Am 21.02.2012 20:36, schrieb Michael Kromer:
Hello Stefan,
well, in real world I would never use LAN as a setting, even on LAN i would use WAN as the primary setting.
That's what I remember from configuring NX Client, too, but I wasn't sure if that's still the best way to do it with X2Go.
We've benchmarked it, and without access to the benchmarks right now (you should find them in some article by Harald Milz in the german issue of the linux magazine some months ago) I can only say: You'd have it better that way.
Indeed, but the client offers two other settings that can be changed, aside from the connection speed slider - compression method and image quality. And the sheer number of choices there makes a full test run rather time-consuming, so I was wondering if anyone had ever experimented with that before.
I would recommend you to use jpeg compression in combination with libjpegturbo, since this makes a real difference - especially on modern netbooks since their processor speed is not the best but in combination with the SSE-instruction sets which are used for libjpegturbo this makes a major performance boost (up to 3x in my lab tests).
The thing is, I'm using the windows client, I'm not sure if and how I could change to libjpegturbo there; and the libjpegturbo stuff is still experimental/testing, something I don't want to force upon my clients. I'm looking for solutions that work with a stock, stable X2Go install.
But: please tell us: what glitches do you suffer?
Everything works great at first, short clips, like Adobe Flash animated advertisements with sound, run rather smooth, but longer videos on youtube experience a "stuck image" effect that only goes away when moving the mouse over the area where the video plays (this helps for a few seconds, then you have to repeat the procedure), also, the sound starts to get choppy. BUT: This *might* be due to something weird in my LAN config or due to the client options I chose. It sure needs further testing and verification before it can be considered a bug.
What settings are you using?
WAN/16m-jpeg/9, audio enabled (pulseaudio). Client used for initial testing was 3.99.1.0 (Windows).
An upgrade to Gigabit will not help you much IMHO, since one session and 100 Mbit is far more than enough. The only point where you could have fun with is with lower latency times - but a dedicated 100 mbit with not too much traffic should be a low latency line anyways ...
Well, 100Mbit and a single user is my test setup, real-world use is more like up to 5 users and the average small office LAN traffic (SMB shares, database connections,...). <snip> Hi, Stefan. I would assume 16m-jpeg would be the best setting for video but, in our non-video application, we were surprised to find that 16m-png-jpeg gave both better performance and clarity. I'm not sure
On Tue, 2012-02-21 at 21:53 +0100, newsgroups.mail2@stefanbaur.de wrote: that compression or bandwidth are the issues although it is not an area of expertise.
My hunch it is the way in which the screen is rendered. One of the devs may be of much more help here. I'm guessing that NX is painting bitmaps and doing so in the same manner for all portions of the screen no matter what the nature of the screen changes.
If video is of critical importance and you are on a WAN, you may want to consider SPICE instead. I am an ardent supporting of X2Go and actually foresee a SPICE plugin to X2Go once SPICE matures as a WAN technology. The big difference for video is that SPICE is an adaptive protocol. If it senses that a portion of the screen is changing, it adapts the video transmission algorithm from painting bitmaps to sending an mjpeg stream. mjpeg is an intra-frame compression algorithm as opposed to the much more WAN friendly inter-frame compression algorithms but it's generally sufficient for a LAN and much better than drawing raw bitmaps.
I've always wondered what the difference is between mjpeg and whatever NX calls 16m-jpeg compression but the performance difference for video is quite noticeable. Perhaps one of the devs could explain the difference to us. Hope that helps - John