[mythtvnz] DVB-T recording artefacts after upgrade to Mythbuntu 11.10 with HVR2200

[David Shepherd]

> On Tue, 2011-11-29 at 14:12 +1300, Stephen Worthington wrote:
>
>
>> The MythTV box I needed to add an aerial amplifier to uses a Nova
>> TD-500 card, which is a later version of the Nova T-500.  The tuners
>> on Nova T/TD-500 cards are not the most sensitive, but their usual
>> problem with reception is caused by the lna (low noise amplifier)
>> option not being on.  In recent drivers, it seems to be on by default,
>> or automatically controlled, but it used to be common to have to add
>> this to /etc/modprobe.d/options-dvb.conf to force it on:
>>
>> options dvb_usb_dib0700 force_lna_activation=1
>>
>
>> The fact that you are having reception problems on the Kordia
>> multiplex only is likely because it is usually the highest frequency
>> and is therefore the hardest to receive.  When I use rabbit's ears on
>> my laptop tuner, in Palmerston North, I can almost always receive the
>> TVNZ multiplex (lowest frequency), but almost never the Kordia one.
>>
>> The force_pid_filter_usage=1 option is new to me, but a little web
>> research shows that it will just help in reducing the traffic out of
>> the USB tuners to the PC, which helps reduce CPU usage.  It should not
>> affect reception problems, unless your CPU is getting overloaded and
>> can not cope with the USB traffic and is dropping packets.  Dropped
>> packets would cause severe reception problems.  So check your CPU
>> usage during recording - it should be very low if everything is
>> working correctly.
>>
> I thought the HVR2200 would have been a real PCI card.
>
> I have used the force lna option from the start..
>
> The Mt Egmont problem was with a nova-500-td.
> But with no internet access, little attempt to fix was feasible.
>
> This reveals the kernel module option status:
> cat /sys/module/dvb_usb_dib0700/parameters/force_lna_activation
> cat /sys/module/dib3000mc/parameters/buggy_sfn_workaround
> etc
>
> USB pid filter option does not solve the problem.
>
> Because reception problem seemed to affect Kordia only (poss frq
> selective), I have replaced antenna & cabling (RG6).
>
> The new UHF antenna gives more signal but made no other difference..the
> problem looked like corrupted data packets.
> This problem only started in last few months.
>
> Thankfully the "buggy single frequency network" option works..
>
>
>
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>
Well, I confirmed that my randomly recurring artefacts in DVB-T recordings
are in the stored recording.  I can reproduce exactly the same pixelation
every time at the same point in the recording and skipping back and
forward doesn't make any difference.

I also tried upgrading the driver via the instructions on the linuxtv
wiki.  The media stack compiled and installed correctly, the card was
detected fine, the firmware loaded but I couldn't get it to boot.  I
double checked the firmware files and downloaded again etc but no luck. 
So I backed it all out again and will post to the v4l forums.  Here's the
dmesg output in case anyone has any suggestions.

[    5.056004] saa7164_downloadfirmware() no first image
[    5.056063] saa7164_downloadfirmware() Waiting for firmware upload
(NXP7164-2010-03-10.1.fw)
[    5.056066] saa7164 0000:04:00.0: firmware: requesting
NXP7164-2010-03-10.1.fw
[    5.056699] saa7115 4-0021: saa7115 found (1f7115d0e100000) @ 0x42
(ivtv i2c driver #0)
[    5.232781] saa7164_downloadfirmware() firmware read 4019072 bytes.
[    5.232783] saa7164_downloadfirmware() firmware loaded.
[    5.232785] Firmware file header part 1:
[    5.232787]  .FirmwareSize = 0x0
[    5.232788]  .BSLSize = 0x0
[    5.232789]  .Reserved = 0x3d538
[    5.232790]  .Version = 0x3
[    5.232791] saa7164_downloadfirmware() SecBootLoader.FileSize = 4019072
[    5.232797] saa7164_downloadfirmware() FirmwareSize = 0x1fd6
[    5.232798] saa7164_downloadfirmware() BSLSize = 0x0
[    5.232799] saa7164_downloadfirmware() Reserved = 0x0
[    5.232801] saa7164_downloadfirmware() Version = 0x1661c00
[   10.496512] saa7164_downloadimage() image corrupt