I did some meticulous. Black box testing.
I chopped the video file to different lengths using mencoder - ovc copy. It started having this problem right slightly above 1g bytes size.
I'm not sure if it's due to the buffering limitations on client ( I have been using bubbleupnp on phone to play ), I tried to use vlc as a new client on laptop to remove this possibility. But I couldn't figure out how to setup the codecs. Currently my vlc player doesn't recognize any of the video formats.
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)
ThanksYang