Forum Discussion

jifster's avatar
jifster
Joining in
2 days ago

Intermittent Picture Quality on Streambox

Hi, I've had VM since June 2025. What I noticed is that when I changed channel, for the first 10 seconds or so, the picture quality would be slightly 'jerky'. After this the picture is then smooth, as I would expect.

Since the Premier League has started I now observe that the 'jerky-ness' occurs during the programme. It lasts for a few seconds, and then returns to smooth. This continues regularly during the programme. I hadn't noticed it before and the issue is not limited to Sky Sports, I also see it on BBC1 etc.

I liken the 'jerky-ness' to when a stream is at 25hz and not 50hz. e.g. NowTV without Boost.

Anybody else notice this behaviour?  Any advice?

 

5 Replies

  • Ive posted about this OP and im having exactly the same issues, all started with that friday night football and now its most noticeable on the sports channels and the fact other folk are now reporting this, is seems to confirm its at Virgins end.

  • Roger_Gooner's avatar
    Roger_Gooner
    Alessandro Volta

    There are two causes of jerky behavious for streams.

    1. The channel change (not a bug)
    When you tune to a channel, the box requests a low-bitrate segment first to start playback quickly (known as adaptive bitrate streaming or ABR). It will take a few seconds for the ABR to ramp up to HD/UHD during which the video might look blocky or slightly jerky but it's perfectly normal behaviour.

    2. The subsequent jerkiness (a network issue)
    The Stream box uses ABR which adjusts video quality based on available bandwidth. If WiFi fluctuates the box may drop to a lower bitrate, switch frame rates (e.g. from 50fps to 25fps), skip frames or rebuffer. As a first step always use an Ethernet cable for connection. If this doesn't fix the problem, then it's caused by something else such as congestion on the coaxial side of an optical node.

  • mattw992's avatar
    mattw992
    On our wavelength

    I'm on stream boxes, have two, one wired anf one over WiFi and can confirm that at certain times this juddery effect happens more frequently of late. I think issues started a few weeks back, just when the football season began. I know VM had an outage of sorts on the Friday night with many customers losing their TV service. 

    Since the rebooting of their servers it seems to me that this juddering has affected channels when there is more users watching. Hence why Sky sports in particular has been affected. In my opinion it's a server issue, one where it cannot handle the amount of users connected and it struggling to maintain the frame rate, it's like very slight buffering and it's unable to pump out the required bandwidth to all those connected. As the last poster said wait until the picture is smooth, pause the stream for a second or two, then un-pause and watch it without going back to live. 

  • newapollo's avatar
    newapollo
    Very Insightful Person

    Sorry, I don't have the Stream box, however I do have a  couple of 360 boxes which run on the Horizon system which is the same one that Stream boxes run on.   

    I don't know if this will work with the Stream boxes but people with 360 boxes that have had a slight stuttering issue have been able to solve it by pressing pause for a couple of seconds.

  • I had this last night - the ticker on Sky News and Sky Sports News show it clearly as well of course looking at the actual picture.

    I checked the diagnostics which were fine, as were the Sky Sports UHD channels, so I don't think it was a local signal issue.

    All seems well on the little I've looked at today.