Judder issue after skipping adverts?

Channels Apple TV Troubleshooting
#1

In the last week or 2 I’ve been experiencing an issue with frame rate judder. It happens when I first tune to a channel or start watching a recording, or more frequently right after I skip an advert break in a recording. What it looks like to me is that the frame rate gets out of sync and the picture has a slight judder. Usually pressing pause for a few seconds and then pressing play solves the issue. It doesn’t happen every time I start watching something or skip an advert; I’d say it’s about 50% of the time.

Setup details:
Channels DVR: 2017.12.13.1901
Channels ATV: 12.14.53 beta
Apple TV 4K, tvOS 11.2.5 (15K5539b)
Deinterlacing Mode: Linear (50 FPS)
SDR Mode Switching: On App Launch

The Apple TV is set to 4K HDR 50Hz as default with range and frame rate matching enabled. I’m not seeing the issue with any other apps on the ATV. Any ideas?

Issues with HDR/SDR settings [UK Freeview]
#2

No one else experiencing this? I’ve also noticed it sometimes occurs when a channel switches from the programme to an advert and back (I’m letting it play as normal, no interaction from me). I’m wondering if there are subtle changes in the stream that the decoder is coping with well.

However, I’ve tried to eliminate any potential equipment issues by trying different HDMI cables and connecting the ATV directly to the TV vs going through the AV receiver. No change in behaviour.

TV: Sony KD-55XE9305
AV: Sony STR-DN1080

#3

Pretty strange. Nothing comes to mind that could cause this.

I’m planning a major upgrade of our a/v libraries for the next beta, so perhaps this will go away once we sync up with the last year’s worth of fixes in ffmpeg.

#4

Good to know. I remember reading somewhere that there is some kind of strange issue between Sony Bravia TVs and the ATV 4K frame rate matching feature, but I can’t for the life of me remember where I saw it. But I’m not sure that’s what I’m seeing since I only have the issues in Channels. Infuse, Plex, Netflix, Amazon etc all seem to be fine.

#5

Just to double check, this is with in-home streaming at Original Quality right?

#6

Yes, in home and original quality.

#7

Could these issues be related? Video stall during h264 recording playback

#8

No change in what I’m seeing, but I’m starting to think this affects H264 channels/recordings only. I don’t watch or record MPEG2 channels very often, but I’ve not noticed this judder issue with them.

#9

Did this go anywhere, i am seeing the same issues in the UK on certain channels, looks very similar to a frame rate mismatch, but isn’t as TV is set to 50hz. It only seems to effect H264 HD channels, but i see it often when i am watching channels that aren’t live. It never seems to happen on Live TV from what i can notice.

#10

Still happening for me as well. I do wonder if it’s somehow related to frame rate switching since it seemed to start roughly around the same time as that feature came available. My ATV4K is set by defaullt to 4K@50Hz SDR with auto frame rate and HDR matching switched on. Channels is not set to change HDR modes (it shouldn’t need to with my default settings). I see the stuttering on H.264 channels usually after skipping adverts, but not always, and sometimes on its own without me initiating a skip forward.

I don’t see this issue with any other app (Plex, Infuse, VLC, Netflix, Amazon, etc), so I’m fairly certain it’s some sort of interaction with Channels.

#11

I have my system setup by default 4K@60Hz, HDR so seems it’s not specific to a 50/60 SDR/HDR default config. I do have switching enabled though so guess we’re both technically running things at 50Hz/SDR when using channels.

I also do not see this in other applications, everything else is satisfyingly buttery smooth since Apple implemented it, which make this all the more frustrating :frowning:

#12

Maybe a go fund me to send Aman to the UK for a week?

1 Like
#13

I can sort VPN access to my network instead . . . . .

#14

Sent over an alpha build to try out

#15

Thanks, will check it out and let you know if i see any improvements.

#16

I think this sounds like something I’ve been seeing, also with live TV channels in the UK (HD & SD). Its not very easy to reproduce and sometimes I can hear a slight audio glitch just before the video starts to look like a frame rate mismatch (though its not). Sometimes returning to the guide and tuning to the same channel solves it, sometimes having to do this twice and other times quitting Channels solves it.

Just for reference, full gigabit LAN, appletv4k, channels 3.1.8 and an HDHomeRun Quatro.

#17

Thanks, will test over the next couple days and let you know what I see

#18

Have watched a few recordings this evening, don’t see any change using the alpha build. Still getting judder after skipping forward or back on H.264 recordings. Pausing for a few seconds still clears it. Don’t have issues when watching live.

#19

Thanks for the alpha build invite, however I’m still also suffering the same problem with this build.

#20

I am also still seeing the same issues with the Beta build, no noticeable change at all.

Gareth