Stutter watching Live TV on ATV (non-4k)

Channels Apple TV Troubleshooting
#30

I just sent another round in playing at "Original". For the first 20-30 seconds I didn't notice any stuttering and only saw it dropping 1-5 output frames every 10 seconds or so. Then the rate continued increasing until it was just stuttering all over the place, dropping 50-60 frames every few seconds unabated.

I sent in my diagnostics at this point.

Then I continued testing to see what the highest working bitrate was. 8Mbps still had lots of dropped output frames, unfortunately, but 6Mbps was almost zero (maybe 50 frames per minute, or even less). That's better than before (I think).

One thing I noticed: with the current latest betas on my DS1520+ and my Apple TV, I see the stats reporting ~93seconds of buffer at "Original" but it seems to max out at 5seconds with any of the transcoded versions. I think this is new, but I could very much be misremembering. Anyway, it didn't seem to negatively affect my ability to jump forward/back with any of it.

I hope this all helps, but please just let me know if you need any more data or diags. Thanks so much for digging in for all of us!

#31

You may also want to swap out that ATV.. I have 3 ATV's all hard wired to the same switch and have zero issues. Those speedtest numbers were really bad over your LAN. You also said you have no issues with other clients. The common point seems to be your ATV. Grab one from Walmart or bestbuy, try it and if it doesn't fix it then return it :wink:

#32

We've noticed an issue where bringing up the stats for nerds causes frame dropping. Without the stats enabled do you still see the stutter?

#33

You're right that there's an Ethernet anomaly, but over Wi-Fi I'm getting ~200Mbps, so I don't think that's the issue.

#34

With "Original" I was seeing the stutter consistently, yeah.

#35

200 is still slow. I am getting nearly 500 with a $20 device.

#36

Wi-Fi introduces a lot of variables. In my environment, 200 is consistent with other Wi-Fi devices, for sure.

#37

And that $20 device is likely using a more modern chipset for wifi, whereas the Apple TV HD (non-4K) is 6 years old, which in streaming devices is positively ancient. That's not a proper comparison.

1 Like
#38

Yeah but if ethernet is a problem on that ATV then what else is having an issue. Plug a laptop into that cable and run some tests. If everything is fine then it's your ATV.

#39

this could be unrelated to OP’s issue but here’s another data point: I was experiencing pretty bad stuttering with the experimental video driver only. Default was fine. After a reinstall the experimental is back to being buttery smooth.

1 Like
#40

A 4k stream only needs 20Mbps.

1 Like
#41

Yeah, I think we're (likely) getting off on a tangent here with the speeds because nothing about the Channels app indicates there is a network speed issue, but... to put this to bed:

Ethernet

  • Speedtest App on ATV using Ethernet: 94Mbps up, 94Mbps down (it's a 100Mbps Ethernet port)
  • Port 57000/speedtest on Ethernet with no other apps running and nothing streaming to Channels: 20Mbps-40Mbps (varies wildly, almost like the app itself can't keep up)

Wi-Fi

  • Speedtest App on ATV using Wi-Fi: 351Mbps down, 399Mbps up (I'm on gigabit fiber)
  • Port 57000/speedtest on Wi-Fi: 210Mbps reported

No other apps (Plex, VideoStation, Infuse, Apple TV+, Netflix, etc) have trouble with stuttering on this Apple TV or network. It really is limited to channels only. AND... if I'm streaming to my M1 Pro-based MacBook Pro, iPhone, or iPad (all running the Apple Silicon app), I can stream at full bandwidth and not experience any stuttering.

So it's Channels (only) on this Apple TV (only), and I'm pretty confident that the network is solid.

I wish there were a way to look at Activity Monitor on the Apple TV to see if my theory about Channels just hitting a CPU wall is correct.

#42

Instruments on macOS may let you see cpu activity.

I'm uploading a TestFlight build which could help if that is in fact the problem.

1 Like
#43

Good luck streaming any of the 4K Jellyfish test videos with only 20Mbps.

#44

I tested this briefly earlier today and the difference was instantly noticeable. I set it to "Original" quality, then started playing the same file I've been having trouble with, and it just started playing. In the past, even "success" meant seeing it stutter for 5 seconds at startup and then settling in. This was, smooth, silky 1080p right from the get go. I loaded up the geeky stats and confirmed. No dropped output frames.

I only tested for a few minutes, but it seems like this is the answer.

2 Likes
#45

Ok, yeah, we watched a show for an hour (CBS recording from TVE) and had zero stutter/skips. I'm calling this one solved, but I do have a question...

Is this issue somewhat new? I swear 6 weeks ago this wasn't there, but... maybe I just overlooked it back then?

1 Like
#46

My guess is this started with one of the tvOS 15 updates. Performance took a dive on those old A8s

1 Like
#47

Makes sense. And thanks for digging in and finding a fix for us all!

1 Like
#48

Most of us don't use 6+ year old devices! So was it really a fix for us all?

#49

Seems like it given that there were some folks with current-model Apple TV 4K units experiencing the exact same stuttering.

1 Like