I just bought a new LG C2 OLED TV and have been using the Shield TV for 4K in place of my old ATV HD which was limited to 1080p. However, I notice some frequent judder on some programs (e.g., "Father Brown" on Britbox and "Transatlantic" on Netfilx.) No judder experienced under the old ATV HD with the Panansonic plasma. Will the ATV4K eliminate it or is it caused by particular LG picture modes and not the streaming box?
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Resolved Will ATV4K eliminate Shield TV Judder?
- Thread starter marstan
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The shield can eliminate judder if the app has that capability built in or one uses a 3rd party refresh rate app such as “Refresh Rate” app found on google play store.
Personally i use apple tv 4k for streaming services and the shield for plex type stuff so i don’t have to mess with setting the refresh rate manually.
Personally i use apple tv 4k for streaming services and the shield for plex type stuff so i don’t have to mess with setting the refresh rate manually.
I am unsure why this problem would show up here rather than say, an NVidia Shield forum where owners could swap suggestions. I know there are some setting that need to be set on both* TV and the Shield TV to get the desired results.
Because I had already exhausted that possibility by checking with those folks who pointed toward a match frame rate "beta" setting which does not work. So naturally I turned toward the ATV forum to see if it would resolve the issue.
Clear enough for you?
I wasn't be rude but more about pointing people to what would be a more likely source of info.
Can you explain the differences in audio? I am only interested in 2 channel audio so is it the downmixing that differs? BTW, what is responsible for the audio management? the streaming box (ATV/Shield) or the LG? They both have audio controls. Not clear how this is done.
On the video side, the ATV seems to display everything in Dolby Vision whereas Shield does not per the picture settings on the LG OLED. Also under the ATV I can change the OLED brightness settings in the LG controls when in Dilby Vision picture mode whereas under the Shield the brightness settings are grayed out and not available. Now, I don't know what Dolby Vision really is or whether the Shield or ATV is correct in how it does it. I do know that I like the option of reducing OLED brightness and eliminating judder and the ATV does that.
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It only displays everything in Dolby Vision if that’s how you’ve set it to.
Recommended settings are 4KSDR then make sure Match Dynamic Range is enabled then Dolby Vision will only get used as and when the content requires it.
Ok. Thanks for that.
When I first fired up the ATV, it asked to install Dolby Vision to which I said yes. Apparently, that was then the default. Now I see all the other settings. I presume Apple has some documentation somewhere on all these settings?
Thank you again.
I know a fair amount about audio and computer monitors but little about consumer video where I have been stuck in 1080p world for the last 12years.
Apple TV supports Dolby Digital Plus which means DTS-MA audio has to be transcoded. Shield TV will play lossless tracks without transcoding.
I presume DTS-MA digital output through eArc only and not the optical digital output? In any event, transcoding doesn't necessarily mean lossy; it could be sample rate conversion from 96/24 to 48/24 which is not really lossy like MP3 type compression and either of which is outside the audible range. Now, SRC from 96 to 48 does move the digital cutoff filters down but I am not sure that these filters alias down into the audible range any more these days. I am guessing the optical output of DTS-MA on either the Shield or Apple is 48k/24 at least for 2 channel if not 5.1? (Optical is all I have as I don't use a receiver and don't have access to ARC; and I don't do surround).
Yes optical can't do lossless DTS-MA. Pouring a full bucket of water into a smaller one, such as when you transcode from 96 to 48, is going to throw away data and is therefore lossy.
You are talking about an optical out port on a TV?
It may be technically lossy but there is no audible signal in what is "lost" from sample rate downconversion from 96 to 48. Remember the sample rate represents approx half the frequency captured so 96 captures up to around 48khz and 48 captures 24khz both well beyond the audible range of human hearing. The real lossy codecs throw away data in the audible range and substitute interpolation for the missing data - definitely not pleasant for massed strings or voices, for example. I think the only benefit of the higher pcm sample rates was moving the brickwall analog cutoff filters so far up that they can't alias distortion back into the audible range. More sophisticated filtering may have solved that problem now so, if true, those higher sample rates no longer serve a useful purpose for listening.
Yes, talking about the optical out on the TV. By the way, when I look at the DTS-MA or TD tracks on all my video recordings they are almost all 48K/24bit and usually all multichannel with no separate 2 channel mix. So probably SRC not necessary but downmixing to 2 channel for sure. So even ATV will output 2-channel 48k/24, right?
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There are a lot of people and at least one study that disagree with this statement.
Yes, but are they credible? Citations would ordinarily accompany such a statement but I don't think we want to go down that rathole here.
There are many other factors in audio much more important than sample rate. The effects of room and loudspeaker distortion, for example, are orders of magnitude greater than any possible audible differences between 96k and 48k. Better take care of those before you even begin to worry about sample rate resolution.