Diagnosing lip sync causes

[CubsWin]

I have a 622 receiver receiver connected to a Hitachi Rear Projection TV by HDMI and connected to a Sharp Aquos LC32D62U in another room by both a 35ft component cable and a coax cable from the TV2 output. I have noticed that the lip sync on my Sharp Aquos always appears to be off, regardless of which input I use, but my other TV is fine. I'm trying to determine what is causing this lip sync problem. Is it an issue with my Dish receiver or could it be caused by my long cable runs? Or is it possible that my TV itself has some sort of inherent problem with lip sync that causes everything to be out of sync? If anyone has any ideas, I would appreciate the info. Thanks.

 

[Fitzie]

A few months ago I sent an email to Dishtech to ask about lipsync solutions. The response I got was that there are several causes, and Dish continues to search for a solution. My understanding is that most of the problem on lipsync issues with HD material is the individual setup a person has, and the fact that HDTVs with better processing capability (and flexibility) can create a better solution than Dish currently has the ability to do. My problems with lipsync issues with SD programs, which require minimal video processing, has been little to none.

Another problem, over which Dish presumably has little control, is that some of the material Dish relays to us apparently has the lipsync problem built-in when Dish gets it. I can see where this would present great problems for live shows and shows "recorded live."

Hope this helps a bit.

fitzie

 

[CubsWin]

My problems with lipsync issues with SD programs, which require minimal video processing, has been little to none.

I should clarify that my lip sync issues also exist for SD programming and there is no noticeable difference between SD and HD. The lip sync issue appears on all channels, not just on occasional program here and there.

 

[Fitzie]

If the delay is the same, perhaps a receiver with variable delay capability would be your answer. However, since you have 2 TVs and only one has the problem, the Aquos, logical analysis would say the problem is in the Aquos. Unless, of course, the Aquos is the one at the end of the 35 foot run? Then the problem could be in the Aquos, the cable, or the length of the run. The one time I tried using a TV at the end of a 25 foot cable the results were not good. Maybe a signal booster?

fitzie

 

[bebop]

For what it's worth, I have a 722 receiver, and a 37" Aquos. I almost never see the sync issue with HD (maybe 1% of the shows). I do see it on the SD channels when the receiver is set to sync with HD - but I expected that. To confirm - you do have the receiver set to sync to HD and not SD, correct?

 

[tastim]

You say you have component cables running to TV2... along with the Coax.... that would mean that you are getting picture from the TV1 tuner, and sound from the TV2 tuner.... that would explain your problem right there.

Without seeing your setup, I couldn't give you a 100% answer... but that is my first hunch....

Do this... instead of watching the HD picture, switch the Sharp to Channel 60 (or 73) or whatever it was modulated to.... if that fixes the problem, you need to run RCA audio cables to TV2 from the TV1 ports along side your component cables.

The only other solution, if you want to watch HD from TV2 is to get another HD receiver for that TV.

 

[CubsWin]

First of all, to clarify the last post... I have my 622 connected to 2 different inputs on my Sharp Aquos. Input #1 gets both component audio and video from the component outputs on the 622 receiver. Input #2 gets audio and video from a composite cable via the RF output on the 622 receiver. There is no crossing of sound and video between tuners.

I finally had some time to troubleshoot a little further, so I connected an old DVD player to the component inputs on my TV and found that the lip sync was dead on. I had been worried that maybe my TV had some inherent problem, but that doesn't appear to be the case. I also did further testing between both inputs previously mentioned, Input #1 (component) and input #2 (composite). Even though those inputs are from 2 different tuners, they both have equally bad audio sync on my Sharp Aquos. The weird thing though is that the HDMI output, which is connected to my Hitachi rear projection TV in the family room, has no issues whatsoever. Why would the audio be fine through HDMI, but not the others?

At this point, the only thing I can really think of is to upgrade to a 722 and hope that fixes the problem, but I'm no longer under contract with E* and really don't want to extend it for a replacement receiver that may or may not fix the problem. Does anyone have any other suggestions?

 

[KKlare]

Try the Menu-6-7 (Dolby Digital) setting for RF vs Line. I use line, but I'm not sure which is right for RCA vs RF outputs or if it only changes one of the outputs as I'm using HDMI instead.
-Ken

 

[CubsWin]

Try the Menu-6-7 (Dolby Digital) setting for RF vs Line. I use line, but I'm not sure which is right for RCA vs RF outputs or if it only changes one of the outputs as I'm using HDMI instead.
-Ken

No difference there.

 

[Mike_H]

Extend your coax and drag the receiver over by the tv in question. Then try shorter cables and give it a shot. Try to give that remote TV the same shot as the local one and see what happens.

What it sounds like is some sort of error correction going on within the signal processing causing a glitch. Perhaps your long cables are not sufficiently shielded, or there is some sort of interference in your area.

 

[CubsWin]

What it sounds like is some sort of error correction going on within the signal processing causing a glitch. Perhaps your long cables are not sufficiently shielded, or there is some sort of interference in your area.

If that was the case, wouldn't I have had the same problem with the DVD player connected through the same long component cables? I'm using RapidRun cables, which are designed for long runs.

 

[Mike_H]

If that was the case, wouldn't I have had the same problem with the DVD player connected through the same long component cables? I'm using RapidRun cables, which are designed for long runs.

Maybe, maybe not. Only way to totally eliminate cable issues is to change the cables. Eliminate the distance issue by changing the distance.

Eliminate variables to identify the issue.

 

[kwindrem]

I have a 622 receiver receiver connected to a Hitachi Rear Projection TV by HDMI and connected to a Sharp Aquos LC32D62U in another room by both a 35ft component cable and a coax cable from the TV2 output. I have noticed that the lip sync on my Sharp Aquos always appears to be off, regardless of which input I use, but my other TV is fine. I'm trying to determine what is causing this lip sync problem. Is it an issue with my Dish receiver or could it be caused by my long cable runs? Or is it possible that my TV itself has some sort of inherent problem with lip sync that causes everything to be out of sync? If anyone has any ideas, I would appreciate the info. Thanks.

Lip sync can be created by several factors: the source material, audio video encoding delays, satellite receiver decoding delays, video processing in the display or other up/down conversion.

Modern TVs have varying about of video delay depending on the internal processing. I suspect that's what you are seeing. The Aquos has more delay than the Hitachi.

It is also possible the TV2 output has a different delay than the TV1/HDMI output.

Propagation delays in the cables themselves will NOT be an issue. You're talking about the speed of light - hardly significant over 35 ft.

Most modern A/V receivers have an adjustable audio delay to compensate for lip sync errors. You may find that setting audio delays in your AV receiver for correct lip sync on the Aquos will be more tolerable since late audio is more natural than early audio. We're used to hearing sound late when the source is distant since sound travels so much slower than light.

I've seen severe lip sync problems on some material while other material is dead on. Content providers and broadcasters haven't fully come to terms with signal path delays associated with video encoding and SD to HD conversion. These delays can approach a full second for MPEG encoding. Plus the delays of various devices in the signal path are cumulative. There isn't much you can do for this program-to-program variation except to complain to your service provider and the originator of the program except to try to fix the error with the AV receiver's audio delay.

I've seen lip sync change after pausing a program and resuming play so there appear to be problems within the satellite receiver. Skipping forward/back, going live then resuming DVR playback often changes the lip sync.

Many A/V receivers incorporate video processing including upscaling SD to HD and deinterlacing. These processes delay the video.

 

[highdefjeff]

Lip sync problems often come from low signal strength which can allow too much corruption in the information sent. Timer information. Sometimes a reboot will allow them to sync again...sometimes not. Getting better quality signal is often times the remedy.

 

[CubsWin]

Thanks for all the feedback. I am still trying to diagnose this. Can someone help me understand where my TV's video processing may come into play here?

It was my understanding that the receiver (in this case a 622) does the video processing and passes it through to the TV. Does the TV still have to do any processing of its own, or is it just receiving and displaying the signal?

 

[highdefjeff]

Some TV's have an AV sync that you can adjust. Yours has a few options that can be tried in regards to audio but not a specific "Audio Sync".

I would switch the component output to the TV1 setting and then check the Aquos to see if there is still a sync problem. If not, TV2 out has an issue, if it does still have audio sync problem, then check your cables.

 

[CubsWin]

Sharp sent a tech out to my house and he replaced the main board in my TV, but I'm still having lip sync problems. Today I discovered another interesting development...

NBC - HD nightly news lip sync was significanly off on my Aquos (component), but fine on TV1 (HDMI) in the family room.
ABC - HD nightly news lip sync was fine on both TV1 (HDMI) in the family room and my Aquos (component).

I flipped back and forth a few times to see if NBC would sync up, but the results remained the same. What would possibly cause this sort of inconsistency in lip sync between channels?

 

[bighick]

Component cables designed for a long run is a joke I am sorry. Component works fine unaltered for about 100 feet. Had that problem with my sharp via HDMI, and just got a 7.1 channel AVR and it synced it up .

 

[Bradtothebone]

Here's another idea:

Your sat receiver is probably set for 1080i output for your Hitachi. The Sharp is probably 720p native (right?). So, the Hitachi doesn't have to do any processing to the incoming signal, but the Sharp does.

Try setting the sat receiver's output to 720p and see if that makes any difference.

Brad

 

[wetz73]

How much difference do you expect to get by shortening a cable by several feet when the signal travels 186,000 miles per second? In other words, your lip synch is off a picosecond for every foot longer your audio cable is than your video cable. It's not a wire-length issue.