Sky Sports recording pixelated and unwatchable

TomWTomW Posts: 453Member
I recently subscribed to Sky Sports HD channels via BT. BT confirmed that the channels were activated on Friday and having checked on Friday evening that the channels were indeed working correctly I set a recording for the Tottenham vs Newcastle match this afternoon. I’ve just tried to watch the recording and it’s completely pixelated and distorted so much so that it is completely unwatchable. I have just recorded another programme on the same channel and it’s fine so I’m not quite sure what the problem is.

I’ve spoken to BT via their (frankly useless offsore based) online chat and they suggested I perform a factory reset. Do you think this is really required and if so will I lose my recordings and settings?

Bearing in mind I subscribed to Sky Sports several weeks earlier than I otherwise would have done specifically to watch this match it’s fair to say I’m pretty annoyed. Especially as my attempt at getting a refund from BT via the online chat for my Sky Sports subscription resulted in a ‘computer says no’ please call our support number scripted answer. I swear BT are the sh****t company for customer support I have ever encountered. As soon as my contract ends I’ll be ditching them and YouView.

Comments

  • VisionmanVisionman Posts: 8,883Member ✭✭✭
    Have you posted this on the BT Community Forum? Because one of their mods will take ownership of it.
  • TomWTomW Posts: 453Member
    Thanks for the tip. Will do.
  • TomWTomW Posts: 453Member
    edited 11 September 2018, 5:03PM

    I should mention here, for the benefit of anyone else with similar issues reading this thread, that having done some further testing I’ve discovered the problem only affects Sky Sports HD and only when recording when the box is in standby. The Sky Sports SD channel is ok. However if a recording is in progress on Sky Sports HD while the box is in standby it will also corrupt any other concurrent recording on any of the other subscription (IP) channels (SD or HD) but not broadcast (Freeview) channels which remain unaffected.

    As I have already mentioned this isn’t a broadband/bandwidth issue as all other subscription channels including HD channels record fine, singularly, or two concurrent recordings, so long as one of them isn’t the Sky Sports HD channel.

    The issue was resolved by connecting the YouView box directly to the router (BT Homehub). Or at least that’s the short answer.

    The longer answer is that between my homehub and the YouView there was a Devolo 500 homeplug and two NetGear Gigabit network switches. It was these or rather a combination of these that caused the problem. The homeplug in of itself wasn’t a problem but in combination with the network switches it was a problem. Likewise a single network switch if connected to the router (bypassing the homeplug) wasn’t a problem but two network switches was a problem. 

    Here is a summary of the set ups I tried and the results.

    1. Working - Connection to router (BT homehub) via a single cable
    2. Working - Connection to router (BT homehub) via one network switch
    3. Working - Connection to homeplug via a single cable
    4. Not working - Connection to router (BT homehub) via two network switches
    5. Not working - Connection to homeplug via a one network switch
    6. Not working - Connection to homeplug via two network switches

    It is pretty clear from my testing that it isn’t a bandwidth issue. BT think that it may be the network switches and/or homeplug and/or some combination of the two are unable to buffer the higher bitrate of the Sky Sports HD channel (apparently Sky Sports HD uses significantly more bandwidth, just over 14MB, whereas other HD subscription channels only use 5 to 9MB). If the buffer was just over, they think that would explain why it also corrupts the second channel. So basically a resourcing issue for multicast over a certain bitrate on the switch. At least that is what they suspect. I’m not quite sure in that case why I can record two HD subscription channels so long as one of them isn’t Sky Sports HD as that would require more resources than recording Sky Sports HD without any concurrent subscriptuon channel recordings and it also doesn’t explain why recording Sky Sports HD is fine when the box is switched on (as opposed to standby).

    It’s all very peculiar but at least I now have a solution albeit longer term it will mean drilling a hole through a wall to route a network cable into the lounge or purchasing another homeplug purely for the YouView box.


  • TomWTomW Posts: 453Member
    edited 11 September 2018, 5:09PM

    I should post here, for the benefit of anyone else with similar issues reading this thread, that having done some further testing I’ve discovered the problem only affects Sky Sports HD and only when recording from standby. The Sky Sports SD channel is ok. However if a recording is in progress on Sky Sports HD while the box is in standby it will also corrupt any other concurrent recording on any of the other subscription (IP) channels (SD or HD) but not broadcast (Freeview) channels which are unaffected.

    As I have already mentioned this isn’t a broadband/bandwidth issue as all other subscription channels including HD channels record fine, singularly, or two concurrent recordings, so long as one of them isn’t the Sky Sports HD channel.

    The problem was resolved by connecting the YouView box directly to the router (BT Homehub). Or at least that’s the short answer.

    The longer answer is that between my homehub and the YouView box there was a Devolo 500 homeplug and two NetGear Gigabit network switches. It was these or rather a combination of these that caused the problem. The homeplug in of itself wasn’t a problem but in combination with the network switches it was a problem. Likewise a single network switch if connected to the router (bypassing the homeplug) wasn’t a problem but two network switches was a problem. 

    Here is a summary of the set ups I tried and the results.

    1. Working - Connection to router (BT homehub) via a single cable
    2. Working - Connection to router (BT homehub) via one network switch
    3. Working - Connection to homeplug via a single cable
    4. Not working - Connection to router (BT homehub) via two network switches
    5. Not working - Connection to homeplug via a one network switch
    6. Not working - Connection to homeplug via two network switches

    It is pretty clear from my testing that it isn’t a bandwidth issue. BT think that it may be the network switches and/or homeplug and/or some combination of the two are unable to buffer the higher bitrate of the Sky Sports HD channel (apparently Sky Sports HD uses significantly more bandwidth, just over 14MB, whereas other HD subscription channels only use 5 to 9MB). If the buffer was just over, they think that would explain why it also corrupts the second channel. So basically a resourcing issue for multicast over a certain bitrate on the switch. At least that is what they suspect. 

    I’m not quite sure in that case why I can record two HD subscription channels so long as one of them isn’t Sky Sports HD as that would require more resources than recording Sky Sports HD without any concurrent subscription channel recordings. It also doesn’t explain why recording Sky Sports HD is fine when the box is switched on (as opposed to standby).

    It’s all very peculiar but at least I now have a solution albeit longer term it will mean drilling a hole through a wall to route a network cable into the lounge or purchasing another homeplug purely for the YouView box.

  • RoyRoy Posts: 14,201Member ✭✭✭
    The trouble may not be with the pathway from YouView box to router, but with the pathways to other devices connected, or potentially connected, to those switches.

    Unless you have your IGMP arrangements just so, the switches are going to try to broadcast this multicast traffic  to every other device out there, which is quite a load for them.

    This article explains it better than I can, but basically you need to try to ensure your switches are multicast-savvy, and if so, set things up so they are only sending the multicast packets along the one pathway to the (presumably) one multicast receiving device on your network.
    ‘Does television exist for us to watch, or do we exist to watch television?’ - Noah Hawley
  • TomWTomW Posts: 453Member
    Thanks for the info Roy.

    The switches are just bog standard NetGear gigabit switches, I’m not sure that they’re configuarable. It’d be too much faff in any case especially as I now have a work around.

    What I don’t understand, if it is indeed a multicast routing issue, why does it only affect one channel and only when recording when the box is in standby?

    Also I did try a maintenance mode reset (keeping recordings) and that solved the problem albeit only for a few minutes on the first recording that I did afterwards. Then I was back to square one. If it were a problem with the homeplugs or switches why would a maintenance mode reset cure the problem (albeit temporarily)?
  • John29John29 Posts: 20Member
    You'll need a managed switch that does multicast.
    What you have are unmanaged stitches. As Roy commented this means they flood all ports with the multicast traffic.

    Multicast is a funny beast. My Asus router counts all my YouView streams as upstream traffic. I had to install a modified QoS script on my Asus-wrt Merlin firmware as a single HD stream on the YouView box is faster than my 7Mb upstream. QoS was throttling it.

    A very high percentage of the time problems streaming multicast are down to powerline adapters, and occasionally switches.

    A TP-Link TL-WA860RE with dd-wrt flashed and set up in client mode makes a cheap effective wireless bridge for a YouView box while retaining the same number of sockets.
  • Tim CTim C Posts: 325Member ✭✭
    John29 said:
    You'll need a managed switch that does multicast.
    What you have are unmanaged stitches. As Roy commented this means they flood all ports with the multicast traffic.

    Multicast is a funny beast. My Asus router counts all my YouView streams as upstream traffic. I had to install a modified QoS script on my Asus-wrt Merlin firmware as a single HD stream on the YouView box is faster than my 7Mb upstream. QoS was throttling it.

    A very high percentage of the time problems streaming multicast are down to powerline adapters, and occasionally switches.

    A TP-Link TL-WA860RE with dd-wrt flashed and set up in client mode makes a cheap effective wireless bridge for a YouView box while retaining the same number of sockets.
    A managed switch is NOT necessary , just one that supports IGMP Snooping , like the TP-Link SG105. Cheaper and easier than a managed switch.
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