Sky+ sound synch probs

[kevbaz]

hi guys

got a really annoying issue with the sound synch with our sky+, it seems to be completely ramdon and sometimes worse than others.

is this a common fault? is there anything we can do?

cheers

Kev

[macbeth]

Originally Posted by kevbaz

hi guys

got a really annoying issue with the sound synch with our sky+, it seems to be completely ramdon and sometimes worse than others.

is this a common fault? is there anything we can do?

cheers

Kev

Where is the sound synch issues. If it on the playback of the recordings your having a sound sink issue you can try a planner rebuild by pressing service on remote, then hiding menu press 0 1 select, then select planner planner rebuild. If that fails to works this would delate all recordings you you an try the full system reset options below planner rebuild. Service call if that fails.

If it on live tv picture this is happening, sorry to say that the nothing that you can do. If it in warranty to call the warranty company for them to come out.

[Old_nick]

Sound sync issues can be linked to dish alignment. Look at the signal strength and quality, and see if both are quite high.

[Proppinupthebar]

Originally Posted by Old_nick

Sound sync issues can be linked to dish alignment. Look at the signal strength and quality, and see if both are quite high.

No, I can't see how they can be. Dish alignment can cause stream errors, so with video packets being by far and away the largest bitrate to a service, if you have dish alignment problems then the video should suffer breakup first. Lip synch errors are not caused by dish alignment problems.

Theres time stamps in MPEG streams which should keep the video and audio in synch. What STB type are you using?

[Old_nick]

If the signal quality is bad, the processor in the box will be working overtime to correct errors. If the box is overloaded with errors, it will start to drop data packets, and since video has a higher priority, sound data will be dropped first, and this can cause sync problems.

[Proppinupthebar]

Originally Posted by Old_nick

If the signal quality is bad, the processor in the box will be working overtime to correct errors. If the box is overloaded with errors, it will start to drop data packets, and since video has a higher priority, sound data will be dropped first, and this can cause sync problems.

Nick, thats not how it works.
If the signal quality is crap then the tuner/front end will do all the error correction, not the MPEG decoder. The MPEG audio and video decoding is done in parallel not serially, so nothing has priority.
As I've said, if the stream is errored (and the Reed Solomon and Viterbi error correction can't correct) then the video data will suffer most as it makes up more of the stream. An errored audio stream will not lose just its PTS time stamps and lose lip synch.
In short, a misaligned dish does not cause lip synch errors.

[Smithy99]

You know he's right don't you?

[Old_nick]

Not sure..... I've seen sound sync problems on my box when the dish was out of alignment. Any suggestions ?

[Proppinupthebar]

Originally Posted by Old_nick

Not sure..... I've seen sound sync problems on my box when the dish was out of alignment. Any suggestions ?

What kind of box and which channels? Dolby or standard stereo.

The movie channels do seem to sometimes drift in and out.

[Old_nick]

Thomson HD box, Dolby output, most channels (I usually watch BBC or Sky One). The problem completely cleared when I realigned the dish after fitting a quad LNB.

I also noticed another strange anomoly the other day - our dish is on a wall overlooking a flat roof, which we can easily access by climbing out of the office window. A couple of weeks ago my wife decided to go out on to the flat roof to clear some leaves from the gutters whilst I was watching something on Discovery HD, and at one point she was slighly obscuring the dish when she climbed a ladder. At that point the HD picture completely froze, whilst the sound continued with no stutters. When she cleared the dish, the picture suddenly resumed from a later point in the programme, with no picture breakup at all. Very odd.