Large (high bitrate) MVK's stutter?

Community Archives WD TV Live Firmware
1

Hi everyone,

Large blu-ray rips seem to stutter (video over 10 GiB). It does not happen immediately (well this depends on the movie but generally speaking it takes some time for the issue to roar its head). Most of the time, I can get 20 minutes of viewing, this time I got almost 40.

Then audio drops out and video appears choppy. Rewinding and (re)playing the stuttering section appears to work but once the first stutter is over the fence, it seems to happen more frequently.   I’m using Windows XP as an OS but I fail to see how this can be the issue.

I’m now transferring the movie to an external hard drive.

So far the possible culprits may be:

  • My network (which is 1 gigabit capable)

  • My computer

  • The WDLIVE HD

I’m excluding the movie as a possible source because for the time being I can confidently say it always happens with large rips. I have not tested sufficient smaller rips to make a definitive statement about those.

I’ll let you know whether it plays fine on the external drive. I’m assuming it will leaving either the player or the network as possible causes.

2

Check your network connections and possibly your computer. 

I routinely stream very large MKVs (20 - 40GB) from my NAS to our home theaters without any stutter and/or audio drop-outs.  The only time I’ve experienced anything like you’ve described is with my friends setup up, and it always was due to his crappy network setup; bad or loose connections, bad cables, etc.

3

The network should be fine (cables then, I’ve installed them myself and triple checked when I did). However, not so long ago I’ve installed a new VLAN-switch. I’m going to stream from another workstation which I’ll plug into the same switch my worstation is in and see whether this can rule out the network + computer. 

As expected, playing the MKV via an USB drive worked. No stuttering at all.

4

Alright, it seems that streaming MVK’s with a bitrate around 13-14 Mbps is not an issue. But higher than 16 may cause stutter.

So we might be able to safely rule out the computer and focus on the network. It may still be the player but next time I find a MKV that stutters, I’ll feed it to the WDLIVE via another system. I’ll also test the link bandwidth but I’m guessing I’ll come close to 90 megabit as per previous testing I once performed.

5

Try the free version of thisto test your LAN.  Run it from another computer that’s on your network with the computer you’re using as the media server as the target. 

For comparison, I have run it from one of my computers to test the speed of both my gigabit network and my NAS.  With a 5GB test file, I get about 400Mb/s writing, and 600Mb/s reading from my NAS.  These numbers are consistent with that published for my NAS and is more of a limit of what the NAS’s HDD (and the NAS itself) can do.

Back to your MKV’s.  Not sure if your MKVs are full rips or comperessed.  If compressed, then they will be at a lower bitrate than uncompressed “passthrough” rips.  I only do the latter, and my MKVs (from BD) will run anywhere from the low 20’s to about 40Mb/s.  Therefore, if you’re running full BD rips you’ll need to get high read numbers when you run the LAN Speed program; at least > 40Mb/s.  I believe the BD spec is something like 48 Mb/s.

Good luck and keep posting your progress.

6

I actually bought that tool but I like Ipef better.I don’t know whether it got any better since I last used it, but LAN speed test gave too optimistic numbers:neutral_face:

I got around 800 megabit  (network is gigabit capable)  with Iperf so the network was certainly good for the 100 megabit connection to the WDLIVE. Iperf will not be limited by any storage medium as it will fully saturate the available bandwidth.

But that was before a hardware change as I added a managed switch.

Via USB the WDLIVE can play everything so I’m afraid the most likely candidate for error is the samba code on the WDLIVE. As soon as my GF yields the laptop I can measure the bandwidth to rule out the hardware change or rats in the basement :p.

And yes, tjkaz, the MKV’s that stutter are full blu-ray rips. The compressed one’s never stutter. So this very much indicates a bandwidth issue. But you are saying you have not problems playing >30 megabit rips? Are you on the latest firmware?

edit: but I assume Synology is using NFS? Or is that Samba too?

Just to be clear, the 90 megabit mentioned in an earlier post is with the ethernet adapter set to 100 megabit:-).

edit 2: I know that with Windows Vista and later, the file sharing has been optimised. I’m getting more convinced it is the folder sharing that is not performant enough. If I could just find a willing victim to watch the movie again when I share if with a Vista computer and then with Linux lol.

7

I connect my WDTVLive+ to the NAS via DLNA.  I do not use samba nor NFS.

Transformers, Transformers 2, Avatar, and others like that tend to be high bitrate with DTS audio and no stutter or audio dropouts. 

8

Previous WDTV firmware releases had significant problems with high bitrate files.  I used the Synology DS-210j (DLNA and Samba) and would end up with stutter etc.  WDTV support response  

It looks like there is not enough bandwidth for such a high bitrate. The only thing I can recommend is reencoding the movie(s) to a lower bitrate. Sorry for the inconvenience. 

Here was Synology’s response:

---------------------------------------------------------------------------------------------------------------------------------------------------------------

Thank you for your patience.  Sorry for the delay.

 

Our engineer performed an extensive test on this by using the constant bit rate movies that you have provided.  He found that the max bitrate that WDTV can afford is around 50Mbit/s and this looks most likely to be WDTV’s limitation.

 

The test machines he used as media resource include notebooks (Lenovo X200), DS210j, DS410j, DS209+II, DS1010+ and others NAS units.  The test router is Netgear WNDR3700 Gigabit router. 

The test videos are the ones has constant bit rates, ranging from 10Mbit/s, 15Mbit/s, 20Mbit/s to 70Mbit/s.

 

The testing procedure is to set up the test machines as media resource with no other functionality enabled (to eliminate any performance variables). 

The results shows that WDTV will start to stutter when the bit rates goes above 55Mbit/s.  Our engineer believed that bit rates of around 50Mbit/s is a safe zone where the movie would not stutter. 

 

Please note that all movies does not have constant bit rates. In a lot of blue-ray/HD movie, there may be some scenes that will have bitrates above 50Mbit/s.

 

Please contact WDTV support and inquire about possible limitation of WDTV and let us know how it goes.  If needed, we are willing to provide the constant bitrate movies for you.

 

Thank you and kind regards,

-----------------------------------------------------

Here are the test files they used:

https://docs.google.com/leaf?id=0B4ntknOqXQN6YTdjYzlkMGUtOGY2Yy00ZmIzLThmZWMtMzM5ZDFmZjAzMmNm&hl=en_US

Since the time of this testing (April 2010), I disconnected my WDTV Live from the main viewing TV- and bought a Boxee Box.  I recently tested the WDTV Live with the same files I had problems with, and was able to succesfully watch them stutter-free.  I haven’t tested the bitrate files again, but suspect there have been improvements (after the 1.04.?? regression). Use the test files above and find out your bandwidth limit. 

9

btw, the maximum bitrate spec may be 40Mpbs for video, but scenes can exceed this often (for short bursts)

http://www.m4if.org/resources/profiles/

more simply explained:

http://forum.doom9.org/showthread.php?p=1313636#post1313636

10

Well, that would explain a lot and actually confirms our suspicions to a large extent. But I think the problem might be a little more complicated. I will eventually report back my tests but having a job means limited time to hog the tv during the evening.

There is little doubt that the samba code is the most likely culprit. This may or may not be in conjunction with the OS used: I find lots of google clues Vista and higher performs better than XP. The problem is that you may have to watch 20 minutes or more of the a movie you’ve already seen and frankly that is beyond boring. What I will do is, when I have a stuttering movie, transfer it to my Vista laptop (gigabit ethernet nic) and then replay it from the top. I’ll even use the same network cable that is normally plugged into my desktop system.

Since only parts of the movie stutter, it may very well be those burst we are seeing. I’ll set up a program that records bandwidth usage so I can see where bursts occur. However, does anyone have knowledge of  a program that can graphically examine a movie (mkv file) so I can predict where the bursts will occur? That way I can compare the numbers with a bandwidth measuring tool (which will - or should if common sense prevails - report higher Mbps numbers when you factor in the transmission overhead).

But thanks, your post is very informative. It is just a matter of verifying whether I’m seeing the same issue.

So a general workflow would be:

  1. Do some testing as to what bandwidth I have over samba shares. I’ll use Lan speed test and another tool.

  2. Examine a stuttering MKV to confirm the presence of high bitrate sections (tool needed here, if you know of any…)

  3. Try and find out what the WDLIVE can handle and thanks to mbryanr we have a good baseline here.

  4. Use a bandwidth measurement tool on the computer and take a good close look how high the bandwidth usage is when the high bitrate sections are being played.

edit: I can only find a 70 Mbps test file with the link you provided?I’m not too lazy to search more but my time for today is up:(.

edit 2: oh never mind. the webpage had to load:). Thanks again! They will hopefully provide very useful. I’m just wondering whether I should make them into an MKV …hmm

11

Alright, I’ve found a tool. At first glance it aren’t the peaks in bitrate that make the video stutter. I have a file with  peaks into 50 Mbps (51,7 to be exact) and several (over 8) peaks in the lower 40 range, and those play unhampered. The average bitrate is only 13 Mbps though.

The files that do stutter, have a considerably higher sustained bitrate (the next file I’ll talk about is an odd one out). I have this MKV with an average bitrate of about 17,5 Mbps. This one played fine for 40 minutes before stuttering began. I should have kept watching it but instead I transferred it to a hard drive. So I have no way of knowing the stuttering would have continued over the entire movie.However, this average bitrate is a bit tricky. There are a bunch of very dark scenes (no light) that really pull down the average bitrate. Moreover, the end of the movie credits take a long time and further pull down the average bit rate. The section that stuttered had a bit rate around 28 to 33 Mbps.

So for now I need to conclude that a high sustained bitrate is more of an issue than the peaks. Perhaps the WDLIVE uses a buffer that can provide some kind of a safety net, but when a high bitrate section continues for a certain amount of time, this buffer gets empty at some point and stuttering begins.

Now, that is what I make of it, and it may very well be wrong. It may still be that some piece of software on my computer interferes with transmission briefly. However, I believe this not to be the case as I did my best to exit all security related software and any others that might hamper performance.

12

This might work on some files:

http://www.winhoros.de/docs/bitrate-viewer/

13

Exactly the tool I’ve used to draw this early conclusion.

14

Jeroen1001 wrote:

 

So for now I need to conclude that a high sustained bitrate is more of an issue than the peaks. Perhaps the WDLIVE uses a buffer that can provide some kind of a safety net, but when a high bitrate section continues for a certain amount of time, this buffer gets empty at some point and stuttering begins.

 

Now, that is what I make of it, and it may very well be wrong. It may still be that some piece of software on my computer interferes with transmission briefly. However, I believe this not to be the case as I did my best to exit all security related software and any others that might hamper performance.

 

I conclude same.  It’s most likely due to situations where the buffer gets emptied prior to being replenished. 

Since I have not seen this with the Live+, I presume that either the Sigma chip (8655 vs 8654) or its buffer is different and has a slightly higher capability than the Live.  I believe there’s more internal memory in the Live + compared with the Live, but it’s not clear how much of that is allocated to buffer space versus all the other App ■■■■ that’s being added with each FW update.

Good work and keep posting your results.

15

Don’t rule out the OS. Tranfer rates between XP to XP are lower than let’s say Vista to Windows 7. The common factor for slower rates is always Windows XP from my experience. That having said, rates should be good enough for streaming the most demanding blu-rays. Which brings us full round to the WDLIVE Samba code that is not performant enough and is therefore too demanding on the buffer we assume it has.

I’m going to try to play those high bitrate files now. I think DU meter can present a graph of what I’m uploading to the WDLIVE when I set the firewall to refuse or discard all non-local traffic. I’ll also do the Lan test thing. I hope it confirms all my “educated” guessing.

edit:

Since clicking the DU meter stopwatch and pressing play at the WDLIVE is a 2 man job, I need to wait until someone can assist me (darn).  I can say the file duration of the test files is not long enough to cause stuttering. Hence, they all play fine because the WDLIVE is probably buffering enough to get through.

What I did find out is that the maximum throughput rate recorded was 70,8 megabit (if DU meter is accurate). Actual data payload will be a bit less due to overhead. Even with the overhead, there should still be plenty of headroom for the most demanding blu-rays. Question ofcourse was whether these rates can be sustained.

16

I’ve did some testing and got back with the following.

General notes:

Server: Windows XP SP3 (gigabit network card)

Client: Vista Laptop  SP2 (gigabit network card)

  • Laptop is forced to 100 megabit full duplex to mimic a WDLIVE. Actually the laptop was set to auto negociate and the switch was set to  100 megabit full duplex. Why? Intel driver bug. If I set it to a forced setting, performance is near 2.4 megabit. Which is quite impossible.

  • The network cable in the WDLIVE was connected to the laptop instead to rule out a bad cable and to eliminate some other variables.

Test A: _NOT_ using the hard drive (so transfer direct from memory)

  • Iperf reports a bandwidth of about 93 Mbit in borh directions (so read and write)

  • Lan Speed Test reports a banwidth  of 88 Mbit   in both directions.

Conclusion: Network is fine. No problems here.

Test B: A windows share on the server, is mounted as a drive letter on the laptop

- Did not bother with Iperf (it might be possible but I don’t really know)

  • Lan Speed test reports a read speed of about 70 Mbit and a write speed of about 85 Mbit.

Conclusion: should be sufficient for streaming any blu-ray movie.

Oddities:

  • DU meter maxed out at 50 megabit while the other tools report higher number as you could read above.

I’ve not investigated why yet.

17

A PC-to-PC test isn’t necessarily very meaningful.

If you look through ubuntu (and other *nix) forums, you find folks having problems with low rate “caps” between Samba and a Wintel PC, and thousands of tuning tips.

If you look through Popcorn forums, you find folks having problems with low rate “caps” trying to serve to their player.

If you look through Mac forums, you find folks having problems with horrible speeds between their Mac and a Samba server.

If you look through…

It almost seems like Samba’s the problem. :wink:

And, for what it’s worth, at least one poster a while back said that the exact same file played from a Server version of Windoze played fine, but played from the home OSes (XP, Vista, 7) ran into the same bitrate cap everyone else was hitting.  So, it seems Samba *can* work faster… it just doesn’t.

A lot of conspiracy-minded folks just think that Microsoft home OSes “cripple” SMB when dealing with anything other than another Microsoft implementation of SMB. :stuck_out_tongue:  You see that claimed quite a bit, as well.

18

The above is mainly to make sure the network is fine. It is pretty hard to test a WDLIVE with tools without having SSH access to it.

But I do happen to have a server Windows 2008 R2 server that is almost complete. So I should be able to verify whether it solves these issues some time soon. But, at least I know the network is likely to be just fine. A quick test of the link between the server and the WDLIVE and I’m good to go.

It is pretty annoying having a 40 TiB server in the works and then having to haul out a hard drive just to play those high bitrate movies!

19

I can all but guarantee that this is not due to any problems with the files themselves, the speed of his network, or the Plus’ capabilities.

Every single blu-ray rip I’ve tried has played without flaw on this player, and I’m not talking recompressed versions, but full raw rips from the disc. However, I experienced exactly the same issue as the OP once I upgraded to the latest - 1.06.16 - firmware. Suddenly movies that previously played fine would stutter for no reason. They would start off playing fine, but eventually just start skipping and stuttering, like the players were trying to catch up on the stream or were choking on the content.

Once I downgraded to the previous 1.05 version of the firmware, these problems went away. I have no idea what WD broke with the latest firmware, but this problem sounds so similar to what I experienced that I highly recommend trying a downgrade before spending hours recompressing video and/or diagnosing network issues.

/twocents

20

Dewey wrote:

I can all but guarantee that this is not due to any problems with the files themselves, the speed of his network, or the Plus’ capabilities.

 

Every single blu-ray rip I’ve tried has played without flaw on this player, and I’m not talking recompressed versions, but full raw rips from the disc. However, I experienced exactly the same issue as the OP once I upgraded to the latest - 1.06.16 - firmware. Suddenly movies that previously played fine would stutter for no reason. They would start off playing fine, but eventually just start skipping and stuttering, like the players were trying to catch up on the stream or were choking on the content.

 

Once I downgraded to the previous 1.05 version of the firmware, these problems went away. I have no idea what WD broke with the latest firmware, but this problem sounds so similar to what I experienced that I highly recommend trying a downgrade before spending hours recompressing video and/or diagnosing network issues.

 

/twocents

While this might be the case for you, I guess I got lucky and have not experienced any stutter issues with 1.06.16B with either of my two Live+ units.  If it were a FW issue, I would expect to see it as well, but have not.  FWIW, I stream to my two Live+ boxes directly from my NAS via a Gb wired connection using DLNA (media server).