RDP sound latency with RDesktop client and Server 2003 Terminal Services

[dhicks]

Hello All,

I'm just testing our thin client setup- old RM all-in-one machines, network booting with a gPXE image loaded from a floppy drive:

start - Etherboot/gPXE Wiki

and loading Slax from a TFTP / web server. Slax includes rdesktop, which is then set to connect to the Windows Server 2003 Terminal Services machine we currently use for SIMS clients:

rdesktop -f -k en-gb -r sound:local 10.0.0.54

Obviously, sound doesn't matter much for SIMS so we've never thought to check before. However, it turns out that playing a YouTube video works fine except that the sound turns up a couple of seconds behind the graphics. The sound itself seems quite good quality, just late.

Is this due to Server 2003 - is the problem solved with Server 2008 R2? Is the problem with RDesktop, or Slax - is there anything I can do client-side to sort the problem? Is the issue to do with our network - is it just too slow?

Is there anything I can install server-side to sort this problem out?

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David Hicks

[dhicks]

Okay, investigating further I've found this explanation of RDP 7's sound capabilities:

What

This seems to imply that you'll need both Server 2008 R2 and an RDP 7 capable client. Is that correct? Does sound work better with RDesktop (which supports RDP 5.2, I think) connecting to Windows Server 2008 R2, or does it make no difference? Is there another free RDP client available for Linux at all? If not, what other (free...) options are available for connecting a Linux client to a Windows server - how well would VNC work? How's about a propriatory protocol like 2X or similar?

--
David Hicks

[joe90bass]

we use 2008R2 std servers and a mix of axel thin clients and Thinstation on old PCs and also Thinstation on Samsung SM thin clients. I've not noticed any lag on these, but sound quality is poor and sometimes stutters a bit. But then for what these do (web browsing and word, etc) I view sound as a bonus not a requirement!

[Axel]

Joebass90,

How would you describe sound and mm in general on your M80 terminals - say in reference to Youtube...?

[SYNACK]

Okay, investigating further I've found this explanation of RDP 7's sound capabilities:

What

This seems to imply that you'll need both Server 2008 R2 and an RDP 7 capable client. Is that correct? Does sound work better with RDesktop (which supports RDP 5.2, I think) connecting to Windows Server 2008 R2, or does it make no difference? Is there another free RDP client available for Linux at all? If not, what other (free...) options are available for connecting a Linux client to a Windows server - how well would VNC work? How's about a propriatory protocol like 2X or similar?

The original RDP protocol was never designed to handle sound, drive and printer redirection etc so as a protocol it really was not the best initially. This is where citrx got their in and made the protocol better, faster and less bandwidth hungry. With newer and newer versions of windows RDP has become better and better to the point where RDP in Vista/2008 was vey simmilar in bandwidth usage and ability to citrx. This all relies on the version of protocol that is implemented though.

I can watch full screen HD video over RDP wia wireless from my Windows 7 Media center to my Vista laptop (RDP6) without frame dropping or sound issues as this implements a newer protocol. Older versions will stutter video hopelessly, Windows XP does support a bit of the newer stuff via updated client software but not to the extent of Vista/7. With Vista and 2k8R2 SP1 they will be releasing RemoteFX which fully implements what the beta of 7 did and allows the pushing of raw directx over the network to be rendered on the thin client.

Sound probably won't work that much better under 2008 if limited to a RDP5.2 client as this is still Windows server 2003 level. A client that has RDP6 (vista) or RDP7(7) support will however get lots of these benifits. I think that your sound issue may have been magnified by using flash as it should not be that long a delay but it is definatly noticable. The client software also plays a role as it must be programed in such a way to play the sounds and render frames as soon as possible which does not always happen with limited CPU or memory and /or interfacing with other subsystems (sound) under the clients host OS.

I did do a rather extencive search about a year ago to try and find a linux RDP client that had higher level support and was unable to find anything above 5.2 at that time, this may have changed but it is unlikely as I am sure it would have been publicised. I wanted to use the better video streaming and multimoniter support for something at the time.

VNC in comparison is aweful, even with the video mirror driver it is still trying to cope with copying what is on the screen rather than rendering right to the client itself, you are also limited to one user of VNC.

Proprietary protocols could offer a good solution, Sun Global Desktop for instance offers products that are multiplatform and provide good performance and hp offers a system with so little latency that you can do CAD remotely but these can be pricey.

If you have access to two Windows Vista or even better two Windows 7 Pro machines try RDPing into one from the other to give it a test, the results when doing something like playing fullscreen movies in Media Player are impressive and should give you a good indication of what is possible over your network with that technology.

[joe90bass]

Joebass90,

How would you describe sound and mm in general on your M80 terminals - say in reference to Youtube...?

Thinking about this I probably should have left Axel off the list above. You just reminded me that I haven't got around to enabling the sound and testing on the M80's yet! Surprised the teacher who uses them hasn't nagged me about it, she's normally the first to complain about anything..........

[dhicks]

we use 2008R2 std servers and a mix of axel thin clients and Thinstation on old PCs and also Thinstation on Samsung SM thin clients.

I couldn't get Thinstation to boot on any of the 3 different machines I tried it on - did you have any trouble getting it working?

--
David Hicks

[Axel]

.......If you have access to two Windows Vista or even better two Windows 7 Pro machines try RDPing into one from the other to give it a test, the results when doing something like playing fullscreen movies in Media Player are impressive and should give you a good indication of what is possible over your network with that technology.

I would agree with everything Synack says above but would want to add I don't believe local rendering for Flash is currently supported on RDP7 due to the competitive conflict between Microsoft v. Adobe - so running an MPG movie (Windows Media Player) would take advantage of local client rendering, but Flash, ie Youtube or Iplayer doesn't so runs as normal from the server...

HTML5 could provide a unifying method to run multi-media on thin clients (and I-phones!) - its hard to see Microsoft, Adobe and Apple ever agreeing on each others technology

[dhicks]

I did do a rather extencive search about a year ago to try and find a linux RDP client that had higher level support and was unable to find anything above 5.2 at that time

I understand Axel's thin client devices are based on RDesktop, I imagine running under Linux. If they've modified RDesktop, are we entitled to the source code to those changes under the GPL?

If you have access to two Windows Vista or even better two Windows 7 Pro machines

Nope, the head has the only Windows 7 machine in the school, all the rest are Windows XP or Linux. It's worth pointing out that our Linux LTSP server was working fine until Edubuntu 10.04, complete with Flash and sound and everything - now it conks out after 14 logons.

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David Hicks

[SYNACK]

LTSP runs slightly differently, it runs the process on the server box and then packages up the whole shell and pushes that out to the client as whole windows and so is able to use a bit of the clientside power for the decoded on some things. Well that is my understanding from when I looked into it a while back. The later versions of RDP are also moving in a similar direction but useing differing technologies and probably leaving a bit more back at the server.

Good catch on the modded rdesktop possibility, it would be great if this was made avalible although to support it fully you would probably need directx9 hardware (or smae spec OpenGL) on the client end.

If you can get a hold of a Windows 7 Pro CD from somewhere then you could just install that on a couple of test machines. Windows 7 is like Vista in the fact that you have a 30 day grace period before it needs to activate. You can install it without a key and I don't think that this is in breach of any terms.

[joe90bass]

I couldn't get Thinstation to boot on any of the 3 different machines I tried it on - did you have any trouble getting it working?

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David Hicks

I've attached the document I used. It's not mine, I got sent it by our supplier when resolving issues we had (long story...) It relates to using Samsung SM711NTs, but it works fine with our old Evesham PCs as well. I am using PXE boot, not local storage

[dhicks]

Good catch on the modded rdesktop possibility

Nope, scratch that - Axel's RDP implementation is from the ground up, licensed from Microsoft.

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David Hicks