Question

Audio Drop on Line IN

  • 21 October 2019
  • 7 replies
  • 80 views

Greetings,

 

I have issues when playing Apple TV or any line in device where the audio drops out when compression is set to Automatic or Uncompressed. When compressed is selected, there is no audio drop, but the sound and the video image are about 5 seconds out of sync.

This is a new challenge- the system has been working perfectly for two years +

 

Submitted a diagnostic with confirmation # 2047042191

 

Thank you


7 replies

 

This is a new challenge- the system has been working perfectly for two years +

 

Has it worked perfectly with uncompressed line in, ever? As soon as I had to use this mode, I ran into problems and using compressed was not acceptable for the sound delay. The only way I was able to get this to work was by ethernet wiring back to the router those Sonos players that are in the zones where it is necessary to have the TV audio play in sync with the on screen pictures.

Greetings,

 

I have issues when playing Apple TV or any line in device where the audio drops out when compression is set to Automatic or Uncompressed. When compressed is selected, there is no audio drop, but the sound and the video image are about 5 seconds out of sync.

This is a new challenge- the system has been working perfectly for two years +

 

Submitted a diagnostic with confirmation # 2047042191

 

Thank you

It’s obviously a network bandwidth issue, so consider moving other network devices on the 2.4ghz band, over to the 5ghz band, where practicable.

You could also try changing the routers 2.4ghz WiFi channel, as that may reduce potential interference from neighbouring devices. 

Then consider lowering the quality of the audio source being provided as that too may help, otherwise its likely going to be compressed audio.

I will just briefly mention that if the 'Source Name' device is set to AirPlay Device in the line-in Settings that too will add ~500ms delay to the audio so ensure that is not selected in those settings.

Ken,

The root cause for this seems to not be the bit density that needs to be streamed but the very small buffer that is possible to allow video and audio to remain in sync; that is why the Airplay trick with a bigger buffer is very useful where streaming of pure audio sources is concerned where this sync isn't needed and where folks will not accept compressed mode for subjective reasons. With the small buffer, even a small issue results in music play stuttering.

How does one lower the quality of the audio source if the source is TV?; and I wonder if where a Firestick or Chromecast is the source for the TV video+audio, moving the source quality down from Best to Better if not all the way down to Good, will be a solution to reduce the bandwidth requirement for Sonos as well and allow wireless music to play in sync with the video at the cost of some sacrifice in picture quality. Something I need to test out to see if this allows my unwired Sonos zone to join the party properly.

Kumar

 

To reduce the quality of an audio source from the TV, I was actually thinking of it playing a PCM stereo audio source, rather than a DD5.1 audio source.

 

I do not normally encounter any difficulty getting uncompressed line-in PCM stereo audio to lip-sync with the video playing on my TV screen, whether that’s from an (HDMI) attached cable box or a built in App or terrestrial channel. It’s hardly discernible, particularly with the internal TV speakers or attached Sound-bar/HT System switched off, (or they can be left on and adjusted with lip-sync slider if the TV or HT/Sound-bar supports that feature). However, it’s quite a different outcome when trying to lip-sync playing  5.1 channel audio, in my experience, and I would say to always avoid that.

 

My own Sonos line-in source name, can be set to AV Component etc. and it will work fine, but choosing AirPlay Device as a source name will obviously (additionally) buffer the playing audio and cause a lag. It’s best therefore if that option is not chosen.

 

Those are the points that I was trying to cover in my earlier post.

Kumar

 

To reduce the quality of an audio source from the TV, I was actually thinking of it playing a PCM stereo audio source, rather than a DD5.1 audio source.

 

 

I have moved my Firestick audio setting from Dolby Digital Plus - whatever that is - to stereo sound via HDMI. In any case, all my TV audio is via just speaker pairs, so the DD thing must be a waste. I will have to see if this now allows the wireless zone to also play without stuttering as the wired ones do, because now the line in on the Connect that is wired to the TV line out should be getting a lower bandwidth signal...perhaps that will have an effect on downstream burdens on Sonos net.

If it does so play, I owe you one!

I thought I would look it up... Dolby Digital plus is the compressed version of Dolby Atmos. It’s what Apple, Netflix, Amazon etc; have moved to for their (Ultra HD) streaming Movie services. Dolby TrueHD is the uncompressed lossless version of Dolby Atmos, this will more likely be found on Blu-ray Movie discs. The DD+ Codec requires an HDMI-ARC connection to the TV, whilst Dolby TrueHD will need the new HDMI-eARC port.

 

I learn something new everyday. 😀

The key is also how much bandwidth each passes, which determines what kind of connection is required. Which is probably why Sonos is still Dolby Digital only, since the majority (?) of the sold home theater devices are still connected with optical, which limits what can be sent to the Sonos.

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