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Lip sync issues with dnla client on recording service.


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Hi

 

Using DVBViewer latest version, a BGT3600 dual DVB-T, Dual DVB-S tuner card and recording service set to unicast over a wired network.

 

I get lip sync issues with an OPPO-103D Blue ray player set as a DNLA renderer when sending either TS or MPEG to the renderer.

 

 

The problem I'm seeing is that the OPPO103 seems to need one value of lipsync delay when playing SD TV and a differnent value (much more audio delay) when playing HD material - certainly when acting as a live stream renderer.

 

 

Just so I can rule out DVBViewer in this - Am I correct in assuming that DVBViewer cannot possibly be causing lipsync issues as its recording service is simply sending received packets over the LAN and that nothing it does could change the realationship between sound and vision as these are locked togther inside the transmitted packet and are as transmitted by the TV company etc.?

 

I need to rule this out before appoaching OPPO with a bug report.

 

 

Currently use of OPPO as a DNLA renderer is hopeless due to this issue.

 

K

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Just so I can rule out DVBViewer in this - Am I correct in assuming that DVBViewer cannot possibly be causing lipsync issues as its recording service is simply sending received packets over the LAN and that nothing it does could change the realationship between sound and vision as these are locked togther inside the transmitted packet and are as transmitted by the TV company etc.?

That's the way it should be.

 

Did you get lip sync issues with recordings too? Then you could try another DLNA server with this files.

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That's the way it should be.

 

Did you get lip sync issues with recordings too? Then you could try another DLNA server with this files.

 

 

I will investigate this evening. I am suspecting that the Oppo is the problem.

 

They have recently added a lipsync adjustment feature on the player. But my problem is that I need tow very different delay values to make vision and sound line up for SD and HD material. You really shouldn't have to change this setting when switching TV channels. Discrepancy in the two settings is around 80mS.

 

I'll experiment with recordings.

 

Thanks fr the suggestions.

 

K

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I have had this issue on a 2011 Sony media streamer device and on two 2014 model Samsung devices (TV and BD player). Noticeable with HD more than SD, as you say.

If you take a recording, copy to usb stick/drive and play directly on your device (if possible), it should play fine without any lip sync issues.

 

There is Another forum thread on this subject from a year ago - At the time, I discovered removing some of the profiles from within upnpprofiles xml file helped, also ensuring the EU variant of TS/MPEG H.264 profile is included for live tv and recorded streams. Inclusion of the EU streaming lines to the xml file is now standard with recording service... (writing from phone, so cant check right now).

 

I noticed with the config files of other applications like jriver and mediaportal, there are many more specific profile lines for EU users and for major manufacturers.

I was able to adjust the upnpprofile xml file so HD channel lip sync was almost unnoticeable.

From memory, there is some line to add that allows you to enter a value to pre-render streams on your PC, or repackage to MKV, or add audio delays... these are related to the FFMPEG codec installed with Recording Service.

 

Provided the DLNA hardware streamers conform to EU standards or ISO standards (LG conformed to US standards a year or so ago), then things should work fine. Suggest try to avoid using wifi if possible. Things improved greatly when I wired the house with Cat5. Even 500mb Powerline adaptors are better than wifi - certainly for HD.

 

This might help...

https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#safe=off&q=ffmpeg+dlna+server

Tony

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There will always be differences in lip-sync error for different formats but your estimate of 80 ms difference between SD and HD would be more than we normally see. Have you witnessed this difference on multiple program samples? I work for a company that produces lip-sync correction products for home theater use and we have seen video delays over 200 ms on some 4K displays and that allows the audio to come well before the accompanying image and is pretty much un-watchable without adding an audio delay to compensate.

 

Delays are larger when you send HD because the data moving is so much larger but a format that is not the TV's native format will add even more delay For example if you send a 1080p TV a 720p format it has to convert 720 to 1080 and that takes time. Depending on the algorithms it could even take longer to convert 480 to to 1080. A conversion from interlaced formats to progressive takes "at least" half a frame (16 ms for NTSC and 20 ms for PAL) so when you consider all the possible changes in resolution, frame rate and interlace status there's a lot of variation in video processing delays and hence lip-sync error.

 

The other thing to keep in mind about lip-sync error is that it is impossible in the real world so our subconscious reaction to this impossibility is to avoid noticing it. Most people can avoid consciously noticing over 40 ms of lip-sync error but once you notice it and begin to look at the lips instead of looking away from the faces to avoid it you will see far smaller lip-sync error than you ever saw before.

 

If you don't realize this - that there is a fairly high "threshold of recognition" - ignoring as much as 80 ms error for some viewers - that drops precipitously (to as little as 1 ms for some) once it is exceeded and the problem enters your conscious mind; you might think lip-sync error has changed - has increased - when in fact it is the same but you are now seeing it.

 

And lip-sync error varies radically from program to program - often over 50 ms - so if you haven't used but one sample program so far (questioned above) it's possible that program contained excessive lip-sync error to start with and a small addition my have raised it above your threshold of recognition now making you more sensitive to detection. To guard against that possibility I'd suggest re-watching some content you previously saw no lip-sync error in and see if you now see lip-sync error you previously ignored.

 

Research at Stanford over 20 years ago statistically documented the negative impact on viewer perception lip-sync error causes even when it's not consciously noticed. The adjectives they used describing the negative impact (feeling the characters were more agitated, less successful, less persuasive, less truthful, etc) are the same kind of feelings we have when someone doesn't make eye contact with us but ironically it seems to be reversed and it is the "viewer" who is not making eye contact with the characters as he tries to avoid noticing the impossibility of lip-sync error.

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Hi

 

Many thanks for taking to time to advise me re this.

 

I did some experimenting.

 

I recorded 30mins of BBC1 and BBC1HD using DVBViewer using the web interface for the recording service. These recordings were made with the TS format.

 

When I access the recorded files via DLNA on the oppo103 they both play nicely and good lipsync is achieved with a single setting on the oppo of +140mS. Similarly when I copy the files onto a USB stick and plug this into the oppo - same result.

 

 

Did some more investigating with watching live TV over the network and I get variable results. Sometimes it looks OK and other times sync is bad.

 

I hear and understand Nexsen's points re psychology of this but when its bad (100mS difference as in original post) it is really really obvious. Actually unwatchable.

 

So it looks like I have an intermittent issue. Oh good.

 

 

My HTPC (where the recording service and tuners reside) sits below the oppo next to the AV pramp and TV. Both are connected to a recently acquired ASUS AC87U router by 1m ethernet cables. This has 1GB eth switches and I think is of competent quality - certainly network access and file transfer is very fast and browsing drives on other network pcs seems little slower than browsing local drives. .

 

Ironically I can watch HD TV from my laptop over 11n wireless using DVBViewer client on laptop without obvious lipsync or other issues.

 

My TV is a pioneer plasma and my AV preamp is an ARCAM AV8 and this has a number of settop boxes plugged into it. The AV8 also has a lipsync delay setting and this was set when originally installed to compensate for the TVs video processing delay. When the set top boxes switch between SD and HD no lipsync issues are obvious.

 

So I may have to follow Tony's kind advice and investigate the upnpprofiles xml. I looked briefly at this and it looks quite complicated :-) I might be some time.

 

 

Thanks again for taking the time to help me out with this. I'll let you know how I get on.

 

K

.

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So I may have to follow Tony's kind advice and investigate the upnpprofiles xml. I looked briefly at this and it looks quite complicated :-) I might be some time.

forget it

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