MythTV assumes demux1 when frontend1 is in use, but no demux1 device is available only demux0

[Matt <maff667@…>]

When using a TBS-5520SE the following devices are available: demux0, dvr0, frontend0, frontend1, net0

mythtv-setup and mythtv backend seem to make the assumption that if frontend1 is chosen then demux1 should be used even if no such device exists.

I think i have narrowed it down to line 606 of streamhandler.cpp

QString demux_fn = CardUtil::GetDeviceName?(DVB_DEV_DEMUX, dvb_dev);

and/or lines 2077-2096 of cardutil.cpp i.e. the GetDeviceName? function.

hope that's helpful.

The same issue appears to effect the astrometadvbt2 usb device. And a workaround would be to rename frontend1 to frontend0.

Cheers

Maff

Reference urls with more details: ​https://forum.mythtv.org/viewtopic.php?f=36&t=2156&p=10617#p10617 ​https://forum.mythtv.org/viewtopic.php?t=1582

[Mike Bibbings]

This behaviour stems from a very old trac ticket (2009) ​​https://code.mythtv.org/trac/ticket/5061 which mentions HVR3000 and HVR4000 cards. Prior to this change demux0 was always used.

Today there are many devices which have two frontends per adapter but only 1 demux/dvr, demux0, dvr0. Only one of the frontends can be used at anyone time with this demux/dvr.

For example TBS 6522 has two frontends for each adapter, frontend 0 is DVB-T/T2 demux0, frontend 1 is DVB-S/S2, demux0.

Whilst it is possible to "hack" by sym linking demux0 to demux1, this is not very user friendly.

A change in cardutil.cpp CardUtil::GetDeviceName? is required. To maintain existing behaviour, test to see if demux<n> exists where <n> is the frontend number, if the test fails return demux0. Similarly for dvr<n>.

Attached is a patch, tested against current master (but can be backported to mythtv 29 and 30 if needed).

Test system Xubuntu 18.04 with TBS 6522 PCI-e Dual DVB-S/S2,DVB-T/2 and Astrometa USB DVB/T/T2 tuners.

Patch also applied to my production system, which has Hauppauge QuadHD DVB-T/T2 and TBS-6981 Dual DVB-S/S2 tuner, with no ill effects.

Mike

[Mike Bibbings <mike.bibbings@…>]

In 2437415c7/mythtv:

Error: Processor CommitTicketReference failed

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[Klaas de Waal <kdewaal@…>]

In 82a59c1298/mythtv:

Error: Processor CommitTicketReference failed

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