Dear VNC developer.
Introduction of
"ZYWRLE":Enhanced VNC codec for Motion picture
1. Introduction
The lossy codec based on Wavelet transform is frequently
used in compression of natural image, motion picture and
audio stream.
But it isn't almost used in Remote Desktop protocol like
VNC because classical lossless run-length codec like ZRLE
has high performance in peculiar image which has big mono
color region like desktop image. The lack of lossy codec
cause low performance of motion picture in VNC.
We introduce new codec "ZYWRLE(ZLib YUV Wavelet Run Length
Encoding)" which applied wavelet transform partially and
is based on ZRLE. In this new codec, network traffic reduced
to 15%-50% traffic of ZRLE when we play motion picture.
2. Highlight of Evalution of ZYWRLE
Result of ZYWRLE for motion picture
+-------+-------------------+------------------+------------------+
|quality| Raw tile(Mbytes) | Total(Mbytes) |Raw tile|PSNR(RGB)|
| | Out | Raw |rate | Comp.| Raw |rate| rate(%)| (dB) |
+-------+------+------+-----+------+------+----+--------+---------+
| ZRLE |125.8 |125.8 |100 |117.1 |392.2 |29.8| 32.1 | INF. |
| Hi | 53.85|167.58| 32.1| 52.10|370.96|14.0| 45.1 | 28.025 |
| Mid | 31.83|264.05| 12.1| 20.56|378.50| 5.4| 69.7 | 23.980 |
+-------+------+------+-----+------+------+----+--------+---------+
* Comp. rate of ZRLE(about 30%) goes to 15%(Hi-quality)/5%(Mid-quality)!
3. Reference Implementation(C source code/patch for VNC Servers)
* Core Codec of ZYWRLE
http://mobile.hitachi-system.co.jp/publications/ZYWRLE/zywrletemplate.c
* Patch for [EMAIL PROTECTED] V1.0.2
http://mobile.hitachi-system.co.jp/publications/ZYWRLE/UltraVNC-102-ZYWRLE-diff.txt
* Patch for LibVNCServer 0.8.2
http://mobile.hitachi-system.co.jp/publications/ZYWRLE/LibVNCServer-0.8.2-ZYWRLE-diff.txt
I think that Any VNC server can be applied ZYWRLE easlilly using one of these
patch.
4. License of ZYWRLE
Though ZYWRLE is our intellectual property and was developed for
our micro-VNC, We Hitachi Systems & Services, Ltd. decided make it
open source. You can use it with no fee for commercial and/or
non-commercial purpose. The above reference implementation are released
under our BSD-like license. More detail, see top of zywrletemplate.c.
5. More detail
See our ZYWRLE page(http://mobile.hitachi-system.co.jp/publications/ZYWRLE/)
We are glad if your VNC server supports ZYWRLE.
Thank you.
---
Noriaki Yamazaki
Administrator of micro-VNC
Research & Developement center
Hitachi Systems & Services, Ltd.
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