Forum Discussion

Gampell15BH's avatar
Gampell15BH
Tuning in
10 months ago
Solved

Audio out of sync , some channels only

Some channels , e.g. All the BBC HD channels and Sky News in HD are wildy out of sync. Other channels such as ITV1HD are either fine or very very close to fine . The bad ones are close to unwatchable...
  • newapollo's avatar
    newapollo
    10 months ago
    Gampell15BH wrote:

    thank you, I can share more info, I was using a Soundbar,  a Sennheiser AMBEO Plus connected via HDMI (eARC socket),  but to remove that from the equation I disconnected it and just listened to the audio output from the TV speakers,  there was no difference, it was equally out of sync.  Re connecting the soundbar I tried both PCM 2.0 and "follow content" and I feel the PCM setting was  alittle better but still not right,  and it is NOT a solution since my soundbar is Dolby Atmos capable and I need to send dolby bitstream to it,  (remembering the sync issue is there regardless of whether or not the soundbar is connected).

    Here is an interesting thing,  watching Have I Got News for you with the audio output set to Follow content (recommended) the sync was terrible, but using the "watch from start" feature and viewing the same program through iPlayer the sync was fine.  It's only live over the air programs on certain channels that have the issue (ITV1HD  on 103 is fine).

    This may be due to a signal problem. It usually affects the picture but it may possibly affect the audio too.The live channels on VM are carried in muxes (the same way that freeview carry channels) 

    You mentioned Sky News HD and all BBC HD channels being out of sync.

    Sky News HD and BBC2 HD are carried on same mux, along with GB News, Sky Kids HD, Sky Nature HD, TNT Sports 2, Sky Sports Golf and Al Jazeera Arabic.  If it's a signal fault I would expect all of them channels to have the same audio/sync issue.

    ITV+1, CH4 and CH4+1 are all carried on the same mux as ITV1,  so if ITV1 is OK then the other three should be too.

    Check all your VM cabling is snug and tight and free from any kinks, especially the white coaxial cable, and the small white cable adapter.

     

Gampell15BH's avatar
Gampell15BH
Tuning in
10 months ago

thank you, I can share more info, I was using a Soundbar,  a Sennheiser AMBEO Plus connected via HDMI (eARC socket),  but to remove that from the equation I disconnected it and just listened to the audio output from the TV speakers,  there was no difference, it was equally out of sync.  Re connecting the soundbar I tried both PCM 2.0 and "follow content" and I feel the PCM setting was  alittle better but still not right,  and it is NOT a solution since my soundbar is Dolby Atmos capable and I need to send dolby bitstream to it,  (remembering the sync issue is there regardless of whether or not the soundbar is connected).

Here is an interesting thing,  watching Have I Got News for you with the audio output set to Follow content (recommended) the sync was terrible, but using the "watch from start" feature and viewing the same program through iPlayer the sync was fine.  It's only live over the air programs on certain channels that have the issue (ITV1HD  on 103 is fine).

newapollo's avatar
newapollo
Very Insightful Person
10 months ago
Gampell15BH wrote:

thank you, I can share more info, I was using a Soundbar,  a Sennheiser AMBEO Plus connected via HDMI (eARC socket),  but to remove that from the equation I disconnected it and just listened to the audio output from the TV speakers,  there was no difference, it was equally out of sync.  Re connecting the soundbar I tried both PCM 2.0 and "follow content" and I feel the PCM setting was  alittle better but still not right,  and it is NOT a solution since my soundbar is Dolby Atmos capable and I need to send dolby bitstream to it,  (remembering the sync issue is there regardless of whether or not the soundbar is connected).

Here is an interesting thing,  watching Have I Got News for you with the audio output set to Follow content (recommended) the sync was terrible, but using the "watch from start" feature and viewing the same program through iPlayer the sync was fine.  It's only live over the air programs on certain channels that have the issue (ITV1HD  on 103 is fine).

This may be due to a signal problem. It usually affects the picture but it may possibly affect the audio too.The live channels on VM are carried in muxes (the same way that freeview carry channels) 

You mentioned Sky News HD and all BBC HD channels being out of sync.

Sky News HD and BBC2 HD are carried on same mux, along with GB News, Sky Kids HD, Sky Nature HD, TNT Sports 2, Sky Sports Golf and Al Jazeera Arabic.  If it's a signal fault I would expect all of them channels to have the same audio/sync issue.

ITV+1, CH4 and CH4+1 are all carried on the same mux as ITV1,  so if ITV1 is OK then the other three should be too.

Check all your VM cabling is snug and tight and free from any kinks, especially the white coaxial cable, and the small white cable adapter.

 

  • Gampell15BH's avatar
    Gampell15BH
    Tuning in
    10 months ago

    I've had a virgin engineer check all the cabling , so and he replaced a couple of internal and external runs but it has made no difference , I also came to the conclusion it is certain Muxes , but how to get it resolved ? How even to get it acknowledged so I don't waste time listening to people tell me to change delay settings in the box (which can only add more delay and will impact all channels)

    • Zach_R's avatar
      Zach_R
      Forum Team
      10 months ago

      Hi Gampell15BH,

      Thank you for your posts and welcome to our community forums. We're here to help.

      I'm sorry to hear of your recent audio sync issues. To clarify, the issues still remain on multiple (but not all) channels following a technician visit, both when connected to a sound bar and not connected to a sound bar?

      Thanks,
       

      • Gampell15BH's avatar
        Gampell15BH
        Tuning in
        10 months ago

        Sorry not to respond earlier , I am travelling away from home since 22nd, but...yes you are correct that after an engineer visit the issue still persists , I do not blame the engineer he was very helpful and in fact is returning on 29th , but I think he does not have any solution .

        I made some more tests and suspect it is related to audio codec. I have box set to "follow content" so the codec is changing according to each broadcaster and each program and I found that in general the sync issue was occurring when the codec is dolby digital +,  however when I changed the box setting to PCM 2.0 the delay is still there so the delay has occurred (if I am correct) before that transcode to PCM .

        I am home on 26th and another visit is planned by virgin engineer on 29th 

        Guy