Auto Lip Sync - Do I have All The Right Components

Discussion in 'AV Receivers & Amplifiers' started by MultiRoom, Aug 20, 2012.

  1. MultiRoom

    MultiRoom
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    I have the following equipment:

    Windows Media Center
    Marantz NR1602
    Panasonic VT30 (50 inch)

    I have enabled auto lip sync on the amp, and I have set the audio delay to 0ms on the audio delay menu of the amp.

    Depending on the material I play, I get varying levels of video delay, meaning I have to adjust the audio delay every time I watch something different. Surely the point of auto lip sync is that this should be taken care of for me and I shouldn't need to be constantly adjusting the delay?

    I have ruled out the media centre and the content as being to blame by plugging the media centre directly into the TV, via HDMI, and experience no delay on video whatsoever, meaning that the delay when running through the amp must be the amps fault.

    A couple of questions, could it possibly be to do with the HDMI cable that's running from the AMP to the TV? If this wasn't high enough spec would it not be able to support the auto lip sync feature of the AMP?

    Also, I assume the HDMI cable that is running from the media centre to the AMP has nothing to do with it, since the auto lip sync is about the amp receiving a signal back from the TV about video/audio timings?

    Also, I find it odd that in the NR1602 manual it says that you can only adjust audio delay if you have auto lip sync feature switched to ON. Logically, I would have thought that audio delay is a manual version of auto lip sync - but perhaps I'm misunderstanding.

    The NR1602 is running the latest firmware. The VT30 was updated by an on site engineer perhaps 3 months ago.

    I am using the HDMI 2 port on the TV, which is the only one labelled ARC.

    Would dearly love to get this working.
     
    Last edited: Aug 20, 2012
  2. Mark.Yudkin

    Mark.Yudkin
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    Auto lip sync means that the TV will tell the amp the length of time it takes to process the video, allowing the amp to configure itself automatically. Apart from the problem that many TV's just give some fixed averaged value, this mechanism does nothing to address sync errors in the stream. However, your problem is with the source stream:
    The problem with errors in the source material is that as far as the rest of the system is concerned, the source is by definition perfectly synchronized, and hence there is no error to be corrected.

    The trouble is many sources systems just aren't correct. SKY for example, is infamous for its continually varying levels of inaccuracy. Manual correction is the only resolution, cursing can provide some alleviation of the aggravation involved.

    All HDMI cables of all versions support all features supported by the cable's speed and ethernet over HDMI capability. Lipsync is supported by standard speed cabling and doesn't need ethernet, hence all HDMI cables supports lipsync. BTW, there is no such thing as a version number when applied to cables, and such claims are in fact banned. There are exactly 5 cable types (one being for cars).
     
    Last edited: Aug 20, 2012
  3. MultiRoom

    MultiRoom
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    Thanks for your reply Mark, I'm always grateful for help.

    No, it's definitely not the source material.

    If I play the source material directly to the TV and skip the amp, the synchronisation is always perfect. Therefore, I believe I should be able to watch the same material through the amp with auto lip sync enabled and see and hear this material perfectly synced also.

    The varying degrees that the sync is out is surely the whole reason you don't have a 'one size fits all' audio delay setting?

    I'm having to set mine to anywhere between 50ms and 95ms, and as mentioned, have to do this for different material. I'm thinking this is to do with the way my TV processes the different image signals and has different delays depending on what it does with the image.

    If bypassing the amp I do not see any lip sync issues whatsoever. This proves the amp is responsible for it - now I'm just trying to see whether auto lip sync can help. In my mind it's name suggests this is exactly what it was designed for.

    I understand that sync issues in source material cannot be dealt with by the auto lip sync feature, since it perceives them as perfect already, which surely is what the adjustable delay should be used for.

    Ross
     
    Last edited: Aug 20, 2012
  4. Mark.Yudkin

    Mark.Yudkin
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    Now I'm confused. You said it was a variable delay depending on the source, now say the TV gets it perfect. But if the TV is perfect, then not only is the source perfect, but the TV also knows what it's doing and how much it has to delay, and hence isn't one of those "fixed delay" models.

    Are you able to determine what's different about the sources? For example is it NTSC vs PAL, 1080p vs 720p vs 576i, or other combinations of this sort?

    Is it possible that when your amp is in the chain, it causes the source to perform video processing? If so, could you try it with a non-media PC source (these frequently have a range of problems).? And more importantly, could you turn off all video processing and scaling, etc in the amp and configure it for pure video passthrough in the original format and resolution, so that the TV is doing all the video processing?
     
  5. MultiRoom

    MultiRoom
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    Hi Mark,

    No, I said it was variable depending on the material. The source is always the same, I only have a media centre.

    It seems that if I set my delay at 40ms than I have mostly an OK solution, except for when I play my 720p rips, which need to be adjusted to 95ms.

    This suggests to me that the TV is upscaling them, and introducing delay.
     
  6. MultiRoom

    MultiRoom
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    Right, solved the problem. Rang Marantz, and they asked about some generic feature, which in my case is called Viera Link, was switched on. They said switching it off may help. It did.

    I am happy. For the first time everything I watch is in perfect sync.
     
  7. steverobertsbbc

    steverobertsbbc
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    Viera Link is Panasonic's HDMI control feature. Without it switched on, ARC would not work on my G20 plasma with my Onkyo NR515 amp. With it switched on, when I'm watching TV and I turn my amp on, the TV speakers turn off and the TV sound then appears through the home cinema speakers. When I adjust the volume using the TV remote, it adjusts the amp volume. It didn't make any difference to auto lipsync either way, I've never been able to get that feature to work.
     
  8. Mark.Yudkin

    Mark.Yudkin
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    Rather surprised that enabling CEC (Panasonic name: Viera Link) should break lipsync - the features are supposed to be independent. Anyway, ARC will no longer work as you've disabled it.
     
  9. Nexsen

    Nexsen
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    I realize this is an old thread but lip-sync error seems to be getting worse not better so I thought I'd correct some things that some of the above comments might have implied.

    The current HDMI (below 2.0) Auto lip-sync correction (a trademarked feature) - when it actually works - only switches between two fixed audio delays (one for interlaced and one for progressive video). It does NOT consider resolution or frame rate and has no way of correcting lip-sync error in the arriving signal which is common. All it can hope to do is offset the video delay caused by the TV and it can only do that "approximately" - maybe within 10 ms - since it only considers interlaced status.

    Video processing within the TV is fastest when it doesn't need to "re-map" for the difference in its native resolution. A 1080 TV for example will take longer (perhaps 10 ms longer) to re-map 720 video than when fed its native 1080 resolution video. That's almost as much as the 16 ms difference (1/2 frame at 30 fps) between interlaced and progressive. And frame rate also matters: a 24P frame is 42 ms compared to 33 ms for 30P. To really "do it right" all 64 possible HDMI formats (or combinations of frame rate, interlaced status and resolution that have different video processing delays) need to be covered and the current HDMI feature can only cover 2.

    How the current feature works: During the EDID session (like plug and play for computers) the TV is supposed to pass 2 video latency values - one for interlaced and one for progressive - and 2 associated audio latency values which the AV receiver is supposed to subtract to determine the audio delay it needs to add.

    But amazingly - years after this highly touted HDMI "feature" - most TV's do not pass these 2 simple values. My new Samsung's and Vizio's don't but I have an older Toshiba TV that does. So it isn't a matter of new versus old.

    In HDMI 2.0 the feature has changed and is called "dynamic lip-sync correction" whereby the TV is "allowed" to send latency values any time it likes via the CEC lines. Again "optional" but it would be "possible" for a manufacturer to send different latencies depending on resolution and frame rate - not just interlaced status - whenever they change. If a manufacturer actually chose to do that and if you have an HDMI 2.0 TV that supports this optional feature PLUS an HDMI 2.0 AV receiver that supports this dynamic lip-sync correction feature the TV's contribution to lip-sync error might be truly solved.

    But realistically what is the chance manufacturers who haven't even bothered to support the current 2 latency values will start sending 64 different latencies in their HDMI 2.0 sets? I'm not holding my breath!
     
  10. mlhifi

    mlhifi
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  11. mlhifi

    mlhifi
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    It's my turn to say I know this thread is old (it's even older now!) but I wanted to thank Nexsen for succinctly describing just how the auto-lip-sync is supposed to work and indeed how it could be made infallible! (maybe that's going too far!). I knew about it, but didn't know the ins-and-outs, so thank you again.
    I too have a Yamaha AVR and a Panasonic TV and lip-sync is a problem now and then. However, I don't understand how the OP got the problem resolved by turning Viera Link off... turning it off stops ARC from functioning. If this is still being monitored, I'd be interested to know how it turned out.
    Best regards all.
     

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