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mokojono · 2011-12-28, 14:11

I have discovered a fix for this problem, but it isn't a very nice one.

If you start the video and then open the audio options menu and toggle "Output stereo to all speakers" the problem goes away. It doesn't matter if it is on or off to start with, merely changing it fixes the problem.

There must be some kind of bug in the audio handling code that causes buffering and is cleared by changing this option.

pro510 · 2011-12-30, 22:15

Switched over to using NAS to store media and now I'm getting the buffering issue. My NAS is 2C/4T Atom with 2GB RAM and running WHS 2011. All is on a wired GB network. Playback PC in Win 7 64 bit with 3.2GHz C2D, 4GB RAM, and ATI 5450. File copies fly along at over 60MB/s. Playing 1080p mkv causes buffering, and serious at that. When the buffering apears it can take upwards of 10 seconds to fill the buffer up. Network utilization in task manager shows erratic spikes and utilization of about 2-3%.

Seems to me this can't be a hardware issue, more likely the way XBMC buffers does not play well with SMB shares (too many small reads maybe).

Graham

jasmill1969 · 2011-12-31, 05:10

I'm all of a sudden having major buffering issues. I'm on a NAS as well. Anyone else having problems with Eden buffering?

mokojono · 2011-12-31, 16:20

I think the issue is with the network rather than the sound decoder, even though toggling that option fixes it. My guess as a programmer who hasn't looked at the source would be that it is a priority issue. Decoding takes priority over buffering and causes the CPU to be delayed long enough to create issues when streaming over SMB. Changing that option I mentioned resets something and fixes the priorities.

pro510 · 2011-12-31, 17:29

pro510 Wrote:Switched over to using NAS to store media and now I'm getting the buffering issue. My NAS is 2C/4T Atom with 2GB RAM and running WHS 2011. All is on a wired GB network. Playback PC in Win 7 64 bit with 3.2GHz C2D, 4GB RAM, and ATI 5450. File copies fly along at over 60MB/s. Playing 1080p mkv causes buffering, and serious at that. When the buffering apears it can take upwards of 10 seconds to fill the buffer up. Network utilization in task manager shows erratic spikes and utilization of about 2-3%.

Seems to me this can't be a hardware issue, more likely the way XBMC buffers does not play well with SMB shares (too many small reads maybe).

Graham

UPDATE: Turned off Jumbo frame (4K) support in my NIC driver and that cured it. However, turned my PC on this morning and it's back to buffering. So changed Jumbo frames to 2K and it's working again. Further investigation is needed.

I will say that when I am having issues, network utilization shows between 0 and 2% and very erratic (not the 2 to 3% I mentioned in my previous post). Clearly not enough to keep up with a 30Mb/s film. When working correctly, network utilization in task manager shows almost steady around the 3% mark as expected on a GB network.

Graham

mokojono · 2012-01-01, 17:22

pro510 Wrote:UPDATE: Turned off Jumbo frame (4K) support in my NIC driver and that cured it. However, turned my PC on this morning and it's back to buffering. So changed Jumbo frames to 2K and it's working again. Further investigation is needed.

I will say that when I am having issues, network utilization shows between 0 and 2% and very erratic (not the 2 to 3% I mentioned in my previous post). Clearly not enough to keep up with a 30Mb/s film. When working correctly, network utilization in task manager shows almost steady around the 3% mark as expected on a GB network.

Graham

You are confusing MB (megabytes) and Mb (megabits). At 30MB/sec 1GB of data only lasts ~30 seconds.

30/1000 = 0.03. Add some overhead for protocol and filesystem stuff. 2% erratically sounds reasonable.

Maybe it is a driver bug. What NIC chipset do you have? I use an AMD board but I have a feeling that the NIC is not part of the AMD chipset, probably a Marvell or other craptacular rubbish.

pro510 · (This post was last modified: 2012-01-01, 19:01 by pro510.)

mokojono Wrote:You are confusing MB (megabytes) and Mb (megabits). At 30MB/sec 1GB of data only lasts ~30 seconds.

30/1000 = 0.03. Add some overhead for protocol and filesystem stuff. 2% erratically sounds reasonable.

Maybe it is a driver bug. What NIC chipset do you have? I use an AMD board but I have a feeling that the NIC is not part of the AMD chipset, probably a Marvell or other craptacular rubbish.

Not confusing anything. I was talking about Mega bits (Mb), not Mega Bytes (MB). So a 30Mb/sec (rate of the film) = 3% of a 1Gb network. 30 / 1000 * 100 = 3%.

I have a Realtek chip in the viewing PC and a Marvel Yukon in the NAS.

It seems that each time the PC starts it has terrible buffering. I can tweak something in the driver and that stops the buffering until the PC restarts again.

Graham

mokojono · 2012-01-02, 12:33

I have to do the fix for every video. Strangely once it is done if I restart the same video it is okay.

Damnatus · 2012-02-18, 18:43

same issue.
setting:
i have a pc, a htpc running xbmc and a selfbuilt NAS running on freenas 8 ftp: 90 mb/s, smb: 40 mb/s
they are all connected to a gigabit router. wired not wlan!

this is what i tested so far:

-if i play a 720 or 1080 file from the NAS on the htpc in xbmc i get the buffer issue.

-same file playing from the NAS on streaming to the pc --> no buffer issue.

- when i create a smb share on my pc and then stream it to the htpc ---> no issue.

according to this neither xbmc, smb, the network connection nor the NAS can be the problem. :confused2: