Sound sync

@sam_nazarko I need to bring to your attention the other issue I face. I have sound going through spdif digital to my sound system and it accepts AC3 direct throughput. The video is going to my TV via HDMI. When I play AC3 videos I need to delay the audio by .250ms to get the sound to sync exactly so I have this as the same for all media. There is no need to delay the sync for non AC3 video as it is perfect without a delay - the delay set for AC3 causes sync issues for non AC3 video. Do you have any suggestion what I should do so I don’t have to keep changing my non AC3 audio from .250ms to no delay so the sound is in sync? Is there a way to have the sound delay for only AC3 video? Your thoughts are appreciated. I know I have raised this in the past and you said all audio should be in sync at the same delay bu this is definitely not the case. Are there other settings I should be applying in Audio out that you recommend?

Hi Wayne

Some TVs incur post processing which can delay the audio. We have seen this on the Vero 1 and other devices as well. The audio is being bitstreamed when it is sent as AC3. This means that the Vero is not modifying the audio stream at all, it’s just passing it to the TV.

The TV may be slower at decoding the audio than expected, hence the lip sync issue. The issue is that while I can add *.25s delay for AC3, it’s not a one-size-fits all solution. Not everyone will have this issue – and those using a receiver may then find that their audio is 0.25s behind.

Are you playing back using TV speakers? If so – then there may not be much benefit bitstreaming the content’s AC3 track. If you have speakers or a receiver, then there may be a better way to connect the audio up. The AC3 decoding on the Vero 2 will get you two LPCM channels which should sound fine. I am not sure if a TV will have a better sound decoder – an amp, yes.

Please describe your setup in more detail

Sam

Hi Sam

I have a Sony Soundsystem which I send all sound to from the Vero 2 via SPDIF digital. I don’t use the TV speakers at all. Is there a 2 channel audio out I can send to the Sony - I dont think there is? I used to have both SPDIF optical and 2 channel output from the original Apple TV and everything was always in sync. Do you think because all the sound is going through the SPDIF that could cause a delay? The Sony Home Theatre System is DAV-IS10. http://www.sony.com.au/product/dav-is10

For now I have the set delay at -.125 so it is just acceptable for both AC3 and non AC3 audio. This is my little workaround which I am trying not to pay attention to when watching! Thanks for all you attention to my issues Sam you are great.

Kind regards,

Wayne

Hi Wayne,

Thanks for clearing it up.

Yes there is – just untick ‘AC3 passthrough’ and AC3 videos will be downmixed to 2.0 stereo. You may need to enable ‘Boost center channel’ if the voices are too quiet.

Unfortunately Kodi doesn’t support setting delays for different types of files, so the above is probably the best way of resolving this issue.

I think the digital output causes a delay. One of your components (TV) is faster than the other, so the audio has a small synchronisation issue.
Sam

Hi Sam,

I would prefer to keep Digital Output on with AC3 as that way I get the full 5.1 Dolby Digital experience. I meant to ask is there a way of having left and right RCA coming out of Vero 2 as well as SPDIF Digital? cheers

Sorry for misunderstanding.

Yes – analogue audio output is possible. There is another small hole next to the SPDIF output and this can output Analog via a 3.5mm cable.

The audio output is simultaneous – so you won’t need to change any settings.

Sam

Awesome thanks I’ll give that a try :slight_smile: