HD TV Playback Sucks a little in XBMC?
#31
Oh well scrub using Argus TV anyway. It can't find any HD channels. I have gone through and tweaked every setting that was advised. No joy for Argus in the UK it seems.

It's down now to messing with 1080i or 1080p settings and deinterlacing etc. I did do this before with no luck, but haven't tried 1080i yet.

Can anyone confirm for sure the exact broadcasting standards for Freeview in the UK?
Reply
#32
Well that is up to each broadcaster, and varies as far as I understand. Perhaps running mediainfo over one of your troublesome files would help?

I do have a couple of windows machines with XBMC installed, merely out of curiosity. If (ahem I say again) you can provide us with a sample stream, I am willing to test and to compare linux/windows (albeit not on an nvidia card, although I may be able to arrange that too.)

So record something, ensure that is demonstrates your problem, then put it on dropbox or mega or somewhere. The files get big quickly, but a 1-2 minute clip should be enough, as long as it demonstrates the problem.
If I have helped you or increased your knowledge, click the 'thumbs up' button to give thanks :) (People with less than 20 posts won't see the "thumbs up" button.)
Reply
#33
Freeview HD in the UK is encoded as MPEG-4 AVC High Profile Level 4 which means it cannot be 1080p50. Audio is AAC or E-AC3.

For raid517 - with 1080p or 1080i, the letter means either progressive or interlaced. With an interlaced picture, it is displayed by lighting all the odd pixel rows, then all the even pixel rows. If the picture was 1080i50 then there would be 50 fields per second, which would make 25 frames per second (a frame being the entire picture, a field being either all the odd or all the even rows).

If the content is 1080p50 then there are again 50 frames per second but each one is shown progressively (after each other). As each frame is the entire picture, this is obviously better for content including fast motion etc.

Look here http://www.100fps.com/video_resolution_vs_fluidity.htm for some examples of what can happen by using the wrong setting or a de-interlacing method thats not very good.
Learning Linux the hard way !!
Reply
#34
(2014-09-30, 09:27)black_eagle Wrote: Freeview HD in the UK is encoded as MPEG-4 AVC High Profile Level 4 which means it cannot be 1080p50. Audio is AAC or E-AC3.

Do you have a reference for that anywhere, by any chance? I'm merely intrigued - everything I can find suggests that Freeview uses 1080p25 or 1080i50, switching based on the GOP size of the MPEG stream. It was introduced in 2011, so it's possible that they've gone wholly to 1080p now, but I can't confirm that.

The DTG D-Book 7 Part A would tell us, but that's only available to members of a secret cabal...

I hate not knowing things Smile
Reply
#35
Certainly Smile http://www.dtg.org.uk/news/news.php?id=3270

Note I said it cannot be 1080p50, not that it is.
Learning Linux the hard way !!
Reply
#36
D'oh - yes, you said 'cannot be 1080p50' and I read it as 'cannot be 1080p25', which is what confused my tiny brain.

Pay attention, 007...
Reply
#37
With I tried 1080i, both with interlacing and without. If anything 1080i playback with interlacing is worse.

Anyway this presents a problem, as even if it did work (which it doesn't). this would require me to constantly manually switch between 1080i and interlacing for TV and 1080p without interlacing for local video playback.

I think the effect is best described as being identical to that that you can see if you try to play an incompleted video download in VLC. Even if it is nearly complete, you will see a very similar 'smearing' effect. this is down as far as i understand it literally to dropped 'bits' - part of the data signal being dropped or being incomplete.

Some folks might wish to attribute this to poor signal strength. Not so.I have extremely strong signal bars (usually full) when scanning for channels. Also the fact that there are no dropped bits in TVPortal when using this exclusively (both back and front end) to watch TV would also seem to put that theory to bed too.

Also for those guys claiming that issues like this are almost unheard of, there's an entire section on the XBMC Wiki that goes on at length about the issues confronting Windows users and DVB playback. It even says what has been said here already which is that although DVB performance in Windows with XBMC can be very variable it is usually rock solid and trouble free in Linux.

It doesn't hint at all at any possible long (or short) term viable resolution to the problems of poor DVB performance in XBMC in Windows, which doesn't seem encouraging.

The next thing I guess is to try to post the logs and maybe see if I can grab a stream that shows the problem. I'm not quite certain how to do either of these. Should I just record some video with the XBMC PVR?

Edit:

Also to be clear, I will mirror the settings of any guy here who says he is in the UK and has a Windows machine XBMC and MediaPortal as the backend and who says he can get this to work flawlessly, or any other set up they can get to work flawlessly.

My PVR set up right now that involves having to launch a full instance of MediaPortal from within XBMC just to watch TV, is a bit of a 'dogs breakfast' of a solution. Very inelegant really. So much so in fact that my wife refuses to touch it and has taken to watching a small portable TV in the kitchen.

I need to sort it out and get a super simple set up going, so my other family members don't disown me, lol.
Reply
#38
(2014-09-30, 12:57)raid517 Wrote: With I tried 1080i, both with interlacing and without. If anything 1080i playback with interlacing is worse.

There should be no need to alter the TV settings. The issue is that your tuners are receiving - and thus XBMC is decoding and displaying - either an interlaced signal or a progressive scan signal. Interlacing really relies on 'persistence of vision', i.e. the fact that your eye doesn't notice one set of lines fading on the screen while the next set is drawn, although it made more sense on a CRT (that faded slowly) than it perhaps does on a digital monitor.

Deinterlacing is the process of using this information to make 'full' frames for display, instead of showing lines 1,3,5,7... 1077,1079 and then 2,4,6,8...1078,1080. There are many ways to deinterlace, many using different mathematical formulae to merge between frames. That's what XBMC does when you switch on deinterlacing and select an algorithm: it tries different ways of merging the interlaced fields into a single frame, and then sends that to your TV as a progressive image. That means your TV never even sees an interlaced signal and thus it never changes mode.

(2014-09-30, 12:57)raid517 Wrote: I'm not quite certain how to do either of these. Should I just record some video with the th XBMC PVR?

Yes, that'd be a start.

1. Record something that shows the artefacts
2. Make a note of the scene and time at which you see the artefacts
3. Play the recording back through the Live TV menu - are the artefacts still there?
4. Play it through the files menu - are the artefacts still there?
5. Upload the file somewhere so someone else can test it, looking for the same behaviour in the same scene
6. Switch on debugging and grab a debug log of a stream (live or recorded) that shows the behaviour
Reply
#39
Well how about some recommended UK Freeview settings maybe? Or should I doa sperate log for all possible settings?
Reply
#40
(2014-09-30, 12:57)raid517 Wrote: My PVR set up right now that involves having to launch a full instance of MediaPortal from within XBMC just to watch TV, is a bit of a 'dogs breakfast' of a solution. Very inelegant really. So much so in fact that my wife refuses to touch it and has taken to watching a small portable TV in the kitchen.
I need to sort it out and get a super simple set up going, so my other family members don't disown me, lol.

Clearly then, as XBMC should be able to play your channels just fine, we need to try and diagnose the root issue.

(2014-09-30, 13:21)Prof Yaffle Wrote: 1. Record something that shows the artefacts
2. Make a note of the scene and time at which you see the artefacts
3. Play the recording back through the Live TV menu - are the artefacts still there?
4. Play it through the files menu - are the artefacts still there?
5. Upload the file somewhere so someone else can test it, looking for the same behaviour in the same scene
6. Switch on debugging and grab a debug log of a stream (live or recorded) that shows the behaviour

This really is the best way to proceed. Without at least a debug log (wiki) of you playing an affected channel, everyone is just making wild guesses as to the cause/solution. Screenshots of your audio and video settings in XBMC would also help (and yes, wrong audio settings can affect video playback). A recording of an affected channel containing the smearing you describe would also be extremely helpful.

People can try to help you, but you need to supply the requested things to help them do that.
Learning Linux the hard way !!
Reply
#41
Yes it's just finding the time. Later today perhaps. Smile
Reply
#42
Either you want help or not. We have been asking for a debug log and sample file for ... ever.

The time you have taken posting could have been taken up with supplying useful info.

Please, post what we ask for. That's why you posted isn't it? For comment from people who can help?
If I have helped you or increased your knowledge, click the 'thumbs up' button to give thanks :) (People with less than 20 posts won't see the "thumbs up" button.)
Reply
#43
Right I solved this. It took £60, nearly 5 days work and an academic licence for Windows 8.1 pro with media centre to do it, but I did it.

The way I figured it, Windows Media Centre had always been pretty good for watching TV. Fair enough that MediaPortal and others take a stab at it, but clearly getting paid for your work seems to put a lot more polish on things.

So my plan was to simplify everything as much as possible. No uneeded codecs, no unnecessary third party apps etc. And bingo it worked! Not without a massive effort on my part though. It's ironic, probably, that something that was supposed to be relaxing and fun has nearly killed me to try to get working properly and has cost me the best part of £3000 to put together too.

I am still not quite finished yet. I still have to teach myself how to use EventGhost and VoxCommando so I don't have to worry too much about using a remote. I think I might leave that for a few days though, lol.
Reply
#44
So are you using media centre just on it's own, or as a backend for XBMC?
If I have helped you or increased your knowledge, click the 'thumbs up' button to give thanks :) (People with less than 20 posts won't see the "thumbs up" button.)
Reply
#45
As a backend. Depressingly however it worked for about 4 hours an then the same problems re-emerged. This was on a raw system I am now down to one possibility - and an expensive at that. The only thing I can think is that maybe my tuner cards aren't up to it and I might have to buy something much more expensive. There is a jump between these less expensive cards and the next ones up which have any kind of decent reviews on Amazon. But even that isn't guaranteed to work.
Reply



Logout Mark Read Team Forum Stats Members Help
HD TV Playback Sucks a little in XBMC?0
This forum uses Lukasz Tkacz MyBB addons.