non-Playback PVRs and DVD Recorders may not fully use the dynamic EPG, and just use it as a way of setting start and stop times when you initially request the recording, rather than accepting EPG updates after you've set a show to record.