Google Summer of Code 2010/VNC
Summary
QEMU's built-in VNC server only supports the Hextile encoding. Hextile only uses tile-based compression. Other encodings are more popular such as Tight and ZRLE that use zlib-based compression. These encodings significantly reduce the bandwidth required by VNC.
Owner
- Name: Corentin Chary
- Email: corentin.chary@gmail.com
Detailed Summary
QEMU's built-in VNC server only supports the Hextile encoding. Hextile only uses tile-based compression. Other encodings are more popular such as Tight and ZRLE that use zlib-based compression. These encodings significantly reduce the bandwidth required by VNC. This project would start by implementing support for Tight or ZRLE. Both encodings support a combination of tile-based compression and zlib-compression. Initially, one would implement zlib-compression only and compare the results to our Hextile implementation. Depending on progress, tile-based compression mechanisms (such as Tight's gradient algorithm) could be explored. At each stage, we expect that performance comparisons are done to determine the effectiveness of the additional algorithm. Additional compression mechanisms like Tight's JPEG encoding could also be evaluated.
Encodings
Feature Matrix
Servers
| Server | Raw | CopyRect | RRE | CoRRE | Hextile | ZRLE | ZYWRLE | zlib | tight | zlibhex | Ultra | UltraZip |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| libvncserver | y | y | y | y | y | y | y | y | y | y | y | y |
| tigervnc | ||||||||||||
| ultravnc | ||||||||||||
| tightvnc | ||||||||||||
| realvnc | ||||||||||||
| qemu | y | y | n | n | y | n | n | y | n | n | n | n |
Clients
| Server | Raw | CopyRect | RRE | CoRRE | Hextile | ZRLE | ZYWRLE | zlib | tight | zlibhex | Ultra | UltraZip |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| libvncclient | y | y | y | y | y | y | y | y | y | y | y | y |
| tigervnc | ||||||||||||
| ultravnc | ||||||||||||
| tightvnc | ||||||||||||
| realvnc | ||||||||||||
| gtk-vnc |
describe some encodings here