Pictures breaking up, "Discon..." increasing

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Pictures breaking up, "Discon..." increasing

Postby RobBrownNZ » Mon Jan 25, 2016 11:47 am

Hello,

Could someone please tell me what the number in the "Discon..." column of the monitoring page of the TVSource web interface means?

I am having bad picture breakups which make live TV quite unwatchable. The picture will be fine for a while, and then it will start breaking up and then turn into a full-screen psychedelic mess of artifacts. Sound stutters during this time as well. While this is happening, on the monitoring page the "Discon..." number will increase to 45 or so, but "Errors" is always 0.

A little background... I'm in New Zealand, watching 720p and 1080i broadcasts through DVB-T. I was happy with my TV setup except that my server (Ubuntu 64 running on an ASRock Q1900B-ITX motherboard) crashed every few days and I suspected a hardware problem. I shifted to a different PC (a Core generation dual-core Pentium) and this is around the time that the problems started. It was also around this time that I updated DVBLink TVSource to version 5.5.0.12217.

The problem exists with various combinations of the following:
1) Server hardware - as above, I've tried the Celeron J1900 and the Pentium motherboards, these have different RAM etc and I've even installed a few different versions of Ubuntu on different hard disks.
2) TV receivers - Hauppauge HVR-1700 single tuner and HVR-2210 dual tuner, and SiliconDust HDHomeRun dual tuner.
3) Clients - Kodi 15.2 and 16.0rc1 on Linux (Raspberry Pi), Android (Nexus Player and Samsung phone), and Windows; VLC on Windows.

I'm pretty sure that the only remaining possibilities are my antenna setup, and the TVSource software. I think it's unlikely that it's the software, otherwise there would be hordes of DVBLogic customers complaining about it! So I'll be looking into my antenna soon.

I've set the Log Level in the DVBLink Settings to "Extended Info" but there's nothing in the logs at all about discon... (nections?)

If you're still reading, thanks for your time! Hopefully finding out what that "Discon..." number means will give me a clue as to where my problem lies.

Actually another question: is there any way to downgrade the TVSource software, just so I can rule that out as the cause of my issue?

Cheers,
Rob.
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Re: Pictures breaking up, "Discon..." increasing

Postby the_man » Mon Jan 25, 2016 3:01 pm

The "Discon ..." is Discontinuity count.

The @toga user has described a quite clearly "what it is":
toga wrote:To answer this question: The receiver of a DVB transport stream has two means to verify the integrity of the data:

a) Every packet in the TS has an error bit, that is set by the receiver’s hardware when an uncorrectable bit error was found in the packet. This indicates that the signal quality is poor or any other – most likely physical – problem exists so that the data bits are wrong.

b) Every packet in the TS has also a small 4-bit counter field that is incremented for each packet by the sender. With the help of this field, the receiver can detect when packets are missing in the packet stream it receives, simply by comparing the counter field in the next packet with the expected value which is calculated by the last packet’s counter+1. When they differ, packets got lost, and that’s called a “discontinuity error”. (That counter is actually one individual counter per each stream packet id PID, so discontinuity errors can be detected for each PID stream individually.)

DVBLink software shows errors of type a) in the “Errors” column, and type b) in the “Discon…” column.

So the meaning of “Discon…” is not “disconnect”, but “discontinuity error”.

For the possible reasons: Discontinuity errors indicate that packets somehow are dropped at or before DVBlink can process the TS stream. It can mean that the hardware (CPU, bus, etc.) is not fast enough to transfer the data from the receiver’s hardware (PC card, USB stick, etc.) to the system.

In your case, IIUC, you’re using a HDHomeRun hardware, and from its website, it seems that it is an external box that sends the TS data via the local network. Maybe you should check the network connection, temporarily disconnect all other devices from the network, and/or try a direct cable connection from the HDHomeRun box to the DVBLink PC. Also you might want to check the network driver, or any network related software (like filters, personal firewall, or anti-virus software with network inspection).

I hope that helps.


So, the firstly should be checked the hardware: Antenna, cables, connectors ...
NETGEAR RNDU2000; Synology DS112j, DS 212j, DS213+, DS 712+; Western Digital WD ex2; Asustor AS3, RPI2 ...
PCTV 460,461e,292e; TT 4400, 4650CI;DVBSKy S960; DD octopus net; Inverto sat2ip multibox; TBS DVB-C ...
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Re: Pictures breaking up, "Discon..." increasing

Postby gillidk » Tue Jan 26, 2016 6:37 pm

I have totally the same errors on my setup..... Works fine for 1-2 minutes before psychedelic picture.... This happend couple of days ago, and the only thing I know happend is that I got a new build (dvblink) on my Synology DS1512+. I have a Vu+ solo2 sat-tuner with blackhole.
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Re: Pictures breaking up, "Discon..." increasing

Postby Oberon » Tue Jan 26, 2016 6:46 pm

gillidk wrote:I have totally the same errors on my setup..... Works fine for 1-2 minutes before psychedelic picture.... This happend couple of days ago, and the only thing I know happend is that I got a new build (dvblink) on my Synology DS1512+. I have a Vu+ solo2 sat-tuner with blackhole.

DVBLink for Dreambox uses http for data delivery. So stream errors are apparently produced by dreambox itself. Please check if you can watch TV on your dreambox locally and, also, using the dreambox web panel.
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Re: Pictures breaking up, "Discon..." increasing

Postby RobBrownNZ » Tue Jan 26, 2016 10:13 pm

the_man, thanks for the excellent reply. I'm a little wiser than I was before.

Oberon (or anyone), can you please tell me if I can downgrade TVsource?

I'm currently installing Windows on one of the PCs, so I can see if the problem is Linux-related.
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Re: Pictures breaking up, "Discon..." increasing

Postby Oberon » Tue Jan 26, 2016 10:17 pm

RobBrownNZ wrote:Oberon (or anyone), can you please tell me if I can downgrade TVsource?

Possible, but I do not think that your issue is software-version related. I would say it is hardware-related.
You can try disabling speedstep in BIOS to see if it helps.
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Re: Pictures breaking up, "Discon..." increasing

Postby RobBrownNZ » Thu Feb 04, 2016 9:43 am

A quick update: I installed Windows on my Bay Trail board and it ran for a couple of days without any breakups. I took this to mean that the problem was software, not hardware.

Since then I've upped the RAM on the board to 4GB (Windows in 2GB just isn't nice), installed XUbuntu 15.10 32-bit on the board, and updated the firmware images I'm using by extracting them from the Windows driver. Unfortunately updating the firmware required recompiling the kernel because it checks the image sizes and the newer images are (of course) different.

The result is that my box has now been running for 3 days with no picture breakups. I couldn't begin to say what fixed the problem, but frankly I'm worn out so I won't be investigating any further.

The only thing left to do is re-activate TVSource. Is my Linux 64-bit purchase good for activating the Linux 32-bit installation?
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Re: Pictures breaking up, "Discon..." increasing

Postby Oberon » Thu Feb 04, 2016 9:46 am

RobBrownNZ wrote:The only thing left to do is re-activate TVSource. Is my Linux 64-bit purchase good for activating the Linux 32-bit installation?

Yes. Please write an e-mail to info at dvblogic.com and they will swap your activation.
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Re: Pictures breaking up, "Discon..." increasing

Postby RobBrownNZ » Fri Feb 05, 2016 12:06 am

Excellent. Thanks for your help, Oberon.
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Re: Pictures breaking up, "Discon..." increasing

Postby markusrr » Sun Sep 04, 2016 8:31 pm

Hi,

I hav the same Problem - Core i3; 4 PCI DVB-C Cards; Gigabyte Mainboard; Details:

Intel(R) Core(TM) i3-4130T CPU @ 2.90GHz
MemTotal: 7874640 kB
04:04.0 Multimedia controller: Twinhan Technology Co. Ltd Mantis DTV PCI Bridge Controller [Ver 1.0] (rev 01)
04:05.0 Multimedia controller: Twinhan Technology Co. Ltd Mantis DTV PCI Bridge Controller [Ver 1.0] (rev 01)
04:06.0 Multimedia controller: Twinhan Technology Co. Ltd Mantis DTV PCI Bridge Controller [Ver 1.0] (rev 01)
04:07.0 Multimedia controller: Twinhan Technology Co. Ltd Mantis DTV PCI Bridge Controller [Ver 1.0] (rev 01)

Ubuntu 16.04.1 LTS (Xenial Xerus)
Linux version 4.4.0-34-generic
64 Bit

DVBLink Server 5.5.0 12350
DVBLink TV Adviser (DE, AT, CH) 5.5.0 12217
DVBLink TVSource 5.5.0 12217

While investigating I used Intel Performance Counter Monitor Tool --> They require to add kernel module msr and deactivate NMI Interrupts, which you get using the following commands:

Code: Select all
echo 0 > /proc/sys/kernel/nmi_watchdog
modprobe msr


Above is not permanently of course, for those of you who want to try:
Code: Select all
sudo echo msr >> /etc/modules
sudo echo 'kernel.nmi_watchdog=0' >>/etc/sysctl.conf


After that I did not have any more Problem for a day. Could one of those be the root cause in my case?

Cheers,

Markus
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