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View Full Version : HD Content Slow Streaming - Do I Need a New Router?




Icarus73
Jul 23, 2012, 09:41 AM
Hello friends,

It's next to impossible to stream HD content to my ATV(2nd gen), which is separated from my router by 1 wall and about 30 feet.

Even on my ATV (3rd gen) it's better but still quite slow to buffer and finally play. I'm talking about home sharing, as this is how I mostly use my ATV.

My router is a 802.11n AirPort Express (the old kind that plugs into the wall). It's located immediately next to my 27'' mid 2011 iMac. I've used the WiFi diagnostics tool built into OS X, and it appears that it's simply a weak signal. I'll attach a screenshot.

Would I benefit from an airport extreme or another brand of router? Thanks!



jetlife2
Jul 23, 2012, 09:56 AM
That is not a weak signal. That is a fantastic strong signal. -45dB signal and -102 dB noise. Transmit rate is 144Mb/sec.

For context, That is 2X what I get. My signal to noise is about 20dB worse. No problems.

If you are suffering from buffering, etc. the problem is somewhere else in the setup. You mention home sharing so the content is being served up by the host computer that is running itunes. I would troubleshoot the connection of that computer to the network. I would also check the CPU load on that computer, in case it is being dragged down by some other process.

How is the performance on SD content? What is the encoding on the HD content that has the problem?

Cheers

leigh103
Jul 23, 2012, 10:11 AM
It's worth noting that 144Mb/s isn't the throughput, it's the link speed. Other factors, like packetloss - or as suggested other network/disc issues with the host machine can attribute to problems.

I've done extensive diagnostics to perfect airplay mirroring, and whilst graphs suggest everything should be working properly, there's lots of outside factors which can affect throughput.

Getting another router won't help - unless you want to move to 5GHz, but tweaking your settings might. The first thing to do is change the multicast rate, to 'high'. This is a hidden setting in the new airport util - google this to find it, or download Airport Util 5.6, as it's easier to find.

You're also using channel 2 - if there's other wifi networks in your area, it could be affecting the managment of the packets hitting both networks. Generally wireless uses 'wide' channels - so the traffic can actually be on more than 1 channel. To overcome interference, routers can work with each other to transmit the data cleanly, but only if the base channel is the same. You should always pick the quietest channel, but it's recommended to use the same channels as other routers - which are generally odd numbers. Using an even number actually hinders this management, and can make interference worse.

Use ethernet where possible. Obviously this might not be an option with an Express, but having too many wireless devices can create load on the wifi part of the network. Also depending on your setup, if you have another router handing out IPs via DHCP you may have collision zones, which create bottlenecks in your traffic.

Lastly, I updated my Express to the latest firmware. Using Wireshark on my network, it showed my iMac was chatting to my AppleTV every 5 secs - for no reason. Updating the firmware stopped this - a little random really, but it's worth mentioning.

EDIT: I also get buffering on ATV2, playing 1080p content from my phone - I assume this is related to downscaling to 720, but it's a bit of a guess.

mattopotamus
Jul 23, 2012, 10:27 AM
I always use to have issues with HD content stopping to buffer and then I bought airport express and have not had the issue once. BASTARDS want my monies!

edit: I just re-read you already are using the airport express....i have no answers then :(

HobeSoundDarryl
Jul 23, 2012, 10:49 AM
Unplug :apple:TV, wait 30+ sec, plug it back in and try again. I think there's some bugs in the :apple:TV as this works for me every time it seems to get bogged down.

Also, I think I'm noticing a relationship that if I add any new video to my iTunes library and I don't close and then re-open iTunes, I can also get a lot of slow downs.

I think there is also a relationship between having the iMac sleep each night and these kinds of problems (as it seems to be less frequent if I don't put the Mac to sleep).

I'm all wired Gigabit so I expected my own media to flow like a rocket from computer through AEBS to :apple:TV3. Instead, I often have to do both of the above after watching just a few things on :apple:TV.

After the cold reboot, all works as I generally expected. But only for a while. Then, files seem to buffer slower and slower until I feel forced to do the above. Try it and see if it works for you. If so, let's hope Apple fixes the bugs soon.

leigh103
Jul 23, 2012, 01:22 PM
Unplug :apple:TV, wait 30+ sec, plug it back in and try again. I think there's some bugs in the :apple:TV as this works for me every time it seems to get bogged down.

Also, I think I'm noticing a relationship that if I add any new video to my iTunes library and I don't close and then re-open iTunes, I can also get a lot of slow downs.

I think there is also a relationship between having the iMac sleep each night and these kinds of problems (as it seems to be less frequent if I don't put the Mac to sleep).

I'm all wired Gigabit so I expected my own media to flow like a rocket from computer through AEBS to :apple:TV3. Instead, I often have to do both of the above after watching just a few things on :apple:TV.

After the cold reboot, all works as I generally expected. But only for a while. Then, files seem to buffer slower and slower until I feel forced to do the above. Try it and see if it works for you. If so, let's hope Apple fixes the bugs soon.

^ Rebooting's defo worth a try, however this problem to me sounds like a routing issue. Could be that your reboot refreshes the devices network connection, rather than the software in the device - I'm just guessing tho, but it might be worth factory resetting your router.

After my diags, I don't have any issues with any streaming - so if it were a bug in the software, you'd think there'd be more people with this problem.

Btw - I work for an ISP in the UK, in the hardware team (just incase you guys are wondering why I keep sticking my nose in :p).

I think wireless has to catch up with Apples ideas (802.11ac :)) - it's currently not a perfect solution, but I've got it all working pretty sweet now, and I don't mind sharing any information I have - the info out there currently is fairly pathetic from what I've found.

HobeSoundDarryl
Jul 23, 2012, 02:47 PM
Thanks for the feedback. I'm using Apple AEBS for my router. I would think that would be an ideal router between the iMac where the videos are stored and the :apple:TV3 where they are pulled and then pushed to the HDTV.

I'm all wired- no wireless. All gigabit over tested cat5e cable until the :apple:TV (which is hardware limited at 10/100).

I'd like to defend Apple and say it's not some bugs somewhere in this all-Apple chain, except there are a lot of people posting on Apple's own discussion boards about these kinds of issues. Also, the old :apple:TV1 didn't have this problem with the exact same setup, cabling, router, etc (but I couldn't feed it 1080p video).

I've shared what seems to work from me. I can't seem to pin it down to just one thing (an iTunes bug, an :apple:TV3 bug, both, neither) but the speculation on Apple's discussion boards is that it's an iTunes bug: something about how many connections are established via home sharing and timing out... possibly related to "energy saver" sleep/wake cycles but maybe just an unfixed bug in iTunes.

Some discussions imply this is a wired-only problem (that switching to wireless seems to be a temporary solution). But not everyone agrees.

leigh103
Jul 23, 2012, 04:07 PM
Without wanting to thread jack (it's all related I guess)...

I'd still factory reset your Extreme, anythings worth a try when you're diagnosing something - if not just to tick off things that arent causing the problem. If you can't find out what's causing it, find out what's not causing it :)

I use a Time Capsule now, same router portion as the Extreme obviously, and i noticed better performance when using the older Airport Util. Setting the multicast rate made the biggest difference.

Whilst I can't say for sure that it isnt a bug in iTunes, I have managed to resolve most of the issues I've had with wireless streaming/mirroring etc - using all apple gear and latest iTunes such as yourself. I've tested the appletv wired and wireless, and my iMac is always wired (GigE) - and it never seemed to make a difference. It was always the router that seemed to affect it.

Using 5GHz has also helped a little. But do a factory reset which will clear out the routing tables, set it up fresh - don't use a backup, download the 5.6 AP Util, give your devices static LAN IPs, set Multicast Rate to 'High' and use wide channels. Also, as I said, use the quietest odd numbered wireless channel you can find - if you're gonna be testing wireless.

Could also test your Hd streaming before you reconnect all your other devices as well??

One other thing - could it be the codec of your video? Maybe try a number of different sources, and maybe a HD trailer from iTunes. Test other devices, other websites - anything you can think of.

I never really had strong confidence in the Apple support forums, but I gave up reading when I heard someone whining about airplay, when they had a 10Mb/s DSL connection - 'surely that's quick enough'. Gave me a laugh tho.