Opened 9 years ago

Closed 8 years ago

#8758 closed patch (Upstream Bug)

Correction to the Danish DVB-T frequency table

Reported by: Kenni Lund [kenni at mythtv dot dk] <kenni@…> Owned by: robertm
Priority: critical Milestone: 0.25
Component: MythTV - DVB Version: Master Head
Severity: medium Keywords: DVB-T frequency table Denmark
Cc: Ticket locked: no

Description

The settings of the current DVB-T frequency table for Denmark is too specific to find all available channels. The attached patch should solve this.

The following changes are made with the patch:

HP code rate "2/3" -> "Auto" (FTA broadcaster "DigiTV" uses 2/3, but the commercial broadcaster, BoxerTV, uses 3/4)
LP code rate "None" -> "Auto" (Copenhagen local broadcaster uses 1/2)
QAM "64" -> "Auto" (DigiTV and BoxerTV uses QAM64, but CPH local broadcaster uses QAM16)
Guard Interval "1/4" -> "Auto" (DigiTV and BoxerTV uses 1/4, but CPH local broadcaster uses 1/16)

The attached file, channel.conf, shows a full scanning made with w_scan, which found 51 channels in total, from all of the three mentioned providers. After applying the attached patch to MythTV, MythTV found all 51 channels as well.

Attachments (2)

Danish_DVB-T_frequencytable.patch (1.0 KB) - added by Kenni Lund [kenni a kelu dot dk] <kenni@…> 9 years ago.
channel.conf (7.2 KB) - added by Kenni Lund [kenni a kelu dot dk] <kenni@…> 9 years ago.

Download all attachments as: .zip

Change History (16)

Changed 9 years ago by Kenni Lund [kenni a kelu dot dk] <kenni@…>

Changed 9 years ago by Kenni Lund [kenni a kelu dot dk] <kenni@…>

Attachment: channel.conf added

comment:1 Changed 9 years ago by robertm

Milestone: unknown0.24

This should be okay for .24 assuming the channel scanner gurus find it acceptable, would be nice not to leave the Danish out in the cold. (har har)

comment:2 in reply to:  description Changed 9 years ago by wirbel

Replying to Kenni Lund [kenni at mythtv dot dk <kenni@…>]:

The settings of the current DVB-T frequency table for Denmark is too specific to find all available channels. The attached patch should solve this.

The following changes are made with the patch:

HP code rate "2/3" -> "Auto" (FTA broadcaster "DigiTV" uses 2/3, but the commercial broadcaster, BoxerTV, uses 3/4)
LP code rate "None" -> "Auto" (Copenhagen local broadcaster uses 1/2)
QAM "64" -> "Auto" (DigiTV and BoxerTV uses QAM64, but CPH local broadcaster uses QAM16)
Guard Interval "1/4" -> "Auto" (DigiTV and BoxerTV uses 1/4, but CPH local broadcaster uses 1/16)

The attached file, channel.conf, shows a full scanning made with w_scan, which found 51 channels in total, from all of the three mentioned providers. After applying the attached patch to MythTV, MythTV found all 51 channels as well.

Actually it's a bad idea, since your change will break tuning for cards not supporting 'AUTO' for those fields. The change to LP code rate doesnt change anything at all, since there is actually no location known to use a DVB-T low priority stream (LP is not used, it doesnt matter what you put there).

Applying this patch will force opening new bug reports from users whose dvb cards will not tune anymore.

comment:3 Changed 9 years ago by anonymous

Opinion here is that any driver not supporting 'auto' is broken. Therefore I'd urge you to report the bug upstream so that it can be fixed. We cannot be expected to include workarounds for bugs external to MythTV, especially when it's to the detriment of users with working drivers.

comment:4 Changed 9 years ago by Kenni Lund [kenni a kelu dot dk] <kenni@…>

Let's take the discussion on the dev list, that's what it's meant for. I've posted a reply there.

comment:5 Changed 9 years ago by anonymous

Opinion here is that any driver not supporting 'auto' is broken

Wrong. Wether or not a driver may support 'AUTO' depends only on the hardware used. So a driver developer has only the chance to use the capabilities the hardware supports. If a hardware doesnt support it, the driver will not report AUTO in its capability flags.

In other words, any software using dvb hardware should check the capability flags and only if there flags like 'FEC_AUTO', 'GUARD_AUTO' are announced AUTO for those should be used.

comment:6 Changed 9 years ago by stuartm

So 'AUTO' is basically useless. Great.

comment:7 Changed 9 years ago by robertm

Status: newassigned

Hot potato!

comment:8 Changed 9 years ago by robertm

Resolution: Won't Fix
Status: assignedclosed

Seems like the answer to this is "no" pending further discussion between kenni and janne

comment:9 Changed 9 years ago by stuartm

Priority: minorcritical
Resolution: Won't Fix
Status: closednew

comment:10 Changed 9 years ago by stuartm

Owner: changed from Janne Grunau to stuartm
Status: newaccepted

comment:11 Changed 9 years ago by Kenni Lund [kenni a kelu dot dk]

A summary of my observations and the overall problem:
My current DVB-T tuner is capable of autodetecting all parameters, and apparently it only uses the frequencies from MythTV, the rest of the parameters in the frequency table in MythTV are ignored. So an auto-capable tuner WILL find all the mentioned Danish channels with the current frequency table, but if a tuner which doesn't support "Auto", relies on the frequency table in MythTV, it will only find the FTA channels in DK, but not the commercial Boxer channels or the local CPH channels.

One way to fix the scanning for non-auto capable tuners with the current implementation, would be to add one frequency table for each broadcaster, each with the same frequency range, but with different parameters. However, this breaks auto-capable tuners, as they will find the same channels multiple times. So with the current channelscanner implementation, the existing Danish frequency table in trunk is the best we can do.

comment:12 Changed 9 years ago by robertm

Milestone: 0.240.25

comment:13 Changed 9 years ago by stuartm

Owner: changed from stuartm to robertm
Status: acceptedassigned

comment:14 Changed 8 years ago by stuartm

Resolution: Upstream Bug
Status: assignedclosed
Summary: [TRIVIAL PATCH] Correction to the Danish DVB-T frequency tableCorrection to the Danish DVB-T frequency table
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