DVB-T lip sync problems

    I'm using 7025+ with DVB-T tuners and I have problems getting correct audio sync. With live transmissions audio seems come about 200-220ms ahead of picture. I'm able to "fix" this with Dreamboxeditor by adding delay to each channel, this also seems to fix recordings made after the change. But still it looks like the sync is not always exactly correct, although it's much better than before.


    But I have also a problem if I watch recording made with other hardware: Topfield pvr-t and DVB-T PC-card and also VLC transcoded material: all have similar audio sync error and audio is ahead of picture. Looks like the error is even bigger, something like 300ms or more. All this material playbacks correctly when watched with PC videoplayers.


    So what is wrong? I have tried latest DVB-drivers (and also older ones) but they are all the same.


    I noticed that the delay can be set with proc/stb/audio/audio_delay_pcm but how can I use this setting during playback? I know how to put a value there but how can I make Dreambox to actually use it?

    I just ran across your post about correcting lip-sync error and thought I would mention this review of three dedicated lip-sync correction units:



    http://www.audaud.com/article.php?ArticleID=3011


    Maybe the unit you have will work but all av receivers I have ever seen make it impossible to achieve perfect lip-sync by overlaying the screen with menus during the adjustment.


    Since lip-sync error changes a little (sometimes a LOT) from program to program and DVD to DVD the audio delay must be adjusted at the beginning of every one if you want to eliminate it and its ill effects on viewer perception. Often it may take a few minutes for appropriate talking heads to come along and it often requires some tweaking as you go along for several more minutes. You need to be able to make those adjustments while watching without menus overlaying the screen.


    All three of the dedicated digital audio delays in the review allow fine tuning the delay while watching without image disturbance and all three have over 600 ms delay in contrast to av receivers which sometimes offer only 80 ms which is definitely not enough.

    I already had noticed the article and was thinking about that Felston delay unit.


    But it sounds weird that I have buy something like that to fix a problem that cleary is in the Dreambox 7025's firmware/hardware. I know that there are audio delay variations between different channels and programs but this problem is something else. Delay also seems to change during playback of some .ts files.


    I have also Dreambox 7000S and it does not have these audio/lip sync problems. And it plays the same .ts files without audio delay problems.


    So what is wrong in 7025+? Why can't it do the same?