Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 


1090 posts

Uber Geek
+1 received by user: 182


  Reply # 834530 11-Jun-2013 22:39
Send private message

Yep just tested on Four and can't fault it. But choice is quite easy to reproduce. So yeah I jumped to a conclusion on it being related to SD channels only. I reckon it's been happening for more than a few days. Can't quite put my finger on when it started. I feel like its been happening since 1.3 final. Actually this fault has existed before in MediaPortal 2-3 years ago but was fixed. Doubt it's the same fault though because as you mention it only seems to be happening on the Kordia mux.




1101 posts

Uber Geek
+1 received by user: 67

Trusted

  Reply # 834533 11-Jun-2013 22:57
Send private message

mcraenz: I reckon it's been happening for more than a few days. Can't quite put my finger on when it started. I feel like its been happening since 1.3 final. Actually this fault has existed before in MediaPortal 2-3 years ago but was fixed. Doubt it's the same fault though because as you mention it only seems to be happening on the Kordia mux.

I don't know that I agree with you here regarding the fault existing previously.
I quite regularly watch Parliament TV and this was not happening last week; it is tonight.
If you check the MP log, look at the timing of the following entries:

TVHome.ViewChannelAndCheck(): View channel=
TvHome.RenderBlackImage()
succeeded:Succeeded TvControl.VirtualCard
TvHome.OnVideoReceived()
TvHome.StopRenderBlackImage()

The first entry tells you when the request to change channel is sent to the TV Server.
The second entry tells you when the MP screen is blanked.
The third entry tells you when the TV Server reports that the channel change is complete.
The fourth entry tells you when video data is seen.
The fifth entry tells you when the screen is unblanked.

I'm seeing higher times between entries three and four.
If this is an MP issue then I think it would be related to TsReader, but it could be codec related too.

[edit: entries three and four, not two and three - long day yesterday]

 
 
 
 


778 posts

Ultimate Geek
+1 received by user: 103


  Reply # 834552 12-Jun-2013 06:38
Send private message

Asmodeus:
turb: Me too. Prime and Choice.


Me too!

You have to play around with the skip buttons or just wait to make it work properly again. Doesn't happen every time but definitely often


Are using WMC too?




HTPC: Antec NSK2480B case, AMD A4-5300 CPU, Asus F2A85-M LE mobo, WD Caviar Green 64Mb 2TB HDD, HD Homerun, Win7 Home Premium, RAM 1600Mhz 4Gb.
iPad air 2


601 posts

Ultimate Geek
+1 received by user: 40

Subscriber

  Reply # 834617 12-Jun-2013 09:48
Send private message

Ive had that happen since the 1.3 betas. Just always thought it was my system - switched to Win7 around the same time. And it could quite be mainly the kordia channels that do it for me. I know Prime does for sure, choicetv does it occasionally, really cant remember if any others do though. And Ive noticed it only does it going into the actual TV show, not in the commercials - its a conspiracy to stop us watching bad TV! :p

1101 posts

Uber Geek
+1 received by user: 67

Trusted

  Reply # 834655 12-Jun-2013 11:05
Send private message

askelon: And Ive noticed it only does it going into the actual TV show, not in the commercials - its a conspiracy to stop us watching bad TV! :p

I think ads would naturally have more I frames. Hence the black screen is less obvious.

Those of you using MP...
Is the problem consistent across different codecs?



1090 posts

Uber Geek
+1 received by user: 182


  Reply # 834670 12-Jun-2013 11:18
Send private message

I think it's across multiple codecs. Pretty sure I tried with MS codec but I'll confirm tonight.




1006 posts

Uber Geek
+1 received by user: 29


  Reply # 835845 12-Jun-2013 14:56
Send private message

turb:
Asmodeus:
turb: Me too. Prime and Choice.


Me too!

You have to play around with the skip buttons or just wait to make it work properly again. Doesn't happen every time but definitely often


Are using WMC too?


Yup :)

761 posts

Ultimate Geek
+1 received by user: 323

Subscriber

  Reply # 835957 12-Jun-2013 16:59
Send private message

I've had this problem for ages with windows media center with default decoders. It varies in severity and I have seen it on Four (sometimes), Prime (less occasionally) and Choice (often). It's slightly subjective, but I personally think it also varies between ads and the actual show. E.g if I skip and stop early in the ads it can take ages for the picture to resume and sync to the audio. If I overshoot it still takes a while, but I think it syncs up faster. Might be purely my imagination however.

1101 posts

Uber Geek
+1 received by user: 67

Trusted

  Reply # 835990 12-Jun-2013 17:25
Send private message

The more comments I read, the more I think this issue is independent of software. Even largely independent of codec and splitter. The biggest factor is the head-end encoder.

To a large extent codecs and splitters are "mechanical". Feed in X; get out Y.

My understanding is that codecs aren't able to fully decode frames until they hit the start of a new GOP (group of pictures). Now, I know that is not entirely accurate for h.264 which doesn't have to have closed GOPs, but the principle still applies - codecs wait until they have enough context before turning on their output. Otherwise they'd output... garbage. Some codecs may require slightly less context than others due to their internal design... however there are still non-negotiables.

If you encode a stream with short GOPs and lots of safe entry points and/or I frames then the codec can build up the required context and turn on the output quickly.
If you encode a stream with longer GOPs and few safe entry points and/or I frames (more complex inter frame references) then the codec takes longer to get its context and turn on the output.

The first case takes more bits than the second for the same picture quality.
We know that Freeview is running at capacity. With the addition of Sommet I suspect Kordia is fine-tuning to try and steal as many bits as possible for Sommet while maintaining the picture quality of the other channels in the mux as best as possible. Stealing bits always has a cost!

1101 posts

Uber Geek
+1 received by user: 67

Trusted

  Reply # 835992 12-Jun-2013 17:31
Send private message

One last comment...
The point in time at which you change channel can make a difference. If you happen to switch at an optimal time (ie. shortly before a safe entry point), the picture may appear quickly. Other times it may take longer. The GOP length is most likely not fixed, so that is another variable.



1090 posts

Uber Geek
+1 received by user: 182


  Reply # 836005 12-Jun-2013 17:48
Send private message

I can see how this would cause the skip forward or channel change to take a little longer but what about when the picture totally freezes never to continue.




778 posts

Ultimate Geek
+1 received by user: 103


  Reply # 836013 12-Jun-2013 18:07
Send private message

Who can we complain to? Is it Kordia or Freeview?




HTPC: Antec NSK2480B case, AMD A4-5300 CPU, Asus F2A85-M LE mobo, WD Caviar Green 64Mb 2TB HDD, HD Homerun, Win7 Home Premium, RAM 1600Mhz 4Gb.
iPad air 2


1101 posts

Uber Geek
+1 received by user: 67

Trusted

  Reply # 836015 12-Jun-2013 18:22
Send private message

mcraenz: I can see how this would cause the skip forward or channel change to take a little longer but what about when the picture totally freezes never to continue.

MP is not totally frozen right. Just the picture. Audio continues in the background?

I think its related. I'd compare it to what happens with corruption or interruption in the stream. Basically the codec gets into a situation where its internal context is screwed or it can't find a suitable entry point... or maybe the codec takes too long to sort itself out and this messes up the renderer. In any case, something hits the "give up" threshold. I don't know much about renderers, but most codecs will only attempt to decode "garbage" for so long. This situation is more likely when the complexity of the stream encoding is higher.



1090 posts

Uber Geek
+1 received by user: 182


  Reply # 836016 12-Jun-2013 18:24
Send private message

Yep just the stream, MP is fine. Yep makes sense. Bloody annoying, but makes sense. Thanks for all the good info :)




1 | 2 
Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic


Donate via Givealittle


Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Amazon introduces new Kindle with adjustable front light
Posted 21-Mar-2019 20:14


A call from the companies providing internet access for the great majority of New Zealanders, to the companies with the greatest influence over social media content
Posted 19-Mar-2019 15:21


Two e-scooter companies selected for Wellington trial
Posted 15-Mar-2019 17:33


GeForce GTX 1660 available now
Posted 15-Mar-2019 08:47


Artificial Intelligence to double the rate of innovation in New Zealand by 2021
Posted 13-Mar-2019 14:47


LG demonstrates smart home concepts at LG InnoFest
Posted 13-Mar-2019 14:45


New Zealanders buying more expensive smartphones
Posted 11-Mar-2019 09:52


2degrees Offers Amazon Prime Video to Broadband Customers
Posted 8-Mar-2019 14:10


D-Link ANZ launches D-Fend AC2600 Wi-Fi Router Protected by McAfee
Posted 7-Mar-2019 11:09


Slingshot commissions celebrities to design new modems
Posted 5-Mar-2019 08:58


Symantec Annual Threat Report reveals more ambitious, destructive and stealthy attacks
Posted 28-Feb-2019 10:14


FUJIFILM launches high performing X-T30
Posted 28-Feb-2019 09:40


Netflix is killing content piracy says research
Posted 28-Feb-2019 09:33


Trend Micro finds shifting threats require kiwis to rethink security priorities
Posted 28-Feb-2019 09:27


Mainfreight uses Spark IoT Asset Tracking service
Posted 28-Feb-2019 09:25



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.