Recording DVB-T2

[Nutty Timbo]

Hello.

 

I have managed successfully to use DVBViewer to record all six UK Mux's at the same time, with six tuners placed in a suitable PC, without any problems. This has been true for more than one machine, operating system, and different tuner manufacturers. There have always been a number of 'bugs', which remain outstanding, but on the whole, all the set-ups have worked successfully.

 

That was until our area in the East Midlands of the UK (Waltham Transmitter) whent through DSO, which introduced a number of problems. The greatest of these was the switching of one Mux to the new DVB-T2 256-QAM based system for the Freeview HD transmissions. This left five Mux's as DVB-T1, and another purely for DVB-T2. The tuners for T2 transmissions are not only rare, but also expensive in comparison with the standard tuners, which has meant only one dual-tuner card (a TBS 6480, I think) has been purchased. This has posed a number of problems for recording.

 

Firstly, if an HD program has been selected, if the TBS card is already taken, the program cannot record. Equally, even if it is known HD programs are in the queue, if an SD program gets there first, the HD tuner will be allocated next if applicable, or DVBViewer will attempt to allocate an SD tner to an HD program, if the tuner is higher in the order than the T2 card.

 

As altering the priorities of the tuner cards does not address the problem, is it possible to specifically specify use of a particular card for a particular recording, thus making sure an HD program will be paired with a T2 card?

 

If anyone else has, or has had a similar problem, I would be so grateful to hear of the solution, as currently all I can do is dedicate HD recordings to one machine having only the one card present/activated. Thank you in advance of any help.

 

Tim.

[Tjod]

Use the Channel groups. Move all DVB-T2 channels in the channel list editor in group B.

And remove group B from all DVB-T (not DVB-T2) cards.

http://en.DVBViewer.tv/wiki/Options_Service_-_Hardware#Channel_groups

 

And move the DVB-T2 card via drag and drop at the last position in the list of tv cards.

[Nutty Timbo]

Hi Tjod.

 

Thank you so much for the advice - I will look up the link re. Channel Groups, and try it out with my card.

Help very much appreciated!

 

Kind regards, Tim.

 

 

 

Edited for grammer/spelling...

Edited February 8, 2012 by Nutty Timbo

[uglyned]

This only works to an extent.

 

I have 1xDVBT-2 and 2xDVB-T tuners. The DVB-T2 tuner is far more sensitive than the other 2 and the other 2 suffer a lot of discontinuities.

 

I'd like to be able to use the DVB-T2 one for all recording, but have it reserved if a DVB-T2 recording is due to start before an imminent recording would finish.

 

Basically, I think we need the same 'Is DVB-T2 device' functionality for T that there is already in place for DVB-S2.

[Nutty Timbo]

Thank you, Uglyned..

 

Yes, I agree that the T2 cards need a similar treatment as for S2 - maybe the programming team will take note of this fact.

 

The TBS DVB-T2 cards can handle both T1 and T2 streams. Thus they can still be used with the T1 Mux's. However, this still requires that one of the Dual Tuners is assigned specifically for the T2 Mux (as there is only one HD Mux on Freeview, one tuner will cover all HD streams). If this isn't done, there is the possability of both the TBS tuners being assigned to one of the other five Mux's, even if an HD programme is imminant, since DVBViewer is unable to desciminate between the two.

 

The 'sensativity' issue you are experiencing can be handled very easily. Set the sensativity of your aerial/amplifier for the normal T1 cards - ie, set the signal to as higher strength as the cards can accept without causing discontinuities. Then for the more sensative T2 card/cards, use an attenuator (Maplin's sell them cheaply), or something such as a signal splitter, which has the same effect of reducing the signal strength, so the signal reaching the more sensative tuners is less thsn for the other cards. Then both can sit happily side-by-side, neither suffering any discontinuities. I have got similar problems even with SD DVB-T cards, since some manufacturer's cards are more sensative than others (eg, Hauppauge and KWorld, as well as Avermedia, all have varying degrees of sensativity, even within one manufacturer's products. I find USB devices far more sensative than internal tuner cards).

 

Thank you for your input/advice...

[Griga]

I'd like to be able to use the DVB-T2 one for all recording, but have it reserved if a DVB-T2 recording is due to start {...} Basically, I think we need the same 'Is DVB-T2 device' functionality for T that there is already in place for DVB-S2.

The 'Is DVB-T2 device' functionality won't do what you want. You can achieve exactly the same functionality by using channel groups. The only difference is that DVBViewer doesn't assign the DVB-T2 channels automatically to the appropriate tuner. You have to configure it manually. What you want would require a different hardware/tuner management.

 

Besides that, a 'Is DVB-T2 device' functionality wouldn't be as useful as 'Is DVB-S2 device'. There are lots of ready-to-use satellite transponder lists available where transponders are already flagged correctly as DVB-S resp. DVB-S2. So if use them for scanning, DVBViewer and TransEdit are able to flag the scan results accordingly. But this does not apply to DVB-T. Without a transponder list that already contains the DVB-T2 information, 'Is DVB-T2 device' is pretty useless.

[uglyned]

But I can manage my own transponder list for my own transmitter and mark the DVB-T2 mux.

 

The problem now is I don't want to hand over my best tuner to only one mux. I need it available to record from other muxes when there is no DVB-T1 recording imminent.

[Tjod]

The Recording Service never checked if there will be a recording for a tuner in the future.

 

You get the seam behaviour as by DVB-S2 if you add all DVB-T channels to group A and all DVB-T2 channels to group B.

Than disable group B for all DVB-T cards.

[uglyned]

Currently DVBViewer will not try to record a DVB-S2 stream with a DVB-S device but it will try (and fail) to record a DVB-T2 channel with a DVB-T device.

 

If it could identify a T2 stream and a T2 device it would know not to do that.

 

Then I could set my 2 T devices to preferred, meaning that the T2 device could still be available for T muxes, as a last resource.

 

Locking a T2 device to T2 only channels is wasteful.

[Griga]

but it will try (and fail) to record a DVB-T2 channel with a DVB-T device.

Not if you set up the channel groups correctly. The way to go is:

 

- Assign all DVB-T channels to channel group A (already done by default).

 

- Assign all DVB-T2 channels to channel group B (see channel editor, right-click -> context menu -> set channel group does it for all channels contained in a root/category at once).

 

- Go to options -> hardware -> channel groups and untick the B checkbox for all DVB-T devices, thus prohibiting DVBViewer to use them for group B (resp. DVB-T2) channels.

 

- Make sure that A *and* B are ticked for all DVB-T2 devices, thus allowing DVBViewer to use them for A and B (resp. DVB-T and DVB-T2) channels.

 

Then I could set my 2 T devices to preferred, meaning that the T2 device could still be available for T muxes, as a last resource.

Won't work, because "preferred" only applies to allocating a new device. Keeping an already used device has a higher priority. E.g. if you switch to a DVB-T2 (resp. group B ) channel, DVBViewer is forced to use a DVB-T2 device, provided the channel groups are set up as described. However, if you switch back to a DVB-T channel, DVBViewer will go on using the DVB-T2 device, even if there is a "preferred" DVB-T device, because device changes are avoided if possible.

 

There were already endless discussions about this matter regarding DVB-S/S2. The "Is DVB-S2 device" checkbox doesn't prevent the described DVBViewer hardware management behaviour. What you would actually need is a "use always when possible" hardware status setting as provided by DVBViewer GE. It has a higher priority than keeping an already allocated device. However, this setting creates other possible problems. That's why it has not been added in DVBViewer Pro yet.

 

If you really dive deep into this matter you will see that it is very hard to find a hardware management that handles heterogeneous tuner combinations satisfyingly under all conditions. However, users mostly don't think so far. Developers have to...

 

There are two other approaches for solving the issue:

 

1) Set up your DVB-T2 devices for channel group B only. This will let DVBViewer use them only for DVB-T2, but never for DVB-T.

 

2) Dump your DVB-T devices, equip your PC with DVB-T2 devices throughout and live happily and problem-free ever after

[Griga]

P.S: By using the channel group feature it is also possible to let TransEdit select an appropriate device and automatically assign scan results to the correct group according to the DVBViewer channel group configuration. All you have to do is to create and use separate transponder lists for DVB-T and DVB-T2, set the first one to group A and the second to group B. See here (-> set group):

 

http://www.DVBViewer.com/griga/TransEdit%20E/MainWindow.html#File

 

...and here (-> groups):

 

http://www.DVBViewer.com/griga/TransEdit%20E/SettingsWindow.html#Hardware