My Humax Forum » Freeview HD » Aura UHD

Lip Sync, need to reduce delay

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    SueH

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    Joined: May '21
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    Hello,

    I recently purchased a Humax Aura 4k 2tb.

    On recordings the video runs behind the audio. I can increase the interval between video and audio by using the settings but it does not allow me to reduce the delay. Eg +10ms +20ms etc but no - 10ms option.

    I have tried stereo and surround settings on the Humax but no difference.

    My TV is a LG CX 55 inch 4K Ultra HD Smart OLED TV and I am using TV speakers with 2 Bluetooth surround speakers.

    Is there a way I can reduce the delay rather than increase it?

    Thank you.

    | Sat 22 May 2021 22:21:47 #1 |
  2. grahamlthompson

    grahamlthompson

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    A bit puzzled. Video takes longer to decode than audio so the audio should only need a delay. The actual broadcast delays the audio already so you should only need a positive audio delay to correct minor timing differences. Does your TV not have an adjustment in the settings menu ?

    Example of what a digital programme stream has within it.

    General
    ID : 16517 (0x4085)
    Complete name : D:\Vbox recordings\Only the Brave__Channel 4 HD__15-02-2021_00-05.mp4
    Format : MPEG-TS
    File size : 4.09 GiB
    Duration : 2 h 14 min
    Overall bit rate mode : Variable
    Overall bit rate : 4 342 kb/s
    FileExtension_Invalid : ts m2t m2s m4t m4s tmf ts tp trp ty

    Video
    ID : 301 (0x12D)
    Menu ID : 17664 (0x4500)
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : High@L4
    Format settings, CABAC : Yes
    Format settings, RefFrames : 4 frames
    Format settings, GOP : M=8, N=24
    Codec ID : 27
    Duration : 2 h 14 min
    Width : 1 920 pixels
    Height : 1 080 pixels
    Display aspect ratio : 16:9
    Frame rate : 25.000 FPS
    Standard : Component
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : MBAFF
    Scan type, store method : Interleaved fields
    Scan order : Top Field First
    Color range : Limited
    Color primaries : BT.709
    Transfer characteristics : BT.709
    Matrix coefficients : BT.709

    Audio
    ID : 302 (0x12E)
    Menu ID : 17664 (0x4500)
    Format : AAC
    Format/Info : Advanced Audio Codec
    Format profile : LC
    Muxing mode : LATM
    Codec ID : 17
    Duration : 2 h 14 min
    Bit rate mode : Variable
    Channel(s) : 6 channels
    Channel positions : Front: L C R, Side: L R, LFE
    Sampling rate : 48.0 kHz
    Frame rate : 46.875 FPS (1024 SPF)
    Compression mode : Lossy
    Delay relative to video : -1 s 152 ms
    Language : English

    Text
    ID : 305 (0x131)
    Menu ID : 17664 (0x4500)
    Format : DVB Subtitle
    Codec ID : 6
    Language : English

    Menu
    ID : 300 (0x12C)
    Menu ID : 17664 (0x4500)
    Duration : 2 h 14 min
    List : 302 (0x12E) (AAC, English) / 301 (0x12D) (AVC) / 305 (0x131) (DVB Subtitle, English)
    Language : English / / English
    UTC 2021-02-15 00:05:02 : en:Only the Brave / en: / / / 02:14:58 / Running

    | Sun 23 May 2021 11:10:12 #2 |
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    SueH

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    Thank you Graham for taking the time to reply, yeah we are puzzled too. The TV is fine on live viewing so don't really wish to have to change its settings back and forth everytime I use the Humax. But increasing the delay, even by 10 to 20ms makes the delay worse. So I'm assuming I cannot decrease the delay in the Humax settings? Interestingly it is intermittent eg dragons den was out of sync BBC2 yet BBC3 recording was perfect. Winer if it is to do with the broadcast and the fact we have upgraded to a 65 inch TV so it is more obvious. Unfortunately only used the Humax with the new larger screen TV

    | Sun 23 May 2021 11:16:57 #3 |
  4. grahamlthompson

    grahamlthompson

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    SueH - 4 mins ago  » 
    Thank you Graham for taking the time to reply, yeah we are puzzled too. The TV is fine on live viewing so don't really wish to have to change its settings back and forth everytime I use the Humax. But increasing the delay, even by 10 to 20ms makes the delay worse. So I'm assuming I cannot decrease the delay in the Humax settings? Interestingly it is intermittent eg dragons den was out of sync BBC2 yet BBC3 recording was perfect. Winer if it is to do with the broadcast and the fact we have upgraded to a 65 inch TV so it is more obvious. Unfortunately only used the Humax with the new larger screen TV

    I have a LG C9 but the audio is never used as I have 4K AVR with a Dolby Atmos speaker setup. I do feed a Kitchen TV when both the lounge TV and the Kitchen TV are watching the same source the handshake forces the audio to pcm stereo. My better half is very susceptible to lip synch errors even ones with a few milliseconds error. I just have the one delay set on the AVR and both lounge and Kitchen TV lip synch is perfect. Apps like Prime have no issues either. I use a 4K firestick for Prime, Netflix and Disney +. HD channels use a different audio codec (AAC) which the box transcodes to Dolby Digital on output. SD uses PCM stereo. I would expect your TV to cope with either.

    On my LG C9 If I choose Settings All Select Sound and then additional. There are options for audio including AV sync Adjustment.

    Suggest you have a play with these.

    | Sun 23 May 2021 11:35:19 #4 |
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    SSThing

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    SueH - 24 mins ago  » 
    Thank you Graham for taking the time to reply, yeah we are puzzled too. The TV is fine on live viewing so don't really wish to have to change its settings back and forth everytime I use the Humax. But increasing the delay, even by 10 to 20ms makes the delay worse.

    You will be surprised by how much adjustment you may have to do.
    I have numerous sources running through my AVR and on occasion I have needed to apply well in excess of 100ms adjustment.
    Just because adding "10 to 20ms makes the delay worse" don't stop there. It may appear worse because the phase is different but try adding progressively more, you may just find that it works.

    | Sun 23 May 2021 11:51:52 #5 |

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