Hacker News Reader

Comment by IshKebab | Hacker News Reader

RDP doesn't pass through graphics primitives. You're probably thinking of X11.

Sending graphics primitives turned out to be the worst way to do remote desktop. All modern solutions just use video codecs. NX (the best solution on Linux) even switched from X11 forwarding to a video codec in NX4.

VNC is inefficient because it is ancient and uses extremely inefficient methods to encode the graphics. GIF is really inefficient too but you wouldn't say that means the idea of encoding animated images as bitmaps is a bad one.

View on HN

The original incarnations of RDP, going back 20 years and more, preferred graphics when it could. Back then, it was more bandwidth efficient, and most programs actually used the GDI primitives to draw directly onto the screen, so it actually worked.

But IIRC, by 2007, it switched completely to sending tiles just like VNC.

However, if you read the protocol descriptions, you get the wrong idea that primitives are still used.

Similarly, most X11 clients have been doing everything client side for ages, but many people still believe that peimitives dominate.

VNC, the protocol, isn't at all inefficient. There are some encoding methods which are inefficient, but I'd say that more "modern" encoding methods such as "tight" aren't all that bad, depending on how they're implemented. There has also been a recent addition of h264 to some implementations.

An example of a truly inefficient encoding method is ZRLE. It is a tiled zlib and run-length encoded format that can't be split up into multiple jobs because future computation depends on past computation.

They got things right with the tight encoding method of which there are two variants: zlib (lossless) and jpeg. With zlib, you can have up to 4 separate zlib streams, which means that you can utilise 4 CPU cores for encoding in parallel. The jpeg method has no such limitations.

Yes it does.

https://learn.microsoft.com/en-us/openspecs/windows_protocol...

In the past, maybe Windows XP to perhaps Windows 7 era it did — not sure exactly when they stopped using primitives. But not since a long time. It's just (lossy) compressed bitmap streaming nowadays.

RDP on Windows from Windows now uses h264 by default.

Interesting. Here is some background: https://techcommunity.microsoft.com/t5/security-compliance-a...

I guess “by default” means if both client and server have the required hardware support and there aren’t too many concurrent sessions.

Reply on news.ycombinator.com