Why is Apple TV 4 playback so choppy?

BarryXSharp wrote:

vazandrew: I don't see that as being necessary nor pertinent to assessing this issue. However, just to settle this I will test my ATV4 at my son's house who has a different ISP and his own home LAN. Of course he doesn't yet have this issue as he does not own or use the new ATV4. Now if the issue persists at my son's house will that satisfy you and Winston ?

Having seen what you have been prepared to write here before it was removed, no it wouldn't satisfy me.

I've been a member of these forums longer than most people here and that includes you. I've seen people come and go. Many people provide very constructive and polite responses/advice. You persist on saying there's not an issue with the ATV4 because you do not have the same issue being reported here. That is only a very small piece of helpful information and a single data point. My posting that was removed was well intentioned but obviously was considered as breaking the forum rules.... Adviz and myself have repeated and persisted in trying to figure out what all is going on with our ATV4 playback issue. I also believe we've presented our case clearly and I've even accepted to test at a different location. So, bear with me and let's see what happens at my son's house when I test the ATV4 to see if the same issue I have at home repeats itself.

When a person reports an issue here, it's not very constructive to respond, 'well it doesn't occur for me and therefore is not an issue'. Unless it's prefixed with say FYI this really is not helping the people who are having the issue.

For those people that do not have the issue articulated here by Adwiz and myself can you indicate if the media download progress bar keeps ahead of the playback at all times or at leasts keeps pace with the playback of movies ? Thanks. I ask this as the issue I'm seeing is related to the playback reaching the media download point on the progress bar and then stalling waiting for more data as indicated by a spinning cog wheel.

I used the hotspot feature on my iPhone to test my dads issue (similar to what you report) we were able to confirm it was an issue with his network specifically. he then continued to dig and found that there was a deep/hidden firewall setting that was impacting his network (I'll see if he remembers the details of where/what setting). Even though other services/devices were not impacted the ATV4 seemed to be more sensitive. The hotspot feature allowed us to test onsite without having to move any devices just connecting to a different wifi network with his 2013 MacBook and the ATV4...

Protodd: Thanks for that info. I downloaded a movie this evening (it was a pre-ordered one) on my iTunes. I then use Home Sharing on my ATV4 to play the movie. To my astonishment the progress bar showed the data streaming in at a high rate and reached its furthest travel point by the time the movie playback barely got to 10 secs into the movie play. The movie played flawlessly as one would expect.

I've never seen the progress bar move across so quickly as it did this evening. This movie data was transferring from my MacBook Pro8,3 over to my Apple TC 802.11ac via direct ethernet cable and then across my 802.11ac home Wi-Fi LAN to the ATV4. The distance between the TC and the ATV4 is some 20 feet at best and completely clear of any obstacles.

So I now have several cases where playback stalls all the time, stalls sometimes occassionally and no stalls at all. All of this on the same Wi-Fi network. The worst stalling has always occurred when streaming the movie data from the internet (presumably from Apple Servers located who knows where) after renting/purchasing on the ATV4. When stalling, it's clear as the progress bar crawls along and playback readily catches up to the data download point.

I will admit that this evening I booted the ATV4 (powered it up I mean) before playing the movie via Home Sharing. So I wonder if the boot-up of the ATV4 had something to do with its marvelous performance for me.

When you say you used your iPhone's hotspot feature to test your Dad's issue, what exactly did you do and observe for this test to reveal it was specific to your Dad's network ? I do not use a firewall. My setup is very simple. I have FiOS for my ISP with a 50 Mbps download service. It always performs at this level whenever I've tested it and have done so when I've had movie playback stalling on my ATV4. The FiOS router connects to my Apple TC 802.11ac's WAN port. The TC provides the Wi-Fi service for mob home. My ATV4 connects to this Wi-Fi network and does not connect using ethernet. I have used a direct ethernet connection from the TC to the ATV4 and that has not improved or reduced stalling when renting/purchasing movies on the ATV4 rather than on iTunes and Home Sharing to the ATV4.

I'd appreciate you posting back your hotspot testing details. However, if it pertains to a weird firewall setting it may not help me because I don't use a firewall.

Thank you.

So, this movie I just played via Home Sharing from my Mac played flawlessly. So now I used the ATV4 to goto Movies and selected the movie I had purchased on my iTunes and selected it to play. This caused the movie to stream from the internet and from the Apple movie content server rather than from my Mac using the Home Sharing feature. I wanted to see how this method played back.

This time it was flawless with no stalls. The data progress bar kept well ahead of the play position at all times. After 10 mins of viewing the data progress bar was at the 50% position.

So either I must have a transient flaky home LAN or the ATV4 will at times simply not buffer data quick enough to avoid stalling the playback. I'm at a loss how to determine which is to blame for the stalling issue.

I've done some more testing.....

I connected my ATV4 directly to my Apple TC router via ethernet at around 11:30 am PST today and purchased a movie on the ATV4 I've wanted for some time now and it appears to be streaming to the ATV4 very well. The progress bar as shown on the TV after some 3:22 was at the 30% mark and well ahead of the playback mark. I let it go for another 30 mins to see if the playback catches up with the progress bar point. So far this is very revealing, and if this playback without stalling continues I will invest in a cable between the ATV4 and my router. I may have to insert a switch as all the ports in the router are in use, but can take out the networked printer for testing at this time.

I'm now left with what's up with my home LAN Wi-Fi. The router and the ATV4 are but 20-feet apart with a clear line of sight.

Continuing on here.... I paused the movie playback and the progress bar continues to move to the right quite speedily. It now reached the 80% mark while pausing playback..... and now it has reached the 100% mark indicating the full movie has downloaded to the ATV4 buffer(s) (my ATV4 is a 64GB model). I would say the 100% was reached within 5 to 10 minutes easily. The movie is stated to be 4GB HD in size on iTunes. So with my ISP's 50 Mbps down service that's 6.25 MBytes/sec. Thus at 6.25 MBytes/sec the 4GB movie file should completely arrive in around 10.7 minutes.

To make the measurement more accurate, I powered cycled the ATV4 and streamed the movie again to precisely time how long it takes to get to 100%. It took 5:40 mins to reach 50%. It took 11:28 to reach the 100% mark. This result is very good.

I'll now run the same test using Wi-Fi to the ATV4.

Could it be time of day I wonder ? If Apple movie content server becomes overloaded then streaming would be affected, right ? I'll keep testing using the direct ethernet cable at various times during the day/night to see how consistent the streaming is.

Using Wi-Fi connection to the ATV4 the complete movie download took 11:15 to reach the 100% mark.

So, my conclusions are

1) My Wi-Fi and ethernet connection provides the same performance and downloads at around 50 Mbps and is being achieved during midday.

2) The movie playback stalling issue is not an issue with the ATV4 software/hardware not buffering data.

3) The stalling is caused by either a transient home Wi-Fi performance variation or poor streaming from Apple movie content server or my ISP's 50 Mbps service is not living up to my contract.

4) As I've tested my ISP's download speeds to be 50 to 53 Mbps during the periods where I've had serious stalling I'm eliminating my ISP for being the culprit for movie playback stalling issue.

5) I'm therefore left with the stalling issue being a transient home Wi-Fi performance issue or Apple's movie content server does not stream the movie data fast enough at certain times of the day.

Spoke to my dad and he clarified, it wasn't a firewall setting rather IPv6 on the router that he disabled and that seemed to resolve his download issue.

I cant imagine that one of the biggest streaming providers would have an issue at certain times of day that would be so severe that it would cause the issue your dealing with. But weirder things have happened.

your sporadic issue reminds me of an issue I dealt with a few years ago. I have a cabin about an hour away so I go often and stay for extended periods so I would take the ATV 2 with me. I started to see big issue about a week after the Forest department installed some sort of pump near my property line. I could get great wifi on my MacBook or iPhone on the back porch but outfront or inside it was useless unless I was connected via Ethernet but only for 5-15 minutes intervals every couple hours. After about 6 months I started to realize I could hear the pump every time I went down (very faint) I know the ranger so we met up to take a look. Although they wouldn't pay for anything, they allowed me to build an enclosure for the pump and I added some RF insulation. Long story short, 60$ in material and a 6 hours in the man cave (garage) and another hour in the field for install here I am 5 years later without any relapse. I know now what your dealing with and don't discount the possibility of a neighbor or something in the neighborhood in general either...

Hello all, I wanted to concur that I too have been experiencing choppy playback through my ATV4. I have a pretty higher end set up. 2015 75" Sony Bravia XBR, Marantz 4K Reciever, and used all audioquest hdmi cables. ATV4 is defective. All my other devices playback flawlessly. I'm just going to plug in my ATV3 until Apple figured out the issue. I have spent hours modifying settings. I just want to enjoy a crisp picture without watching my HD content skip frames during playback. I don't have a solution unfortunately but I wanted to let others know you aren't crazy. If I figure something out I'll be sure to post it here. I also wanted to add I don't think it's network issue. My ATV4 is plugged in directly to the router and here in SoCal I get 50 Mbps down.

Hi Everyone,

i bought the new apple tv 4th gen today and i am having the same problem, when i go to the movies section and select preview nothing will happen and it will get stuck trying to buffer, it seems to me this issue is with apple tvOS software itself, so i restarted the apple tv and choose the same preview again and it worked instantly, i went a head with another movie preview and it's stuck again, tried every movie and nothing works.

i am upgrading from apple tv 3rd gen and never had this issue before with buffering. this is weird, so i downloaded speed-test and i get full speed (25 Mbps down and 6 Mbps up), so i thought maybe plugging a direct Ethernet cable to my apple time-capsule router will solve this issue.. and guess what.. nothing changed.. so definitely this issue is with apple tv software which should be updated to resolve this bug.. other apps like YouTube/Netflix work fine.

update: problem is solved for me without any intervention, i guess apple servers were overloaded when i tried the first time.. everything works now.

For the most part the issue with movie playing stalling using my ATV4 has not been a problem since my last posting. However, last night the issue happened again as just as severe to when I first struggled with this before. I now have a switch in the ethernet connection between my Mac and the ATV4. The Mac also connects to this switch which is connected directly to my Apple 2TB Time Capsule 802.11ac router. So streaming from Apple's servers means data from the router goes to the switch and then onto the ATV4. If I'm streaming from my Mac the data goes from my Mac to the switch and then onto the ATV4. This connection is a 1GbE so it can handle 100 MBytes/sec easily. My download service is 54 Mbps and testing this on my Mac and using SpeedTest on the ATV4 shows I'm obtaining this speeds.

Last night I had rented a Movie via iTunes and waited for it to full download to the Mac. I then used the ATV4 Home Sharing to stream this rented movie from the Mac to the ATV4. It was terrible, with many stalls and the movie was really unwatchable.

I was very annoyed as you can imagine. So in desperation, I power cycled the ATV4 and started the rented movie again. This time the ATV4 buffered the incoming data well ahead of the playback, and after maybe 8 to 10 minutes into the movie I checked to see how much data the ATV4 was holding and it was at 100%.

Not sure what to make of all of this at this time. However, given that I have a switch between the ATV4 and the Mac and also between the ATV4 and the router I can watch the switch's activity LEDs for data movement to the ATV4. When I had the stalling situation I noticed that the LEDs were flickering crazily but the movie play was stalled. What does this indicate ? My guess is that for whatever reason the ATV4 is refusing to accept the incoming data or that there's some form of many many retries for moving the data from the Mac or the router/Apple to the ATV4. Given that the issue was resolved after I had power cycled the ATV4 I'm apt to believe the issue was in the ATV4 buffering hardware/software. The only way I see to determine what's going on in this situation is to 'sniffer' the traffic on the ethernet between the ATV4 and the Mac and between the ATV$ and the router. I will be figuring out how to do this and have something setup so that when this situation arises again I can obtain more meaningful data that hopefully will lead me to some conclusion(s) about this stalling issue.

I've finally nailed this problem down. Here's what I came up with showing a tcpdump of the traffic between my MacBook Pro8,3 (17-inch, late 2011) using Home Sharing on my ATV4.

For any with an interest in knowing how I went about collecting the TCP/IP traffic between my MBP,8 and my ATV4 for performing this test here's the info.

I performed this test under 10.11.3 again today and collected some tcpdump information. Here’s what I did step by step

1. First I made my iTunes purchased movie Interstellar movie memory resident using Terminal and executed the cksum command to read the complete Interstellar movie file from my iTunes library. Here’s the command I executed

cksum /Volumes/BIG-1-iTunes-Movies-TVshows/Music/iTunes/iTunes\ Media/Movies/Interstellar/Interstellar\ \(1080p\ HD\).m4v

2. The I executed the following tcpdump command

sudo tcpdump -nvvv -i en0 '(src host barry-17inch-macbookpro-el-capitan.local and dst host apple-tv4.local)' -w ./tcpdump_raw_output

3. Now I started the playback of the Interstellar movie on my ATV4 using Home Sharing from my Mac->iTunes. I stated it from the beginning.

4. After 0:35 into the movie playback the movie play stalled completely. I waited some 5 mins to ensure it had stalled permanently and it had.

5. I noticed the tcpdump that was started in step 2 had stopped collecting information.

6. Now I executed another tcpdump to read the output of the tcpdump started in step 2. The tcpdump I ran was

sudo tcpdump -r ./tcpdump_raw_output >./tcpdump_output

7. I viewed the file ./tcpdump_output using the vi editor and present the last few lines here

14:48:10.421962 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53686: Flags [F.], seq 602191, ack 2787, win 4096, options [nop,nop,TS val 402340655 ecr 80963604], length 0
14:48:14.740197 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53690: Flags [.], ack 559, win 4096, options [nop,nop,TS val 402344967 ecr 80967920], length 0
14:48:14.740255 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53690: Flags [F.], seq 65804, ack 559, win 4096, options [nop,nop,TS val 402344967 ecr 80967920], length 0
14:48:18.021941 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53693: Flags [.], ack 559, win 4096, options [nop,nop,TS val 402348238 ecr 80971200], length 0
14:48:18.022015 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53693: Flags [F.], seq 131341, ack 559, win 4096, options [nop,nop,TS val 402348238 ecr 80971200], length 0
14:48:19.794735 IP6 barry-17inch-macbookpro-el-capitan.local > apple-tv4.local: ICMP6, neighbor advertisement, tgt is barry-17inch-macbookpro-el-capitan.local, length 24
14:48:19.823588 IP6 barry-17inch-macbookpro-el-capitan.local > apple-tv4.local: ICMP6, neighbor solicitation, who has apple-tv4.local, length 32
14:48:38.558001 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53697: Flags [S.], seq 612491368, ack 2448809869, win 65535, options [mss 1440,nop,wscale 5,nop,nop,TS val 402368188 ecr 80991731,sackOK,eol], length 0
14:48:38.560249 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53697: Flags [.], ack 1, win 4105, options [nop,nop,TS val 402368189 ecr 80991734], length 0
14:48:38.565174 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53697: Flags [.], ack 575, win 4087, options [nop,nop,TS val 402368194 ecr 80991737], length 0
14:48:38.566703 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53697: Flags [P.], seq 1:163, ack 575, win 4096, options [nop,nop,TS val 402368195 ecr 80991737], length 162
14:48:43.612994 IP6 barry-17inch-macbookpro-el-capitan.local > apple-tv4.local: ICMP6, neighbor advertisement, tgt is barry-17inch-macbookpro-el-capitan.local, length 24
14:49:09.208713 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53697: Flags [.], ack 576, win 4096, options [nop,nop,TS val 402395518 ecr 81022369], length 0
14:49:09.208752 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53697: Flags [F.], seq 163, ack 576, win 4096, options [nop,nop,TS val 402395518 ecr 81022369], length 0
14:49:14.263726 IP6 barry-17inch-macbookpro-el-capitan.local > apple-tv4.local: ICMP6, neighbor advertisement, tgt is barry-17inch-macbookpro-el-capitan.local, length 24
14:49:14.390541 IP6 barry-17inch-macbookpro-el-capitan.local > apple-tv4.local: ICMP6, neighbor solicitation, who has apple-tv4.local, length 32
14:49:23.556729 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53698: Flags [S.], seq 3678166563, ack 1463805717, win 65535, options [mss 1440,nop,wscale 5,nop,nop,TS val 402408301 ecr 81036715,sackOK,eol], length 0
14:49:23.558390 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53698: Flags [.], ack 1, win 4105, options [nop,nop,TS val 402408302 ecr 81036717], length 0
14:49:23.562105 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53698: Flags [.], ack 575, win 4087, options [nop,nop,TS val 402408305 ecr 81036720], length 0
14:49:23.563617 IP6 barry-17inch-macbookpro-el-capitan.local.daap > apple-tv4.local.53698: Flags [P.], seq 1:163, ack 575, win 4096, options [nop,nop,TS val 402408307 ecr 81036720], length 162

Here’s the shell script I used to perform the above steps.

#!/bin/ksh
echo check-summing Interstellar movie file to make it memory resident
cksum /Volumes/BIG-1-iTunes-Movies-TVshows/Music/iTunes/iTunes\ Media/Movies/Interstellar/Interstellar\ \(1080p\ HD\).m4v
echo Starting tcpdump to gather data to ./tcpdump_raw_output
sudo tcpdump -nvvv -i en0 '(src host barry-17inch-macbookpro-el-capitan.local and dst host apple-tv4.local)' -w ./tcpdump_raw_output
echo Starting tcpdump analysis with output going to ./tcpdump_output
sudo tcpdump -r ./tcpdump_raw_output >./tcpdump_output
echo launching vi to examine the tcpdump analysis file ./tcpdump_output
vi ./tcpdump_output
exit 0

Hello Adwiz, I read through your last reply but did not make out what your conclusion actually was? Could you explain, for those of us who can't follow the output of what you pasted, in plain english the results of your TCP dump please : ) Thank you.

There might be many reasons for this issue to occur. I'm having the exact same issue: ATV 4 has the choppy playback, while ATV3, plugged via the same Ethernet cable, does not.

one reason could be, of course, buggy tvOS. I bought my ATV 4 on the day it came out, saw the issue and switched back to the ATV 3, thinking it was the software issue. But two new versions of tvOS later the issue still persists. Which makes me think this might actually be a hardware issue. And the two primary suspects I have are:

1) the Ethernet port doesn't correctly autonegotiate the protocol (for example it might "detect" a 10 megabit half-duplex instead of 100 megabit full-duplex).

2) the flash storage is too slow/bad.

It sounds like not all people have this issue, so I'm curious if there's a connection between flash storage size. My ATV 4 is the 64 gigabyte version. I'm wondering if those who don't have the problem all have the 32GB version... If so - this would put the problem squarely on to the flash storage.