1080P .MKV playable?

 

Exactly right. If anyone can get 1080p working fine over WiFi, that alone means it’s entirely possible. You and me can do it, many others can as well.

 

However it’s not the AppleTV 2 that causes the problem, it’s XBMC.

 

I know that sounds weird… but my personal experience can prove this. Every version of XBMC on my AppleTV 2 has had buffering issues for the past 8 months of versions. This is over WiFi. It will play for about 5 minutes and then need to buffer for 30 seconds, again and again.

 

Where as when I use ATV Flash, no issues what so ever. I can load huge 1080p movies in seconds, and experience not a single mid-stream buffer.

 

There must be some sort of issue with the way XBMC buffers content on the AppleTV, where as ATV Flash doesn’t have this issue.

Ey guys you have a problem with your network.

Apple tv 2 works faster using wifi n (5ghz) that using ethernet… at least to me… Besides my mac mini placed from the router to 5 meters of distance can download to 9-10 MB/s (80 mbits)

Shame on me, I fell for Stingray’s praise of the Flash aTV and ordered one. What a bummer. Complex, incorrect installation instructions. Impossible for me to set up support for external USB hard drives. The entire Apple TV seems buggy after installation. And worst of all, it won’t play large 1080p files worth a damn. I could have had more fun setting fire to my $30. Compared to XBMC, this thing is from the stone age. Save you money.

Complex? How? It’s not any more complex than XBMC.

No where does anyone say that any software, XBMC and ATV Flash included, can allow for playing content off of a USB drive. It’s not physically possible to do that with an AppleTV. That’s not anyone’s fault but Apple’s.

If you’re experiencing bugs, just reinstall. ATV Flash is far less buggy than XBMC.

Also, my ATV2 plays large 1080p videos just fine. If you can’t, something is wrong on your end. But considering myself and many others can, it’s obviously not the software that is the problem.

My praises are legit. This software is fantastic. Before you bash it and declare that burning your money is more worth your time, why don’t you upload a debug log while you’re trying to play problematic media so someone can help you fix it.

ATV Flash is a much cleaner experience than XBMC on the AppleTV. If your experience differs, try putting a little effort into diagnosing your problems before you write it off.

Hi,

Actually, your “math” is not considering the fact that when watching a compressed movie, the bandwidth requirement changes during play. So, the argument is simply incorrect. Clearly, one cannot simply divide the file size by its length to estimate the bandwidth requirement (and therefore if it fits or not the network capability). This kind of “computation” does not give any meaningful information regarding how well or not a network is going to support playing a given HD file. Similarly, the “average bitrate” reported during compression gives very little info too.

I can think of one specific case where we can estimate the bandwidth in such a way, however. One can compute the actual bandwidth requirement of a 1080p movie as a function of each pixel encoding: 1920x1080 image pixels, times 25 fps, times 4 bytes per color, etc. which gives hundreds of MB/s. This is actually why the spec of our dear HDMI cables is in the order of Gb/s. And, no one would argue that wireless technology having this kind of bandwidth is not for the average consumer :wink:

Luckily, we have compression. Converting your compressed movie stored on your hard drive into video signal your TV can display implies (1) communicating from a source where the compressed data is stored, and (2) a hardware/software solution (an algorithm) to convert the compressed data into a signal the TV understands. Most people tend to quickly blame (1) if they experience shuttering, frame drops, etc. But, (2) is equally important, if not more. As indeed pointed out by your experience with another software.

Let me give some bit of technical insight now. Depending on the codec used to encode/compress the movie, the quantity of data required to recreate a group of actual frames will vary. Depending on the software/hardware implementation of this codec, the quantity of data also varies. Worse, depending on the content of the group of frames, the quantity of data required varies. This is why people usually experience (more) frame drops during fast moving scenes than during close shot dialogues, for instance. This is explained by how compression works, I’ll let interested readers look at the underlying principle of such algorithms. But, you can get a (very approximative) intuition by thinking that compression works by storing the difference between two images. In a fast scene, there are a lot of differences between 2 consecutive images: there is a lot of information in this difference, that has to be stored in the compressed file (and therefore a lot of information to communicate to rebuild the 2 frames). In a slow scene, there may be a lot of similarities between 2 consecutive images, and therefore less information to store. This is a gigantic simplification, but it gives an intuition. For instance, to give a number, the official spec max bandwidth requirement of Mpeg-4 is around 40 Mb/s, if my memory is right. But almost all the time, you don’t need that much bandwidth: frames have often a lot similarities. However, I have personally observed network spikes in the order of 50 Mb/s (with all the IP/Ethernet overhead) during playback of very fast scenes of a MP4 full HD movie, meaning a movie can requite this max. bandwidth. 

So, for instance, one way to reduce frame drop is to lower the quality of the decoding. Decoders usually apply a series of post-passes (called post-processing) to improve the quality of the image. This post-processing is usually computationally intensive on the device, and can require additional data (which leads to increased bandwidth requirement). For instance, you can do a small test on your laptop with your favorite player, if it has a decent set of tunable post-processing options, and see the CPU load and disk I/O change slightly. I don’t know for a fact, but it is not impossible that the ATV flash player uses simply less bandwidth either because it applies less post-processing, or because it is better implemented. And, there is also of course the fact that some decoders (have to) downgrade a 1080p encoded video into a 720p video, which can again be implemented more or less effectively.

Now, back to the possible causes and solutions to a bad playback situation for a 1080p movie (but it’s applicable to any compressed movie, actually). IMHO, the first thing to test is the device. To test it, you must set up an environment with some confidence that the weak link can only be the device. 

Start by putting the network out of the picture, by plugging your box to a gigabit-capable network using a wire, and take your most demanding movie (I usually test with the first minute of the intro scene of Matrix Reloaded in, full HD/ MP4 (8.8GB). If the decoded quality is perfect and you have absolutely no shutter, you’re on a good track for probably any other movie). You must also have the movie stored on a very fast device, to be sure it’s not the bottleneck. I use a Intel RAID-5 server with a GB link and an excellent SAMBA implementation, so no problem there. Have someone lend you one (or equivalent) if you don’t own such a device. You can test with your desktop/laptop, but be careful it may be the weak link at some point. In particular, be careful about the protocol used to distribute the files to your box, it’s usually SAMBA or NFS, they should be well supported by your testing platform.

One of the first thing to investigate is indeed the decoding software/hardware combination. Frame drop can actually come from your tiny box unable to process the data fast enough, because you are saturating its computing capabilities. This is actually where the software part really comes into play: a well implemented decoder will rely as much as possible on the hardware acceleration for decoding, using all features of the DSP/processor. A medium-quality implementation will use more “software” instructions (soft-decoding) that are processed by the general-purpose part of the processor, which is usually way slower. And, as writing a software decoder can be deployed “easily” on more devices than writing a hardware-specific decoder, quite a few decoders are still relying on slow soft-decoding for some parts of the algorithm. My advice #1: try all possible players you can find, and see if one works better than the rest. Again, a well-implemented decoder that uses all hardware acceleration capabilities can change everything. From my personal experience, this is a huge factor.

If you still don’t have any satisfactory result, try another box with the exact same setup (have people you know lend you theirs for a test). I’ve seen astonishingly different results between boxes. I have tested 5+ different boxes, ranging from $100 to $500. The apple TV is great, but not for full HD. I however love this tiny box (I have one in my bedroom). I have found my happiness in the living room with a Popcorn Hour for my 1080p playing, FYI, it’s a good value for the money.

At this point, you now must have a perfect quality playback. It is now time to start plugging back your standard system. The first thing to plug back is your video computer server / NAS (if you borrowed this part). Usually, this goes smoothly, as it is unlikely you have major problems there. If you do, well, maybe try a different server software (e.g., WHS or whatever), or at worse replace this part of the link. There are some very effective small NAS for a couple hundreds.

Now comes the hard part. Plug back your network solution in place of the wired ethernet. If you use wireless, my personal opinion is that you are very likely to have problems for real full HD movies decoded with top-notch quality. I’ve conducted very extensive tests, and was never fully satisfied. Even 720p can be very tough for wireless, for demanding movies. If you experience some problem here, you are facing 2 choices. (1) Use wired ethernet instead of wireless. I know it’s disappointing, but very likely it’s the only ultimately reliable solution on the long term. FYI, after many, many, many tests (and I am a computer scientist, so also after any possible software tweaking possible) I gave up with wireless, and I have set up a cable between my basement and my living room. (2) Or, return to the box testing / player testing step, and see if there’s a player giving you satisfactory video quality while respecting the capability of your network. Very likely, you will have to accept a slightly lower video quality, provided you ever find a player that can meet your network capabilities. 

Now, let me conclude with a few tips/advices:

  • Tweaking your wireless network, changing the router, changing the wifi dongle of the device, etc. This can have a dramatic impact on the bandwidth. A good MIMO environment, well calibrated on the good (with less interference) canal, etc. can give excellent wifi performance. Yes. But remember my first number: a full HD MP4 movie can spike at up to 60Mb/s in a wired environment. Add on top of that all the overhead coming from wireless (error correction, encryption, etc.) and you see that a wireless budget of 100 Mb/s may be required to guarantee a smooth, top-notch quality full 1080p playback. Very likely, you will never end up having such bandwidth available with a customer-quality wireless network. And honestly, even enterprise-grade networks have difficulties reaching this bandwidth. It means, if you are set up for a wireless solution, you have to accept the idea of frame drops and shuttering, and/or lower quality decoding.

  • Using powerline adapters. It is NOT going to give you a significant improvement. The technology is good for long distance vs. wifi w/o repeaters, but a good wireless solution in a good environment can actually beat powerline adapters. I have tested a few, and the improvement over a basic wifi N is marginal. Despite a top theoretical down bandwidth of 100 Mb/s or more, in practice your house wiring will extremely likely introduce a lot of noise, quickly dividing this number by 2 or 3.

  • Re-encoding your movie using a lower quality encoding / less demanding codec. It is, after all, not always a bad idea. In terms of picture, for most movies the difference between 720p and 1080p will not change a lot your experience. For instance, assuming you have standard eyes, you must be within 9 feet of a 50 inch TV to start seeing the difference between 720p and 1080p.

 

Good luck,

 

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You can use a Slinglink Turbo which I heard they are pretty good as you dont have to drag a wire across the house just need one by your router and one in the room you need to get a wired connection.  You get them from Best Buy or Walmart to try out and see if it helps.  If not can always take it back which is a plus.  They use them to stream your tv from one part of the world to another through internet so cant see why it wouldnt help if it can do this.  

From Slingbox.com:  By providing a direct hard-wired connection from the Internet to your Slingbox or computer, you limit issues with your network conditions, enabling the best possible video quality via our SlingStream® video compression technology and the most reliable connection for your computer.


 

Jackson - You are missnig the point that you need to have an actual wired connection on the other side. The Slingbox is mainly designed for people travelling.

 

This is how it is set up:

Location 1

Router ----> Wire ----> SlingWhatever

 

Location 2

Router (or other hardwired internet connection) ----> TV

 

Simply put, all this arguing is pointless.  Some people have no problem streaming 1080p, some people don’t.  Personally I’ve seen more issues than flawless playback.  If you are primarily going to be using this device, it makes FAR more sense to get a 720p version.  Then it’s a WYSIWYG situation, and you don’t have pages upon pages of arguments as what works and why going over almost half a year.

 

My suggestion for anyone who is having problems and wants an easier wired solution, do this: Run an ethernet cable from your room with the router either within or outside the house and you can either connect it directly to the device, OR you can connect it into a wired switch, router or, if you want to be cool like me, hook it up to  your old wireless router and turn that into a wireless switch, giving your iPhone/iPad/whatever a much stronger signal in the other room. 

 

I’m living proof that carting a cable around the outside of my house is a more than sufficient way of doing what needed to be done, it’s been running like that for over 2 years now.  Other than that, you play with fire.  You might have luck, but you might not.  I bought this device so I didn’t have a “might not” situation.  Last thing I want to do is get the entire family together, sit them down, start playing a show and then going “AH YOU PIECE OF CRAP” because it doesn’t work for whatever reason.  That said, I have ample failsafe methods in place to protect against any possible failures, :)  I take my moving watching and sanity seriously.

 

Hell, I still remember trying to stream 720p over a TERRIBLE wireless B network.  Being ~100ft away from the main router through walls and walls and walls and walls killed my signal.  I get 1mbps speeds if I’m LUCY using that kind of connection.  Those were some terrible, terrible months.

I have my atv2 connected via Cat5e to my time capsule where I have a folder with MKV files. Standard DVD files work with no issue but MKV of blurays continually buffer. I have tried both media player and xbmc. Any suggestions?