Originally Posted by Bob K.
I suspect there may be enough overhead (not sure if the transport method is TCP, UDP, SMB, etc.) that it's still just not enough bandwidth for the high bitrate sections of 1080p videos.
I'll keep troubleshooting, but for now I'll be pursuing gigabit LAN or just play high bitrate videos through an attached USB hard drive.
I did some more troubleshooting and used Wireshark to watch the packet flow through the MCA1001 to my blu-ray player. Wireshark confirms that the protocol used is CIFS (SMB) and TCP.
I've used a different computer, I've removed the router from the topography, and I've attached a laptop directly to the switch to which the blu-ray player is attached. I've confirmed absolutely that the file streams correctly in all configurations where the MCA1001 adapters are not in the packet path. Lastly, I connected two MCA1001 adapters directly together with a short piece of RG6 cable and then streamed the video through that arrangement: The stuttering immediately returned. I've even used different communications frequencies on the MCA1001 adapters. Performance is similar across all 4 adapters, so I think that rules out a defective adapter.
It seems there's some kind of incompatibility or limitation on the MCA1001, or there's simply so much overhead in the MoCA specification that it won't successfully pass high bitrate video.
I'm totally stumped about why I get consistent 84 Mbps read speeds when using LAN Speed Test (even with huge test files--which still uses CIFS and TCP protocols) yet can't get videos at less than half that bandwidth to pass correctly.
Edit: I've done some more research and I think the problem may be related to the TCP Window size. Using jperf, if I use the default 8 Kbytes TCP Window size, I only get throughput of around 23Mbps. When I manually set the TCP Window size to 128 Kbytes, I get 90Mbps. I've looked at my Wireshark captures and fooled with every TCP setting I can find (using TCP Optimizer http://www.speedguide.net/downloads.php
), but I can't seem to change the stuttering. More details in this thread starting with post #83: http://forums.smallnetbuilder.com/sh...?t=1246&page=9