Rant: Why is A/V sync so bad?

#1

Every day when watching content of one variety or another I experience A/V sync problems. Sometimes the audio gets ahead of the video, sometimes it lags behind.

I know the root of the problem is that the audio and video content take drastically different paths from the source to the viewer's eyes and ears. Different processing and transmission steps introduce different amounts of latency. Syncing that stuff up is a difficult problem, but not an unsolvable one. Why does it manifest itself so frequently? Is it a failing of the various standards that don't allow the various components to talk to each other and work out their various latencies? Or is it just poor/lazy engineering? I wish I just had a knob on my remote that I could turn at any moment to move the audio ahead/behind to manually sync stuff up.

#2

Looks like I need to buy one of these...

http://www.js-technology.com/store/product.php?id_product=55

#3

What are you watching on and where are your streams coming from ? I have never experienced A/V sync issues and We have Apple TV , Shield and FiretvCube. WE have Amazon Echo Studio and Samsung Soundbar and no A/V sync issues.

Using HdHomeRun Quatro and Prime

#4

I'm not referring to any specific setup. At one point or another, I notice some kind of A/V sync issue regardless of what I'm watching or how I watch. It just seems like a persistent, intractable problem.

#5

Knowing what you are watching on and where you are running the Server will help other forum members to help.

#6

Here's my setup:

  • 1 HDHR Quattro via Cat5 to Netgear gigabit Ethernet switch
  • 1 HDHR Prime via Cat5 to Netgear gigabit Ethernet switch
  • 1 2009 Mac mini running DVR software via Cat5 to Netgear gigabit Ethernet switch
  • Netgear Ethernet switch via CAT5 to LAN port of Netgear 802.11AC WiFi router
  • Amazon Fire Stick 4K to LAN via 5GHz WiFi (Channels app measuring 300+ Mbps to server) and to 37" Samsung 4K TV via HDMI
  • Samsung 4K TV to Bose Solo 5 soundbar via (optical) Toslink
  • Everything in audio path from Channels DVR app to Firestick config to Samsung config is set for Stereo/PCM audio only (Samsung TV can't passthrough Dolby Surround to Toslink, so I set to Stereo/PCM as far up the food chain as I can)

Again, I didn't intend this as a plea for help. Just an observation about the state-of-the-art in general. Don't get me started on the horror show that is mis-matched aspect ratios out in the wild (eg. 16:9 content letterboxed to 4:3 SD and pillboxed or stretched on a 16:9 HDTV just kills me)

#7

Does the issue happen when using the HDHR app to play the same channels?

I have had only a few random times where things got out of sync, mainly with TVE channels on my Shield, Refreshing the stream helps.

If u disable Tuner sharing on the client device, then the channel data stream is DIRECT from your HDHR tuner hardware and the channels sever is not involved with the data stream.

Is the clients set to Original for video quality for home viewing? anything else will mean the sever has to transcode.

2009 Mac mini :stuck_out_tongue_winking_eye:
well, i dont do macs, but that is 11yrs old....maybe it can't handle the workload, have u checked it status ram and hdd usage etc, maybe it needs a tuneup. A reboot?

Also, check the HDHRs tuner stats at the time it happens, see if signal stats or lock is low or fluctuating.

#8

It could be the way the TV processes the optical connection to the soundbar. It might work better connected a different way.

1 Like
#9

Oops. It's a late 2012 Mac Mini (confused it with my long decomissioned 2009 iMac).