somehow it seems that the quality of video playback is not dependent on bit rate (all my videos are encoded at 2000bits/s bit rate ), the smaller files (700MB) play fine, without any stops. but when I play the larger files, they constantly go into buffering (about every 2 seconds, pausing for about 10 seconds ).
I cut out the first 10 minutes of my big video (the total video is 4.4GB, 100minutes, I cut off the first 10min, about 500MB), then play it. it plays very smooth. this has been tested and reproduced very consistently.
I checked all the factors: disk is fairly fast, writing/reading speed when plugging this usb to a computer, is about 35MB/sec , way over the 2000bits/sec bandwidth needed for the video. network bandwidth capacity is about 2.5MB/sec, I used several client apps, they show the same behavior, so it's not that the clients are busy.
this looks to be a general problem to many DLNA/uPNP servers , I tried rygel, mediatomb, minidlna, and pogoplug, clients used were vlc, bubbleupnp etc.
so how is this possible? is there a fix? (of course a workaround is to cut my files into sections, but that's too cumbersome)