Some PDC videos don't stop taping until a short while after a programme has finished. The BBC claim that they send out the stop signal promptly, so why is it some videos keep going?
It may be that some video manufacturers have caused this because of Channel Four's implementation of PDC. Reportedly, C4 do not send a stop signal at the end of each programme. So in order to make sure that a programme has really finished and that the PDC signal hasn't simply been lost temporarily, the video keeps going for 30 seconds after the signal is lost. Since C4 were the first channel to broadcast PDC, some video manufacturers may have built their machines to work with C4 and assumed that other channels would implement PDC in the same way.
It always annoyed me more than it didn't work at all on my local ITV region and AFAIK still didn't work for years after 2003. Incredible support for it was so patchy and any plans were dependent on what your local region wanted to do (or not do in the case of HTV).
It's all coming back to me now, you had to also programme the
scheduled
finish time too for PDC to work. If you added any padding, the algorithm was messed up, and the programme would not record
I don't think that was the case. The PDC code only included the start time and that was broadcast throughout the programme. As far as I remember the end time was irrelevant. That was it was handy if the programme overran too.
I suppose in theory since it would have been known about possibly for months just how long the (pre-recorded) programme would have been it didn't need an end-time as you'd just record for around 30/60 minutes. Live programmes on the other hand would have had a scheduled duration but of course if it overran and the actual duration wouldn't have been known until the credits rolled... there must have been a "stop recording" code, surely?
It's all coming back to me now, you had to also programme the
scheduled
finish time too for PDC to work. If you added any padding, the algorithm was messed up, and the programme would not record
I don't think that was the case. The PDC code only included the start time and that was broadcast throughout the programme. As far as I remember the end time was irrelevant. That was it was handy if the programme overran too.
I'm not sure, if the programme over ran, the whole essence of PDC was to keep recording beyond the published end time. I'm sure when I added padding to the end time setting on my Sony VCR the PDC function would fail, and the machine would revert to the manually set values. Of course that may have been how Sony implemented the system. PDC along with RDS must rank amongst the most loosely and sloppily applied implementations by receiver manufacturers. Even my 2014 model Peugeot incorrectly handles RDS AF, only 30 years after the spec was published!
Despite its flaws, I don't think anything exists in this day and age that even comes close to being a simple and reliable way to making sure a programme is recorded in full. Even Freeview/Freesat PVRs seem to struggle if a programme is running late as, in my exeperience anyway, the EPG isn't always updated and/or the recorder doesn't pay attention to any late changes.
Despite its flaws, I don't think anything exists in this day and age that even comes close to being a simple and reliable way to making sure a programme is recorded in full. Even Freeview/Freesat PVRs seem to struggle if a programme is running late as, in my exeperience anyway, the EPG isn't always updated and/or the recorder doesn't pay attention to any late changes.
Depends on the broadcaster. I've only had a BBC programme fail to record on Freeview once I think, but I record far fewer things from other channels. I seem to recall similar with PDC. Of course these days it's not a total disaster if something fails to record, thanks to 'catchup' services ( Not available to everyone of course)
Despite its flaws, I don't think anything exists in this day and age that even comes close to being a simple and reliable way to making sure a programme is recorded in full. Even Freeview/Freesat PVRs seem to struggle if a programme is running late as, in my exeperience anyway, the EPG isn't always updated and/or the recorder doesn't pay attention to any late changes.
Properly implemented DVB EIT p/f (Present / Following I think) record triggering works pretty flawlessly in my experience on the BBC channels. It's triggered by the action of playout in the suite. It won't cope with programmes changing channels - but if the programme is still scheduled correctly, the record start is usually pretty spot on for the ident introducing it.
The BBC use EIT p/f triggering to index BBC Redux, their internal off-air archiving system and it's very unusual to find a show on that which has a dodgy start or finish.
You can also enable EIT p/f triggering in TV Headend and other open source PVR apps. Freeview, Freesat and Sky also use it I'm pretty certain.
You can also enable EIT p/f triggering in TV Headend and other open source PVR apps. Freeview, Freesat and Sky also use it I'm pretty certain.
That's interesting. I have DVB-T2 and DVB-S2 TV cards and use SmartDVB and, sometimes, DVBDream and DVBViewer. I've never known it work reliably with that. My experience in the past (2015 and earlier) of Sky+ was unreliable too in terms of recordings being cut off if a programme overran, even if the EPG was updated.
You can also enable EIT p/f triggering in TV Headend and other open source PVR apps. Freeview, Freesat and Sky also use it I'm pretty certain.
That's interesting. I have DVB-T2 and DVB-S2 TV cards and use SmartDVB and, sometimes, DVBDream and DVBViewer. I've never known it work reliably with that. My experience in the past (2015 and earlier) of Sky+ was unreliable too in terms of recordings being cut off if a programme overran, even if the EPG was updated.
The EPG updates are a separate issue - as the EIT p/f is sent slightly separately to the EPG (Sky and Freesat use proprietary EPG schemes, but respect EIT p/f - which is why you get Now/Next listings on non-Sky/Freesat receivers even if you don't get the full EPG)
If the scheduling system is a mess because they can't keep up with very last minute decisions made in playout, then there are occasions when EIT p/F doesn't work properly, but they are quite rare. It works surprisingly well most of the time (and is effectively fed by the same backend triggers that would have updated / triggered PDC I think)
Most DVB capture software for PCs doesn't use EIT p/f by default, and instead offers pre- and post-record padding as many broadcasters across Europe don't use EIT p/f dynamically as the UK broadcasters do. (Suspect padding on Sky+ boxes also masks the accuracy of EIT p/f)
TV Headend does support it - and supports it well.
TV Headend does support it - and supports it well.
I turned on the 'use EPG running state' a few days ago and it works great, hits it right on the start of the ident. Presumably there's no way to tell it to record a few seconds earlier as it doesn't know when the next programme will switch to being the 'now' event?
