[x-cimo]

I've got image glitch such as square, line, pixelisation more or less frequantly. Sometimes its fine some other time I see them every second.

It's not my antenna, I can play the tuner feed directly in vlc without issue, the recording done by xmbc are also fine when played directly on my laptop, however when played in xbmc I see theses problemes (they are not issue in the file).

What could it be? Is the tv streaming going over UDP or TCP?


I don't think it's the video card since 1080p blu ray rip play in xbmc without issue...

[Dam0]

if you are attempting this over wifi, maybe try a pc that is wired vie ethernet?

a long time ago, i experienced similar problems, and i replaced my wifi router with a faster one.

hope this helps,
Dam0

[margro]

@x-cimo: which settings are you using for the addon? TSReader or ffmpeg? Did you enable the "fast channel switching" setting? If yes, please disable it...
Are your running the frontend and backend on different machines?
Which build are you using?

[x-cimo]

Hey Margo,

I am on 1Gbps.

However my setup is unconventional for home user. Network share are provided by a Solaris ZFS NAS running SMB. ( I get > 1Gbps throughput )
The backend is a Windows 2012 Server running on VMware ESXi5.1
Tuners are Silicondust ATSC (dual).

The front end is running on Windows8Pro with TSReader and fast channel switching is enable.

Since I reported this problem, I also tried For the record, and it's showing similar but less frequent/harder to see glitches.

Again it's just playback by "live tv" that's affected. Either true livetv or watching recorded tv. However the recorded tv file them self do not contain artifact.

What protocol is use for tv playback? Is it TCP or UDP? Is it the same for any PVR backend? If it's UDP I will need to look for packet drop between the backend and the frontend. I already looked for drop from the network tuner to the backend and that part is fine.

As FTR is also affected, I don't think it's that much related to the media portal addon, however it might be a bit of a lack of robustness on the XBMC frontend.

I will look more into this tonight.

[margro]

Thanks for the information.

The "Fast channel switching" option is known to cause glitches for some people, so you should disable that one.

Streaming is done from the timeshift buffer files via a Windows share, so the protocol is SMB (mainly TCP port 455 nowadays if I remember correctly).
The glitches might indicate a temporary buffer underrun (playback too close to the end of the timeshift buffer file).
You could try to increase the channel switch delay option for both pvr addons to see if that helps.

Both FTR and the MediaPortal pvr addon use almost the same code for reading from the timeshift buffer file, so that could explain why you see the same effect for both backends.

[x-cimo]

Thanks for your help Margo.

I did more testing and it looks like the issue is outside the PVR addon...

Basically I tried what you suggested by increasing the channel switch delay etc. Still the same.

I then tried playing the file with Win8 video player & Windows media player directly from the SMB share. (Outside of XBMC), and similar glitches are present!
I then copied the file locally on the system (it copied at a steady 104Mb/s ( ~800Mbps..) ). The result was improved but similar.

I then tried VLC from both network share, and local disk and NO ISSUE whatsoever.

The nvidia driver for my Geforce GT 640 (brand new) are up to date.

So before I start blaming Windows8, I tried the same test on my Win8 desktop, and with the windows player/win8 player, the video just don't play (unsupported video format). VLC play it just fine again.

Questions: Does XBMC install some codec or something (it might be the cause of my glitch!) Because something on my htpc let play the .ts file in media player. If that's the case I could try to look that path.

I would try to install that codec on my win8 desktop to see if I get similar result. If I don't it's likely gonna be something about my htpc.

Thanks.


EDIT: I opened a thread in the windows support section @ http://forum.xbmc.org/showthread.php?tid=144089

[margro]

XBMC uses internal codecs. It uses the ffmpeg library for playback.

[x-cimo]

FYI: Disabling DVXA2 hardware acceleration fixed my problem..

I am not sure why it cause issue on my system ( Intel Q6600, Nvidia GT 640, windows 8 ).