HD TV Playback Sucks a little in XBMC?
#1
OK just finishing up a little after building my media Media Centre PC. Purely for reference (and so noone thinks my stuff is too slow to work properly, I am using a Zotan ZBox EN760 Plus as the base for my system. It's a tiny little box, but capable of playing most modern games on high and extreme settings. (It was basically intended to be Steam's Steambox, before Steam decided they couldn't get their controller ready on time). The Specs .can be found here: http://www.zotac.com/products/mini-pcs/z...tions.html

I am using two ASTROMETA DVB -T2 USB tuners, which despite their deceptively inexpensive price, give excellent performance in almost all other applications I have tried.

However I have noticed that Live TV performance in XBMC isn't so hot. Notably the image quality seems much poorer than in Media Portal. There is also (for want of a better word) quite frequent 'smearing' where portions of the playing video will appear to 'blend into each other.' This only seems to happen as far as I can tell on the HD channels and not anywhere else.

Some of you guys might think I'm being picky but it happens on average about once a minute and is sufficient to be annoying and to put me off the idea of watching live TV in XBMC.. After all the whole idea of HD is hugely increased image quality, so this intermittent glitching really serves to spoil this impression. In Media Portal itself there is still some occasional smearing, but it's much less frequent and much less severe than in XBMC. It would be great if there was none at all in either, but at least in MediaPortal it's a little more bearable.

Also the image quality in MediaPortal for LiveTV seems to be significantly better than for XBMC. (I guess someone is bound to pop up and say that as they use the same back-end that there should be no difference, but that really is my experience.)

I would love to wait for the developers to come up with a solution for this. I sincerely hope they do, as TV watching is a big part of my media centre experience. However in the interim I have looked at using Advanced Launcher to launch an instance of MediaPortal inside XBMC to handle Live TV and recording. This may seem like a cobbled together solution - and it is, but what am I supposed to do? XBMC can handle a lot of media types really well. It also has a lot of excellent media streaming resources and plugins. Mediaportal can't beat it in this regard. But MediaPortal TV performance is better, as is the EPG and recording functionality.

There are some frustrations in this approach too obviously. Firstly It means I have a whole unused section within XBMC for 'LiveTV'. Second to get to my Media Portal entry in Advanced Launcher, I have to navagate/click through about 3 or 4 different directory levels before I get to launch my app.

I seem to remember in the old (very old) days of XBMC when it ran on the old first gen XBox from MS, you could edit and change the entries in XBMC main menu (the bit you see at the start with 'pictures', 'videos' 'music', 'programs' etc.) and add your own entry. I wonder if that's still (or ever was?) possible. Ideally I could remove the default 'Live TV entry and add my own LiveTV entry, which would execute an advance launcher command upon selection to launch MediaPortal.

Being able to add one's own entries to the main menu window would have another advantage - and one that has been omitted from XBMC for several years now, in that ideally I would like to add my own section here for 'games'. this is a dedicated media centre PC. It's strictly for home entertainment, it won't be used for anything else, so clearly having a single interface to meet the majority of my needs would be helpful.

Second, unless you are very familiar with MediaPortal you might not know this, but how do I get MediaPortal to start up with the last watched TV channel in either fullscreen or minimised mode? (I haven't figured out which I prefer yet). Advanced Launcher allows one to add arguments to any executable, so if it's just a case of adding arguments what I wonder are these?

Third., failing being able to add my own entries to the XBMC main menu window, I would at least like to be able to add my Advanced Launcher program entries to the main 'programs' section. I'm sure my old XBox based XBMC did a better job of separating music, programs, games, movies etc than the more modern version does.

All input would be appreciated.

PS

Sorry for the long post, but after 72 hours non-stop configuration I just want to get this thing finished.
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#2
You post no debug log (wiki)
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#3
You do know many of the available skins offer direct customisation in the way that you are looking for, whilst also supporting a dedicated games menu ?

Also, turning off live tv in the system menu will remove the entry on the main menu.
Learning Linux the hard way !!
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#4
Right, I have solved most of this. I haven't solved XBMC's poor DVB performance and it turns out there is no way to launch Mediaportal from start in full screen TV mode. So that may never be fixed, or at least the DVB issues may only get fixed when the developers get around to prioritising DVB functionality - if they ever do.


There is still a big problem though, which makes my XBMC seem like something of a hack-job, which is that although I can create menu entries in Advanced Launcher for all of my PC based games and apps, I can't (as far as I can see) create individual entries on the XBMC home screen to move my apps to. For example say I wanted to (as a test case) to create an advanced launcher entry for VLC and I wanted to include a link to this advanced launcher entry in my default 'Programs' folder on the XBMC home screen, how exactly would I do this?

Also If I want to create a custom entry on the home screen and add my own advanced launcher apps to this how would I do it?
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#5
That is very skin dependent.

And XBMC plays TV from DVB sources perfectly here. I guess you have operator/setup error.
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#6
What operator set up error? You are aware we are using completely different systems aren't you? I have done *nothing, I repeat *nothing* out of the ordinary.

It really cheeses me off when people ask for help and just get told it's something you did, or its your fault. It almost seems like some kind of illogical denial.

Why not just look at the problem and look for ways it might be resolved?


Edit

Well thanks for trashing this thread anyway. I don't think just saying 'its your fault' is particularly helpful. I will probably have to try to open another thread.

I get that some of you guys are fanatically loyal to this project and don't like anyone mentioning any faults, I'm a big far too. But if there's a problem then there's a problem and rather than sweat about how the problem arose, isn't ot just more sensible to try to track it down, try to resolve it - and maybe learn something useful in the process?
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#7
As you have mentioned Windows Media Centre at some point (pretty sure you mentioned stuff looking better using MS drivers?) you might like to check out this thread -> http://forum.xbmc.org/showthread.php?tid=193310

Not sure if it will help you at all, but thought I would mention it in case you had missed/not realised this existed.

I don't use Windows anymore (for various reasons) but the support guys for the backend and frontend are very active from what I have seen, so if you were to try it out, I'm pretty sure they could help if you still appear to have issues.

A final thought I have is that as you said both XBMC and MediaPortal suffer from 'smearing' on HD channels, perhaps this is down to the tuners and/or USB performance. Again, I can't really comment on that as my tuners are PCI cards, but it might be something to consider.
Learning Linux the hard way !!
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#8
I don't think nickr intended to 'trash the thread' - he was trying to say that your experience isn't typical. I have DVB-T2 USB tuners connected to my tvheadend back end, and I've noticed no smearing or artefacts on SD or HD TV on any of my XBMC installations. So, it may well be that it's something unique to your setup:

1. Your broadcaster - the codec, bit rate, something else that's perhaps showing up an issue in XBMC (or perhaps being masked in other applications)
2. Your tuner cards and/or drivers
3. Your video card and/or drivers
4. Your video settings, e.g. deinterlacing if these are 1080i broadcasts
5. The version of XBMC (and thus the version of ffmpeg) you're using

... etc. The point is that many of us watch HDTV through XBMC without issue, so you can't just dismiss it as 'HDTV ... sucks ... in XBMC', as that's patently not true. It's not a case of people leaping to the defence of the indefensible - folks just need more insight into the nature of the problem, the pattern, the channels, the parameters, and so on. I don't know if a debug log would help, or whether it's more a pattern that the on-screen decoding information would reveal, or whether swapping out bits of kit is the way to isolate it.
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#9
Thanks, there something of a more considered answer in last post. But this does seem like kicking the matter into the long grass a little. It would make more sense to me if these artefacts were present in any other application. They aren't. There are a few Windows DVB PVR clients I have tried XBMC, NextPVR, MediaPortal and the supplied software from the manufacturer of my TV cards - and it's only playback in XBMC that is a bit off.

I think instead of shouting the breeze, maybe some helpful suggestions would be useful? I would love to use WMC as a back end, but due to licensing issues (my school game me an enterprise version of Windows 8.1) I can't have this.

But I am curious in any case, how much of a difference does the back end make? I think from speaking to you guys, it can probably make a significant difference, so maybe changing my back end would be helpful?

I have heard a lot of good reports about Argus TV. It seems a bit of a pain in the butt to configure, but if it solves a problem, then what the hey.

(2014-09-29, 16:09)black_eagle Wrote: As you have mentioned Windows Media Centre at some point (pretty sure you mentioned stuff looking better using MS drivers?) you might like to check out this thread -> http://forum.xbmc.org/showthread.php?tid=193310

Not sure if it will help you at all, but thought I would mention it in case you had missed/not realised this existed.

I don't use Windows anymore (for various reasons) but the support guys for the backend and frontend are very active from what I have seen, so if you were to try it out, I'm pretty sure they could help if you still appear to have issues.

A final thought I have is that as you said both XBMC and MediaPortal suffer from 'smearing' on HD channels, perhaps this is down to the tuners and/or USB performance. Again, I can't really comment on that as my tuners are PCI cards, but it might be something to consider.

I would love to be able to use WMC as a backend, or to use the MS DVB decoders specifically to decode DVB content. However, as I said for various reasons above, I can't use WMC. I can however use WMC DVB decoders in MediaPortal, as these are still present in Windows 8.1 Enterprise. But you can't install WMC on Enterprise versions of windows. I might ask them anyway if there is a way for XBMC to use the native Microsoft DVB decoders. No harm in asking I guess.
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#10
Just thinking out loud here... there are multiple pieces at play:

XBMC, which does the decoding and rendering (inc. ffmpeg for the real work)
The PVR addon, which gets the stream from the backend.
The backend itself, which does all the heavy lifting in terms of actually getting the stream from the tuners.
The operating system, which sits between the backend software and the drivers (e.g. the HAL).
The tuner drivers, which sit above the hardware.
The hardware.
The aerial connection.
... and so on, including video drivers, the card, etc.

Apologies if that's at all patronising anyone's level of knowledge, but that's what we need to consider to find the issue.

Trying a different application on the same PC eliminates most of the lower-level issues, and pushes the issue up towards the addon and/or XBMC. If VLC or similar will lock to the backend and display the programme correctly then everything up to the backend software would seem to be good (some random incompatibility notwithstanding).

Trying a different backend eliminates another piece of the jigsaw - it changes the nature of what gets sent to XBMC and changes the addon in XBMC that would receive it.

Trying a Helix nightly is another variable, in that it's got a much more recent internal ffmpeg which may or may not be relevant. Likewise an older version of XBMC to see if that helps.

From my scan of your other post, you're on Freeview, which is 1080i, yes? So it's possibly an interlacing issue, and it's possibly a bug in XBMC's deinterlacing routines (whichever you're using).

You could also try recording the stream and playing it back locally, or mapping a drive and playing back in file mode - either way bypasses the addon completely, so that's another element out of the way. You could also try re-encoding such a recording to strip out interlacing (e.g. Handbrake's decomb settings) to see what that does, as that eliminates deinterlacing as no longer required.

You could vary the OS - XBMCbuntu live? - although that's obviously a non-starter if your preferred backend is on the same system. You could try the Android or iOS client to see if that changes anything - with or without the same addons vs file mode access to the recordings.

</randommusings>
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#11
That's a mega helpful and thoughtful thread dude. I will mull over everything that has been said and report back. Smile
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#12
There is a difference between dvb (or should I say interlaced content) playback in windows and Linux from the same backend. I have tried a few settings in XBMC windows to no avail, but I am yet to try digging around in the nvidia drivers settings. But for me its no big deal - I only watch content in windows when downloading games. Have you tried the XBMC builds in the dxva testing thread?

I don't think the back end will make much of a difference to quality of playback, all they are doing is dumping the ota stream to a HDD. I'd say tuners (poor reception = artifacts) and playback method would have more of a impact.
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#13
I'm not so sure about using Argus TV as my back end now. It requires SQL server, and as I also run Windows games on this system and have Advanced launcher set up for these, I'm trying to keep my background processes to a bare minimum. Back to the drawing board perhaps.
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#14
(2014-09-29, 22:00)teeedubb Wrote: There is a night and day difference between dvb (or should I say interlaced content) playback in windows and Linux from the same backend. I have tried a few settings in XBMC windows to no avail, but I am yet to try digging around in the nvidia drivers settings. But for me its no big deal - I only watch content in windows when downloading games. Have you tried the XBMC builds in the dxva testing thread?

I don't think the back end will make much of a difference to quality of playback, all they are doing is dumping the ota stream to a HDD. I'd say tuners and playback method would have more of a impact.

You see I'm not alone. 2 out of 2 users so far think XBMC DVB decoding in Windows 'sucks a little' lol. I'm tempted to leave it alone. I can launch MediaPortal via Advanced Launcher in XBMC and get rock solid 100% stable performance, both on SD and HD channels. If I switched to Argus TV as my back end, this needs a fairly substantial install of MYSQL server - and some other components too.. I want to keep my system as lean as possible with as few background processes as possible so that game playing and TV watching both remain a viable proposition.

The only problem is that it all looks like a bit of a rough old hack job at the end of the day and is extremely unlikely in it's current format to pass the wife test.
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#15
So why not try and improove XBMC by providing a sample stream for people to try and figure out what is wrong?
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